Damage Analysis Report: Hammenwoning + Karnbarn

DAMAGE ANALYSIS AND REPORT

Hammenwoning + Karnbarn

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Building address : Rotterdamseweg 155 Building owner : TU Delft Inspection date : 6/3/2012 Inspectors: Dominika Linowska Narutai Riangkruar

4187237 4181557

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CONTENTS 1.

Introduction 1.1 Object and Aim 4 1.2 Methodology 4 2.

The Buildings 2.0 The Site 6 2.1 The Complex 7

2.2 The main entrance

7 2.3 Hammenwoning 7 2.4 Cow barn 7

2.5 The churn barn, ‘Karnschuur’ 8

2.6 Haystacks and grass silo 8

2.7 Material & architectural overview 9

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Hammenwoning damages - 10

on wall level - west facade 3.1 Description

3.2 Diagnosis

3.3 Advice 4.

Area A - Hammenwoning 4.1 Description 4.2 Diagnosis 4.3 Advice

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5.

Area B - Hammenwoning 5.1 Description 5.2 Diagnosis 5.3 Advice

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6.

Area C - Hammenwoning 6.1 Description 6.2 Diagnosis 6.3 Advice

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7.

Damages on the material level

7.1 Purple brick & mortar & pointing 18 7.2 Orange brick 19

7.3 Orange brick mortar & pointing 19 7.4 Bluestone 20 7.5 Plaster 21

7.6 Wood (window frames) 22 8.

9.

Karnbarn damages 8.1 Description 8.2 Diagnosis 8.3 Advice

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Karnbarn damages contributed by roof 9.1 Description 9.2 Diagnosis 9.3 Advice

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10.

Karnbarn damages contributed by tree roots 10.1 Description 10.2 Diagnosis 10.3 Advice

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South facade - Area A 11.1 Description 11.2 Diagnosis 11.3 Advice

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South facade - Area B 28 12.1 Description 12.2 Diagnosis 12.3 Advice

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East facade - Area A 29 13.1 Description 13.2 Diagnosis 13.3 Advice

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East facade - Area B 30 14.1 Description 14.2 Diagnosis 14.3 Advice

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Karnbarm damages on material level 15.1 Description 15.2 Diagnosis 15.3 Advice

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16.

West facade - Area A 16.1 Description 16.2 Diagnosis 16.3 Advice

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17.

West facade - Area B 16.1 Description 16.2 Diagnosis 16.3 Advice

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18.

Karnbarn damages on material level - south facade - Area B 18.1 Description 18.2 Diagnosis 18.3 Advice

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19.

Conclusion 36 20.

Sources 38

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1. INTRODUCTION 1.1 Object and Aim of the Analysis and Report This document is the final report of the Building Conservation Assessment [AR0015] course at TU Delft.

This report was produced under the supervision of Rob van Hees, Silvia Naldini and Barbara Lubelli.

The main goal of this assignment was to understand the various damage processes which occur in buildings, especially within old ones. This educational excersise asks to carefully analyze and investigate a given building from the exterior as well as the interior.

Students were asked to take photographs, sketch, as well as measure their findings. The objective was also to use the MDDS software to document and help aid in our findings.

The assigned site currently belongs to TU Delft and is actually located on the campus. This building is heritage-designated; more information regarding history and program will follow.

1.2 Methodology First, a visit to the location took place. Quick sketches as well as photographs of the object to be studied were taken.

As a group, we chose which walls in particular we wanted to focus on. Since we opted for the main facade of the Hammenwoning as well as the barn, analysis of all four faces of the latter building was necessary. We started two MDDS files for each of the seperate buildings in order to categorize the damages and materials, etc in a more clear manner.

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Figure 1.1 Diagram showing selection of areas to be studied in report

Figure 1.2 Sketch by Narutai

Figure 1.3 Sketch by Narutai

Figure 1.4 Screenshot of MDDS layout

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2. THE BUILDINGS 2.0 The Site Located on Rotterdamseweg 155, the ‘Hammenboederij’ is the last remaining piece of ancient architecture on the TUD campus and is now a heritage designated building. The area is part of an old farm located in Delft dating back to around the year 1550. Ar first, the southern part of the old city centre of Delft had no buildings. The area of the subject of this report was built on an open field away from the heart of Delft’s city wass fortifications (Figure 2.2). During its postwar years, around 1970, Delft was really expanding. The University received an area in the south of the campus for further development. The site now belongs to TU Delft.

Figure 2.12 Google maps view of the location within TU Delft campus

Figure 2.13 Delft, ca.1900

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2.1 The Complex As the city grew larger, the plot of Hammenwoning was bought for the construction of the TU Delft campus, therefore the size of the plot was reduced to its current size nowadays.

Hamenboerderij consists of 5 parts which are all monuments:

1.The main entrance to the complex

‘Hammenport’

2. A large Villa called the ‘Hammenwoning’

3. The cow barn

4. The churn barn

5. Haystacks and grass silo

Figure 2.1 Aerial view of the complex, Ruben Smits, 2011

2.2 The main entrance The gate was constructed in 1608 with a refined decoration with the early-Baroque style which was prospered during the Dutch golden age in 17th Century where the port was constructed.

2.3 Hammenwoning The major reconstruction and intervention was made when the last owner before the complex became property of TU Delft bought the land. Paulus Zeeuw wanted to demolish the old Hammenwoning and reconstruct it to the style he preferred – 17th century façade which once only applied on the right side of the west façade. The front façade of the building was preserved while the others were newly design. It was also at this time when the Karnschuur was separated from the Hammenwoning.

