From building plan to SIP panels: panel grid, junctions, calculation and bill of materials
How a request for a house in SIP panels runs through FlowCraft: the architect's plan, a 3D model with the panel grid, the junctions to the system's details, the calculation of wall, floor and roof, the heat loss and the bill of materials.
FlowCraft automates entire business processes, from the request that comes in to the invoice that goes out. For a builder working with SIP panels, that starts with the architect’s plan.
How a request runs
The same house as in the video, step by step.
1. The architect’s plan comes in
A request comes in by email, with the plan as a PDF. The platform reads the floor plans of the ground floor, the first floor and the attic, the section and the four elevations. The section gives the floor levels and the 40-degree roof pitch; the elevations give the height of every window and door.
2. A 3D model with the panel grid
On the plan, the 3D model of the house grows on the existing basement. Then the grid of SIP panels goes onto the walls and the roof.
Panel width, maximum length, thickness and joint rule are settings. At 1.20 m wide and up to 5.80 m long, every opening gets a joint on both sides and the roof a joint halfway up. The floors are I-joists with an OSB deck; the roof rests on a ridge beam and one purlin per slope.
3. The junctions, as the system’s details prescribe
Floor and wall meet the way the system detail prescribes. The I-joists bear on the SIP wall, the deck runs to the outer face of the panel and the first-floor wall stands on that deck (SIPA BEST 2, Fig. 15). The facade leaf of facing brick and cavity stands on the basement wall and runs past the floors without a break to the underside of the roof; the hollow-core slabs run under the SIP wall up to the facade leaf.
Three system rules apply to this house. The floors are I-joists, because a 230 mm SIP floor deflects too far over 6 m. Attic: a hung floor against the eaves wall (SIPA Fig. 16), the wall bevel-cut up to the underside of the roof panel (Fig. 17); at the attic the floor therefore stops at the wall’s inner face. The roof rests on a ridge beam and a purlin at the joint halfway up each slope, in GL24h on posts above the first floor’s load-bearing walls.
4. In the BIM viewer
The section along the line of Section AB sits beside the architect’s drawing. Every part is an element: every panel, every I-joist and every beam. You click it and see its size, system, weight and where it sits on the plan.
5. The calculation of wall, floor and roof
A finite-element analysis on the real parts. The wall panel beside the door takes the wind and the load of roof, wall and floor edges. The I-joist floor spans 6.1 and 4.4 m over three supports; the roof panel spans 3.77 m from purlin to ridge beam.
At 600 mm centres, SJL 45 and SJL 60 do not reach the 8 Hz natural frequency. The platform chooses SJL 90 300 at 600 mm centres, and SJL 45 240 at 600 mm for the attic.
| Check | Result |
|---|---|
| SIP wall, deflection under wind (limit H/300) | 2.2 ≤ 9.3 mm |
| SIP wall, compression in the OSB skin | 0.62 ≤ 11.6 N/mm² |
| floor SJL 90 300 at 600, w_inst imposed (L/300) | 9.3 ≤ 20.3 mm |
| floor, natural frequency | 8.8 ≥ 8 Hz |
| floor, point load 1 kN | 1.08 ≤ 1.5 mm |
| floor, moment · shear per joist | 10.7 ≤ 15.4 kNm · 4.6 ≤ 9.9 kN |
| roof panel, deflection (limit L/300) | 9.0 ≤ 12.6 mm |
| purlin · ridge beam GL24h 140 × 240, bending | 9.9 · 11.2 ≤ 15.4 N/mm² |
| post under the ridge beam, buckling | 1.9 ≤ 5.5 N/mm² |
Wind to EN 1991-1-4 (26 m/s, terrain II), checks to EN 1995-1-1, joist values from STEICO (ETA-06/0238). The OSB deck is not counted as composite.
6. Heat loss and cooling load per room
With the U-values of the build-up, the platform calculates the heat loss of every room to EN 12831-1. For the summer, EnergyPlus calculates the cooling load on a design day in Brussels, with the front facade facing north-west.
| The house | |
|---|---|
| heat loss (outside −8 °C) | 4,798 W |
| cooling load, peak | 6,262 W |
| heating demand per year | 5,188 kWh |
| cooling demand per year (26 °C) | 2,288 kWh |
| U external wall · pitched roof · window | 0.12 · 0.12 · 1.1 |
| Heat loss per room | |
|---|---|
| living area and kitchen (20 °C) | 1,661 W · 24.1 W/m² |
| study (20 °C) | 212 W · 23.7 W/m² |
| entrance hall and stairs (18 °C) | 318 W · 15.9 W/m² |
| toilet (18 °C) | 29 W |
| shower (24 °C) | 210 W |
| bedroom 1 (18 °C) | 223 W · 13.4 W/m² |
| dressing room (18 °C) | 73 W · 7.3 W/m² |
| bedroom 2 (18 °C) | 214 W · 14.2 W/m² |
| bathroom (24 °C) | 603 W · 34.5 W/m² |
| utility room (18 °C) | 145 W · 12.5 W/m² |
| bedroom 3 (18 °C) | 228 W · 20.7 W/m² |
| landing (18 °C) | 201 W · 8.8 W/m² |
| attic (16 °C) | 963 W · 9.3 W/m² |
Outside −8 °C (NBN EN 12831-1 ANB), 309 m² heated floor area.
