Green Building Forum - Cellulose as cavity fill Tue, 25 Aug 2026 11:34:09 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Cellulose as cavity fill https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306607#Comment_306607 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306607#Comment_306607 Wed, 28 Aug 2024 03:20:11 +0100 wookey
Is it to do with slumping over time because it's relatively heavy?

I recall that for filling timber cassettes they wet it to make it 'stick' in place (even when dried out again - papier-mache style).

The bag also says it is not suitable for blowing, which also seems odd. This stuff is routinely blown into timber cassettes isn't it?

I do like the way it comes as a compact and quite solid block which you have to break up in a box with a paint-stirrer.

I couldn't find a supplier of glassfibre 'bits' fill at all. I could find EPS balls but I'm not a huge fan of those as they tend to escape. And there was plenty of mica, but that's quite poor insulation.]]> Cellulose as cavity fill https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306612#Comment_306612 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306612#Comment_306612 Wed, 28 Aug 2024 11:06:22 +0100 djh https://www.thermofloc.com/en/info/good-to-know/faq which says: "THERMOFLOC can not be used for cavity wall insulation in every country. Please contact our office for detailed information about building regulations in your country." That implies it's a legal issue.

I'd imagine if it is possible in this country they'd want to blow it in to avoid slumping as you say. I can't see any reason it wouldn't work (modulo slumping) if you DIY, but my thought is worth what you paid for it :)]]> Cellulose as cavity fill https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306620#Comment_306620 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306620#Comment_306620 Wed, 28 Aug 2024 22:10:32 +0100 Mike1 Posted By: wookeyIs there any reason not to use cellulose fluff in cavities?
No doubt the main issue would be a high risk of deterioration, or worse, due to damp. It's startling to see how much water can run down the inner face of the external leaf in heavy rain.]]> Cellulose as cavity fill https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306622#Comment_306622 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18181&Focus=306622#Comment_306622 Thu, 29 Aug 2024 03:57:07 +0100 wookey