Air Tightness Checklist

Air Tightness Checklists are a great way of ensuring good air tightness practice is being followed throughout your project. Download ours for free!

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Air Tightness Checklist

Our air tightness checklist is designed to help developers monitor air tightness throughout their project. It is intended as a guide only. Where complicated junctions are involved or where construction is being undertaken with different build systems we would advise you to seek our advise for your specific project.

For further advice or a quote for air tightness testing on your project please contact us.

Air Tightness Test


  • Ensure an solid air tightness line is defined on the construction drawings and that air tightness is discussed in the project specification. 
  • In timber construction the air tightness layer is generally the internal membrane or OSB layer, with all joins fully taped.  For masonry construction it is generally the plasterboard layer however we strongly advise that it should be the internal blockwork skin and that this skin is treated with an air tightness coating, such as Blower Proof or Passive Purple (as the blockwork itself is not air tight) with all joins at floors, ceilings and openings/penetrations fully sealed. 

First Fix

  • Seal the perimeter of the floor
  • Seal any joins in the floor such as beam/block joins or floorboards
  • Seal joist penetrations (or use joist hangers where possible)
  • Seal any pipework or cables which penetrate walls or floors
  • Seal cavity closers and window and door frames against the wall construction
  • Masonry Construction: Point the internal blockwork skin or ideally coat blockwork in an air tightness product such as Blowerproof or Passive Purple
  • Timber Frame Construction: the vapour control layer should form a continuous airtight barrier – ensure all laps and joins are fully taped with a high quality air tightness tape. We recommend Pro Clima tapes such as Pro Clima Vana Air Tightness Tape
  • Structurally Insulated Panels (SIPs): this building system can lead to great air tightness test results however many self builders believe the system is air tight in design and that they do not need to worry about air tightness – it is important to ensure that all panels are fitted together carefully and an air tight seal is created – we recommend Pro Clima tapes for this. 
  • Seal perimeter of plasterboard ceilings prior to fitting plasterboard walls
  • When installing plasterboard with the dot and dab method ensure it is installed with solid lines of adhesive along top, bottom and sides of each room and around service penetrations in line with the British Gypsum installation guide.
  • Seal any pipework or cables which penetrate walls or floors
  • Ensure the soil stack is sealed around the perimeter where it enters floors and ceilings

Tip: Many builders seal the bottom of plasterboard (before skirt is fitted) with expanding foam as an extra air barrier. Where doing this we recommend low expansion foam.

Second Fix

  • Seal any joins in intermediate floor construction and around staircases
  • Fit skirting board behind your kitchen units and baths – seal the top and bottom prior to units being fitted
  • Seal pipework where it penetrates plasterboard prior to installing sanitary ware and kitchen/bathroom units and then double check seals (that you can still access) are still in place once everything is fitted
  • Seal around windows and doors (including door thresholds)
  • Seal top and bottom of skirting boards with suitable caulk/sealant
  • Ensure the loft hatch is fitted well with all seals in place and seal around the perimeter
  • Seal around the cooker hood ductwork and boiler flue where it penetrates the wall/ceiling
  • Ensure door seals and threshold strips are fitted
  • Patch any damage to plasterwork
  • Fit loft lids to spotlights where possible (seal in place with mastic sealant)

Our air tightness checklist is designed to be used as a general guide by site management throughout the build. It is also useful to hand out to trades and display in the site office/canteen areas. A printable version can be found here