Hammenwoning is accessible by two directions which are on the east and west façade. The west façade is for main entrance where the patio was decorated with cement plaster to imitate the style in the 17th century.

East façade is mainly the entrance adjacent to the kitchen, laundry and also the entrance to the cellar which is the oldest part of the building constructed in medieval.

The cellar was constructed in the 16th century and appeared to be higher than it is now. Concrete was poured to cover about 30cm of the floor level.

2.4 Cow barn Cow barn stands separated from the Hammenwoning even before the intervention in 1927. The barn has a long rectangular shape according to its function of housing animals. The function inside the barn are the cart barn, calf stable, food storage, cow stable, horse

Figure 2.2 Functions of the complex, Ruben Smits, 2011

Figure 2.3 The entrance gate, Delft Archives

Figure 2.4 Photo of the complex before the reconstruction, Delft Archives

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2. THE BUILDINGS 2.5 The churn barn, ‘Karnschuur’ Karnschuur was constructed in the 17th century and once connected to the Hammenwoning before it was separated in 1927. The function of the Karnschuur is to produce milk and butter. Before the intervention, reed was used as the roof material and was replaced by roof tiles in 1927 when the roof structure was extended. The building is separated into two major functions which are Karnmolen and Karnruimte. In the Karnmolen a large wooden wheel-like structure was placed on top of the ceiling while two of the roof beams were cut off. In the Karnruimte, oven and chimney are still visible and the walls are covered with tile and plaster. Toilet is seen attach to the building, but functionally it was used to serve the Hammenwoning when the two buildings were joint together.

Figure 2.5 Photo of barn attached to the Hammenwoning, Delft Archives

2.6 Haystacks and grass silo Haystack and silo was constructed in the 19th century around 1850 and was used to store the grass and was covered with thatched roof.

According to the time of recent visits, Haystacks has already collapsed. The failure of the structure is suspected to have occurred in less than one year, according to photo taken by Ruben Smits on the Analysis of Hammenwoning in March 2011, the structure was still standing.

Figure 2.6 Haystacks in March 2011, Ruben Smits, 2011

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2.7 Material & architectural overview The plan of the building is quite simple in nature (Figure 2.8). The program comprises of a living room, a kitchen and a bedroom on the ground floor and above a room for the maid.

The roof is made up of two characteristic pitched gables. The timber frame construction is not in its original state, and quite possibly was replaced during the rennovation of the west facade. Currently, parts of the roof constructions are affected by moisture and wood worms. The roof consists of two types of roof tiles.

The east side is made up of early 20th century tiles.

Figure 2.7 Hammenwoning during the day.

Different type of brickwork was used within the four facades. The west side of the Hammenwoning was built in 17th century style by using on older type of handmoulded red-brick, whereas the rest of the house consists of machine-made brick. Also, at the plinth (base) of the building, a darker, purple-coloured brick is used, which is also refered to as the ‘clinker’. (Figure 7.1) Other architectural features include: ornamental steel anchors, wood frame windows, stained-glass elements on the interior as well as the external walls.

The interior finishes in the visisted building are mainly wooden exposed structures, plaster, vinyl as well as wooden flooring. There is a visible mixture of materials which reflect the period they were used in and or rennovated/restored with. Snapshots of the interior material palette are shown on the opposite page. All walls were covered by decorative wallpaper, with a lot of damages visible in it.

Figure 2.8 Stained-glass door detail, interior. photo by Narutai

Figure 2.9 Corner of southwall and westwall photo by Narutai

Figure 2.10 Wooden beams and floor photo by Narutai

Figure 2.8 Hammenwoning original plans provided by Designbyevolution

Figure 2.11

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3. DAMAGES ON THE LEVEL OF THE WALL

Figure 3.1 Front facae of Hammenwoning. 2012. Photo by DL

3.1 Description The west facade is characterized by two gables with a central entrance and a wooden door with a small veranda. The walls are clad in mainly red brick laid out in a cross bond pattern. There are eight white wooden windows (with stained glass on top) decorated with brick arches above them as well as equipped with dark wooden shutters. On the ground level, underneath the windows there are natural stone sills. Bluestone is used for the steps leading to the entrance. Horizontal plaster strips (emulating sandstone) are present throughout the main facade with other decorative elliptical elements. The metal anchors within the facade are visibly designed to be not only structural but also quite ornamental. Darker bricks (also known as clinkers) are situated at the lower level of the wall, at the plinth.

CHANGES FROM OLD TO NEW FACADE Mortar was changed in the new facade: The oldest buildings were cemented with a lime mortar with a higher concentration of air pockets. The lime therefore hardened very slowly when exposed to the weather.

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The mortar was elastic, and the adhesion between the stones and the mortar was not very great. This is one of the main reasons why the walls have many cracks in the masonry. Because of this, settlement or temperature differences occurred within the facade.

3.2 Diagnosis There are 4 visible cracks found on the west facade of the Hammenwoning. Type of crack present: in column or wall - combination of directions - no horizontal cracks - other combination of directions. Possible causes can be: vertical settlement, overloading due to change in resistance, geometrical discontinuities near opening, and or thermal contraction and expansion of facade causing it to move horizontally. Settlement due to a compressible sub soil can be extensive and uneven. Water was also found in the basement level which could contribute to the rotting of the construction due to condensation. In addition to these cracks, there are concerning patches of brick, which will be discussed on the level of the materials.

Figure 3.2 West elevation. Illustration generated by Autocad by Jony Nederend. 2012.

