As PU is one of the best insulates available in the world, it means that, in comparison to other construction systems, the PU SIP is one of the thinnest panels available, achieving the best u-values. As the technical standards become more demanding (lower u-values), then wall thicknesses are increasing to accommodate more and more insulation. These larger wall constructions require more structure, materials, and subsequent cost. This larger wall build up also has more layers with a greater chance of error.
SIP comes in a variety of panel thickness, and some standard u-values are listed below. To achieve a better u value just select the appropriate thickness.
Insulated splines can be used as fixings between wall panels, reducing the amount of cold bridging. SIPit have a unique detail that can completely omit cold bridging. The panels are then fixed with PU adhesive/screws which create a very strong, and airtight structure.
The Polyurethane is an injected foam core with a conductivity λ 0.023w/mok (aged k)
SIPit Panel u-values:
SIPit 95 = 0.27W/m2K SIPit 195 = 0.12W/m2K
SIPit 120 = 0.21W/m2K SIPit 220 = 0.11W/m2K
SIPit 145 = 0.17W/m2K SIPit 245 = 0.10W/m2K
SIPit 170 = 0.14W/m2K
Example U-value Calc:
195 Roof Panel
U-value = 0.12 (W/sq.m/K)
The construction has the following layers:
Thickness (mm), Conductivity (K), Resistance (R)
mm K R
Internal surface resistance 0.1
1 Gyprok Wallboard (12,5mm) 15 0.19 0.079
2 unventilated air layer 150 0 0.16
3 vapour control layer 1 0 0.001
4 OSB 11 0.13 0.085
5 polyurethane board (30 Kg/m3) 173 0.023 7.522
6 OSB 11 0.13 0.085
7 breather paper 1 0 0.001
external surface resistance 0.1
*No interstitial condensation present.
For more information to design your buildings with a lower u-value with thinner wall panels contact info@sipit.uk
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