Straw bale building Training for European Professionals: Infill & Prefab

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INDEX

U2 – INFILL AND PREFABRICATION

U2 DURATION

PAGE 5

U2 Session 1 : Construction Systems Info-Presentation 1 : Construction Systems Info 2: Building Physics (Intro)

3h

7 8 9

U2 Session 6: Construction Plan, Time Schedule Info 1 : Design and Planning

4h

10 11

U2 Session 2: Building Details Info 1 : Building Details Tip: 042 Filling Corners

1h

12 13 15

1 day

16 17 19

U2 Learning Outcomes

U2 Session 3: Hybrid Constructions Info 1 : CUT-Technique Tips: CUT

029-19 CUT-Technique, 030-20 CUT-System, 031 -21 Structural Integrity and Bracing, 032-22 OrganiCUT

Info 2: GREB-Technique

24

U2 Session 4: Infill-Constructions Info 1 : Infill-Construktions Tips: Infill-Construktions

1 day

U2 Session 5: Prefab and Modules Info 1 : Prefabrication Tips:

1 day

38 39 40

4h 2h

42 43 45

(min) 5 days

47

033-30 Adjusting Constructions to Bales, 034-31 Infill Bales: vertical or horizontal, 035-32 Diagonal Bracing/Shear Forces, 036-33 Planking or Direct Plaster, 037-34 Plaster as Bracing, 038-35 Double-Posts, 039-36 Bowing (Buclkling)

040-40 Prefab-Modules in Multistorey Houses, 041 -41 Prefab-Modules with Multibaler

U2 Session 7: Timber Constructions Info 1 : Timber Constructions U2 Session 8: Building Laws U2 Session 9: Praxis Straw Bale, pract. Test

Credits and Impress

27 28 30

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U2 – INFILL AND PREFABRICATION

LEARNING OUTCOME

U2 Level 3 (ECVET credit points: 20) / Level 4 (20)

Knowledge

Skills

Trainees know …

• about the existing national relevant building regulations related to straw bale building • the specific problems organising a straw bale building site and their solutions (weather protection, safety, logistics).

• the symbols to be able to understand plans and construction drawings • appropriate structural and wind proof constructions to be infilled with straw • techniques to fix the bales in the construction • the necessity and the techniques to avoid and to close the gaps (between bales and between bales and construction) • other bio sourced insulation materials, that can be used additionally in straw bale building • the reasons and the techniques to fill in straw in an required density.

• the different infill- techniques and their requirements related to schedule, planing, budget and resources.

• about prefabrication, its specific features of planning, its advantages and disadvantages.

•The details for the adjacent building elements (ceiling, walls, floor- and roof plates) • the details for openings (windows and doors) and for intersections (chimneys, pipes, wires).

•The reasons and the techniques to prepare the substrate with a plane and gap free surface. .

DieTeilnehmenden können …

• control the quality ofexisting constructions in relation to its suitability to be infilled with straw • handle tools and machines which are used generally on straw bale building sites and for simple wood constructions.

• execute different Infill construction methods with the required compression and adjust and fix the bales correctly.

• Fill in straw bales into prefabricated constructions.

• implement diagonal bracing in the construction according to static needs and plans • read and understand the symbolic of plans and construction drawings • fill the holes and gaps with straw and other bio sourced insulation material avoiding cold bridges • calculate building costs related to straw bale constructions • prepare all surfaces for the successive crafts people (plaster, cladding, wind- and air tightness) or execute these these tasks in mutual agreement.

• assemble the supporting wooden structures and the frames for openings.

Competence Trainees: • can organize and attend the building site at all stages and adapt the working process, the use oftools and adequate techniques (planning, preparations, execution, additional crafts) • can take responsibility for the requirements ofthe performance ofstraw as insulation material.

• can co-ordinate and communicate the special needs of infill constructions with other professionals.

• can explain different techniques ofinfill and prefabrication techniques including their advantages and disadvantages.

• Can control the general quality ofbales during the whole building process.

