How to comply with Building Regulations and Standards using SIPs

19 May 2015
How to comply with the building regulations & standards using SIPs

The use of SIPs (structural insulated panels) can be a straightforward route to building regulation compliance as one thickness of insulation can achieve compliance across England, Wales and Scotland.

SIPs typically feature a highly insulated core sandwiched between two layers of oriented strand board (OSB). The panels are designed and cut to each project’s specification, minimising onsite adjustments and waste.

With England, Scotland and Wales all suggesting slightly different approaches to reducing carbon emissions, and setting different targets for new dwellings, we must either accept the additional cost of tailoring constructions for each region, or run the risk of non-compliance.

We must either accept the additional cost of tailoring constructions for each region, or run the risk of non-compliance.

We have modeled three build ups for a two-storey detached house in SAP 2012:

  • SIP roof and wall panels
  • Timber frame with mineral fibre insulation
  • Full fill masonry with mineral fibre insulation

England & Wales

 

Specification 1:

172 mm SIPs for Walls and Roof

Specification 2:

Timber Frame with Mineral Fibre

Specification 3:

Masonry Full Fill with Mineral Fibre

Wall U-value (W/m2.K) 0.16 (365 mm) 0.16 (460 mm) 0.16 (453 mm)
Roof U-value (W/m2.K) 0.15 (281 mm) 0.15 (464 mm) 0.15 (464 mm)
Airtightness (m³/m²/hr @ 50 Pa) 3.0 7.0 7.0
Thermal Mass Low (100) Low (100) Medium (250)
Thermal Bridging 13.364 (y=0.033) 22.665 (y=0.055) 22.665 (y=0.055)
Additional Measures MVHR, standard central heating pump in heated space, 180 litre boiler fed water tank. Natural ventilation with 5 fans, standard central heating pump in heated space, weather compensator, 180 litre boiler fed water tank, waste water heat recovery. Natural ventilation with 5 fans, standard central heating pump in heated space, weather compensator, 250 litre boiler fed water tank, 55 litre solar storage, waste water heat recovery.
TER 17.01 17.01 17.08
DER 15.80 16.98 17.07
TFEE (England Only) 64.60 64.60 64.60
DFEE (England Only) 54.30 59.80 62.50

The modelling found that the improved airtightness and thermal bridging achieved with SIPs limited the need for costly renewables, which are often required when building with masonry and timber frame. The SIP option was also much thinner than the other options, allowing for space savings to be made internally.

Scotland

  Specification 1 Specification 2 Specification 3
Additional Measures MVHR, A rated central heating pump in unheated space, weather compensator, 180 litre boiler fed water tank, 0.75 peak kW photovoltaics Natural ventilation with 5 fans, A rated central heating pump in unheated space, weather compensator, 180 litre boiler fed water tank, 1.40 peak kW photovoltaics, waste water heat recovery. Natural ventilation with 5 fans, A rated central heating pump in unheated space, weather compensator, 180 litre boiler fed water tank, 1.40 peak kW photovoltaics, waste water heat recovery.
TER 12.30 12.30 13.65
DER 12.20 12.20 13.54

SIPs can offer an ‘out-of-the-box’ route to compliance. SIPs can achieve a much lower air-tightness value than that proposed by the notional dwelling specifications. The proprietary jointing system can create a very air-tight structure with air leakage levels as good as 0.07 air changes per hour at normal pressures. SIPs also achieve improved linear thermal transmittance values due to the continuity of insulation at junctions and openings.For Scotland, the stricter CO2 targets of the 2015 building standards did require the use of a PV array. However even here the SIP specification achieves the joint best DER with a smaller, cheaper PV array.

The proof is in the building.

Kingspan Insulation Ltd

Pembridge

Leominster

Herefordshire

HR6 9LA

General enquiries: 01544 388 601

Technical advice: 01544 387 382

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