Scotland


Scotland Building Standards for Flat Roofs

 

New Domestic Buildings

New Domestic Buildings (Dwellings) – Technical Handbook Section 6 Energy

 

The Scottish Technical Handbook for Domestic Buildings looks at the entire building’s performance and CO2 emissions, rather than isolating one particular element. All domestic buildings must be designed and built so their individual Dwelling CO2 Emissions Rate (DER) is no worse than the Target CO2Emissions Rate (TER).

The TER is generated from a package of measures set for each main heating fuel type; if buildings are constructed following the full package, then it is likely that the DER will meet the TER. As a simplified approach, the dwelling can be considered to reduce CO2 emissions to the same level. CO2 Emission Rates are calculated using a calculation methodology called SAP (Standard Assessment Procedure) 2012.

The area-weighted average U-value for flat roofs, taken from the Notional Dwelling specification (used to set the TER target), is 0.11 W/m2K

Existing Domestic Buildings

Existing Domestic Buildings (Dwellings) – Technical Handbook Section 6 Energy

 

For existing domestic buildings, the Scottish Technical Handbook provides specific U-values based upon the particular element (walls, floors and roofs) that is being replaced, renovated or for extensions and conversions. There are different requirements for new elements (extensions or conversions) and the Technical Handbook should be referred to for details on these.

The target flat roof U-value for existing dwellings or new elements are:

 

For replaced or refurbished roofs:                  0.13 W/m2K*   /  0.18 W/m2K**

New elements (extensions):                            0.13 W/m2K*   /  0.18 W/m2K**

 

*Where U-values for wall and roof of the existing dwelling are poorer than 0.7 and 0.25 respectively

**Where the above wall and roof U-values do not apply

 

New Buildings

New Buildings other than Dwellings – Technical Handbook Section 6 Energy

 

Matching the requirements for new domestic buildings, the Scottish Technical Handbook sets a Target CO2 Emissions Rate (TER) for non-domestic buildings based on Notional Buildings that the individual Buildings CO2 Emissions Rate (BER) must meet. The TER is generated from a set of Notional Buildings; if buildings are constructed within these parameter values their BER should meet the TER. CO2 Emissions Rates are calculated using the Simplified Building Energy Model (SBEM).

The actual specification required for a compliant building and necessary building fabric U-value targets may vary depending on the actual overall proposed specification and the outcome of the energy assessment.

The area weighted average U-value for flat roofs, used in the Notional Building specifications for setting the TER, are:

 

Heated + natural ventilation:   0.18 W/m2K

Mech. ventilated / cooled:      0.16 W/m2K

Shell and fit only:                  0.15 W/m2K

 

Existing Buildings

Existing Buildings other than Dwellings – Technical Handbook Section 6 Energy

 

The Scottish Technical Handbook sets specific U-values based upon the particular building element (wall, floor or roof).

 

The target U-value for flat roofs on existing buildings other than dwellings are:

 

For replaced or renovated roofs in previously heated buildings:     0.25 W/m2K

New elements (extension) or previously unheated buildings:          0.15 W/m2K

 

Large extensions should be treated as a new build.

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The figures and information quoted are for guidance only.  Official Building Regulation / Standard documentation should always be consulted.

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