Dwellings Part L1 Compliance

If your dwelling test result is higher than 5 m3/(m2.hr) @ 50 Pa then you are getting penalised and making Part L compliance much more difficult.

The minimum standard for air-permeability is 10 m3/(m2.hr) @ 50 Pa HOWEVER in the real world, you will require significantly lower air-permeability targets to achieve a pass when this figure is entered into SAP. The air-permeability rate used in the 'notional building' is now 7 m3/(m2.hr) @ 50 Pa. i.e. if your dwelling test result is higher than 7 m3/(m2.hr) @ 50 Pa then you are getting penalised in the SAP calculation and making your Part L approval more difficult.

The new Part L1: 2010 only requires a sample of each dwelling type to be tested - although the sample sizes required has increase substantially. Testing should be carried out on three units of each type or 50% of each type, whichever is less.

HOWEVER any dwelling units which are not air tested will be 'penalised'! ALL non-tested dwellings will have +2m3/(m2.hr) @ 50 Pa added to the average result of sample testing for that dwelling type. Therefore, the results of sample tests can never be worse than 8m3/(m2.hr) @ 50 Pa.

If Gladwood carry out your SAP calculations and air testing together this gives more flexibility when it come to completion testing. We can check the ‘as built’ SAP on site in conjunction with the air test result and can make adjustments if required to achieve a Pass where possible.