3.3 Advice A solution would be to concentrate on the largest cracks especially near the exposed anchor in area C. Determine first whether these cracks are old or new.

And if they are structural. Also, another main concern of this wall is to focus on the repair of the damaged red brickwork which will be discussed in area A.

Figure 3.3 The effects of compressible sub-soils. Diagram showing possible crack damages taken from de Vent

Figure 3.4 Diagram showing main cracks on west wall. DL.

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4. AREA A - damages

Figure 4.1

4.1 Description Area A, located on the second storey of the building is mainly focusing on the damages of the orange brick around the windows. Also refer to Figure 7.6.

EXTERIOR INSPECTION When looking specifically at this area, one clearly sees a loss of adhesion on the level of the red brick. These patches illustrated in Figure 7.6 have a more vivid, orange colour (Figure 4.2-4.5) and stand out as visible and concerning damages. Within this area, we also see the second most severe problem areas which are the peeing and rotting window frames (which will be more focused on in section 7.8).

INTERIOR INSPECTION When we visited the interior of the house, on the second storey to be specific, clear moisture problems were spotted on the walls which face the west side.

Please refer to Figure 7.16. This problem is evidently connected with the brickwork damages on the exterior side.

Figure 4.2

Figure 4.3

4.2 Diagnosis Brick work diagnosis discussed in section 7.3 and 7.4 Winow frame hypothesis mentioned in section 7.8.

4.3 Advice If the brick damage such as exfoliation and powdering is due to gypsum formation, avoid further loss of material (protect hand-made bricks).

First we need to confirm the presence of gypsum within the material as well as lime and suphates in the brick and mortar. If there is no gypsum, then it is just soiling, therefore cleaning is not necessary. If for instance, there is lime and sulphates present in the brick and mortar, then the gypsum will form again after cleaning. So again, cleaning is not a solution.

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Figure 4.4

Figure 4.5

Figure 5.5 Screenshot of properties of Area A within MDDS program

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5. AREA B - damages

Figure 5.1

5.1 Description Located on the left side of the west facade. Area B includes mainly the damages of the clinker brick, the crumbling orange brick as well as the crack beneath the window.

EXTERIOR INSPECTION Damages observed mainly on the clinker as well as the red brick. One vertical crack also found under window.

Figure 5.2

Figure 5.3 crack below left sill

INTERIOR INSPECTION Moisture problems evident in basements, crawl spaces and ground floor The moisture problems that arise are: high water level, low temperature and high relative humidity, condensation against the underside of the floor, fungi, rising damp within the building wall.

During the inspection, we found this area (the basement) to be particularly damp and moist and uncomfortable. The interior damages were very closely related to the exterior damage findings.

Figure 5.4 severe patches of vividly coloured damaged red brick

5.2 Diagnosis This is manifested by moist spots above the ground floor. Because brick is a porous material, the moisture from the soil into the masonry is easily absorbed. This moisture is present because of a high water level, poor drainage of rain or leaking pipes from the sewage system, drainage or water supply.

Figure 5.5 Problematic orange brick meeting with clinker plinth

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5.3 Advice Basements or crawl spaces are most prone to moisture damage where ventilation offers no solution.

Increasing ventilation will actually increase moisture transport from space and cause prolonged high humidity in the house which can lead to mold.

Removing the cause may be done by lowering the water level in the whole area or by an interruption of the fluid flow. It seems, that the affixing of a horizontal fluid-and vapor-proof layer is the most reliable solution.

In addition, injection (poriĂŤnvullende system) or impregnation (water-repellent system) with chemical solutions a choice. What often is seen as a solution to the rising damp is by means of mortar, plaster or placing a paneling system. The result is that the moisture content is even higher, and enters through the paneling and manages to emerge again, therefore this method should be strongly discouraged.

It is also possible to block the entering water with a foil or polystyrene. The water can also be removed and reversed by the following methods: with a foam/ concrete mix, with sand and a concrete bottom valve and or with a proper gravel backfill. The condensation which arises in the floor between the two rooms can be solved by completely insulating; though this is not feasible due to the characteristic structure. Spraying polyurethane insulation provides the ideal solution.

Figure 5.6 Interior star crack visible within the wall

There has already been minor (insufficient) repair work done on this vertical damage by using extra mortar to repair the joints and gap forming from the crack.

Figure 5.7 basement with severe moisture damages

Figure 5.8 interior: peeling wall due to moisture issues

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6. AREA C - damages

Figure 6.1

6.1 Description Located on the right side of the west facade, this vertical area zooms in on mainly the crack.

EXTERIOR INSPECTION Automatically our focus was on the fairly large crack (Figure 6.3-6.5) located on the right side of the west facade. We also spotted less minor damages to the red brick than in Area A. INTERIOR INSPECTION Cracks on the inside were present in the same location as the ones spotted on the external side of the west wall.

6.2 Diagnosis Damage on corners of facades: star crack patterns, deformation, and brick spalling, iron reinforcement is exposed, as well as evidence of re-pointing to fill crack is visible.

A lot of damage is caused by various joined materials in walls, which have a different coefficient of linear expansion. As a result, these differences in thermal expansion of the materials exert forces on each other, which often leads to formation of cracks in masonry.

The crack gap tends to grow larger over time because the crumbling wall particles prevent cracks close to pulling a falling temperature. Repairing damage to masonry caused by thermal motion is useless, since the cause of the thermal motion remains. Unless there is another hypothesis, of the rusting anchor causing the damage as discussed in the following paragraphs.

