Part F

Thermal building regulations for Northern Ireland

The Part F 2012 Revised Building Regulations introduced tougher standards for the carbon performance of new buildings – with an aim to reduce carbon emissions by 25% over the previous standard.

Our range of ROCKWOOL stone wool products can help you comply with Part F.


A tougher standard...


Design stage calculations 

Submission of a design stage calculation and specification list to Building Control Bodies before construction begins is now mandatory. (Previously only the as-built calculation was a requirement.


Party walls

Party walls, plus their associated thermal bypass heat losses, must be included in your calculations. You need to insulate and seal party wall cavities or use solid walls to match the notional building.


Thermal bridges

The Accredited Details Scheme ensures that developers only claim enhanced benefits in SAP modelling by using approved accredited construction details which have actually been used. (0.08 for accredited construction details is no longer an option.)


Swimming pools

New indoor swimming pools require a U-value for the basin walls and floor which should be no worse than 0.25W/m²K.


Air permeability

Part F 2012 requires double the number of pressure tests to meet compliance. Generally a value between 5.0 & 7.0 m3/(hm2) will need to be achieved. 15.0m3/(hm2) can be used in small developments but will tend to require further improvement of the thermal envelope.


Thermal mass

The heat capacity of the external and internal building fabric is used in the calculation of TER and DER results, so you must define the internal walls, floors and ceilings along with any party walls. Increasing the effective thermal mass reduces the need for heating and cooling, but the rules for calculating heat capacity mean that items such as internal dry-lining, thermal lining and lightweight constructions will reduce your effective thermal mass.


Fabric limits

The area weighted U-values are maximum values and unlikely to be low enough to comply with CO2 emissions requirements.