Anglia Air Testing Advice Page


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In this advice section we will point out some of the most common leakage points and advise on how best to minimise their impact on the air tightness of a building. The first thing to point out is that you are not expected to build a completely air tight house, There will be a maximum level of permeability built in to your SAP calcs; the highest figure that can be put in to the SAPs is 10 cubic metres per hour. it's also worth mentioning that a dry lined house will never be as air tight as one that is wet plastered but it is perfectly possible, with attention to detail, to obtain a good result when dry-lining.
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	It is important to seal in floor joists to avoid air coming in from the wall cavity. Using joist hangers can be preferable.
	Ensure that the ceiling is well sealed to the wall, using coving also helps. When dry lining it is important to ensure that there is a constant ribbon of adhesive all the way around each board and that there is plenty of adhesive around any holes cut for sockets etc. Similarly light fittings should be well sealed into the ceiling, some types of down lighters need particular attention.
	Fit all the socket and switch faces fitted before the test.
	Pipe work should be well sealed in where it enters the room through the wall or floor. Use expanding foam to fill in the gaps such as under the kitchen sink as pictured here, also in the bathroom basins and under the bath. Just fitting the bath panel without sealing around the pipes will not usually be enough.
	The toilet waste is a common place for leakage to occur. Ensure it is well sealed around and, if surrounded by boxing or units, seal it first as boxing alone is not usually enough. Ensure that all traps are filled with water before the test.
	Pipes to radiators need to be sealed around, as shown here coming through the floor boards on the first floor. If the pipes are coming through the wall behind the rad, don't forget to seal before fitting the radiator to save potential hassle later.
	Window and door frames will need to be well sealed in. UPVC windows and doors will tend to perform better than timber, but if they are well made and fitted there is no reason why wooden types cannot be used.
	This picture shows the use of expanding foam under the window frame to make a good seal before the window board is fitted.
	It is important to make sure that the window and door frames are well sealed both inside and outside. The gap under this sill may cause some leakage.
	Silicone sealant has been used here under the French door frame.
	Window trickle vents should be tightly fitted and closed for the test. Some of the more flimsy type of trickle vent which screw to onto the frame can be a weak point, the best vents are the integral types. Any closeable vents will just be closed for the test, it is not permitted to seal them further by taping over for example. Only vents which do not close can be temporarily sealed with tape.
	A proper loft hatch should be fitted before the test. Wooden or plastic hatches are fine if they are a good, tight fit.


Anglia Air Testing Ltd, Clayland House, 1 Norwich Road, Watton Norfolk IP25 6DA Tel: 01953 880999 Fax: 01953 889960 Email: sales@angliaairtesting.co.uk Registered in England 5896479 VAT Reg. 892843773 Registered Office: 102 Prince of Wales Road, Norwich, Norfolk, NR1 1NY All photographs on this site are the copyright of Anglia Air Testing Ltd