Green Building Forum - External wall insulation on chimney breast

Green Building Forum - External wall insulation on chimney breast Tue, 19 Dec 2023 08:37:35 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300214#Comment_300214 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300214#Comment_300214 Sat, 11 Feb 2023 08:12:48 +0000 listenerspeak
I have been reading the forum recently and managed to get my mother's property funding for external wall insulation which will hopefully be getting done soon.

She has been told they will not insulate the chimney breasts (1.5 m and 1.7 m long) along the gable wall (9m long), because of the heat inside the chimney if it is used in the future.

Will this not cause a big thermal bridge ?

Would she be best to get this externally insulated at her own cost at a later date.

The chimney stacks were both removed to below roof level last year as it was cheaper than repairing the existing render to them at the time. Front has two disused flues and rear has three disused flues. The plan was if the roof was redone to have EPs beads or glass beads poured in and potential insulation over the top??

Chimneys have a 280 mm cavity and juts out from the 9" brick wall externally with a half brick (110mm) wall internally and externally.

Thanks for any advice of comments]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300216#Comment_300216 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300216#Comment_300216 Sat, 11 Feb 2023 10:46:49 +0000 fostertom
EWI the lot. And within the loft space, insulate the stack's inner face as well (the gable end walls too).]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300217#Comment_300217 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300217#Comment_300217 Sat, 11 Feb 2023 10:54:26 +0000 bhommels Posted By: fostertom
EWI the lot. And within the loft space, insulate the stack's inner face as well (the gable end walls too).
+1
If they are worried about the thermal rating of the EWI they could use a mineral wool based EWI product for the chimney, like what is required around flues etc.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300219#Comment_300219 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300219#Comment_300219 Sat, 11 Feb 2023 11:38:01 +0000 fostertom External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300223#Comment_300223 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300223#Comment_300223 Sat, 11 Feb 2023 13:02:50 +0000 tony External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300229#Comment_300229 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300229#Comment_300229 Sat, 11 Feb 2023 16:47:02 +0000 djh Posted By: listenerspeakShe has been told they will not insulate the chimney breasts (1.5 m and 1.7 m long) along the gable wall (9m long), because of the heat inside the chimney if it is used in the future.
Who is 'they'? IIUC the chimneys have been removed or at least can't be used? Find another 'them' that knows what they're doing! Report the original 'they' to whoever is monitoring whatever programme it is.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300234#Comment_300234 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300234#Comment_300234 Sat, 11 Feb 2023 17:24:11 +0000 fostertom External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300263#Comment_300263 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300263#Comment_300263 Sun, 12 Feb 2023 20:28:13 +0000 listenerspeak
Sorry I didn't specify who "they" was, it's the company that has been awarded the contract by the local council who are funding the works so it's not possible to change who is doing the work.

Not sure how to proceed as we are grateful they are doing the EWI and don't want to throw a spanner in the works.

Posted By: fostertom

EWI the lot. And within the loft space, insulate the stack's inner face as well (the gable end walls too).

Will definitely do this in the front loft space but how will this work with the rear being a room in the roof?

Thanks again]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300270#Comment_300270 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300270#Comment_300270 Mon, 13 Feb 2023 12:21:48 +0000 fostertom Posted By: listenerspeakWill definitely do this in the front loft space but how will this work with the rear being a room in the roof?In that case no need, assuming the roof slopes above are insulated and join up with the 'outdoor' EWI on the gable end(s).

Posted By: listenerspeakinsulate the stack's inner face as well (the gable end walls too)

is only necessary if the loft is full of 'outside air' because insulation is at loft 'floor' level.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300271#Comment_300271 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300271#Comment_300271 Mon, 13 Feb 2023 12:24:28 +0000 philedge External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300275#Comment_300275 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300275#Comment_300275 Mon, 13 Feb 2023 16:38:35 +0000 RobL Posted By: bhommelsIf they are worried about the thermal rating of the EWI they could use a mineral wool based EWI product for the chimney, like what is required around flues etc.