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SESSION PLAN S1

U2 – INFILL AND PREFAB

U2

Session Plan U2-S1 : Construction Systems Objectives: Trainees ... understand and are able to explain the three general different construction-options of a) direct-plastering (loadbearing and hybrid, NSS), b) planking on one side (hybrid, NSS), and c) planking on both sides (infill, SSS). understand the needs for infilling the bales in the right density, prevent gaps, fix the bales, direction of the halms and prevent deformation of the construction. know the necessity of structural bracings to withstand the shear forces. know and are able to explain the advantages and disadvantages of the different techniques.

Trainer:

Place:

Class or workshop

Duration:

Min. 2 hours

Equipment:

Straw bales Construction samples

Methods:

Theory

Presentation, lecture

Different structural options of infill and prefabrication and their characteristics and bale requirements Fixing bales in different techniques Compressing bales in different systems Advantages and disadvantages of infill and prefabrication techniques Details of connections: foundation, corners, windows and doors, roof, etc.

Preparing different surfaces for plastering

Documents:

Trainer sheet: T1 Info sheet: I1 How to choose the construction-system, different techniques I2 Construction samples

Practice

Identifying the different systems in construction samples or pictures

Organization:

Presentation, projector, construction samples

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U2 – INFILL AND PREFABRICATION

SESSION PLAN S1 – INFO 1

U2

Construction Systems

airtight- and windproofness only provided by plaster

airtight- and windproofness easier to achieve

diagonal bracing only through plaster (hard to proof)

diagonal bracing through planking , outside: rainproof, inside: installation area

no installation area not suitable for passive houses

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suitable for passive houses

double safety: airtight- and windproofness (but more expansive) rainproof, installation area suitable for passive houses

U2 – INFILL AND PREFABRICATION

Construction Systems

SESSION PLAN S1 – INFO 1

U2

9

SESSION PLAN S5

U2 – INFILL AND PREFABRICATION

Session Plan U2-S5: Construction Plan and Timetable Objectives: Trainees ... have the ability to read and understand architectural plans and construction drawings and the symbols used in. have the ability to read and understand details of windows, corners and connections to the roof and intermediate ceilings. know different structural options for straw bale walls. know the advantages and disadvantages of various solutions. know how to make a timetable for a straw bale building site and estimate times for infill, stuffing and wall preparation. know about the various trades and their works and responsibilities concerning straw bale construction (builder, carpenter, plasterer, roofer, tin smith, window-maker, plumber, electrician,…).

Methods:

Trainer:

Place:

Class

Duration:

Min. 5 hours

Equipment:

Pen and paper Calculators Projector

Theory

Lecture/talk Explanations Practice Basics of architectural plans and construction drawings Different structural options, characteristics and bale requirements Advantages and disadvantages of different techniques Compare the building costs (material, labour, etc.) using different techniques Setting up a timetable for the constructive works Trades on a straw bale building site (who makes what)

Documents:

Trainer sheet T1 Planning basics T2 Characteristics of the different construction techniques Info sheet I1 Design and planning

Practice

Task Interprete a case study comparing the results with other trainees Draw a building detail by hand

Organization:

Prepare a case study for every group of trainees (2–3 persons), study it in order to be able to compare it with the results of the participants.

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U2

U2 – INFILL AND PREFABRICATION

From Design to Construction Plan

SESSION PLAN S5 – INFO 1

U2

11

SESSION PLAN S6

U2 – INFILL AND PREFABRICATION

U2

Session Plan U2-S6: Building Details Objectives: Trainees ... know the details of a wall (connections foundation-wall, wallwindow/door, wall-ceiling, wall-corner-wall, wall-roof) for the different infill building techniques. can do simple non-loadbearing woodworks (install a window frame, make a corner, make connections,…). can read details in plans and architectural drawings. can detail openings in a wall (electricity, installation, ventilation, chimney,…).

