Paint-on- airtightness….really…….are you kidding?

Read on or watch the video below to see how it works


Airtightness is the fundamental building property relating to infiltration (the uncontrolled leakage of air through cracks, interstices or other unintentional openings of a building, caused by pressure effects of the wind and/or stack effect) often exacerbated by  poor design, poor quality construction, bad choice of materials and a failure to work with an holistic approach. The whole purpose of having a workable definition of, and testable levels of, airtightness is so we build better, more durable, healthier, energy efficient houses.

In the UK the Building Regulations are there to provide minimum standards describing airtightness as ‘…the resistance of the building envelope to infiltration with ventilators closed. The greater the airtightness at a given pressure difference across the envelope, the lower the infiltration.’  Defined as air leakage rate per hour per square metre of envelope area at a test reference pressure differential across the building envelope of 50 Pascal (50 N/m2). In the UK current Regs stand at 10 m3/ (m2h) is not a high standard and is usually met by draught-proofing and the use of mastic. A score below 3 m3/ (m2h) is reckoned to be pretty good. The gold standard of low-energy house building – Passive House – requires an airtightness score of just 0.6 m3/ (m2h).

Any product that can improve the security of airtightness, is long lasting, inexpensive, and versatile that requires low skill levels to apply is therefore potentially a winner when it comes to helping UK builders get a buildings performance down from 10 m3/ (m2h). This is not only for new build but importantly in refurbishment. Blowerproof is a proven way to create a permamant secure airtight seal it  has been used extensively across much of Europe, from Estonia to Portugal,  where legislation is a key driver for constantly improving airtightness standards. It has never been widely available in the UK before, however we have been supplying a number of customers with Blowerproof for several months and the feedback we have garnered is extremely positive and reflects the significant usage across mainland Europe as a key tool for those seeking to meet ever more stringent airtightness targets. Blowerproof is a wet applied airtightness membrane used for sealing wall/floor, wall/ceiling joints, penetrations and window jambs. There are two types: a brush version (more thick, fibre reinforced) and a spray version (more liquid) both currently undergoing BBA certification.

Blowerproof is:-

  • Simple to apply
  • Quick to apply
  • Can be applied on humid surfaces
  • Only one product needed for all applications
  • Easy application for electrical lines/pipes for example on a floor/wall connection -see photo
  • Can also be applied direct onto mineral wool insulation
  • Can be applied on polyurethane foam, mainly on window jambs.
  • Highly resistant to puncture
  • Thoroughly tested over many years

dsc_5423_2Blowerproof is a wet applied airtightness membrane for sealing wall/floor, wall/ceiling joints, penetrations and window jambs. There are two types: a brush version (more thick, fibre reinforced) and a spray version (more liquid) both are available un-pigmented (white) or pigmented (blue, drying to black)

Our feedback from users in the UK over this summer suggests that this represents a significant change in the way we make buildings airtight. Spray and paint application broadens the potential to achieve better results, by helping eliminate installation errors.

dsc_5490_2Blowerproof is quick to apply over a wide range of substrates using only one product plus the bonus of solving ‘tricky’ and ‘difficult to reach’ applications such as joist ends, kicker joints and penetrations.

Test reports that are available in English for the following

  • Adhesion on varied surfaces, dry and humid, before and after ageing
  • Elongation and tensile strength, before and after adhesion
  • Damp tightness before and after ageing
  • VOC test report (M1 - done in Finland)
  • Fire test report about fire propagation and fire droplets (done by Warrington/Exova)
  • Project test reports about airtightness, incl. Post occupancy after several years
  • Airtightness after ageing on floor/wall connection; ageing simulated by vibrations accelerated testing

As UK construction moves towards ever improving airtightness standards this will definitely be a product to watch.

Find out more by clicking here where you will find published technical details plus a host of references many with videos /pictures of the installation.