[week 12] building the prototype

System designs 3 and 4 will be mechanical tested because of some adjusments from existing roof systems.

system design 3
It will be made of straw board attached to the soft wood flanges with natural glue.


Figure 12.1, axonometry of system design 3

For a specimen scale 1:2 (35x180x4500 mm) will be needed:
- straw board 6x200x4500 mm
- soft wood 2x 2335x4500 mm
- glue 2x 4.5x25 grams



Figure 12.2, preperation for a scale model 1:2 of system design 3

system design 4
It will be made from only wood and other natural materials.

Figure 12.3, section of system design 4

For a specimen scale 1:1 (75x275x2000 mm) will be needed:
- soft wood 3x 75x275x1200 mm
- soft wood sub beams 50x50x1000 mm


Figure 12.4, testing a scale model 1:5 of system design 4

[week 11] LCA comparison

Now the system design options are determined they can be compared with a Life Cycle Assessment.

1. steel

	weight		E costs
Steel coated, corrugated	8.60	kg/FE	0.02	(eur/year)
glass wool 150	7.50	kg/FE	0.01	(eur/year)
VAPOUR BARRIER	1.00	kg/FE	0.00	(eur/year)
corrugated steel filling	10.92	kg/FE	0.12	(eur/year)
Steel beam Hea 260	8.35	kg/FE	0.10	(eur/year)
gypsum board 12mm	1.56	kg/FE	0.02	(eur/year)
total	37.93	kg/FE	0.28	(eur/year)

Figure 1, life cycle and sub cycles of steel beams.
1.1 life time

The durable materials will make a longer life of components possible. A technical life of 105 years is realistic with components that last three building uses. The total environmental effects will be divided over this technical life for the effects per year.

1.2 construction strength

If the bay distance is two meter, than 260 mm high beams are sufficient.

1.3 thermal insulation

The 150 mm glass wool results in an Rc value of 4. 1 m2K/W.

2. steel-wood

Wood shingles 2x 9 mm	8.64	kg/FE	0.01	(eur/year)
plate straw 18	8.1	kg/FE	0.01	(eur/year)
glasswool 280	14.00	kg/FE	0.02	(eur/year)
VAPOUR BARRIER	1.00	kg/FE	0.00	(eur/year)
plate corrugated	9.00	kg/FE	0.18	(eur/year)
steel C360/100/38 x 2,5mm	12.21	kg/FE	0.14	(eur/year)
			0.00	(eur/year)
total	52.947	kg/FE	0.35	(eur/year)

2.1 life time

disassembling possible for reuse: yes

lifetime: 2 building uses = 70 years

Only the wood shingles should be replaced after one building use.

2.2 construction strength

The steel C profiles are spanning the building every meter.

thickness	2.5 mm
dimensions	C360/100/38 mm
dead+live load	1.5 kN/m2
bending moment	15.2 kNm	< mmax =" 24">

2.3 thermal insulation

The FlexFrame system can fit the criteria if the insulation is thick enough. Because the steel profiles form linear cold bridges of 2.5 mm every meter the thickness of insulation has to be double of the thickness without the cold bridges. Together with 18 mm straw board and wood shingles on top there will be a heat resistance of 4.1 m²K/W.

3 laminated beams

An m² of roof consists of

EPDM-membrane 1.14 mm	1.41	kg/FE	0.05	(eur/year)
plate straw 18	8.64	kg/FE	0.01	(eur/year)
flax wool 140	7.00	kg/FE	0.02	(eur/year)
FJI joists	4.93	kg/FE	0.03	(eur/year)
Vapour barrier	1.00	kg/FE	0.00	(eur/year)
batters 38x50 /1,2m	0.7125	kg/FE	0.00	(eur/year)
gypsum	1.56	kg/FE	0.06	(eur/year)
	25.25	kg/FE	0.17	(eur/year)

3.1 life time

Technically these materials could be reused after 35 years. But this would need more labour than new materials. That is why only one building use is prognosed.

3.2 construction strength

If the bay distance is 0.3 m, than 380 mm high FJI-beams are sufficient.

3.3 thermal insulation

The FJI-beams are negligible as cold bridge. The space in between can be used to place 140 mm flax wool insulation that results in an Rc value of 4. 0 m²K/W.

3 wood joints

4 solid wood

[week 10] final design

Elements of the structure:

Bay of the structure: