Green Building Forum - Expanding Foam or Tape around new windows? Mon, 27 Jul 2026 20:43:21 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300834#Comment_300834 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300834#Comment_300834 Mon, 20 Mar 2023 18:34:29 +0000 Devlin
I should be having some new double glazed uPVC windows installed in about 1.5 months. I know if left to their own devices the installers will do the bear minimum - ACME expanding foam round the edges and finish with a trim. I want a better job done so been looking at alternatives. One of them is this expanding foam which is a little pricey:

https://www.partel.co.uk/product/conpreseal-3v-bg1/

Alternatively this expanding foam doesn’t look too bad:

http://www.soudalairtight.com/INT/raam_schuim.html

Has anyone used any of these products or similar? Is it worth spending the £130 on the expanding foam tape when this expanding foam will do?

Thanks]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300842#Comment_300842 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300842#Comment_300842 Tue, 21 Mar 2023 08:27:59 +0000 tony Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300844#Comment_300844 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300844#Comment_300844 Tue, 21 Mar 2023 09:09:26 +0000 fostertom Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300848#Comment_300848 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300848#Comment_300848 Tue, 21 Mar 2023 09:36:31 +0000 Peter_in_Hungary Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300850#Comment_300850 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300850#Comment_300850 Tue, 21 Mar 2023 10:29:34 +0000 revor Posted By: fostertomHe's not talking sticky 'sellotape' but Compriband-style expanding gapfilling tape.

I have not found this type of tape to be able to withstand exposed conditions. Continuous driving rain in very strong wind saturates the tape which then acts like a downpipe and directs water downwards until it finds a weak spot. It is great to get a nice clean finish between opening and frame but I had to put behind it a silicon bead supported on polyethylene rod of appropriate diameter for the gap. Internally gun applied expanding foam for the internal gap.
Make sure the installers mechanically fix the windows and not rely on the foam to hold in place. It is part of the regs.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300856#Comment_300856 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300856#Comment_300856 Tue, 21 Mar 2023 11:40:39 +0000 Mike1 Posted By: Peter_in_HungaryWhat is the advantage of expanding foam tape as opposed to the usual squirty foam ?
Posted By: revor
I have not found this type of tape to be able to withstand exposed conditions. Continuous driving rain in very strong wind saturates the tape which then acts like a downpipe and directs water downwards until it finds a weak spot. It is great to get a nice clean finish

It does provide a clean finish. Another advantage, when used with timber windows, is that it is air-permeable so it avoids trapping moisture behind an imperfect mastic seal where it may promote decay (not a problem in this case with PVC). However it does need impermeable vertical and horizontal trays behind it to drain water away safely.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300861#Comment_300861 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300861#Comment_300861 Tue, 21 Mar 2023 12:03:37 +0000 fostertom
We talked before (but can't find it now - anyone?) about
Posted By: revorContinuous driving rain in very strong wind saturates the tape which then acts like a downpipe and directs water downwards until it finds a weak spo
and
Posted By: Mike1does need impermeable vertical and horizontal trays behind it to drain water
and I thought a way emerged to escape that risk/mitigation.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300863#Comment_300863 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300863#Comment_300863 Tue, 21 Mar 2023 12:19:24 +0000 djh Posted By: Devlinhttp://www.soudalairtight.com/INT/raam_schuim.html
Is that a genuine site? Why is it taking Javascript from the w3schools.com website? Why is the product illustrated - "Flexifoam" - not listed on https://www.soudal.co.uk/pro/products ?]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300865#Comment_300865 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300865#Comment_300865 Tue, 21 Mar 2023 13:51:24 +0000 borpin
To clarify from the OP, is this inside or outside sealing, air tightness or weather proof?

External, My reveals are rendered but I used a stop bead so that there is a gap of about 15mm between the stop bead and the frame. This was filled with EDPM expanding foam tape. Very watertight works a treat (10 years old now).

