From £138.31 + VAT per 50m x 1.5m roll

Vapour control and airtightness membrane – Ampatex DB 90 

Ampatex DB 90 vapour control and airtightness membrane is:-

  • a BBA certified, highly tear resistant fleece membrane, with an Sd value of 20m, that regulates the moisture flow through walls, roofs and floors.
  • finished with a smooth surface ensuring tapes bond incredibly well.
  • perfect for ensuring the correct moisture flow through building structures using vapour open and vapour closed insulation materials.
  • an easy to use membrane for providing a continuous internal air tightness layer.

Product overview

Where is it used?

  • On the inside of timber/metal frames/dry lining, on the inside of roof structures or on the top side of floors.
  • Can be installed from the outside of roof structures during refurbishment.

How is it used?

  • Ampatex DB 90 vapour control membrane can be bonded, using Ampacoll DT double sided tape, to the underside of rafters or the inside of timber studs prior to being boarded over or counter battened.
  • If using on the inside surface of wood fibre insulation boards, apply Ampacoll Primax primer and Ampacoll DT double sided tape to the surface at regular intervals to allow the membrane to be bonded to the surface.
  • Once each row of membrane is in place simply tape the joints with Ampacoll XT airtightness tape.
  • All joints should overlap by at least 100mm and the perimeter should be sealed prior to counter battening or being over boarded with plaster board.
  • Once the joints are taped it forms an air tight, moisture regulating layer.
  • Any penetrations, such as joists, pipes, cables or ducts should be sealed with Ampacoll BK 535 penetration sealing tape.

How much will you need?

Each roll of Ampatex DB 90 vapour control membrane is 100m long and 1.5m wide. It covers an area of 140m2 accounting for overlaps.

Frequently asked questions

Do I need to tape the joints?

Yes, you should always tape the laps, usually with the Ampacoll INT or the XT tape. This ensures the air tightness of the membrane and that it functions correctly to reduce moisture flow through the walls from the interior.

What are its properties?

  • The Sd value of the membrane is 20m which is fairly high for a vapour control membrane. However, it makes it ideal when OSB has been used on the outside as a sheathing board as it maintains the correct vapour diffusion gradient across the wall.
  • Ampatex DB 90 is also waterproof so can be used when refurbishing a roof from the exterior.
  • It has good tear resistance, 160N/5cm

Technical details

Pricing & shipping

This product is on a 1.5m long roll and will be sent by courier, costing around £20 + VAT

Roll length [m]Roll width [m]Roll Area [m²]Membrane weight [g/m²]Roll weight [kg]Sd value [m]Single roll cost [£]3+ rolls [each]

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