Sat, 02 May 2026 09:59:53 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304325#Comment_304325 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304325#Comment_304325 Tue, 21 Nov 2023 14:54:06 +0000 SarahLW
Hoping you wonderfully knowledgeable people can make sure I can repair holes in my eps, with silicon render.

I recently changed my internet provider and to cut a long story short I have just realised that I now have two holes in my external wall insulation through to the brick where a m8 screw has been stuck in (wiggled around a lot) and removed.

Should I just use expanding foam and cut off any that expands out the hole?


Also any recommendations for new fixings in future, on research I can see two options.

Heavy duty, drill a hole through insulation and into the brick behind insert some sort of tube to protect the insulation and then a normal fixing into the brick behind. I found the following products

tube only by swifix at the ewi store
https://ewistore.co.uk/shop/external-wall-insulation/swifix-single-tube-fitting-pack-of-10/?attribute_colour=White&mh_matchtype=&mh_keyword=&mh_adgroupid=&mh_network=x&gad_source=1&gclid=CjwKCAiAx_GqBhBQEiwAlDNAZpLww1VdfaqRNOE1fxY1w6Ga0Hh4aUwqlZcLFtxPBmXToj6uQfOXihoCoTYQAvD_BwE
Or
complete solution by Fischer Thermax
https://www.fischer.co.uk/en-gb/products/fixation-on-etics-insulation/fixing-in-substrate/thermax-8-and-10/stand-off-installation-thermax-8/45682-thermax-8-120-m6-2

They both also do a screw-in plastic grip for things like cable ties that only goes into the eps.

Has anyone used either system and got any feedback?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304326#Comment_304326 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304326#Comment_304326 Tue, 21 Nov 2023 15:34:58 +0000 Peter_in_Hungary Posted By: SarahLWShould I just use expanding foam and cut off any that expands out the hole?
Yes, that is what I have done but added a bit of left over thin film render over the top to protect the foam. (It degrades in sun light without covering).

The fixings into EWI or through EWI to the bricks very much depends upon the weight to be supported. e.g. cable fixings and an outside light I have used EWI fixings (but IMO the light was about the limit) Gutter down pipe I fixed through to the real wall. For the down pipe I just used a long enough pipe support screw with a normal plastic rawlplug through to the wall.

I can't get excited about any additional heat loss due to the occasional fixing through to the wall.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304341#Comment_304341 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304341#Comment_304341 Wed, 22 Nov 2023 13:04:10 +0000 sgt_woulds
If it helps I have a document I send out for EWI fixings suggestions.

Loadings are based on woodfibre density so need to be checked with manufacturer.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304393#Comment_304393 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304393#Comment_304393 Sat, 25 Nov 2023 11:44:04 +0000 SarahLW https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304416#Comment_304416 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304416#Comment_304416 Wed, 29 Nov 2023 11:01:01 +0000 sgt_woulds
The mastic leaves a permanent flexible bond and consolidates any crumbly edges in the render.


A couple of things I've learned using these nylon spiral fixings:

1) Make sure whatever you fix will cover the large plastic screw head as otherwise, it can look a bit rubbish.

2) If fixing into woodfibre EWI pre-drill with a smaller bit and use a hoover to clear the hole

3) Expect the first screw you put in the grind up the thread against the render on the way in.
Chuck it away and use another one. Never attempt to get a duff nylon fixing all the way in - they WILL jam.
They can be a right pig to get out again when they jam.

4) Buy twice as many fixings than you actually need due to point 3.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304704#Comment_304704 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18031&Focus=304704#Comment_304704 Thu, 21 Dec 2023 02:19:16 +0000 wookey
For fixings I've used a lot of fischer FID50s into woodfibre (not EPS) and they are pretty solid. They are holding up my soil pipe and drainpipes, and a plastic block onto which an outdoor tap is mounted. They will not be as good in EPS as it's much less strong but may still be adequate. There is a FID100 version which of course holds better.

I second sgt_would's advice to use some goop under the head as it is screwed in. I've been using coloured silicone that matches the render which works really well. I would use coloured modified silane goop but have not found any suppliers doing a decent range of colours for that yet. I have not had any trouble with the render damaging the fixings. I have silicone render - perhaps others are thicker/gravellier? I did not need to pre-drill either. (That will depend on your board density).

I've not yet used any stand-off fixings that go all the way through to the wall (because the FID50s work so well) , but either of the suggestions you posted seem fine and would be the sort of thing I'd pick should I need to attach something sufficiently heavy/loaded.]]>