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Figure 6.1

The major crack depicted in Figures 6.3-6.5 looks as if it’s quite serious since the steel anchor is exposed. At first, we hypothesized that this exposure yielded to a cold bridge within the structure. In the end, we concluded that this is does not involve any cold bridging.

To conserve the aesthetics of the building we decided that it would be beneficial to fix this problem.

We finally concluded that this is in fact the corrosion of the hidden anchors which led to the star crack formation in the wall. In order for this occur, carbonation of mortar began along with a present reduced pH. This led to rust formation as well as simultaneous expansion which yielded to the crack. In order for this damage to occur, the follwing conditions must be present: moisture, oxygen as well as chlorides (upon inspection, salt was detected within the brick and in the mortar).

Figure 6.2

6.3 Advice A solution would be to redo the whole section (with compatible pointing and mortar) of the brickwork after replacing the anchor with an expandable anchor.

In order to perfirm this task, one must primarily assess the structural integrity of the facade and structure of the building. If the structure is too weak due to the severe rusting of the anchors, replacement of stainless steel anchors will need to be done. If the rusted iron anchors are in an acceptable condition, than Cathodic Protection shall be used, which causes less damage than a simple expandable anchor replacement. The application one of these possibilities is then necessary: Passive Cathodic Protection or the Active Cathodic Protection. After this procedure, constant monitoring of cracks as well as structure must be made.

Figure 6.3

Figure 6.4

Figure 6.5 exposed steel rusted anchor

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7. DAMAGES ON THE MATERIAL LEVEL 7.1 Purple brick / clinker + pointing + mortar Description Darker brick found closer to the ground level at the plinth. When produced, the brick was fired at a higher temperature, thus stronger and more dense.Yet problem areas still found within this material.

Diagnosis scaling: Detachment of scale-like, relatively thin (< 3 mm) part of a material. Layers parallel to the face of the stone. Possible damage from high water / moisture level from the ground efflorescence: White residue was found on the plinth of the facade in the clinker brick (purple brick) as well as the pointing. Hypotheses: related to water-penetration from the ground (earth retaining wall). This occurs when the water soluble salt in masonry products is extracted by water. Once the water evaporates, the salt hardens and forms unsightly white streaks on the brick. crust: the crust formation occurs maybe with the participation of iron oxide coming from inside the material, but the other components, which form the dark/ black layer, come from outside.Crust could be caused due to atmospheric pollution is the formation of black crusts that are primarily comprised of gypsum.

Figure 7.1

Figure 7.2

algae: since this brick is closer to the ground water level, it is therefore more prone to algae damage, which is not a serious problem.

Advice for efflorescence: Hose down the brick surface with a high-pressure hose or attach a nozzle which can direct a powerful jet of water at the surface. Efflorescence is water soluble, so most of it can be removed with high pressure. To prevent re-growth of efflorescence by spraying a silane/siloxane water repellent sealer onto the brick surface.

Figure 7.3

for crust: If there is a carbon deposit within the black crust, one can use a sodium hydroxide-based-poultice to clean the surface.

If any of the above-mentioned stains are water-soluble you may use a plain clay poultice

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Figure 7.4

7.2 Orange brick Description The longest side of the brick is approximately 20cm long with 1.5cm thick mortar joints. Detachment of relatively thick layers of a material was distinguished (greater then 3mm). The orange brick, especially located in the illustrated areas of Figure 7.6 is extremely brittle and easy to remove, peel, etc. The mortar is has significant loss of cohesion and in most cases can be easily taken out (if not already missing).

Diagnosis spalling, soiling, scaling, exfoliation 1. Rain water causing damage to brick on west facade which has not been properly fired, ie. it is less dense and more prone to damage, falling apart 2. A large amount of sulfates is present in the older brick which does not react well to water, therefore causing damage Advice Removing a larger section (using hammer and chisel) of the facade to replace the damaged bricks. It is also suggested to fix the ventillation problem within the wall, where air and moisture should pass through instead of getting trapped between the wall structure and the insulation.

7.3 Orange brick bedding mortar and pointing Description Severe cracking found in joints. The environmental factors of contraction and expansion are very hard on mortar. This is especially damaging in Delft, since it is an area where there is regular rainfall. The process begins when water enters into the mortar through a crack. When the temperature falls below freezing this moisture freezes and expands. This force causes the the mortar to deteriorate.

Diagnosis 1. Hindered dimensional changes, temperature/moisture induced, difference in behaviour between two types of mortar in masonry 2. Hindered dimensional changes, due to frost action 3. Hindered dimensional changes, due to salt attack, crypto-florescence

Figure 7.5 Examination of mortar joints, Very brittle and easy to take out.

Figure 7.6 Analysis of main damages with similar appearance and location

Advice Using a milling and or grinding device, it is suggested to remove the whole pointing layer in order to replace it with a new, stronger one, Old pointing mortar should first be cleared out down to the bedding mortar.

Figure 7.7 Zoom in of damage patch

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7. DAMAGES ON THE MATERIAL LEVEL 7.4 Natural Bluestone Description: Accents, window sill Natural (grey) stone is mainly used for window ledges and as an accent stone within the brick facade Diagnosis Some small vertical cracks are located within the natural stone. These cracks are minor and are therefore not problematic. The main damage is the green algea situated on the underside of the ledges, where the least amount of sunlight is present. This scenario yields to constant shading and therefore moisture thrives in such an environment.

Figure 7.8

Advice Since algae is not a harmful process to the stone it can be left alone especially since it is not even visible from where it is mainly located.

