Talk:Cavity wall

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Untitled
Alright I have no idea to format this since I don't edit wikipedia often, so here goes nothing. I was reading this article and I stumbled across this section:

"The reason cavity insulation keeps heat in, is that the polymer and air in the cavity are bad conductors and good insulators. This is because the distance between the particles in the air is greater than that in a solid, and also polymer has no electrons in its particles to conduct heat as fast as a metal." Now read that back to yourself, mull over exactly what is wrong with that paragraph. I know that there are electrons in a polymer, but I don't know the specific reason that it is a good insulator, so if someone could come in and edit that bit. For now I will settle for removing the offending sentence to omit this false fact. —Preceding unsigned comment added by 155.101.100.188 (talk) 14:41, 5 November 2010 (UTC)

The science of cavity
The section headed the science of cavity is sloppily written. It needs to be made more precise by someone well acquainted with thermal science. DFH (talk) 19:31, 29 November 2010 (UTC)


 * Changed section title to The science of cavity insulation. DFH (talk) 19:33, 29 November 2010 (UTC)

First paragraph is inaccurate
Not because it's "wrong" but because it covers only a case. e.g. Many would say they don't care about water but mostly about heat insulation. I suspect it's written by someone from a rainy country. -- f s  07:18, 19 December 2010 (UTC)

Need for additional citations
I added the RefImprove template, however, I don't know enough about the subject in order to add reliable citations to the page. It would be appreciated if someone with the relevant knowledge would be able to improve this page. Dean Sharpe (talk) 14:07, 20 June 2011 (UTC)

Building regulations
The article says cavity wall insulation became compulsory in the 1990s. In what jurisdictions? In the UK, the USA, the EU, etc.?
 * Definitely in the US through the International Building Code. Don't know about the EU. I'll look for references.   Acroterion   (talk)   18:01, 10 February 2015 (UTC)

Asstd
'Masonry is an absorbent material, and therefore will slowly draw rainwater or even humidity into the wall. The cavity serves as a way to drain this water back out through weep holes at the base of the wall system or above windows, but is not necessarily vented.'

Water loss primarily occurs by evaporation. Weep holes are often included on recent builds as a secondary backup. Masses of weep-hole-less cavity walls exist, and most such walls never have a damp problem.

'A cavity wall with masonry as both inner and outer skins is more commonly referred to as a double wythe masonry wall.[2]'

It might be one, but is certainly not most commonly refered to as one.

'The typical cavity wall method of construction was introduced in Northwest Europe during the 19th century and gained widespread use from the 1920s.'

Cavity walls have been with us since Roman times. They were the standard method of construction in wet high wind regions long ago, certainly through the 1800s, and were moderately common further inland since the 1800s - though noncavity walls remained in use until well into the 20th century.

' In some early examples stones were used to tie the two leaves of the cavity wall together.[3]'

Yes, and bricks also. Then iron ties which tend to rust & expand in time, then stainless steel. Tabby (talk) 18:26, 11 May 2015 (UTC)
 * If I understand correctly, ties are required elements of cavity wall construction, however that is not unambiguously clear from the article; only that ties (of a specific material) were used in the past, not that ties are always used, only the material has changed over time. I would appreciate if the article itself could be updated with this information (are ties are mandatory/optional? which materials are/were used, and why/why no longer). — Preceding unsigned comment added by 2001:A62:11B0:B701:8FDE:F015:3930:7DB (talk) 07:52, 14 August 2016 (UTC)

