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Weber Saint-Gobain - Official website of the company


Please see below for a list of Weber's most frequently asked questions. We hope that you find this information helpful.



How thick does the insulation board need to be?

Boards are available in thicknesses from 40mm - 200mm, in 10mm increments. The thickness of board is determined by the U-value required. We can work this out for you, please contact Weber for more information on 08703 330070 or email technical(at)

What will the U-value be?

Weber can work out the U-value and condensation risk for you based on the whole wall build up.  You can find a generic U-value calculation table in the EWI Refurbishment Guide but a full analysis is recommended.  Please contact Weber for more information on 08703 330070 or email technical(at)

Can I insulate timber frame externally?

No. Timber frame requires a ventilated and drained cavity and therefore any external insulation is giving no thermal benefit.

See weberend MT

How many fixings do I need?

The number of fixings depends on the substrate and the fixing methodolgy of the chosen system. See relevant specification sheet.

How deep do the fixings need to go in?

The depth of the fixings is dependant on the substrate and the required pull out load. Contact our technical services department for advice quoting the project name and address, call 08703 330070 or email technical(at)

Can EWI systems be repaired?

Yes - please consult your Operating & Maintenance manual. 

How do I fix components such as a rain water pipe or signs to an EWI system?

Any fixings must be anchored back to the substrate, not the applied EWI system. Care should be taken not to compress the system and with this in mind, percussive drilling should not be used. Mastic seals should be applied so as to avoid water ingress, these should then be checked periodically to ensure the efficacy of the seal.

What type of insulation is incorporated in the system?

There are various types of insulation: webertherm EPS (expanded polystyrene) webertherm MFD (mineral wool) webertherm PHS (phenolic) and webertherm PIR (polyisocyanurate).

What finishes are available?

You can choose from scraped texture, spray roughcast textured, light ashlar finish, synthetic finish, dry dash aggregate, brick effect or authentic brick slips.

What temperatures can I apply the materials in?

Generally, cement based materials can be applied between 5°C and 35°C.  Freshly applied materials should be protected from excessive temperature (either very low or very high), direct rain and rapid drying conditions. Common to all cementitious materials, inclement weather or long periods of dampness will encourage the phenomenon of efflorescence (commonly know as lime bloom).