Methods:

Practice

Theory

Lecture/talk Explanations Practice

Details of a wall (connections foundation-wall, wall-window/door, wall-ceiling, wall-corner-wall, wall-roof) for the different infill building techniques

Task Drawing of different details of a wall (connections foundation-wall, wall-window/door, wall-ceiling, wall-corner-wall, wall-roof) for the different infill building techniques Prepare (crosscut), assemble, raise and connect a sample or part of a sample with bottom plate, ring beam, window and corner

Organization:

Plans, drawing and sampels of details

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Trainer:

Place:

Classroom/workshop

Duration:

Min 4 hours

Equipment:

Pen and paper Projector Laptops (optional)

Documents:

Trainer sheet T1 Info sheets I1 Building details I2 Construction systems

U2 – INFILL AND PREFABRICATION

Building Details

SESSION PLAN S6 – DETAILS – INFO 1

U2

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U2 – INFILL AND PREFABRICATION

Building Details

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SESSION PLAN S6 – DETAILS – INFO 1

U2

U2 – INFILL AND PREFABRICATION

TIPS S6 BUILDING DETAILS

U2

042 Timber (P&B) Constructions: Think how to fill the Corners

When designing the dimensions and making the construction plan, take care, that there is space to infill the corners (where two walls meet). Straw bales can only be filled into cavities between posts if they have a minimum clear width of 40 to 50 cm (exception: flakes/parts of bales are filled). This is particularly important when a facade is planked beforehand for diagonal bracing. Carpenters should make the construction plan in consultation with the straw bale builder or at least have it inspected by one. Especially in the case of wall corners, as there are a lot of simple and practical details which have been developed in cooperation with carpenters, structural engineers and straw bale builders and allow the easy infill and compression of the bales in the construction.

easy infill (enough space on both sides)

cannot be infilled from inside

(round) corner needs a mesh or reed-stucco

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SESSION PLAN S2

U2 – INFILL AND PREFABRICATION

U2 Session Plan U2-S2: Hybrid Constructions (NSS) Objectives: Trainees ... know the different hybrid construction techniques and when to use them. know different structural options. know the pros and cons of different solutions. can organize building sites during the infill process ( i.e.: take responsibility to leave the building site rain- and windproof, keep strawstacks fireprotected, remove loose straw after work,…). can take responsibility for the requirements of straw building in a “normal” building routine. know the details (window, roof junction,... ) for hybrid construction techniques.

Methods:

Theory

Different structural options of hybrid construction techniques and their characteristics and bale requirements Fixing bales Compressing bales with different systems Advantages and disadvantages of hybrid construction techniques Details of connections: foundation, corners, windows and doors, roof, etc.

Preparing different surfaces for plastering Viewing and study of existing building samples

Practice

Lecture / talk Practice Explanation

Task: Working groups Preparing simple wooden frames and structures Infill straw bales in standing position (“on edge”) Compress the bales with different techniques Fixing the bales in the construction Airtight/windproof connection to a window Shaving the bales, if necessary Preparing bales/boards for plastering

Organization:

Trainer:

Place:

Workshop

Duration:

Min 1 day (7 hours)

Equipment:

Wood Screws Straw bales Tools Reed stucco

Documents:

Trainer sheet: T1 Info sheet: I1 CUT/CST I2 GREB

20 straw bales for each group Wood parts, boards and joints (screws, nails, brackets, staples) -> see material list Tools -> see tool list

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U2 – INFILL AND PREFABRICATION

Hybrid Constructions – CUT

SESSION PLAN S2 – INFO 1

U2

17

U2 – INFILL AND PREFABRICATION

Hybrid Constructions – OrganiCUT

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SESSION PLAN S2 – INFO 1

U2

U2 – INFILL AND PREFABRICATION

TIPS S2 – CUT

U2

029 Hybrid Constructions: CUT-Technique

If a surface of the straw bale wall is to be directly plastered, only one side has to be planked (and diagonally braced). Straw is a good plaster ground, wood is not.

Exposed wooden planks must be covered with a plaster ground (reed stucco, steicounder-floor, Heraklith - magnesium-bound woodchipboard, mesh). In order to save that labour, to save wood and improving the overall insulation value of the wall, in some cases it’s better to just use 1 post for planking or diagonal bracing (shear/wind forces), the other side is directly plastered. This post should not exceed 4 cm in thickness, with a maximum width of 1 8 cm. The gap in the rest of the wall is closed by good compressed straw bales (if well infilled). The post can be placed on one side of the bale, facing with the straw surface (for external planking), in the middle (for direct plastering of bales on both sides) or inside (for internal planking and installation areas). If one side is planked, the straw filling is correspondingly easier because the bale is simply pushed against the planks. If the post (1 " or 2,5 x 1 4 cm for non-loadbearing, 4 x 1 4-1 8 cm for load bearing walls) is centered, you have to take care that the bales are exactly placed near and above each other to provide a flat surface (always look on the neighboring bales). To prevent bales from slipping out in hybrid constructions (where they are not fixed between two boards), the bales have to be fixed with battens: this is what we do with the so-called CUT technique.

