Workshop -Architectural Heritage Documentation

Archdoc 2020 | Romaanse Poort | 26 - 30 October 2020 | Leuven

Group C:

Farida Elghamry|Nina Georgiadou |Yasaman Kamal Hedayat|Jana Zutterman|Amine Sassi

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

1

On-site Team: Pierre Hallot Pierre Jouan Jimena Quijano

Remote Team: Mario Santana David Andrews Andreas Georgopoulos

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

2

Table of Contents 1. Introduction 1.1 Topic Description 1.2 Working in the time of Corona

2. Historical Context 2.1 History of the Complex 2.2 History of the Attic

3. Construction 3.1 Typology 3.2 Assembly Marks 3.3 History of the Structural System 3.4 Building Assembly 3.5 The Rafters 3.6 Historic Events 3.7 Glossary

5. Documentation Approach 5.1 General methodologies & Recording tools 5.2 Observing, Photograpic survey & Hand measuring 5.3 Total Station 5.4 Laser Scanner 5.5 Procedure for plans 5.6 Photogrammetry 5.7 Comparison of techniques

6. Measured Plans 6.1 Main plan 6.2 Ceiling plan 6.3 Cross Section 6.4 Longitudinal Section 6.5 Rectified Image 6.6 Structural Assembly Detail

7. Conclusion 4. Heritage Value Assesment 4.1 Character-Defining Elements 4.2 The Nara Grid 4.3 State of Conservation

8. Bibliography

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

3

| Introduction | 1.1 Topic Description 1.2 Working in the time of Corona

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

4

| Introduction | 1.1 Topic Description The topic of our survey is the Choir Attic of the Romaanse Poort complex.

The Romaanse Poort complex is the title given to the cloister located on Brusselsestraat, within the first city wall of Leuven and along the Dijle. Officially known as the Sint-Elisabethgasthuis, Sint-Pietersgasthuis, or the Augustinian cloister, the more popular name refers to the oldest part of the existing complex, the Roomanse Poort, which is a sandy limestone gate located on the Brusselsestraat, now functioning as the main entrance to the cloister. The so-called Romanesque gate is an early gothic portal dating back to the first half of the 13th century. 1 Today the complex consists of the farm and the remains of the actual hospital including the hospital chapel, the east wing and part of the south wing.

The Choir Attic

1. Veerle De Laet and Vincent Debonne, “Sint-Elisabethgasthuis,” Immovable Heritage Agency 2020, accessed October 26, 2020, https:// inventaris.onroerenderfgoed.be/erfgoedobjecten/42152.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

5

| Introduction | 1.2 Working in the Time of Corona Archdoc week, like many other things, was unavoidably affected by the COVID-19 crisis. Unlike previous years, we did not have the privilege of having all our facilitators on site and had to communicate with a part of our team online. The social distancing measures also limited our access to the other parts of the building, causing problems in situating our rooms in the context of the whole complex in relation to other groups and even outside.

The tight schedule of the workshop was also affected by the sudden lockdown on 28th of October and we lost 1.5 days on site, which in many ways was vital to the process. Our group lost the day planned for the final photography for the two photogrammetry projects that meant to fix the errors noticed in the trial as part of the learning process, in addition to the chance to create new scans, completing the point cloud in the blind spots near the dormers and above the beams. While the crisis certainly effected the result of the workshop, we learned more than ever how to cope with numerous sudden problems during fieldwork, and still produce results we are proud of, with a strong team and positive attitude despite the mandatory masks.

Figure 1.1 : Romaanseport

Figure 1.2 : Courtyard

Figure 1.3 : Djile River

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

6

Figure 1.4 : External view of the Choir Attic

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

7

| Historical Context | 2.1 History of the Complex 2.2 History of the Attic

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

8

| Historical Context | 2.1 History of the Complex The hospital was founded at the end of the 11th century on a different site, and later moved to its current location in 1222. Although the hospital complex was largely completed by this time, the only remaining fragment of the 13th century buildings is the Romaanse Poort.

In 1363, a fire hit the complex and the hospital entered a period of decline. Later in 1479, the cloister was reorganized by Nikolaas Hellens, and a community of sisters following the rule of Sint Augustine was attached to the hospital. Thanks to the financial reorganization and donations, the buildings went through renovations during the first half of the 16th century.2 This includes the existing 16th century chapel that has been built on top of the original 13th century foundations. Fires hit the hospital again in 1632 and 1718, leading to major renovations in the second half of the 18th century, with the interiors getting a new look.

Figure 2.1 : Complex Transformation, by Sofie Beyen, “De Romaanse Poort: Some Topics of the Masterplan for the Podiumkunstensite”,13.

