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Blowerproof Liquid 'Brush' - A Paint On Airtight Sealing Membrane (5kg)

Blowerproof Liquid 'Brush' - A Paint On Airtight Sealing Membrane (5kg)

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Blowerproof Liquid 'Brush' is a VOC free, water based, flexible, fibre reinforced, polymer providing a unique and sustainable solution for the production of airtight building connections in both new build and retrofit.

Ecomerchant Blowerproof Liquid Brush

The water based polymer is brush applied to create an uninterrupted air and vapour -tight seal around penetrations, and for floor / wall connections, wall / ceiling joints, and roof connections

Blowerproof liquid creates a seamless, continuous air and vapour -tight seal over cracks and gaps. Because the seal perfectly follows the contours of the substrate and in combination with the high flexibility and superior adhesion, the connections remain airtight over the long term. Blowerproof liquid is the fast, flexible and durable solution for all airtight connections.

Ideal for sealing

  • Service penetrations, pipes, cable, ducting etc
  • Floor to wall junctions
  • Ceiling to wall junctions
  • Window / door jambs
  • Steel decks

Blowerproof Liquid  Brush comes in a re-sealable 5kg tub. Allow up to 1kg per square metre on highly porous surfaces for non porous surfaces allow 750grams per square metre. Also available as Blowerproof Liquid Spray - please call for the spray version.

One 5kg tub will cover approximately 83 linear metres at 75mm wide.

Price is per tub

Ecomerchant Blowerproof BBA Logo

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Blowerproof Liquid Brush is a fibre reinforced paste designed for application with a brush,

NB. There is also a spray version for larger / commercial projects. If you have a larger project the spray version may be your best option, please call us for pricing on our applicator service

Ecomerchant Blowerproof liquid brush Liquid Proof Blower Brush Benefits

Versatile for use on a wide variety of building materials like concrete, stone, wood, metal, aluminium, insulation, EPDM, etc. *
Suitable for new buildings and renovation
Seamless and secure even with difficult connections
Quick and easy application
Moist surfaces are no problem
Can be over plastered, rendered or painted
Fully water-borne
Blowerproof Liquid Brush is an optimal product for materials of different coefficients of expansion
Extensively tested for adhesion and elasticity

Material: waterborne polymer paste reinforced with fibres

Colour: Blue colour changes to black as drying is completed

Consumption:  between 0.75 and 1.0 kg / m² (about 1.0 mm in thickness) dependednt on substrate porosity

Substrates: bricks, blocks, concrete, stone, wood, metal, aluminium,  insulation , EPDM, etc. *

Extensibility: 380 % (at 0.6 mm dry film thickness )

Crack bridging > 2 mm ( 0.6 mm dry film thickness )

Diffusion resistance number: 76 854 μ

Storage time : 1 year ( in unopened packaging )

Storage temperature : between 5⁰C and 20⁰C

* Adhesion Reports available on request

Ecomerchant Blowerproof liquid Brush

General application guidance

  • Remove dust and loose particles; remove surface contaminants which may affect adhesion. Treat blemishes; fill holes and cracks ≥3 mm
  • Do not apply when (surface) temperature < 5 ° C
  • Blowerproof Liquid Brush is ready for use, do not dilute with water or solvents; briefly mixing with hand mixer
  • Use a square brush
  • Apply thick enough to ensure air-tightness; indicative consumption: 1.0 kg / m²
  • Avoid during the drying phase contact with any kind of water, other liquids or construction chemicals
  • Cleaning Material: immediately after use with water
  • At least 24 hours to 48 hours to dry before applying another material on the dried - black - finish. (During drying, the colour changes from blue to black).

PLEASE NOTE.Blowerproof must form a continuous unbroken layer of minimum 1mm depth. Check by eye or use a dry film gauge before testing or permanently covering.

Typical Applications

Pipes & Penetrations

Ecomerchant Blowerproof Liquid BrushNumerous energy test reports, performed at the end of a construction project, show that pipe penetrations are in many cases a cause for not obtaining the requested level of airtightness.
For the airtight sealing of pipe penetrations: first plug gaps wider than 5mm with Blowerptoof Gap Filling Mortar or polyurethane foam around the pipe penetrations; then apply 2 layers of Blowerproof Liquid Brush with a flat paintbrush; in all cases, apply a sufficient, well-covering layer to guarantee airtightness.

Window jambs

Ecomerchant Blowerproof Liquid BrushApply a protective tape at max. 5 mm from the side of the profile. This tape needs to be removed shortly after finishing the application of Blowerproof Liquid Brush.  