The name comes from „ Cells U nder Tension“ and from cutting (because we have to cut the bales on the surface to insert the batten).

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U2 – INFILL AND PREFABRICATION

TIPS S2 – CUT

U2

030 CUT-System: Smart and Versatile

In the CUT-technique, on one side of the posts, a squared timber (batten) 25 x 25 mm or 1 ” (best cut from rough, inched planks) is pressed into the surface of the straw bales so that they are fixed in the construction and cannot slip (even when directly plastered). For this purpose we first cut a section along the battens in the bale’s surface (the side of the bale with the folded halms up are easier to cut than the cut surface of the other side) with a sharp knife, grooved bread knife or electric handsaw (two blades, Alligator). The cut is widened with your fingers or our stuffer to a groove. Then the batten is inserted, manually with a 1 m board, which is pulled down on each side by two helpers, with an auxiliary tool or by standing on it) and finally fixed to the side of our CUT posts with (galvanized) 6 cm nails. For load-bearing CUT constructions, we use posts with a cross-section of 4 x 1 6-1 8 cm (4 cm is sufficient to keep the transversal-pressure low and to connect the boards with 2 cm of space on both sides of the nails. Bowing of the posts is prevented by by the nails each 47-50 cm (height of the bales in a row).

The CUT technology is really a sophisticated, versatile, smart, inexpensive and yet simple construction system that shows the straw bales at their best.

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U2 – INFILL AND PREFABRICATION

TIPS S2 – CUT

U2

031 CUT-Technique advanced: Structural Integrity with Planking

A number of tests have shown that both the load bearing capacity and the diagonal bracing of these walls by the means of the plaster surfaces (from 3 cm) is sufficient to build all types of single family houses. And the tests were not made with posts in the cross section dimensions of 4 x 1 8 cm but in the cross-section dimensions of 1 ” (2,5 x 1 4 cm).

In order to be on safe side (in the case of timber construction, we always have something oversized, and this is also a positive fact), we still recommend 4 x 1 8 cm posts for load-bearing walls and one-sided diagonal planking. If this is outside (on the façade), we install the diagonal planks at a distance of 6 - 10 cm (because for exterior side the wood is not diffusively open enough (μ value over 20)) and fill the gaps with a mixture of plaster and straw (as clay is hygroscopic, it draws moisture from the dew point area and keeps our straw bales dry. If a wooden façade is preferred, we plaster the outside with a diffusion-open 1 6 mm DWD plate (μ value approx. 8, similar to lime plaster), then a ventilation layer (min. 5 cm) and then the cladding. For many reasons (building physics, sustainability, residential health, smart design for straw bale walls, self-construction suitability, resource consumption), this externally diagonal braced CUT construction is the best construction for straw ball walls in 1 to 2-storey residential buildings.

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U2 – INFILL AND PREFABRICATION

TIPS S2 – ORGANICUT

U2

032 CUT-Technique organic: OrganiCut

Directly on both sides or on one side plastered straw bale walls can also be produced in CUT technology as vault, semicircular (dome), chain line - thus in any organic (curved) form. In this case, simply curved sections (for load-bearing walls, for example, offcuts from 4 cm three-layer panels, for non-load-bearing walls planks/posts from 24 mm cross-laminated-wood boards) are used as the posts.

Depending on the radius of curvature, the straw bales must be angled (with an electric hand saw) or the wedge-shaped gaps must be filled (stuffed) with straw.

Such curved walls or organic buildings can be covered with a separate roof (on external/internal construction posts), built as a vault in the attic space under an existing roof or covered directly with a flexible (ventilated) roof membrane (EPDM foil and green roof, flexible photovoltaic cells on EPDM shingles; see FabHouse Barcelona), wooden shingles or sheet metal and thus made rain-proof. What has previously been possible only in the concrete spraying method on metal rebars (Flying Concrete) can be produced with this technique organically and with natural building materials.