The monastery was abolished in 1790 under the French rule. Parts of the hospital located at the west of the Dijle were demolished in 1830-1840 and replaced by the new neoclassical hospital by Alexander Van Arenbergh, making the east wing the only remaining wing of the original cloister. Later in the 1960s the majority of the new complex was replaced by the new Sint-Pieters hospital. The restoration of the complex was started in 1980s with its transition into a cultural center.3 Now, the new Sint-Pieters hospital is being demolished and replaced by a theater building, with the complex going through a new phase of renovations.

2. Patrick Allegaert and Belgien, eds., Architectuur van Belgische hospitalen, M & L cahier 10 (Brussel, 2005), 191–94.

3. De Laet and Debonne, “Sint-Elisabethgasthuis.”

Figure 2.2 : Summery of the Age of the Buildings, by Sofie Beyen, “De Romaanse Poort: Some Topics of the Masterplan for the Podiumkunstensite”,17.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

9

| Historical Context |

While the hospital was initially served by brothers and sisters, from the second half of the 13th century it was served only by sisters, without a fixed Foundation of the hospital was founded around 10901095, probably on a site near what would later be the Saint James’ Church

The Wagenhuis buing rebuild and the former granary renovated as a result of the fire of 1993

Renovations due to the financial reorganizations, during the first half of the 16th century

The fire of 1363 causes a period of material and spiritual decline

1250

1090 1222

1261

Changing location In 1222 to the ‘s Hertogeneiland within the first city walls, where the Dominican monastery was founded in 1228 The bishop of Liège’s permission to build a hospital chapel, mentioned for the first time in 1261

Today, the new Sint-Pieter’s hospital is being demolished, to be replaced with a new theater complex

Abolishment of the monastry during the French rule

1363

The designation of the Romaanse Poort as a protected monument 1632

1479

1790 1718

1937 1830s

1960s

2009

The designation of the site as a protected monument

Reorganization of the hospital by Nikolaas Hellens A community of sisters who followed the rule of Saint Augustine was attached to the hospital

1993 2020

Fires in 1632 and 1718 The majority of the neoclassical building replaced by the new Sint-Pieters hospital Demolishing the parts located west of the Dijle to make room for the new neoclassical hospital by Alexander Van Arenbergh

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

10

| Historical Context | 2.2 History of the Attic The Choir Attic is located on the second floor of the southern part of the complex within the building of the former granary. This building is parallel to the hospital chapel and was located on the south east of the original cloister, currently connected to the remaining east wing and the Wagenhuis.

Originally used as a barn, a granary, and a malt attic, the building is a 16th century addition to the complex and was heavily rebuilt in the 19th and 20th centuries in its traditional style with brick and sandy limestone in the openings. The building was hit by a fire in 1993 and then renovated.4 Nevertheless, the interior beams on the late Gothic consoles of the first two floors, and the main roof structure are dated back to the 16th century. The typology of the roof is the same as the roof of the east wing, spanned with three stacked portals (tie beams on principal trusses with braces), always with purlins supported by wind braces. The cut-outs on the lower tie beams show the former presence of secondary beams, and the fact that the Attic was split into two levels.5 Today, the Attic is divided into different parts, including a staircase, an elevator, the hallway, a storage room in two floors, and with the Choir Attic taking up most of the floor. According to the study of Studio Roma for the master plan of the cloister, the main structure of the former granary building, together with the interior space of the attic have a high heritage value.6

4. Allegaert and Belgien, Architectuur van Belgische hospitalen, 195.

5. De Laet and Debonne, “Sint-Elisabethgasthuis.”

6. Sofie Beyen, “De Romaanse Poort: Some Topics of the Masterplan for the Podiumkunstensite” (Opening Archdoc Week, Arenberg Castle, October 25, 2020), 24–26.

Figure 2.3: Heritage Value Assessment of the second floor by Studio Roma, Sofie Beyen, “De Romaanse Poort: Some Topics of the Masterplan for the Podiumkunstensite”, 25.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

11

| Construction | 3.1 Typology 3.2 Assembly Marks 3.3 History of the Structural System 3.4 Building Assembly 3.5 The Rafters 3.6 Historic Events 3.7 Glossary

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

12

| Construction | Upon entering the attic, it can be noticed that the dominating element of the room is the wooden structure of the roof. Not only can the structure help us understand how the roof was constructed, but also it provides clues about building phases, building methods, tools used, and eventually the age of the structure itself.

