Domestic air leakage testing from
ATTMA registered test engineers
ATTMA registered test engineers
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Seal holes around pipes and cables where they penetrate the fabric. Where several service penetrations occur together leave sufficient space between each service pipe / cable to be able to fully seal around them.
Even gaps / holes within the internal fabric (intermediate floors and partition walls) should be filled, as it is likely these will be leakage points for external air that has worked its way around the fabric.
Eaves access doors separate the heated dwelling from an unheated space and should be treated as external doors. It is prohibited for these doors to be temporarily sealed for an air leakage test.
To create an effective air barrier the doors should be draught stripped and fitted with a robust latch. Ineffective or missing seals and the absence of a robust latch can be the primary cause for failing an air leakage test.
It is very common for gaps / holes in the fabric to be concealed behind fitted units, such as fitted kitchens, fitted wardrobes and fitted bathroom units. All gaps / holes / unfinished surfaces should be permanently filled prior to the units being installed as retrospective remedial work can prove challenging.
Blockwork walls are permeable and if untreated will not create an effective air barrier. The use of wet plaster, rather than plasterboard, will make the walls air tight. Alternatively blockwork walls should be treated with a scratch coat (or parge coat) of plaster prior to the application of plasterboard. There are also specialist paint products available that will create an air tight seal.
Drylining is notoriously susceptible to air leakage. Ensure that the plasterboard is continuous (i.e. there are no holes behind fitted units, sinks/baths, etc). When drylining directly on to an external wall the plasterboard should be mounted on ribbons of plaster or adhesive around all the edges rather than dabs. Ensure the joints between boards are sealed and the plasterboard is correctly detailed at joints, corners, reveals and window sills.
It is not recommended that mastic and caulking be relied upon as a permanent air tight seal. The passage of air flow should have been tackled prior to this last line of defence. For example, all gaps / holes / unfinished surfaces that may be present underneath a bath should be permanently filled prior to the bath panel being installed and mastic being applied. However, as it is unlikely that every gap / hole will have been identified and filled the application of mastic and corking throughout the house will undoubtedly result in a better result.
It is very common for gaps and holes to be concealed behind carpenters boxing. This can pose a problem if the boxing itself does not create an air tight seal. All gaps / holes within the fabric should be permanently filled prior to carpenters boxing being installed.
Air that has been free to gather and pass behind plasterboard will likely enter the dwelling at skirting level (as well as through plug sockets, etc). Ideally air flow should be restricted from freely passing behind plasterboard by applying continuous ribbons of wet plaster around each board and applying a flexible mastic behind the skirting. Any areas of missing skirting, for example behind kitchen units, will likely leave a significant gap through which leakage will occur.
If plasterboard has not been effectively sealed then gaps at the base of skirting will need to be filled with mastic or caulking.
Where downlights are to be installed, they should be in place prior to the air leakage test being carried out. Holes in ceilings where downlights are yet to be installed cannot be temporarily sealed for an air leakage test.
The type of downlight installed can have a significant affect on air permeability rates. Downlights that are completely sealed to the room and fitted tightly within the ceiling will have little or no detrimental impact. Downlights that are vented to the room or a type that tilt will result in higher air permeability rates if not sealed within the ceiling void, for example through the addition of downlight thermal hoods.
Loft hatches should be installed prior to the air leakage test and cannot be temporarily sealed. Where possible specify loft hatches that have been specifically rated as airtight. In all other cases ensure the loft hatch is draught stripped and creates a tight fit with the ceiling.
Pocket sprung doors can pose a significant issue when it comes to an air leakage test. The doors will need to be open for the duration of the test and any gaps allowing air to flow from the cavity cannot be temporarily sealed. To create an effective air barrier brush based draught excluders should be installed to fill any gaps.
Lift shafts are usually ventilated to the outside. Lift doors should be treated as external doors and cannot be temporarily sealed during an air leakage test. For an effective seal, fire rated lift doors should be specified. Alternatively the lift doors can be thermally separated from the dwelling through the addition of a second, air sealed door.
It is very common for gaps / holes / unfinished surfaces to be concealed behind boilers, cylinders and MVHR units. Plant cupboards must not be temporarily sealed during an air leakage test. All gaps / holes / unfinished surfaces should be permanently filled prior to the plant being installed as retrospective remedial work can prove extremely challenging. Plant cupboard doors should be draught stripped and fitted with a robust latch.
Plug sockets should be fitted prior to the air leakage test being carried out. Holes in walls where plug sockets are yet to be installed cannot be temporarily sealed for an air leakage test.
Where plug sockets are to be located within drylining there should be a continuous ribbon of plaster or adhesive around the hole cut into the plasterboard.
Sliding sash windows are notoriously susceptible to allowing air leakage. If sash windows are to be a predominant feature in the dwelling design, then compensatory measures should be taken to allow for a high target air permeability rate, or sash windows that have been certified as air tight should be specified.
How Energytest can help
ATTMA registered – As registered members of the Air Tightness Measurement Association you can rest assured that our air leakage test certificate will be accepted as evidence for Building Regulations sign-off.
EXPERIENCE – Our air test engineers have experience of carrying out successful air leakage tests on buildings of all types and sizes.
SUPPORT – For added piece of mind our air test engineers will be happy to assist you with free advice throughout the construction process.
RELIABLE – Building Regulations sign-off is often time-constrained and stressful. We shall attend site at a time that is convenient for you and provide certificates within 24 hours of the test.
SAFE – Like you, we take health and safety seriously. All of our engineers are CSCS certified.
SINGLE-SOURCE-SOLUTION – As well as your air leakage test we can provide:
What our clients say:
“RI Design and Build have been using Energytest over the past 4 years to carry out air leakage testing and creating EPC’s on all our new build projects.
The staff and service we receive is always professional and to the highest standards from the pre-testing to final inspections.
I would have no hesitation in recommending their services and continue using them in the future.”
S Osborne – RI Design & Build
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