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U2 – INFILL AND PREFABRICATION

Hybrid Constructions – GREB

SESSION S2 – INFO 2

U2

25

SESSION PLAN S3

U2 – INFILL AND PREFABRICATION

U2

Session Plan U2-S3: Infill Constructions Objectives: Trainees ... know the infill construction techniques. know different structural options. know the advantages and disadvantages of this solution. can organize building sites during the infill process (i.e.: take responsibility to leave the building site rain- and windproof, keep strawstacks fire protected, remove loose straw after work,…). can take responsibility for the requirements of straw building in a “normal” building routine. know the details (window, roof junction,... ) for infill construction techniques.

Methods:

Theory

Different structural options of infill techniques and their characteristics and bale requirements Fixing bales with different techniques Compressing bales with different systems Advantages and disadvantages of infill construction techniques Details of connections: foundation, corners, windows, doors, roof ...

Preparing different surfaces for plastering Viewing and study of existing building samples

Practice

Lecture / talk Explanation Practice

Task: Working groups Preparing simple wooden frames and structures Infill straw bales in standing position (“on edge”) Compress the bales with different techniques Fixing the bales in the construction Airtight/windproof connection to a window Shaving the bales, if necessary Preparing bales/boards for plastering

Trainer:

Place:

Workshop

Duration:

Min 1 day (7 hours)

Equipment:

Wood Screws Straw bales Tools Reed stucco

Documents:

Trainer sheet: T1 Info sheet: I1 Infill construction techniques

Organization:

20 straw bales for each group Wood parts, boards and joints (screws, nails, brackets, staples) -> see material list Tools -> see tool list

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U2 – INFILL AND PREFABRICATION

SESSION PLAN S3 – INFO 1

U2 Infill (Post & Beam) Constructions

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U2 – INFILL AND PREFABRICATION

SESSION PLAN S3 – INFO 1

U2 Infill (Post & Beam) Constructions

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

033 The Length of the Straw Bale defines the Distance of the Bales

Usually, we design wooden post constructions (especially hybrid constructions like CUT walls) where it is possible according to the length of the bales and not vice versa. This does not mean that windows and doors are not planned where they guarantee the best view or the shortest path. But where a wall has no openings, we can measure the distances of the posts according to the longest bales. This ensures that the straw bales (still bound with strings) will fit completely between the posts and only the spaces/gaps between too short bales and the construction have to be filled with additional flakes. By filling additional layers, we can also compress badly pressed bales (below 90 kg / m3), which is particularly useful when the bales are directly plastered.

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

034 Straw Bale Infill: Vertical or horizontal?

Whether the bales are infilled horizontally in the wall (about 80-90 cm post spacing) or vertically (47-50 cm post spacing), doesn’t matter much for the total insulation value (including construction). The 36 cm balesd have the same direction in both mounting positions. The wood consumption is larger (and thus cold bridges: wood insulates less than half as well as straw) and often it is structurally not necessary.

The 47 or 50 cm is a fixed size (defined by the bale channel) and you don’t have to fill up too short bales with flakes. However, you are more flexible with horizontal bales on edge (all cavities of 10 to 100 cm post spacing can be filled with one or several flakes or one whole bale + one or more flakes). This means that we do not interfere with the architecture of a building. I personally regard grid dimensions of rigid 80 cm only useful for prefabricated modules (see page 1 88).

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

035 Diagonal Bracing: Withstand the Wind Forces

Timber constructions must be designed for vertical load transfer (timber dimensions, prevention of the so-called buckling). Here the loads of the building but also snow are taken by vertical posts and beams, avoiding any deflections (buckling). But building / load-bearing construction must also be stiffened against horizontal wind loads (shear forces). Diagonal reinforcement (bracing) can be achieved through 3 cm plasters on both sides (sandwich-effect), as in the case of load-bearing straw bale construction (proved by tests), but also by boards (from 1 6 mm OSB tongue & groove on the inside, 1 6 mm diffusion open DWD or Agepan tongue & groove on the outside). Other methods to withstand horizontal loads are diagonal bracing with 1 ” (2,5 cm) raw sawn planks, usually mounted at an angle of 45 ° or an inner box out of 10 cm thick KLH panels - glued cross-laminated wood (see S-House Böheimkirchen, AT). Or in case of traditional buildings e.g. diagonal beams to stabilize the connection of a post and beam (known from FachwerkConstructions), but also existing concrete or brick walls, which are the insulated on the outside (Wrapping).