Description: Bluestone Steps The stair to the main entrance consists of four stone steps and one rectangular podium (used as the fifth step). Five black metal posts are supporting the ballustrade.The joints between the steps and the brick underneath are quite loose, a visible gap is seen. The stone is also turning slightly green, with visible moss mainly located between cracks at the joints. There is no pointing or slab foundation underneath the steps which help support the structure properly.

Diagnosis The possible cause for green algae is moisture; as it is closer to the high water ground level. The hypothesis for the crack and diaclase is that there is no foundation beneath the newly added steps and the soil below is not dense enough to support the structure. There is too much moisture content in the earth, therefore displacement occurs.

Figure 7.9

Figure 7.10

Advice Solution for green algae: since this is a minor problem, it does not need to be removed. But if one deems it to be necessary to clean, use warm water mixed with powdered oxygen bleach. Use a stiff-bristle scrub brush until the algae is gone. Rinse the brick with a garden hose and let it air-dry. Solution for diaclase: Replace broken step, fix crack in mortar between blue stone step and clinker brick.

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Figure 7.11

7.5 Plaster Description The 12cm high horizontal line of plaster gives lighter accents (pale yellow/beige) for the main facade of the building. A 2cm coating of this plaster was applied to the layer of brick. We know this is plaster and not sandstone because there was no limestone present; it did not fizzle when chemical was applied at the area.

Diagnosis On the far right side of the west facade, cracking in the plaster is visible. This is caused because of a larger structural crack.

Figure 7.12

Advice Similar to the advice underneath Area C, replacement of the damaged plaster part would be advised. Therefore re-plastering is a possible solution.

Figure 7.13

Figure 7.14

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7. DAMAGES ON THE MATERIAL LEVEL 7.6 Wood (window frames) Description The eight wooden white-painted window frames are clearly damaged (Figure 7.15-7.18) on the west facade. There is severe peeling of paint, mold and rotting wood present.

Diagnosis The number one reason for the above mentioned damages is moisture. Wind-driven rain, mist, fog, frost, etc are all contributers to this phenomenon. We see on the interior of the house (Figure 7.16) that this problem is also present on the internal side of the building.

Advice The initial advice would be to completely replace the window frame with a new timber-frame or an aluminum or plastic white-painted frame. The wooden frame solution would be most preferable in order to preserve the architectural features of the house. Perhaps using a stonger, more dense wood type material would be the ideal solution as the current one is quite prone to damage since it is a weaker type of wood.

Figure 7.15

Another solution would be to only replace the most damaged parts of the frame, which is the lower half, but aesthetically, the materials will not be efficiently copatible with eachother.

Figure 7.16

Figure 7.17

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Figure 7.18

8. KARNBARN DAMAGES

Figure 8.1 West facade of the ‘Karnschuur’ photo taken by Jony Nederend

8.1 Description ‘Karnschuur’ was constructed in 1600-1700 and was attached to the old Hammenwoning until 1927 when the intervention including roof extension was done.

Initially, ‘karnschuur’ was constructed with red and yellow hand-molded brick with plastered plinth. Until the complex was reconstructed, roof extension was added with the height of ca.530 millimetre of machinemolded bricks. The machine-molded bricks were not only used in the roof extension but also used in the renovation of the west and south façade of the toilet while the north side remains the same old material.

Due to the fact that north façade of the barn was once connected to the Hammenwoning whereas separated later in the 20th century, cement plaster was used to cover the low durable bricks which were used to construct the interior walls. The solution of applying cement plaster is seen on the north façade of the barn and toilet.

8.2 Diagnosis ‘Karnschuur’ appears to have suffered from major structural damages both by external causes and internal. Cracks are seen throughout the building and mainly spotted on east and west façade. Plants growing against the south and west façade have caused damages on both structural level and material level.

There are two main contributions to the damage of Karnschuur. Firstly, the removal of roof construction and poor interventions, causing roof sagging and plane deviation on wall level. Secondly, vertical settlement due to disturbed foundation from tree roots penetration on the south façade, causing crack damages on the brick walls, and are seen mostly on south and east façade.

8.3 Advice Solutions would be applied specifically according to causes of damages. Therefore, will be discussed on the level of roof and wall.

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Picture from left to right , top to bottom Figure 8.2 Cement plaster on North facade where the wall used to be interior partition, Photo by Jony Nederend Figure 8.3 Tree roots against South facade showing deviation in plane on the lower part of the facade. Photo by Jony Nederend Figure 8.4 Wall displacement from roof thrust as the roof beam of the rosmolen was replaced for the karnmolen. Here, wall on the north side are tapered toward each other while on the south are falling apart from each other. Photo by Jony Nederend

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9. KARNBARN DAMAGES CONTRIBUTED BY THE ROOF

Figure 9.1 Karnmolen, photo taken by Jony Nederend

9.1 Description On the interior of the barn, originally there were 4-bay roof rafters at every ca.2.50 metres, but one closest to the south façade was removed and replaced by the karnmolen. Overall roof construction was made poorly mainly after the intervention in 1927. Some roof beams were replaced and some are made connected to the old beams with wooden stiffeners.

9.2 Diagnosis Removal of the roof beam (rafter no.1, figure 9.2 ) resulting thrust in roof structure causing the wall to bend outward on the south side, while the walls towards the north façade remain the same. Unstable roof and loads from the activities occurred especially on karnmolen contributed to the sagging roof on the ‘rosmolen’ side of the barn.

