From £203.57 + VAT per 50m x 1.5m roll

Variable vapour control membrane – Ampatex Variano – 1.5m x 50m

Ampatex Variano variable vapour control layer is:-

  • an innovative, highly tear resistant fleece membrane that changes permeability according to humidity.
  • finished with a smooth surface ensuring tapes bond incredibly well.
  • perfect for ensuring the correct moisture flow through building structures with Sd ranges from 0.8 – 60m.
  • an easy to use membrane for providing a continuous internal air tightness layer.
  • used as part of our internal wall insulation and flat roof insulation strategies.

Product overview

Where is it used?

  • Ampatex Variano is used on the underside of unventilated flat roof constructions. It is what makes the whole structure stay dry.
  • On the inside of timber frames/dry lining or on the inside of pitched roof structures.
  • Can be installed from the outside of roof structures during refurbishment.

How is it used?

  • Ampatex Variano variable vapour control layer 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 INT 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.

How much will you need?

Each roll of Ampatex Variano variable vapour control membrane is 50m long and 1.5m wide. It covers an area of 70m2 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.

Is a variable vapour control layer better than a fixed value one?

Not necessarily, different membranes are suitable for different applications. These membranes open up at high humidity levels to allow moisture to come back into the building. This function is not always necessary or desirable.

What are its properties?

  • The Sd value of the membrane varies between 0.8m and 60m. The measurement are made in dry-cap- and in wet-cap-measurements. All measurements are made at a fixed temperature of 23°C and hereafter you’ll find each 4 measurement-results for the relation of RH- to sD-value:
    • RH 3% fixed: sd-value 60.0m
    • RH 3% to 30%: sd-value 57.6m
    • RH 3% to 50%: sd-value 35.3m
    • RH 3% to 80%: sd-value 10.2m
    • RH 50% to 75%: sd-value 4,2m
    • RH 70% fixed: sd-value 2.45m
    • RH 50% to 95%: sd-value 1.3m
    • RH 95% fixed: sd-value 0.9m
  • The tear resistance is good at 180N/5cm.
  • Operating temperatures are between -40 and 80°C

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]
501.5759070.8 – 60m£226.19£203.57

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If you can’t seem to find what you need on our website or you have large quantities of materials to purchase please contact us for a chat and we’ll offer you a more bespoke solution.

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