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

036 Planking or Direct Plaster: Requirements to a Structural Wall

Whether the bales on both sides or on one side are directly plastered or additionally diagonally braced, depends less on the required fire protection (this can be adjusted with the plaster thickness from 3 cm from F30 to F 1 20; compare FASBA tests for fire protection, DE). It’s more depending on wind forces or the need for installation areas (electrics, water, sewage, ventilation) and the montage of e.g. kitchen shelfs. While direct plastered walls are common and thoroughly tested in (load-bearing) straw bale walls for one-to-three-storey buildings without additional diagonal bracing, the wind forces can hit facades so severly that even conventional planking is not enough. So it depends on the architect or structural engineer, where he plans and places the bracing in the construction of the building: in the plastered or planked straw bale walls, by using interior walls for structural bracing (diagonally braced post & beam, KLH, brick, concrete) or - completely separated from the outer walls braced structures usually made out of concrete (Plattenbau). In any case, carpenters naturally tend to prefer diagonal bracing from wood, masonry/brick/concrete builders rather from concrete or bricks and plasterers usually are not asked.

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

037 Plasters as diagonal bracing Layers (Sandwich-Walls)

Nevertheless, it is worthwhile to include the plaster at least in the calculation of the wind reinforcement, particularly in view of the social housing construction and its demanded production prices. No one will be surprised that both sides planked (loadbearing) straw bale walls cost twice or three times as much as directly plastered walls. Even if the entire walls of a building (without windows) are only between 1 8% (single-family house) and 10% (multi-family house) of the costs of a house, no one will ever be able to build a sustainable and ecological residential building according to the prices of Social housing without keeping all the costs as low as possible. Then we leave the field to the (chemical) industry and its lobbyists.

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

038 Wood Dimensions: Double Posts in the width of the Bales

When selecting the statically suitable wood dimension, it is important to consider constructively 4 factors: the deflection (which we want to avoid), the diagonal bracing (against horizontal wind forces), the transverse wood pressing (how far a vertical wooden post is pressed into a horizontal wooden base plate) and finally the size of the surface for the assembly of eg bracing boards or diagonal planking.

In straw bale construction we usually use post dimensions of 6 x 36 cm (or two straw-insulated double posts 1 4 x 5-6 cm) for 1 -2 storey-houses. The narrow side (5-6 cm) of the posts offers enough space (as a rule of thumb: we need 2 cm next to a nail/bracket/screw) to fix a reinforcing board or diagonal planking on it. Even if only one post (usually the inner post of the wall) bears the horizontal loads, the second post offers a possibility to mount all kinds of panels (OSB/DWD-boards, sound insulation, installation areas). Care must be taken in the condensation (dewpoint) area on the outside, to ensure that there is no air gap between the outer panel and the straw, which could lead to convection and thus to condensation. .

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U2 – INFILL AND PREFABRICATION

TIPS S3 – INFILL

U2

039 Wood Dimensions: Buckling & Compression

The deflection (buckling) is thus prevented on the one hand by the timber dimensions on the other hand by screwing / nailing of the planks and boards. Good to know that wood cannot be compressed (significantly) in the length direction. For the cross-wood pressing, 4 x 1 4 or 6 x 1 4 or 6 x 36 cm posts also offer sufficient support surfaces, so it would not be pushed into the base plate (to cause any cracks in the plaster through settling). And regarding the diagonal bracing wooden boards (1 6 mm OSB tongue & groove, 1 6 mm DWD or Agepan tongue & groove) or diagonal bracing (25 mm planks) can be used instead of the earlier used (traditional) corner timber bracings (which are situated in the insulation layer and thus create thermal bridges and make the infill much harder). The building physics requirements must also be met for the planking: outside diffusion open and windproof (in combination with the plaster surface or taping the gaps), inside air-tight (plaster).