We used 150mm platinum EPS mostly, but 150mm rockwool around the external chimney, for the avoidance of doubt.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300311#Comment_300311 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300311#Comment_300311 Thu, 16 Feb 2023 12:31:36 +0000 listenerspeak
Just an update managed to speak to local BCO and they have agreed with the contractor saying to should not be insulated due to someone reinstating a chimney stack and putting a fireplace in future. Said the pointing might be poor and is a risk of ignition if it is clad outside?

Also said you won't notice any difference and it doesn't need to be insulated as there won't be any thermal bridging.

Looks like we will have to do that section ourselves at a later date?

Thanks all]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300312#Comment_300312 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300312#Comment_300312 Thu, 16 Feb 2023 12:42:52 +0000 listenerspeak Posted By: fostertom

Posted By: listenerspeakWill definitely do this in the front loft space but how will this work with the rear being a room in the roof?

In that case no need, assuming the roof slopes above are insulated and join up with the 'outdoor' EWI on the gable end(s).

Posted By: listenerspeakinsulate the stack's inner face as well (the gable end walls too)

is only necessary if the loft is full of 'outside air' because insulation is at loft 'floor' level.

Thanks, will look into the roof once the walls have been sorted]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300316#Comment_300316 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300316#Comment_300316 Thu, 16 Feb 2023 17:57:53 +0000 Nick Parsons
You know that that is bananas, but worrying to think that they don't. The same rationale was used for not internally insulating chimney breasts ('It's a cavity wall, innit?), but that was 40+ years ago, and we knew nothing. Surely things have changed?!

When you do it yourself, use rigid Rockwool to cover yourselves. Lots of suppliers out there, but I use a store which sells EWI.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300320#Comment_300320 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300320#Comment_300320 Thu, 16 Feb 2023 20:43:44 +0000 djh https://www.lgo.org.uk/make-a-complaint/fact-sheets/planning-and-building-control/building-control

helpfully points out that responsibility for meeting building regs actually lies with the owner and not with building control. It also explains how to complain when it is appropriate.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300322#Comment_300322 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300322#Comment_300322 Thu, 16 Feb 2023 21:31:01 +0000 tony
Seems like the contractor is not aware of the responsibilities and are working with building control but the result is producing a proble,

How can they say no thermal bridge, no insulation = thermal bridge.]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300522#Comment_300522 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300522#Comment_300522 Wed, 01 Mar 2023 06:54:19 +0000 listenerspeak
They have extended out the roofline and are definitely not doing the redundant chimney breast walls.

They would not remove the existing render and have just gone over it but I cannot see any adhesive that has been used?

Seem to have not stepped down from the suspended floor level to concrete slab level along the gable wall.

I've tried to attach pictures.

Am I being too picky or expecting too much as she has not had to contribute to the costs of the works and it will probably be better than nothing / existing blown and cracked render?

Thanks again]]> External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300523#Comment_300523 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300523#Comment_300523 Wed, 01 Mar 2023 06:55:30 +0000 listenerspeak External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300524#Comment_300524 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300524#Comment_300524 Wed, 01 Mar 2023 06:55:59 +0000 listenerspeak External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300525#Comment_300525 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300525#Comment_300525 Wed, 01 Mar 2023 06:56:20 +0000 listenerspeak External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300526#Comment_300526 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300526#Comment_300526 Wed, 01 Mar 2023 06:56:40 +0000 listenerspeak External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300527#Comment_300527 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300527#Comment_300527 Wed, 01 Mar 2023 07:10:44 +0000 listenerspeak External wall insulation on chimney breast http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300528#Comment_300528 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17738&Focus=300528#Comment_300528 Wed, 01 Mar 2023 08:07:30 +0000 RobL After all of that, i went round all the gaps between ewi sheets, sprayed in a little water and then some expanding foam type glue. Cut off excess with a sharpened trowel.
Rasped the eps a bit to rough it up a bit, i think its easier then to fix the next coat.
Belt, braces, and then some :-).]]>