Expanding tape (compriband or similar) or not

[dnoble]

Having some conflicting advice on what to use round windows from window supplier and carpenter.

 

Rationel triple glazed alu-clad timber frames going into an MBC timber frame SIPS house. 

 

Should I get expanding tape to fill the gap (22mm tot, or 11mm each side hopefully if everyone's measured correctly), or just use sealant and expanding foam in from the back (cheaper and possibly simpler to do, especially on the big windows).

 

Also do I need a DPM under the base of the window as well as the folded in breather membrane?

 

Any advice appreciated

 

Dan

[Russell griffiths]

Personally in any timber frame structure I would want to form a fully sealed pan/tray type afair, look on you tube lots of examples 

just a piece of damp course will be no use without having fully sealed corners

you should also look at having a slope on the timber frame to allow any water run off to shed outwards. 

 

If you look at some of the vids there is one train of thought throughout, at some time you will get water Ingres, so you need a form of protection. 

[ProDave]

In our case (stick built timber frame) the builders made the window openings 50mm bigger in each dimension. They then lined the window openings with 20mm PIR insulation, fitted the windows, and foamed the remaining very small gap.  The air tight membrane taped to the windows on the inside.

 

Outside, cladding in Wood Fibre, Compriband was used to seal the wood fibre to the windows.

[Onoff]

Did two DG windows recently. Foamed the first and used Compriband on the second. Imo Compriband all day long. Better "seal", less mess, more flexible over time compared to cured foam. 

[JamesP]

Our windows recently fitted. They fixed  Compriband to the frame  prior to install and then added foam after from the inside. 

Works well.