3.1 Typology The Choir Attic has a timber frame structure in Oak, with a multi-tiered portal frame construction. This type of construction is typical for the region at the time and is the same as the roof of the east wing of the monastery. The roof structure of the attic consists of three portal frames build one onto the other, reaching an interior height of 7.29m.

Figure 3.1 : Total view of the structure

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

13

| Construction | A number of elements in the structure help us date the room: the type of carpenter assembly marks, the missing ridge beam and the typology of the structure, the connections of the rafters, and the use of building materials and finishing.

3.2 The Carpenter Assembly Marks Carpenter assembly marks were used by carpenters in medieval times to keep parts of the same construction unit together. For each portal-set, a different number was used. This was necessary because these parts were usually constructed off-site, transported and put back together on the site. The marks are necessary to prevent mixing parts of different portals of the structure. To make the difference clear between left and right, an addition to the number was made for one side.7 An overview of the carpenter assembly marks in the room tells us that the roof structure here was built in one go. The numbers start with one at the east end of the room, in the façade and go up towards the entrance of the room, without breaks or gaps in the count. The 3D-scan of the room shows a kink in the volume of the building. When checking the assembly marks in the storage room, we see a repetition, number 2 is repeated. This means that this beam dates back to another building phase than the roof of the choir attic.

7. Herman Janse, Wooden hoods in the Netherlands 1000-1940. Delft University Press, Delft / National Service for the Preservation of Monuments, Zeist 1989, 29-30.

Figure 3.2 : Flemish count system used between 1300 and 1600, Herman Janse, Houten kappen in Nederland 1000-1940, 30.

Figure 3.3 : Scheme of the assembly marks in the attic

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

14

| Construction |

The angle on which the attic space connects to the part of the building where the hallway and the storage room are located can be explained by the fact that the new structure was not started from the end of the old wing. Instead of starting here, number one can be found at the end façade of the new wing. So they started building lose of the original structure and gradually closing the gap.

Another element that strengthens this hypothesis is a connection between the lower purlins situated in the storage room. We can see a more correct version of such a connection in the choir attic, making the connection in the storage room rather remarkable.

The carpenter assembly marks found on the primary structure are long and scratched with an all. More recent marks, from the middle of the sixteenth century onwards, are smaller and deeper, made with a chisel. This means that the roof structure dates back to approximately the first half of the sixteenth century.

Figure 3.4: The remarkable connection of the purlins

Figure 3.6: Example of the carpentary marks

Figure 3.5 : The normal connection of the purlins

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

15

| Construction | 3.3 History of the Structural System An interesting element in our structure is the absence of the ridge beam, and hence the specific connection of the rafters. This construction type was common in the region from the early 15th century till the first half of the 16th century.

According to the article ‘Middeleeuwse dakkappen in het voormalige Hertogdom Brabant’ written by Dieter Nuytten, 8 the oldest and most straightforward type of roof for the area of Brabant in medieval times, was a common rafter roof. This roof consists of the same wooden frames being repeated one after the other transversal to the building. Through time, this type of roof structure evolved, with the wooden frames being connected to each other in a longitudinal direction as well. Tie beams were introduced to put the structure in tension. This led to a structure in bays: Bigger supporting structures, stacked portal frames connected by purlins, who in turn carry the smaller rafters in between the portal frames.

These structures lead to a more even spreading of construction loads and an optimal use of construction woods, since shorter pieces of wood were now also useful. From about the 15th century this type of roof structure was most common for the area of Brabant.

Keper of Spoor Hanebalk

Hanebalk Korbeel

Standzoon Blokkeel Muurplaat

SPOORGEBINTE

Figure 3.7 : Spoorgebinte structure, Dieter Nuytten, “Middeleeuwse Dakkappen in Het Voormalige Hertogdom Brabant”, 26.

Nokbalk Keper of Spoor

The roof structure we found in the attic space is very similar to what is described above. The most important difference is the absence of a ridge beam at the top of the structure. This leads to the assumption that the structure can be placed towards the end of the transition period between the two construction system mentioned above.

Fliering Windschoor Stijl Kopbalk Fliering Stijl Korbeel Muurplaat Blokkeel Kinderbalk

SCHAARGEBINTE

8. Dieter Nuytten, “Middeleeuwse Dakkappen in Het Voormalige Hertogdom Brabant,” M&L 24, no.

4 (2005): 22–36.

Trekbalk (hier ook: Moerbalk)

Figure 3.8 : Schaargebinte structure, , Dieter Nuytten, “Middeleeuwse Dakkappen in Het Voormalige Hertogdom Brabant”, 28.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

16

| Construction | 3.4 Building Assembly Based on the structure, we assume that the assembly was done in the following phases: Step 1: The construction of the wooden roof starts with assembling the first portal of the frames.