Internally and airtightness, I suspect you will need to do more. I'd be inclined to ask them to leave the inside unfinished and finish it myself. Soudal Flexifoam is wonderful as it expands but does not push against what it finds. Make sure that is what you get as it looks like it isn't as readily available as it was (it is blue) and there may be products purporting to be it around. https://youtu.be/xH8SfIooXYo]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300870#Comment_300870 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300870#Comment_300870 Tue, 21 Mar 2023 15:07:17 +0000 djh Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300879#Comment_300879 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300879#Comment_300879 Tue, 21 Mar 2023 21:37:25 +0000 ChrisinYorkshire Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300880#Comment_300880 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300880#Comment_300880 Wed, 22 Mar 2023 07:14:47 +0000 borpin Posted By: djhSoudafoam Window & Door SWSYes that seems to be the stuff. Good find.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300911#Comment_300911 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300911#Comment_300911 Thu, 23 Mar 2023 09:17:55 +0000 Davey P I believe a critical stage in the installation is to get the butt joints correct so they expand up to each other tight. Not personlly used it yet but I will be shortly.
I'm planning on using it in conjucntion with Souda window and door behind as above. My experience with gun foam is that you really need to pay attention to the instructions and thoroughly remove dust (I blow out with a compressor) and then damp down prior to application. It's especially important on masonry to ensure proper adhesion otherwise you may find it pulls away over time. I've watched quite a few tradesmen applying foam and have yet to witness one following instructions as above. Some of them have been very pedantic about their joinery but seem blissfully ignorant of how to use foam. If you want it doing right............]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300927#Comment_300927 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300927#Comment_300927 Fri, 24 Mar 2023 10:27:18 +0000 Mike1 Posted By: fostertom
We talked before (but can't find it now - anyone?) about
Posted By: revorContinuous driving rain in very strong wind saturates the tape which then acts like a downpipe and directs water downwards until it finds a weak spo
and
Posted By: Mike1does need impermeable vertical and horizontal trays behind it to drain water
and I thought a way emerged to escape that risk/mitigation.
This one: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17655]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300933#Comment_300933 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300933#Comment_300933 Fri, 24 Mar 2023 16:17:42 +0000 fostertom Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300937#Comment_300937 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=300937#Comment_300937 Fri, 24 Mar 2023 18:36:14 +0000 Nick Parsons Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309332#Comment_309332 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309332#Comment_309332 Sun, 21 Sep 2025 13:25:22 +0100 Victorianeco
Aluminium or aluminium-clad windows going onto an external skin of a cavity wall
EWI to follow

What would be the best way to ensure air tightness of the fit?]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309334#Comment_309334 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309334#Comment_309334 Sun, 21 Sep 2025 15:47:03 +0100 djh Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309335#Comment_309335 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309335#Comment_309335 Sun, 21 Sep 2025 16:43:27 +0100 LF Think about cavity closures and insulating reveals in case external insulation bypassed b6 cold somehow. I used air tightness tape too.

I used compriband expanding foam tape for upvc this summer but put good silicon seal on outside on advice from builder, some gaps were too small to tape. I would just flexifoam in future.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309336#Comment_309336 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309336#Comment_309336 Sun, 21 Sep 2025 17:28:48 +0100 Victorianeco
A link to a proven standard detail or similar would be greatly appreciated]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309337#Comment_309337 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309337#Comment_309337 Sun, 21 Sep 2025 20:19:27 +0100 djh Posted By: LFsome gaps were too small to tapeI don't understand this. How can a gap be too small to tape?]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309338#Comment_309338 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309338#Comment_309338 Sun, 21 Sep 2025 20:24:21 +0100 djh Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309339#Comment_309339 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309339#Comment_309339 Sun, 21 Sep 2025 22:19:35 +0100 Victorianeco
If we go Ali I will leave to the fitters who have said they will seal up with EPDM

CWI will be done by subcontractors

EWI will be done by my team to board and then get a silicone render specialist in]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309340#Comment_309340 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309340#Comment_309340 Mon, 22 Sep 2025 07:54:02 +0100 LF
I am talking about compriband foam gap filler not air tightness tape.

My experience from retrofitting in brick cavity 1950s was flexifoam on its own would likely have been enough. Wooden frames and new build likely different.

Retrofitting windows and changing opening sizes and adding lintels in outer brick course, cutting g out bricks that were spanning cavity around the reveal. High quality triple glazed upvc, sides a not flat, some areas had 2 layers of 5 mm tape some 1 layer.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309342#Comment_309342 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309342#Comment_309342 Mon, 22 Sep 2025 11:02:35 +0100 djh Posted By: LFI am talking about compriband foam gap filler not air tightness tape.Ah, sorry. I don't think of Compriband as tape.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309376#Comment_309376 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309376#Comment_309376 Wed, 01 Oct 2025 08:58:58 +0100 fostertom Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309384#Comment_309384 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309384#Comment_309384 Wed, 01 Oct 2025 11:38:58 +0100 djh Posted By: fostertomOK, so what about Compriband-type expanding-strip sealant? I guess, at the right thickness, it's good when continuously clamped, even to say a roughcast render surface. What about the practicalities/effectiveness of applying it around all four (or maybe three) sides of a window reveal (whether masonry or timber) before quickly putting the window into place before the strip expands?AIUI, normal practice is to put the window in place first, and then put the Compriband in the gap before it expands.]]> Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309389#Comment_309389 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309389#Comment_309389 Wed, 01 Oct 2025 13:20:02 +0100 fostertom Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309396#Comment_309396 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309396#Comment_309396 Wed, 01 Oct 2025 18:22:55 +0100 Victorianeco Expanding Foam or Tape around new windows? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309397#Comment_309397 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17788&Focus=309397#Comment_309397 Wed, 01 Oct 2025 19:11:24 +0100 fostertom