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			<title>Green Building Forum - Insulating a century-old cavity wall construction</title>
			<lastBuildDate>Tue, 14 Jul 2026 16:59:26 +0100</lastBuildDate>
			<link>https://www.greenbuildingforum.co.uk/newforum/</link>
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		<title>Insulating a century-old cavity wall construction</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1341&amp;Focus=15484#Comment_15484</link>
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		<pubDate>Tue, 04 Mar 2008 14:59:18 +0000</pubDate>
		<author>jules</author>
		<description>
			<![CDATA[We have moved into a converted barn/stable which is about 100 years old, and which appears to have a cavity wall. The brick walls are over 30cm thick, and have sets of air bricks along the bottom (above the DPC) and above the windows on the ground floor. A stick inserted into the airbrick hits a solid surface at about 17cm.<br /><br />We are about to do the place up, and I'm thinking about insulation. For one room in particular, which is exposed on 3 sides (7m, 5m, 7m), internal insulation would be feasible, but I was wondering about filling the cavity with polystyrene beads. I believe that using PS beads should avoid problems with rainwater crossing the cavity, but I am wondering about cold spots inside, as presumably the inner and outer walls will be tied at regular intervals. Above this room is the roof, containing bedrooms. The house is large and appears dry (probably because it's not at all airtight!). <br /><br />What do people think? <br /><br />Jules<br /><br />PS external insulation is a non-starter ("traditional" building in an AONB)]]>
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		<title>Insulating a century-old cavity wall construction</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1341&amp;Focus=15515#Comment_15515</link>
		<guid isPermaLink="false">https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1341&amp;Focus=15515#Comment_15515</guid>
		<pubDate>Tue, 04 Mar 2008 21:02:10 +0000</pubDate>
		<author>chuckey</author>
		<description>
			<![CDATA[I insulated a victorian cavity  walled nouse with beads about 20 years ago. Very satisfied. Points to look out for :- They don't use enough "glue" so beads will appear and fall out of any holes in the mortar (around waste pipes etc). For the same reason, in one corner of my loft, beads seem to be sucked out of the cavity. the lads did seal the top of the cavity, but not very well  in this corner. I fixed it my self with beads bought from sheffield insulation and some glass fibre stuffed in on  top of them. Also in my case the relatively large holes in the brickwork (1" diam?) were patched up very well with mortar that was dyed to exactly the right colour.<br />        Frank]]>
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		<title>Insulating a century-old cavity wall construction</title>
		<link>https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1341&amp;Focus=15525#Comment_15525</link>
		<guid isPermaLink="false">https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1341&amp;Focus=15525#Comment_15525</guid>
		<pubDate>Wed, 05 Mar 2008 00:06:15 +0000</pubDate>
		<author>tony</author>
		<description>
			<![CDATA[Yes, go ahead and fill.]]>
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