Step2: In the next phase, these portals would be connected to each other with horizontal purlins, with braces supporting this connection.

Step 3: Using the first tier as a base, the second portal of each frame would be assembled above the first one.

Step 1

Step 2

Step 3 + 4

Step 4: The portals would then be connected with the horizontal purlin and the axial braces.

Step 5: Like the previous tiers, the third portals would be assembled on top of the previous layer. The horizontal connection here does not have much structural role and is much smaller, and therefore cannot be considered a purlin.

Step 6: The frames carry the rafters that are connected together with a butt joint.

Step 5

Step 6

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

17

| Construction | 3.5 The Rafters Another element helping to date the elements is the connections of the rafters. To prove this, we take a look at the butt joints at the top of the structure. When comparing the joints in the choir attic with joints that were replaced in the attic above the storage room, we see that they were made differently. The replaced joints show that there is no ridge beam possible there. Early wooden constructions were built without such beams.

They got introduced from around the sixteenth century onwards. This observation confirms our first assumption of the date based on the type of carpenter assembly marks.

Looking more closely to the rafters, we see different saw marks on the wood. This leads to believe that this part of the structure is more recent.

Knowing that in the 20th century there was a fire might explain why they might have been replaced. This can also explain other recent materials used, like the floor tiles, double glazed windows and concrete and steel additional structural materials.

Figure 3,9 : 3D Model of the roof structure

Figure 3.10 : Exploded detail of the Ridge beam

Figure 3.11: Detail of the top portal

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

18

| Construction | 3.6 Historic Events Some traces of events that happened in the past can be found on the structure. For example, we see traces of fire on the lower purlins, and cutouts in the lowest cross beams show that there used to be another floor splitting the room horizontally.

Other traces provide more information about the construction materials.

The seemingly random holes in the lower purlin suggest that the wood was transported by the river. Big cracks in the beams lead us to believe that the wood was still quite green when it was used and drying over time caused the big cracks to appear.

Figure 3.15 : Connection of cross-beam with chimney Figure 3.16 : Connection of main column with the floor Figure 3.17 : picture of the arch brace

Other Observations Additional observations in the room can be made such as a remarkable solution for a chimney flue going through the structure at the end façade.

This is usually the place where a cross-connection of both walls are most important to prevent the structure from widening. Here the cross beams are cut in two pieces resting on a console to let the flue pass through. Also, cracks and cut-outs are filled in some places.

Figure 3.12 : Traces of fire on the lower purlin Figure 3.13 : Close-up to a connection between two purlins Figure 3.14 : Cross beam has rectangular cut-outs

We can observe wall anchorages of the different principal trusses and discolourations at their bottom part. Also, different damage sources can be found such as fire, water and humidity. Damages will be explained more in a designated part.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

19

| Construction |

PRODUCED BY AN AUTODESK STUDENT VERSION

3.7 Glossary BUTT JOINT

COLLAR BRACE

PRINCIPAL RAFTER

UPPER PURLIN MIDDLE TIE BEAM BRACE BRACE 2ND PORTAL FRAME PRINCIPAL RAFTER LOWER PURLIN LOWER TIE BEAM BRACE BRACE PLANE RAFTER 1 PORTAL FRAME ST

PRINCIPAL RAFTER WALL ANCHORAGE

PRODUCED BY AN AUTODESK STUDENT VERSION

PRODUCED BY AN AUTODESK STUDENT VERSION

3RD PORTAL FRAME

PRODUCED BY AN AUTODESK STUDENT VERSION

BRACE

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

20

| Heritage Value Assesment | 4.1 Character-Defining Elements 4.2 The Nara Grid 4.3 State of Conservation

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

21

| Heritage Value Assessment | 4.1 Character-Defining Elements The most important part of this attic is without a doubt its historical roof structure. It was built in the first half of the sixteenth century and till this day it defines the experience of the room. Most other elements in the room were added during more recent renovations, in a less coherent way.

This structure not only shows a layering of history, by its carpenters’ assembly marks, its small fire degradations, and different joints, it also gives an overview of how roof structures were built at that time, in the region of Brabant. At the end of the room, we also see how builder dealt with a chimney flue going through the structure. They put in stone consoles to support the beams that were cut for the chimney.

It was used as a granary and a malt attic.