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SESSION PLAN S4

U2 – INFILL AND PREFABRICATION

U2

Session Plan U2-S4: Prefabrication and Modules Objectives: Trainees ... know different prefabrication and modular building methods. know different structural options. know the advantages and disadvantages of these solutions. can organize building sites during infill process (i.e.: take responsibility to leave the building site rain- and windproof, keep strawstacks fire protected, remove loose straw after work,…). can take responsibility for the requirements of straw building in a “normal” building routine. know the details (window, roof junction,... ) for prefabricated walls and modules.

Methods:

Theory

Different construction options for prefabrication and their characteristics and bale requirements Fixing bales with different techniques Compressing bales with different systems Advantages and disadvantages of infill construction techniques Details of connections: foundation, corners, windows, doors, roof...

Preparing different surfaces for plastering Viewing and study of existing building samples

Practice

Lecture/talk Explanations Practice

Task Working groups Preparing wooden frames and structures Infill straw bales in standing position (“on edge”) Compress the bales with different techniques Fixing the bales in the construction Airtight/windproof connection to a window Shaving the bales, if necessary Preparing bales/boards for plastering

Organization:

Trainer:

Place:

Workshop

Duration:

Min 1 day (7 hours)

Equipment:

Wood Screws Straw bales Tools Reed stucco

Documents:

Trainer sheet: T1 Info sheet: I1 Prefab

20 straw bales for each group Wood parts, boards and joints (screws, nails, brackets, staples) -> see material list Tools -> see tool list

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U2 – INFILL AND PREFABRICATION

SESSION PLAN S4 – INFO 1

U2

Prefabrication and Modules

Kreativer Holzbau & Bauatelier Schmelz)

StrohTec + ASBN, Austria (1 999)

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U2 – INFILL AND PREFABRICATION

TIPS S4 – PREFAB

U2

040 Multystorey Residential Buildings: Prefab-Modules

Straw bale walls in the multi-storey residential buildings have usually seperate loadbearing structures (KLH boards [glued cross-laminated wood]), load-bearing brick walls, concrete columns, concrete slabs as ceilings, (encapsuled) timber posts or Fachwerk-constructions). In many cases, this load-bearing structures are already braced against horizontal wind forces. Such timber constructions can be used similar to the one to two-storey straw bale buildings. Moreover, hybrid designs such as the CUT technology are a good choice. Also Wrapping (with an external thermal straw bale insulation layer) of load-bearing and already diagonally braced KLH plate boxes can also be easily combined with (non-loadbearing) hybrid constructions to support and fix the insulation layer. In the case of increased fire protection requirements, prefabricated modules - which are covered with fire-retardant DWD/Agepan panels can also be fixed to the supporting structure. A solution is provided by an Austrian innovation (system / house / construction), which has been developed in cooperation with the ASBN: 40 cm flakes of so-called (Krone) multibales are filled between Steico posts 36 x 4.5 cm in the grid of 80 cm and outside 1 6 mm DWD, inside 1 6 mm OSB.

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U2 – INFILL AND PREFABRICATION

TIPS S4 – PREFAB

U2

041 Prefab-Module mit Ballenlagen vom Multibaler

Multibaler big bales have a cross-section of 75 x 1 25 cm and are tied up to 9times to provide thicknesses from 30 to 40 cm (or more). 2 such layers, filled into a module, incl. 4 cm base and top plate (Steico plywood) provide the dimension of 80 x 255 cm with individually adjustable insulation thickness (suitable for passive houses). The modules can be connected to each other with a flying feather (tongue) made of 4 cm softfiber boards such as tongue and groove elements. Since the insulation value of straw bales is the highest in the direction of the bale canal (through the flakes), the Austrian multibales are offered as certified construction bales (approved building material) and the filling of 2 layers between the plates (from the top with a funnel) goes quickly and easily. Similar prefab modules are also used for the highest 7storey straw ball house in St. Die des Vosges. As suspended modules in front of the load-bearing KLH construction.