Floor to Wall

Ecomerchant Blowerproof Liquid BrushIn order to obtain a sufficient airtightness of a building, it is important to make the floor/wall connections on the inside of a building airtight. 

Blowerproof Liquid is an airtight coating which is sprayed with an airless spray device on these floor/wall connections. The substrate must be dust free, solid and free from large cracks or gaps before starting the application. Holes and joints need to be plugged beforehand: large holes and joints (> 5mm) can be repaired with a fast setting cement based product or polyurethane foam, small holes and joints (2-5mm) can be sealed with Blowerproof Liquid Brush.

For larger projects Blowerproof Liquid can be sprayed with an airless paint spray device; this fast application method allows applying up to 300 linear meters per day. See more  by clicking on the 'More Info' tab above

For smaller projects, such as private houses, Blowerproof Liquid Brush can be used with a flat paintbrush, suitable for water based products. Apply in two coats; second coat must only be applied when the first coat is completely black.

Wall to Ceiling

Ecomerchant Blowerproof Liquid BrushThe wall/ceiling connections also need to be made airtight, this can be problematic when the surfaces are of two different types of material such as red brick/concrete or steel/concrete. Different construction materials react differently to changes in humidity and temperature, which can lead to small cracks in plaster or another type of finishing, and so creating air leaks. 

For wall/ceiling connections, both spray and brush applied products can be used: 

Blowerproof Liquid sprayed with an airless paint spray device (1 layer) or Blowerproof Liquid Brush which is applied with a paintbrush in two layers. Apply in two coats; second coat must only be applied when the first coat is completely black.

Reports - see downloads by clicking on the 'download' tab above

  • WTCB test reports available, incl. ageing:
  • Damp diffusion resistance factor 
  • Adhesion tests on Aerated concrete blocks, red brick and concrete brick; dry and humid substrates
  • Adhesion tests on OSB and MULTIPLEX; PVC, aluminium, metal, EPDM
  • Adhesion tests of plaster on Blowerproof Liquid coating
  • Elongation at fracture: 250 @ 350%
  • Elongation/tensile strength 120% elongation;  42 N/50mm tensile strength


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    Blowerproof Liquid comes in three forms, the brush applied fibre reinforced paste as described in the previous pages, a slightly more liquid version for roller application called Blowerproof Liquid Roller and as a spray version which is only available via our application service

    We only sell the brush and roller versions online, the spray version is typically applied by a professional applicator.

    Blowerproof is a new product to the UK; throughout Europe the application of a spray airtightness membrane is a common way of achieving the high standards of airtightness enshrined in their building regulations so this product has a huge number of references and case studies including detailed post occupancy monitoring.

    If you have an application that might benefit from the speed and efficiency of Blowerproof liquid spray please get in touch by calling 01793 847 444

    A couple of questions?

    Q. What is the difference between the brush version and the liquid one?

    A.  The Brush version is reinforced with micro fibres the liquid version has no fibres and is slightly less viscous (thick)


    Q. Can I apply Blowerproof myself or do I need a professional?

    A. Blowerproof Brush (which comes in a variety of packaging and sizes) is designed for use by builders, self-builders and competent DIY’ers. The spray applied version requires a professional applicator


    Q. How do I apply Blowerproof?

    A. Follow the instructions in the application guide, basically it is a simple brush-on product similar to using a very thick paint. Use a synthetic bristle brush. For window surrounds, awkward or tricky places, penetrations and gaps locate using the cartridge version and then finish with a brush.


    Q. Why is Blowerproof described as blue/black?

    A. The colour of Blowerproof is a pale blue, when exposed to air the curing process turns it black, this menas you know when a full cure (seal) has been reached. When applying in two coats, for example on concrete blocks, apply the second coat when the first is black that way you avoid the chance of ‘brushing off’ the first coat but importantly its easy to see where you have already painted on the second coat – it will be blue.


    Q. Are there any other colours?

    A. Yes there is a white version specifically used where the topcoat will be plaster and a the black would show through.


    Q. Can I use Blowerproof to seal gaps ?

    A. Yes, especially by using the cartridge,  use a standard skeleton gun to locate a bead of Blowerproof in the gap, no more than 5mm deep, a second bead can be applied when it has cured.


    Q. Can I use Blowerproof to joint boards?

    A. Yes, apply as a bead and push the boards together, ensure a minimum of 2mm is left for the Blowerproof, clean down the board face with a scraper or spatula.


    Q. What can you put over the applied product?

    A. Pretty much anything from paint to plaster, render or dry lining


    Q. How do I know the product will work?

    A. Years of testing and use throughout Europe plus a full BBA certification mean absolute peace of mind


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