Historians question that these were the original usages as the room is very prestigious

4.2 The Nara Grid While the Venice Charter of 1964 to this day serves as the main guideline for heritage conservation, The Nara document from 1994 plays an important role in emphasizing the intangible dimension of heritage and defining a broader view of authenticity. For our heritage value assessment therefore, we use the Nara grid developed by Koen van Balen based on the Nara document in 2005.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

22

| Heritage Value Assessment | 4.3 State of Conservation The room went through major renovations after the fire of 1993. While the main timber structure is dated back to the 16th century, some parts of the structure including a part of the rafters, and braces have been replaced in the renovations.

As part of these renovations, two steel columns were added to the room holding the second floor of the storage space. The floor is tiled, with white plaster painted walls and ceiling, and glass windows.

FIGURE 4.0: Camera positions for the damages

Damages to the Structure:

While the structure is in a reletively good condition, there are multiple signs of damage in the room, mostly caused by water, and some evidence of the fire of 1993.

The principal rafters have discoloration near the bottom in all three portal frames, likely due to water damage.

Figure 4.p1: holes in the purlin

Figure 4.p2 : major cracks a long the braces

Figure 4.p3 : damages in the plaster

Figure 4.p4 : fire-traces marks

Figure 4.p5 : discoloration in the main rafters

Figure 4.p6: water leakeage traces

There are major cracks along the longitudinal axis of the tie beams and the arch braces.

Other Damages:

The wooden rafters next to the windows on the upper dormers have severe damage due to water leakage, and there are damages in the plaster.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

23

| Documentation Approach | 5.1 General methodologies & Recording tools 5.2 Observing, Photograpic survey & Hand measuring 5.3 Total Station 5.4 Laser Scanner 5.5 Procedure for plans 5.6 Photogrammetry 5.7 Comparison of techniques

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

24

| Documentation Approach |

5.1 General methodolgies & recording tools During the Archdoc week, several methodologies and tools were used in order to deliver a completed documentation. In this specific table the total of the manual and digitalized tools used for each of the final deliverables are illustrated.

It is worth noting that unlike previous years, we did not have the chance to make a drone scan for the surroundings of the building complex.

Most of the main drawings are based on a 3D laser scan of the room with the BLK, complemented with manual measurements, the total station, and photogrammetry for more accurate results in the parts where the 3D scan was not detailed or visible enough. In each step, simplified plans were drawn to record the positions of the devices and photographic survey.

Figure 5.1: Table explaining the documentation approach

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

25

| Documentation Approach | 5.2 Observing, Photographic survey & Hand measuring The first step implemented after our visit on site was the general observation of the room and the structure. Some main observatory sketches were prepared and general pictures were been taken. The same night a preliminary research was executed relating to the historical background of the place, existing plans and a structural hypothesis.

As far as the photographic survey is concerned, we observed that the room had quite good access for natural light. Thus, the use of external flashlights was not necessary. We experimented with different DSLR cameras, tripods and mobile applications including a 360 degree picture (using the Vuze camera and application)to capture the overall feeling of the room.

It is also important to mention the role of hand measurements, as an assistant way used for the completion of drawings, wherever was possible.

Figure 5.3: HDR, general picture, Jimena Quijano

FIGURE 5.4: 360 photography by Vuze Camera

FIGURE 5.5: The result of panoramic photography

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

26

Figure 5.6 : prelimary hand sketches of main observations

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

27

| Documentation Approach | 5.3 Total Station Due to the complexity and the detail of our structure, we decided that the total station could not be used as the only recording method in our case. Moreover, because of the circumstances, the time was limited for recording a space entirely with this way. However, the total station played a significant role as an assistant method to laser scanning to confirm the accuracy of our results.

To begin with, the setting of total station was introduced by our facilitators and we all had the chance and access to try this application after their seminar. The tool was placed in specific locations in the attic and paper targets were put on several visible positions in different heights, like on the walls, on the wooden beams and on surfaces close to the windows.

After establishing a local coordinate system, the device was placed in six different positions along the room (1000, 2000, 3000, 4000, 5000, 6000), as it is presented in the plan, that allowed us to measure many points and compare some results. Undoubtedly, not all targets were visible from each position of the total station, but with an average of 5 or more targets recorded from each position, we were able to accurately place them. The final files were given to us by the facilitators, after we were done collecting the raw information.

Other than the main targets, some targets were put on the surface of the portal that was the subject of the photogrammetry model. (Structural Assembly Detail)

Figures 5.8, 5.9 : pictures showing several positiong of the total Station in the Attic Figure 5.7 : Positions of Total Station

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

28

| Documentation Approach |

Figure 5.10 : Total Station reference points on CAD

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

29

| Documentation Approach | 5.4 Laser Scanner Considering the complexity of the structure, the use of laser scanner was crucial for this project, especially due to the limited time on site. While the laser scanner was chosen as the main method of recording by both the students and facilitators, the confirmation or enhancement of the results with the recordings of the total station and some handmade measurements were simultaneously necessary to produce a precise outcome, especially for drawings like the sections.