7. The bill of materials
The bill of materials comes from the same model as the calculation: every panel with its size, thickness, area, weight and the openings cut out of it, and every joist and beam with its length.
| Part | Count · quantity |
|---|---|
| wall panels ground floor, 230 mm | 80 · 120.6 m² |
| wall panels first floor, 230 mm | 57 · 96.9 m² |
| wall panels attic, 230 mm | 24 · 40.8 m² |
| roof panels, flat roof of the rear extension, 230 mm | 9 · 33.2 m² |
| roof panels, pitched roof, 230 mm | 46 · 168.1 m² |
| I-joists first floor, SJL 90 300 at 600 mm | 30 · 230.8 m |
| I-joists attic, SJL 45 240 at 600 mm | 25 · 206.4 m |
| deck OSB/3 22 mm | 224.2 m² |
| purlins and ridge beam GL24h 140 × 240 | 3 · 30.7 m |
| posts GL24h and bevelled wall plates | 8 · 0.35 m³ |
| panels net · gross | 459.6 · 482.2 m² |
| panels volume · weight | 105.7 m³ · 11.2 t |
Net is the panel itself after its cut-outs, gross the rectangle it is cut from. The flat roof of the rear extension spans the short way in SIP panels, up to 4.5 m.
Design values and sources
What the plan does not show, the platform calculates with these values. Each of them is a setting.
| SIP panel | Idelco α-therm SIP 230 mm, U 0.12 W/m²K; 1,200 mm wide, 1,500 to 5,800 mm long; OSB skins 2 × 15 mm, PIR core G 3.0 N/mm² (design values) |
| floors | STEICOjoist (ETA-06/0238): first floor SJL 90 300 at 600 mm, attic SJL 45 240 at 600 mm; OSB/3 22 mm; dry screed 0.35 kN/m² (design value); joist zone filled with mineral wool (assumption) |
| roof | ridge beam and purlin GL24h 140 × 240 (Binderholz, EN 14080) on posts 140 × 140; fv,g,k 3.5 N/mm² and wind on the roof cpe +0.7 (design values) |
| junctions | SIPA BEST 2, Basic SIP Design and Engineering: platform-framed floor (Fig. 15), hung floor (Fig. 16), bevel-cut wall (Fig. 17), wall plate on a square-cut wall (Fig. 18). System rules of this house: I-joist floors; attic: a hung floor against the eaves wall (SIPA Fig. 16), the wall bevel-cut up to the underside of the roof panel (Fig. 17), so at the attic the floor stops at the wall’s inner face; roof on a ridge beam and purlins. |
| base | facade leaf of facing brick and cavity on the basement wall (top −0.40); the hollow-core slabs run under the SIP wall up to the facade leaf and bear 260 mm on the 400 mm basement wall (assumption) |
| roof planes | at the ridge and in the valleys every roof panel is cut vertically on the ridge or valley line, so two panels meet in one joint; this holds for roof planes of the same pitch (assumption) |
| panel grid | vertical at 1.20 m, with a joint on both sides of every opening; roof from eaves to ridge, joint halfway up on the purlin |
| insulation | PIR Idelco α-therm SARKING XTRA λ 0,022 |
| wind and snow | EN 1991-1-4: 26 m/s, terrain category II · EN 1991-1-3: 0.5 kN/m² |
| floor | imposed load 2.0 + 0.5 kN/m² (EN 1991-1-1); deflection L/300, natural frequency ≥ 8 Hz, point load 1 kN ≤ 1.5 mm (chosen limit) |
| heat | inside 20 °C living area and study, 24 °C bathroom, 18 °C other rooms, 16 °C attic; thermal bridges + 0.05 W/m²K |
| windows and ventilation | windows U 1.1 and g 0.5; balanced ventilation with 85 % heat recovery; airtightness n50 1.5 h⁻¹ |
| summer | EnergyPlus, design day Brussels 29.0 °C, cooling to 26 °C, no solar shading; front facade facing north-west |
Does this fit the way you work?
How does a building plan become a panel list at your company today, and how much time does that take? We are glad to come and see you about it. Half an hour is enough to see whether this fits. Book a conversation.