9.3 Advice The removal of the beam on rafter no.1 was related to the history of the ‘Karnschuur’. The beam was replaced by the karnmolen which, at the time, related to the function of the building. We decide not to replace the karnmolen with a proper wooden beam and bracing to support structure, instead steel bracing under rafter no.1 (figure 9.2) will be used to hold the roof structure and maintain the atmosphere of the current condition.

rafter no.3

rafter no.2

rafter no.1

Beam added at the

time of renovation

Figure 9.2 Roof construction diagram, photo and illustration by Narutai

rafter no.3

rafter no.1 rafter no.2

Load transfers to original beam

Figure 9.3 Roof construction diagram, photo and illustration by Narutai

Figure 9.4 Damage mechanism illustration by Jony

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10. KARNBARN DAMAGES CONTRIBUTED BY TREE ROOTS

Figure 10.1 Karnmolen, photo taken by Jony Nederend

10.1 Description ‘Karnschuur’ appears to have suffered from major structural damages both by external causes and internal. Cracks are seen throughout the building and mainly spotted on east and south façade (Figure 10.2).

Plants growing against the south and west façade have caused damages on both structural level and material level.

10.2 Diagnosis Tree growing against south facade contributes to major foundation disturbance. As the tree roots enter the building and damage the foundation (Figure 10.3). The most obvious damage on the south facade from tree roots is the deviation in plane in the place where the roots enter the building. Movement and direction of cracks around the building are also related to this cause of vertical settlement.

Figure 10.2 Damage mechanism illustration by Narutai Riangkruar

10.3 Advice Tree roots control: Removing tree might pose more harm than good, as the tree has entered the building for quite sometimes and the roots themselves play the role of stabilising the structure. However, the process of controlling tree roots from entering further within this fragile building can be performed alongside the conservation process. By installation of cut off walls for root control with appropriate root pruning (an arborist’s advice is required to ensure tree health and stability is maintained) or removal of trees within the influence zone of the footings (2004, Simon Wiltsheir).

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Figure 10.3 Tree roots entering building structure, photo by Jony Nederend

11. SOUTH FACADE - AREA A

Figure 11.2 Crack pattern, Illustration by Narutai Riangkruar

Figure 11.1 Facade drawing, illustration by Jony Nederend

11.1 Description Located on the right side of the facade, spotting a diagonal crack wider on the top and narrow towards the bottom. The crack appears on the corner of facade plane adjacents to stell anchor and drainage pipe and ends close to the tree roots. Widest crack measured 4 cm (figure 11.4).

11.2 Diagnosis - crack and detachment of corner with subsidence base ( moderate to severe)

Figure 11.3 Crack on top of the wall, photo by Jony Nederend

Area a shows that the south facade suffers from tree roots disturbance. Disturbed foundation causing vertical settlement resulting in inclining wall. The right side of the facade appears to be falling apart due to a large crack tapered towards the bottom (figure 11.5).

Hypothesis: 1. Differential heave due to change in soil behaviour, local uplift by tree roots 2. Differential settlement due to change in soil behaviour, difference in soil composition 11.3 Advice Prevent future crack development by improve foudation stability by the method of underpinning by underpin the footings of the building to concrete or masonry or pile to carry the load of the building down to more stable stratum. (2004, Simon Wiltshier)

4.0cm Figure 11.4 Crack width, photo by Jony Nederend

For the current crack, by installing articulation joints can help controlling the movement of crack.

Figure 11.5 Crack end, photo by Jony Nederend

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12. SOUTH FACADE - AREA B

Figure 12.2 Crack pattern, Illustration by Narutai Riangkruar

12.1 Description Damage on area B occurs in the middle of facade plane.

Spotting several star cracks mostly around the anchors.

Interior inspection shows that there is no supporting structure behind the anchor 1 (figure 12.3).

anchor 1

12.2 Diagnosis - star cracks (moderate) anchor 2

Long cracks around anchor area. The damage was unlikely caused by vertical settlement, but it was instead cause by load shift as the support wooden structure was removed from the anchor area. The anchor 1 itself cannot carry any load at all, the load then shifted to another anchor, resulting in increased tension over the anchor area resulting in star crack over the support anchor.

Hypothesis: 1. inadequate tie/anchor system due to the removal of support structure.

Figure 12.3 Crack pattern, Photo and Illustration by Narutai Riangkruar

12.3 Advice Installing a bracing agaist the facade can help carrying the structural load from roof beam to the floor as well as stabilise south wall.

anchor 1

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Figure 12.3 Crack pattern, Photo and Illustration by Narutai Riangkruar

13. EAST FACADE - AREA A

Figure 13.2 Crack pattern , Illustration by Narutai Riangkruar

Figure 13.1 Crack pattern, Illustration by Jony Nederend

13.1 Description The location of the damage appears in the middle of the east facade. Crack in diagonal direction with constant size in plane with deviation from horizontal.

Interior wall shows a crack at the corner between the exterior wall and room partition. Crack measured at its widest as 3cm (Figure 13.4).

13.2 Diagnosis Damage: diagonal crack running in one direction(minor to moderate) Exterior shows moderate diagonal crack in the middle of the plane close to the interior partition. The cause of damage is the result from foundation disturbance on south facade causing corner settlement. Crack appear in the opposite direction from the force (Figure 13.2).

The interior crack is the result from the wall falling apart in opposite direction according to the unstable roof structure on the south facade while the proper roof extension still be able to hold the structure.

Figure 13.3 Crack pattern on east facade, photo by Narutai Riangkruar

Hypothesis:

1. Vertical settlement in the corner from foundation disturbance on south facade 2. Subsidence of interior wall from uneven load on foundation or wall was not constructed on foundation 13.3 Advice Small crack can be improve as well as allow for some minor movements in the future by filing in the crack with flexible sealants. More sustainable way for the structure is to improve the foundation to prevent further crack development.

Figure 13.4 Crack on the interior wall, photo by Narutai Riangkruar

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14. EAST FACADE - AREA B

Figure 14.1 Crack pattern, Illustration by Jony Nederend

14.1 Description Location B located on the right of the facade with an arch-like shape crack over the opening. One horizontal crack also appears under the roof and above the opening. Wall on the right edge seems to be displaced.

14.2 Diagnosis Damage: 1. Arch-like crack pattern over the opening (moderate to servere) 2. Wall displacement (moderate to severe) A severe diagonal crack with / \ pattern over the opening with plane deviation (Figure 14.1). The cause of damage is the result from vertical settlement on south facade causing the support floor to bend. There is also another possibility of the hindered dimensional changes causing bending lintel (Figure 14.4). The trace of this hindered dimensional changes is the horizontal crack over the opening which mostly occurred from temperature induced.

Hypothesis: 1. Overloading due to change in load path, bending of floor that supports damaged wall 2. Overloading due to change in load path, bending of lintel

Figure 14.2 Cracks over the opening, photo by Jony Nederend

Figure 14.3 Gap between wooden frame and masonry wall, Jony N.

14.3 Advice For the damage from missing lintel, temporary lintel made of steel can be replaced to preserve the current condition of the building. Small crack can be improve as well as allow for some minor movements in the future by filing in the crack with flexible sealants.

More sustainable way for the structure is to improve the foundation to prevent further crack development.

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Figure 14.4 Plane displacement, photo by Narutai Riangkruar

15. KARNBARN DAMAGES ON MATERIAL LEVEL - WEST FACADE AREA A

Figure 15.2 Crack pattern, Illustration by Narutai Riangkruar

Figure 15.1 Crack pattern, Illustration by Jony Nederend

15.1 Material A - Cement plaster on hand-molded bricks on west facade 15.2 Description During the seperation of the barn and Hammenwoning, cement plaster was put over the brick facade to make the facade more tolerant to the exterior environment.

(Figure 15.1) 15.3 Diagnosis Damage: Loss in adhesion (moderate to severe) The toilet shows sign of reconstruction where different types of masonry were used - the part covered with plaster are hand-molded bricks (Figure 15.3) and the uncovered are machine-molded. We suspected that the plaster used during the renovation was cement plaster which was widely used from the 20th century, as the material is settled faster than the old lime plaster. While the masonry built at the time of the barn construction is more compatible to lime plaster. This results in the effect that the gypsum plaster prevent the wall surface from breathing. Consequently, the material could break down when there is the presence of moisture.

Figure 15.3 Loss in adhesion toilet wall, photo by Narutai Riangkruar

Hypothesis: 1. material incompatibility between plaster and handmolded bricks, resulting in absorption efficiency.

15.4 Advice The exposed surface of the inner brick wall shows that bricks inside are damaged from applying the wrong type of plaster. As the large plane of north facade is still being covered by the cement plaster. Suggestion is to remove the cement plaster and apply lime plaster which is more compatible to the hand-molded bricks.

Figure 15.4 Intervention in 1927, machine-molded brick, photo Narutai R.

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16. WEST FACADE AREA A

Figure 13.1 Crack pattern, Illustration by Jony Nederend

16.1 Material B - Hand-molded orange bricks 16.2 Description The loss of adhesion on cement plaster allows us to observe the condition of the hand-molded bricks inside. Bricks are suffering from encrustation (Figure 16.2) and it is predicted that the north façade is also having the same problem as it is covered by the same material which is incompatible with the hand-molded brick which contains lime.

16.3 Diagnosis Damage: Encrustation (moderate to severe) The cause of encrustation occurs from the deposit of leached mortar coming from the inside of material which mostly contains calcitic material (Background information MDDS). We suspected that the encrustation is caused by the reaction of lime which contains Calcium Oxide found in masonry and mortar that was used during the time of barn construction. When the 1927 intervention applied new type of plaster on top of the hand-molded bricks preventing the material from ventilating, the Calcium Oxide (lime) inside formed up and attach to the material surface, resulting in white deposit on the brick surface.

16.4 Advice 1. Perform the test to determine whether it is the encrustation by using HCL, if the bubbles are seen, then the damage is confirmed. Furthermore to determine whether the encrustation contains calcium silicate which harder to be cleaned (Background information MDDS) and is considered an â&#x20AC;&#x2DC;undesirable materialâ&#x20AC;&#x2122; in structure (Heritage testing Ltd, Factsheet 8.1). The test to determine Calcium silicate requires X-ray procedure to find the presence of crystalline.

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Figure 16.2 Encrustation, photo by Narutai Riangkruar

2. In order to clean the encrustation, one can apply a chemical substance on the surface or laser cleaning. As the encrustation is occurred by an inorganic compound, therefore the substance or procedure of removing stains is harmful to the environment and human health.

As in the damage condition and size of the monument is rather minor, it is better to leave the damage on the material and try to prevent it from occurring in the future by removing cement plaster which is incompatible to the hand-molded bricks and apply lime plaster on the building surface instead.

Figure 16.3 Encrustation, photo by Narutai Riangkruar

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17. WEST FACADE AREA B

Figure 17.2 Damage location, Illustration by Narutai Riangkruar

Figure 17.1 West facade, Illustration by Jony Nederend

17.1 Material C - Yellow hand-molded bricks on west facade 17.2 Description West facade experienced a biological growth in a major parts. Mostly seen on the area close to the toilet and the areas shaded by tress.