The laser scanner was put in several locations in the attic, between the portal frames and approximately in the middle of the width of the room to avoid blindspots and produce a complete point cloud, as shown in the illustration. In order to calculate the thickness of the interior wall, a number of scans were taken outside the room in the hallway and storage area.

The recording of this area was not reqired, it was considered necessary by the group to have a more accurate representation of the room within the context of the complex. While originally a drone scan of the exterior of the complex was planned to provide the information necessary for the exterior walls of the buildings, due to the circumstances it was not possible to fly the drone and obtain the information.

Other than the main scan done with the BLK 360 Laica scanner, we were also introduced to the SLAM 3D scanning by Maarten Bassier. The room was quickly scanned with the Laica BLK2GO mobile scanner as well, and the two results were compared. The Laica laser scanner was connected directly to the iPad with Recap application, which transferred the information easily to the computer.

Figure 5.12 : Cross Section Point Cloud

Figure 5.13 :Ceiling Plan Point Cloud

Figure 5.14 : Longitudinal Section Point Cloud Figure 5.11 : Positions of Laser Scanner

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

30

| Documentation Approach |

Figure 5.15 : Autodesk Recap Snapshots

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

31

| Documentation Approach | The result of the scan was a 3D point cloud of the atic that was used to produce the final drawings, including the ceiling plan, the two sections, and the floor plan, using Autodesk Recap and Autodesk Autocad 3D programmes.

While the positions of the scanner were ideal to have maximum coverage of the space, It is important to mention that some parts of the attic were not recorded as well as others for multiple reasons.

Firstly, positioning the laser scanner in the middle of the width of the room caused distance from the exterior walls, and created blind spots in some more distant areas like the dormers about the windows or the area between the projection of the storage and the old structure. These problems are clearly visible in the ceiling plan, in which those parts are drawn in dotted lines.

Secondly, the presence of several immovable objects detiorated the documentation process outside the bounds of the room in the entrance hall, storage room.

Thirdly, the limited of timeframe because of covid-19 regulations did not allow us to return on site and finalise the documentation by recording the missing parts.

It should also be noted that the area above the tie beams was out of reach for the scanner, and not as detailed in the final point cloud as the rest of the room. This problem was mainly noticable in the two sections.

Before leaving the site two other scans were taken from above the beam, in order to complete the missing parts. While the additional scans did help with the longitudinal section , the details of the cut-outs of the tie beam on the cross section was obtained by photogrammetry. Needless to say that the area above the tie beam of the upper tiers was unreachable.

Figure 5.16 : Explanation of SLAM documentation Figures 5.17, 5.18 : Positions of Laser Scanner

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

32

| Documentation Approach | 5.5 Procedure for plans Considering the complexity of the 3D model and the structure and the height of the roof, tracing the drawings straight from the uncut Point Cloud would’ve caused problems in details. In order to redraw and copy the traces efficiently, we divided the Point Cloud models in different horizontal or vertical slices based on the drawing, and traced the structure layer by layer. Subsequently, we combined the drawings in order to compose the final document. In areas where information was still missing, the Autodesk ReCap file, pictures, videos and hand measurements came to our aid.

Specifically for the ceiling plan, the structure was traced in two phases, one thin slice around the height of 90cm ro identify the cutting plane, and the rest of the projection above that.

Figure 5.17 : Detail of Point Cloud

Figure 5.18 : Section’s level 90cm

A similar procedure was used for the cross section in multiple layers: Step 1: minimal slice of the Point Cloud, specifically where the section is made, only showing the slicing plane.

Step 2: slice expanded to include the first stacked portal frame, giving the first layer of depth in the drawing.

Step 3: slice of the Point Cloud is expanded to include the next bay, which provides the next layer of depth in the drawing.

Step 4: expanded Point Cloud that includes the next bay and the next layer of depth.

Figure 5.19: Process for ceiling plan

Step 5: expanded Point Cloud that includes the last bay, which gives the final depth of the section.

Step 6: addition of photogrammetry to the Point Cloud to provide more details of the top part of the lower tie beam. Drawing the cut-outs on the upside of the beam is now possible.

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Figure 5.20: Process for Cross section

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

33

| Documentation Approach | 5.6a Photogrammetry for one section To achieve a better understanding of the structure and combine multiple methods, we decided to do photogrammetry for one section of the roof.