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SESSION PLAN S8

U2 – INFILL AND PREFABRICATION

U2

Session Plan U2-S8: Timber Construction Objectives: Trainees ... have the ability to crosscut and connect wooden posts and beams. can fix a baseplate to the foundation, install a windowframe, make a corner and a ringbeam (for roof or intermediate ceiling). can make a production planning and production drawing of a wall with windows and doors. can make a production drawing of ceiling joists. can calculate the amount of materials needed for a timberconstruction (bill of quantities). know the details of a wall (connections foundation-wall, wallwindow/door, wall-ceiling, wall-corner-wall, wall-roof).

Methods:

Theory

Lecture/talk Explanation

Structural engineering (loads/bracing) Wood construction and wood connections Production-planning and -drawing Calculation (bill of quantities) Details Calculate the building costs (material, labour, etc.)

Trainer:

Place:

Classroom and construction site

Duration: 4 hours

Equipment:

Pen and paper Beamer Construction wood Structural boards Machines to cut wood Tools to nail and screw

Documents:

Trainer sheet T1 Info sheet I1 Timber Construction Text sheet X1

Powerpoint:

Practice

Ppt1 :

Organization:

Prepare classroom. Have different types grains talks. Two bales, prepare one in a bad condition (bad shape, high humidity, bad colour, low density, strings removed, with cereal, with herbs, short straw, etc.) and another ideal bale.

42

U2 – INFILL AND PREFABRICATION

SESSION PLAN S8 – INFO 1

U2 Timber (Post & Beam) Construction

43

44

SESSION PLAN S9

U2 – INFILL AND PREFABRICATION

Session Plan U2-S9: Regulations and Organization of Building Sites Objectives: Trainees ... know national or regional regulations relevant for straw bale constructions. know how to organize their straw bale work on a building site. know specific problems of straw bale building site organization. can organize building sites during infill process ( i.e.: take responsibility to leave the building site rain- and windproof, keep strawstacks fire protected, remove loose straw after work,…).

Methods:

Theory

Presentation Talk

Building law or regulations for straw bale building Organization of a building site (materials, tools, machines, waste, access,…)

Security measures (how to behave in case of accidents,…)

Specific problems and risks of straw bale building site organization Storage and protection of straw on the building site

U2

Trainer:

Place:

Classroom

Duration:

Min. 2 hours

Equipment:

Projector Pen and paper

Documents:

Info sheets: X1 Regulations X2 Building site

Practice

Task Short visit of a building site

Organization:

Looking for an appropiate building site in the surroundings

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46

SESSION PLAN S7

U2 – INFILL AND PREFABRICATION

U2

Session Plan U2-S7: Straw Bale Infill and Stuffing Objectives: Trainees ... know about the infill process, right density (compression) and how to avoid gaps. know various methods to compress the bale in a construction. know how to fix a bale in the construction. know how to use the tools required for the infill process (compression, cutting, infilling, stuffing). know how to stuff/fill gaps with straw or complementary insulation materials. know how to prepare the substrates for plastering and cladding. know how to coordinate the infill process with other craftsmen at the building site.

Methods:

Workshop Practice

Trainer:

Place:

Workshop

Duration:

Min 5 days

Equipment:

Straw bales Stuffing tools Cutting tools (Alligator) Compression tools Boards Construction wood

Documents:

Practice

Theory

Trainer sheet: T1

Infill, compress, fix,cut, shave,‌ straw bales and complementary insulation materials in a sample wall Make the wind and airtight connection to the straw bale wall sample Prepare the substrate for plasters and cladding Operate a controlling of the realized work (gaps, density, stability of bales, compression, surface)

Organization:

Prepare sample walls in different construction systems (hybrid, infill, prefab) Organize materials and tools

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STEP – Straw Bale Training for European Professionals UNIT 2 – Infill & Vorfertigung/Prefab (201 7) Editors/Tips: Herbert Gruber, Helmuth Santler (ASBN) Coworking: BuildStrawPro-Team (Erasmus+ Projekt) Design & Photos: Herbert Gruber (ASBN, StrohNatur), Add. Photos: RFCP, provided by Architects & Companies Illustrations/Icons: Michael Howlett (SBUK) This Handbook bases on the Handbook of the Leonardo-Team STEP (201 5)