17.3 Diagnosis Damage: Biological growth present - Algae (minor) A large plane of biological growth was found, in this case, Algae. It is uncommon that the facade exposes to the extreme daylight will be able to grow an algae. Small plants growing up against the facade then cast the shadow on the wall therefore shade the wall throughout the day. Besides, west facade is mostly exposed to the wind and rain, so there is more tendency that algae will grow easier on the shaded part of the facade.

Hypothesis: 1. Climate exposure catalyses algae growth especially on shaded area.

2. Trees shade the area away from sunlight 3. Growth occurs in the area with constant damp and humid, in this case toilet.

Figure 17.3 Algae on west facade, Photo by Jony Nederend

17.4 Advice In order to clean the surface plain water and a deck cleaner can be used to perform the cleaning process.

Power washing and biocide is not recommended as it could harm the surface of the material.

For this case, as the damage is not harmful to the structure, and it gives the aesthetic and value to the heritage building, we decided not to remove it.

Figure 17.4 Algae spotted on the corner of toilet, Photo by Narutai R.

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18. KARNBARN DAMAGES ON MATERIAL LEVEL - SOUTH FACADE AREA B

Figure 18.1 Location of damage, Illustration by Jony Nederend

18.1 Material D - Hand molded bricks on south facade 18.2 Description South facade is the side where the wall make direct exposure to the daylight throughout the day. Black crusts are spotted throughout the facade.

18.3 Diagnosis Damage: Crust (moderate) Photo from the archive shows that south facade was once covered with plaster which protect the wall from exterior condition (Figure 18.4). It was removed later on by unknown reason. The removal of white-washed plaster has made the hand-molded bricks exposed directly to the environment therefore crusts are formed.

Figure 18.3 Crust on south facade, Photo Jony Nederend

18.4 Advice Cleaning with chemicals should be strongly discouraged and should be limited to adding noniogene soap to the water. In case of severe fouling by the addition of hydrogen fluoride.

When cleaning should facade openings, frames, etc. can be covered with plastic wrap so that no damage to wood floors, sills and woodwork can occur.

Consider the condition of the wall, cleaning to process is opted to be perfomed Figure 18.4 Photo of the complex in 1926, Delft archive

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10. CONCLUSION The Hammenwoning is clearly a valuable heritage building with a very characteristic and dated appearance. The damages analysed in this report are not too severe and therefore there is no need for immediate intervention regarding solutions for restorations, renovations, etc. The building studied should be kept in its most original form because of its value.

Preserving it by means of minor repair work and cleaning discussed in all the section in this report under â&#x20AC;&#x2DC;Adviceâ&#x20AC;&#x2122; is the only solution. The main thing that should be focused on is the moisture problem preventions within the external walls in order to further prevent any damages associated with it.

Despite being poorly renovated, the Karnschuur is rich in its historical value as the history of the building can be traced back to the 17th century. Construction method and material used whereas with low efficiency in comparing to the up-to-date construction process worth preserving and be maintained at the current condition. Repair works in cleaning, removing stain as such will eliminate the buildingâ&#x20AC;&#x2122;s spirit of time and are unnecessary as the damages on material level pose no harm on the structure. Specific improvements on structural level are, on the other hand, vital as to prevent the building from further damages which could potentially cause the whole structure to collapse.

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Figure 10.1 Original property of this case study, taken from Delft Archives.

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11. SOURCES Literature: Constantinides, Ian. (1995). Traditional Lime Plaster. The Building Conservation Directory De Vent, I.A.E. (2011) Prototype of a diagnostic decision support tool for structural damage in masonry (Delft) Rots, J.G. 路 Van Hees, R.P.J. Huijts, C.S.T.J. (1984) De ontwikkeling van de Middendelflandse boerderij; een onderzoek in het kader van de reconstructie van Midden-Delfland (Delft) Midden-Delftland Vereniging Melvin, J (2005) Architectuur begrijpen (Singapore) Librero Prof.dr. c.a. Van Swigchem (1974) Monumentenzorg in Nederland (Bussum) De Haan Kruizinga, J.H. (1963) Ornamenten van huis en hof (Bussum) van Dishoeck, C.A.J. Verhoef, ir. L.G.W. | Van der Engel, ir. P. | Dubbelman, R.J. (1995) Renovatie en Onderhoudstechnieken (Delft) TU Delft Stenvert, R. | Van Tussenbroek, G. (2009) INLEIDING in de BOUWHISTORIE (Utrecht) Matrijs Wiltshier, Simon. (2004). Cracking of Buildings due to Shrink/Swell in Clay Soils. The heritage council of New South wales Presentations: Ruben (27th of march 2012)110829 Presentation analysis an design Hammenboerderij Delft by Design by Evolution, File 110315 Analysis Hammenwoning FINAL JPG.pdf Documents: AR0015 Building conservation assessment (2011-2012 Q3) uitreksel monumentenregister Hammenboerderij AR0015 Building conservation assessment (2011-2012 Q3) MDDS Monument Damage Diagnostic System_vs3a.pdf AR0015 Building conservation assessment (2011-2012 Q3) Characteristics_historic_masonry_apr.doc Websites: http://www.buitenwatersloot-delft.nl http://www.delft.nl/Inwoners/Cultuur_sport_en_vrije_tijd/Historie_van_Delft http://www.archief-delft.nl http://www.achterdegevelsvandelft.nl http://www.virtueeldelftslexicon.nl http://erfgoed-delft.nl http://www.hhdelfland.nl Software: MDDS Atlas

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Delft, 12.06.2012

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