The section chosen between the beams 3 and 4, had a lot of details and gave us the opportunity to compare the results of the laser scan, the 2D drawing, and photogrammetry in one part of our longitudinal section.

To achieve the best results, several overlapping photos were taken using the NIKON D750 DSLR model. A total of 80 photos were taken in this process, with a justifiable percentage of overlapping. The photographer kept a distance of around 4 meters from the roof. Subsequently, the Agisoft Metashape software was used for the rendering process.

While the trial round had promissing results, in the process we noticed the white spaces between the rafters are too white and untextured to be effectively processed by the software, and the extreme light from the windows created problems capturing the frame and the top part. Moreover, parts of the structure near the top were too dark and hard to process.

It was originally planned to fix the said issues by using a pole and a tripod to reach the upper parts of the structure, and using artificial lighting to improve the uneven high-contrast lighting situation, since the natural lighting caused changed between the photos, and the dark nature of the structure made us unable to use the ideal exposure settings.

Unfortunately due to the sudden lockdown we were unable to perform the process again to fix the issues and missing parts noticed in the rectified image.

Figure 5.21: Camera position for the photogrammetry

Figure 5.22 : Pictures with overlapping

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

34

| Documentation Approach | Missing parts: Reasons & Solutions 1. Lack of accessibility Use a pole and/or tripod Add artificial lighting 2. Too much light Turn off the lamp Use artificial lighting

Previous Trials 1

3. Too white Get closer to capture texture detail 4. Too much light Take picture at different times Use artificial light Try different camera settings

2

3

5. Lack of pictures Get closer, turn around and take more pictures 4

The camera settings were set as 4016px width, 6016px height f4.5 shutter speed 1/160 50mm ISO1000. Idealy, we would’ve repeated the process taking the issues above into consideration, with different camera settings, a tripod, artificial lighting, and completed the details 5 near the windows by taking more pictures closer to the object and in different times of the day, and from different angles.

Figure 5.23 : Comparisons of Photogrammetry different trials

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

35

| Documentation Approach | 5.6b Photogrammetry for structural assembly detail To accurately document the details of the structure we decided to make a photogrammetry model of one of the joints using Agisoft Metashape.

Like the rectified image, initially, the process was going to be done twice, once as a trial, and once for the final result using a fixed lens, a tripod, and a color charge. Unfortunately, due to the sudden change of plans, only the initial take was accomplished.

For this model, a total of 100 photos were taken using a Canon EOS 600D camera. The photos were taken from a distance of around 1 meter in order to have the maximum detail.

While the photos of the trial take did allow us to create a 3D model of the joint, the high exposure time needed to grasp the details of the dark colored dim-lit surface, together with not using a tripod reduced the amount of detail we wished to achieve.

1

2

3

Some of the problems and the solutions related to the initial model are:

1. Lack of accessiblitiy

Use a pole and/or tripod Add artificial lighting

2. Too White/Untextured

Change the distance Add artificial lighting

3. Darkness of the surface + exposure time Use artificial light Try different camera settings

Figure 5.25 : 3D model from Agisoft Metashape

Figure 5.24 : Position of selected structure for photogrammtery

Figure 5.26 : Examples of the photographic survey

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

36

| Documentation Approach | 5.7 Comparison of techniques During this workshop we had the privlige to work with different recording methods and combine the results to achieve the most accurate representation possible.

If used properly, the total station can be the most accurate device to capture a space. But given the complexity of the work, all the recordings were complimented with the data from the total station, to assure the most accurate results within the same local coordinator system.

Our group made two scans of the room using the Laica BLK360 laser scanner in fixed positions, and the Laica BLK2GO scanner with SLAM technology with the guidance of Maarten Bassier, and so we had the chance to compare the process and the results of the two scans.

While the process of the BLK2GO was faster on site, it produced less detailed pointcloud. However, since the position of the scanner was not fixed in the middle, unlike the BLK360 scanner, it managed to captured parts of the space the main scan had problems grasping. Overall it’s was shown how useful the portable scanner can be for producing a lighter file, in situation where the access to the site is limited.

While the laser scan could not obtain certain small and complex details especially in areas that were too dark or too light, more small-scaled focused methods such as photogrammetry or hand measurements helped to complete the details in the sections.

Through photogrammetry we were able to get precise details of textures and colors for areas we needed to focused on. But the method has it’s disadvantages , with missing parts in the model due to lighting, blind spots, lack of texture of surfaces, and high contrast between the elements making it difficult to work without aa tripod.