Suggested improvements
Some statements are misleading, such as the description of a cavity wall as consisting of "two skins," when actually only the outer veneer is a "skin" and the inner wythe of the wall is usually structural, supporting the veneer through masonry ties. The article also doesn't mention that in modern cavity wall construction, weep holes must be included beneath the windows to provide drainage from potential rain infiltration around window perimeters. Additionally, the article leads the viewer to believe that the terms "cavity wall" and "double wythe" are interchangeable when in fact they are completely distinct construct systems. The article also only mentions insulation in terms of "nonrigid insulation batts" when actually the most common types of modern cavity wall insulation are rigid insulation. The article also doesn't mention modern galvanized steel veneer ties which are common as a cheaper alternative to stainless steel, although they have a shorter lifespan. The illustration "Components on a CMU and brick cavity wall" contains basic errors such as showing flashing and weeps terminating at an exterior paved surface instead of at a minimum distance above grade as required per code. It should be corrected to show that cavity walls are fully grouted under the lowest level of flashing. The illustration does not show an accurate wall footing configuration. The illustration also does not show the planes where the water barrier and/or vapor barrier would be located within the assembly.Hab044 (talk) 16:28, 17 November 2018 (UTC)


 * BATS (rectangular panels) are either fibreglass,mineralwool or polyester fibre and are BIOBREATHABLE which means that any body breath and exercise sweat vapour,cooking steam and general hot water steam that builds up inside house can pass from inside house out through inner masonry leaf (wall) through any insulation bat through cavity air space gap through outer masonry leaf (wall) and out into outside atmosphere.Insulation BATS have to be biobreathable so as all the inside moisture vapour of building is not contained within inner masonry leaf (wall) + 	BIOBREATHABLE masonry walls — Preceding unsigned comment added by Soviet99999 (talk • contribs)

Merge proposal
Cavity wall insulation is small and might be best discussed within the context of this broader topic (so, supporting the June proposal). Klbrain (talk) 12:54, 26 December 2020 (UTC)
 * ✅ Klbrain (talk) 12:05, 30 June 2021 (UTC)

Winter setting
Would be nice to add information on how this structure behaves in winter setting. -- AXO NOV  (talk) ⚑ 10:42, 25 May 2021 (UTC)

Rewrite
I'm going to attempt a rewrite of the article that deals with the pastiche of local practices in a more globalized format. Part of the issue involves the British practice of insulating by putting insulating materials into existing cavity walls, or building new cavity walls without a drainage space between the insulation and the outer wythe. At least in North America, these are very much discouraged practices, and appear to have caused significant issues in the UK. We don't need to write articles that espouse bad practices.

Also, there are a lot of overlapping issues of what a cavity wall is - often, again in North America, the backing might be wood frame with only a masonry veneer, or metal framing. And then there are pressure-equalized rainscreen systems, which may be masonry veneer or something else entirely. I will try to navigate those.

But first, I'm going to attempt a haircut and to weed out the most muddled bits. Referencing will be a work in progress, as references should be from industry best practice references, which can be hard to track down in a form that helps the article. Acroterion   (talk)   03:09, 27 April 2024 (UTC)

Other, similar designs?
I ended up here, on Cavity Wall at English Wikipedia when searching for an English word for the Swedish term Skalmur ("shell wall"). It seems to be about the same thing, with two thin, well-made masonry walls on the out- and inside of a construction (in my case I was dealing with fortresses from the 16th century). But in the Swedish case they were filled with blocks of stone, or maybe earth. No air-pocket between the lining walls and the filling, but also no binding between the inner and outer parts. Air wents was not "invented", or should not be needed as any air-pockets would be unintentional. To me, it seems I have found the almost correct translation, but are there other, similar walls with a different name, more similar to the one I´m looking for? I.e. nice masonry walls (thin) on in and outside, inside filled with stone and mortar, but not really attached to the lining, and with "no" air pockets? And used in the 16th and 17th century... Any help is appreciated. // Martin 78.70.193.152 (talk) 22:09, 9 July 2024 (UTC)


 * If there isn't a space, it's not a cavity wall, merely a method of using rubble between two facing walls to economize on material and labor. A cavity wall by definition has a space for drainage or as a thermal break. Frank Lloyd Wright did something like what you describe, laying stones on either side of a thick form and then filling the middle with concrete. Solid brick walls often used hard face brick for the outside faces and cheaper common brick in the middle. I think most masonry-building cultures have some variant on this practice.00:29, 10 July 2024 (UTC) Acroterion   (talk)