Figure 5.27 : Point Cloud for Longitudinal Section

Figure 5.28 : SLAM Scan of sections

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

37

| Measured Plans | 6.1 Main plan 6.2 Ceiling plan 6.3 Cross Section 6.4 Longitudinal Section 6.5 Rectified Image 6.6 Structural Assembly Detail

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

38

| Measured Plans | After analyzing the space, our team decided on the following deliverables: Other than a floor plan, a ceiling plan was crucial in our case in order to present the entire roof structure with details. It was decided to cut the roof at the level of 90cm, showing most of the roof while still cutting through the openings. The main plan has an assistant role here, showing the general space organization of the room.

The cross section shows the structure of the portal frames clearly while cutting through the openings, to show the connection between the interior space of the room and outside. Unfortunately due to the circumstances obtaining a scan of the exterior was not possible, therefore, the exterior has been drawn based on hand measurements and photographic evidence of the building. This drawing looks in purpose towards the east facade, which includes the chimney and four windows.

To have a complete grasp of the room the longitudional section has been made looking towards the north. While the exterior walls have the same issue as the cross section, for the interior wall between the main room and the storage area and hallway we had the opportunity to place the scanner outside and record the storage room as well. This room is not part of our main space, however the roof has been included in the ceiling plan.

Figure 6.2 : Window Top Detail

Figure 6.3 : Window to the outside Detail

Naturally, some elements could not be traced accurately since some areas were not completely visible in the point cloud. Such elements that have been completed by observations and photos and have not been recored precisely by the scanner are presented here with dashed lines.

It’s worth mentioning photographic evidence and the Autodesk Recap scan file have been significantlly influencial in the completation of the drawings after the ArchDoc week, since we did not have access to the site.

In addition to the main 2D drawings, this chapter includes the rectified image of part of the longitudional section, as well as the photogrammetry model of one of the joints of the structure.

Figure 6.1 : Structure Details

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

39

| Measured Plans | 6.1 Main Plan

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

40

| Measured Plans | 6.2 Ceiling Plan

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

41

| Measured Plans | 6.3 Cross Section

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

42

| Measured Plans | 6.4 Longitudican Section

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

43

| Measured Plans | 6.5 Rectified Section

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

44

| Measured Plans | 6.6 Structural Assembly Detail

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

45

| Conclusion |

During the course of the ArchDoc week, we experienced different methods of heritage documentation firsthand, and were able to analyze the advantage and disadvantages of each technique. Having the privilege of working with most sophisticated tools of recording, we were able to obtain a great amount of detailed information in a short period of time.

Doing the exercise in a historic environment with a wholistic approach, we developed a certain attention to details, required to properly document a historic building.

The COVID-19 crisis unavoidably challenged and enhanced our communications skills, as we had to consult tutors abroad, and later produce the dossier in lockdown, working together but apart. While we lost valuable time on site due to the situation, the crisis proved the importance and benefits of digital documentation more than ever. Where the site was not accessible, the scans taken from the room came to our aid to confirm certain details of the space, and to help analyze the structure.

Unlike physical documents, the digital survey allowed us to have equal access to all the information we obtained during the lockdown, each from our own home. In our case, being in lockdown and only having access to the information we obtained during the short workshop, the laser scan proved to be the ideal method, with limiting the time needed on site for obtaining the information.

Given the circumstances, it was an honor to still be able to work with professionals in the field of heritage documentation from all over the world, and would like to thank our on-site facilitators Pierre Hallot, Pierre Jouan, and Jimena Quijano, as well as our remote team Mario Santana, David Andrews, and Andreas Georgopoulos for this unforgettable experience.

Figure : Full Team

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

46

| Bibliography | Allegaert, Patrick, and Belgien, eds. Architectuur van Belgische hospitalen. M & L cahier 10. Brussel, 2005.

Beyen, Sofie. “De Romaanse Poort: Some Topics of the Masterplan for the Podiumkunstensite.” Presented at the Opening Archdoc Week, Arenberg Castle, October 25, 2020.

De Laet, Veerle, and Vincent Debonne. “Sint-Elisabethgasthuis.” Immovable Heritage Agency 2020. Accessed October 26, 2020. https://inventaris.onroerenderfgoed.be/erfgoedobjecten/42152.

Janse, Herman. Houten Kappen in Nederland 1000-1940. Delft : [Zeist]: Delftse Universitaire Pers ; Rijksdienst voor de Monumentenzorg, 1989.

Nuytten, Dieter. “Middeleeuwse Dakkappen in Het Voormalige Hertogdom Brabant.” M&L 24, no. 4 (2005): 22–36.

ArchDoc Workshop Report | October 2020 | Group C: The Choir Atic

47