Single Skin House Wall

[J_Ashley]

Slightly off topic, but I’m guessing a few people here might have relevant knowledge.

A house that we’re looking at potentially buying is end of terrace house, but it turns out the entire semi-detached wall is single skin/half brick thickness (i.e. 4.5”). Its the standard two storey with a pitched roof in height (approximately 7.5m), although the loft has also been converted into a living space.

The outside of the single skin wall has been rendered, and the inside has been plaster boarded (I’m guessing with some form of insulation on the rear), so heat retention and weather protection are probably as good as they’re going to get.

Obviously the house is pretty old (Victorian, so likely 130+ years old), and there are no signs of problems with the single skin wall. It’s only the side walls that are single skin (I’m assuming more terraces houses were originally planned) as the front and back are normal full brick width (9"), so maybe that makes it less important. What are people’s thoughts with regards to structural integrity looking forward? A case of “something would have happened already if it was going to”, or is that optimistic?

The notion of such a thin wall seems worrisome to me, but equally I know little about these things, so perspective with experience would be appreciated.

 

[sunnybob]

Make sure the mortgage company knows. If they and their insurers are OK with it, then youre fine. If they dont like it they wont lend the money.

 

[MikeG.]

Half-brick walls were usually upstairs only, so I am surprised to hear it is two storeys (plus gable) high. Structurally I'm sure you'll be fine (it's stood there for a long time without issue). In terms of comfort and fuel cost, though, I wouldn't be so confident.

I absolutely would not assume there is any insulation behind the plasterboard. You should be able to tell by measuring the wall thickness at a window. A brick is about 105mm wide, render is about 20mm deep, and plasterboard plus skim about 15mm. That's 140mm. Subtract that from your measured wall thickness and the remainder is the depth available for insulation. If the wall measures about 165 then I reckon that's just plasterboard on battens. I'd want to see around 200mm wall thickness before I relaxed a bit.

 

[HOJ]

Is there any evidence or possibility of another terrace having been on the end? the party walls in my terrace are single skin, built in the late 1800's.

 

[eezageeza]

There are lots of victorian houses round here with single skin outer walls, so it must have been commonly done for a time at least. They are all still standing so presumably its not a structural issue, but the advice to make sure your insurers are aware of it seems sound!

 

[J_Ashley]

The number that you would expect to be next door is missing, i.e. the street skips a number. However, the gap between our house and the neighbouring semi detached is certainly not big enough for another house. So it look like nothing was pulled down. (The gap is owned by next door, so the single skin wall cannot be widened externally, and internal alterations would be beyond what’s practical).

Additionally, this neighbouring semi detached house is attached to a symmetrical semi. They are still victorian, but look grander/more expensive than the regular terraces. My guess is potentially the row of terraces was meant to continue, but, for some reason, these two grander semis were built after a change of plan. This would explain why there is a house number missing (2 semis built instead of 3 terraces), and would also be a good reason why our entire detached side wall in single skin.

The surveyor highlighted the wall issue, although he probably came across as more ‘disappointed‘ than very concerned. He says the rest of the house was built to a good quality for the time, so for the end terrace wall to be single skin was unnecessary really. In recent years, money has also been spent on the house by the previous owners, so it’s not like there are a host of other issues that put us off.

Basically, we want to make sure we are not unnecessarily worried about something that’s not a huge issue. But, at the same time, we don’t want to ignore what could be an obvious big problem for further down the line (I.e. the side of the house basically being a tall garden wall!).

 

[MikeG.]

You mustn't think of that wall in isolation. It has two walls of maybe 2/3rds the height attached to it at right angles, only some 5 or 6 metres apart (typically). They are what provides the bracing and structural strength. Like I said, it's been standing there a while. If there were to have been any problems with it they would have shown themselves before now. Much more important is the thermal performance of such a low spec wall.

 

[sunnybob]

having been born and raised in similar houses I can make a very good guess as to what happened.
I am fairly sure you are in a large city. That terrace would have originally been longer, but the house next door and several more along were destroyed by bombs in the war. The builders removed all the old rubble sometime in the early fifties and built more upmarket houses in the space available.
I grew up playing on bomb sites exactly like that, the entire street of 50 houses were lost behind my street, eventually they cleared the land and built a factory.

 

[J_Ashley]

Yes, it’s an inner city house, but I’m confident that there was no bombing in the city during the war period. Additionally the two semi detached properties that do not fit in with the terrace style still appear to be of Victorian age, and, as far as I can see, appear on historic maps from the late 18th / early 19th centuries.

Hopefully it seems like my concerns over the structure are probably a bit over the top. Final thought on that note - would the conversion of the loft to a living space (including stairs) add any extra stresses to that wall (as these are recent changes)?

Are there any obvious feasible improvements that can be made to improve the thermal efficiency of a single skin wall? The layout of the house means that most ‘living’ (beds, sofas etc) will be away from the single skin wall, but I’d still like to limit energy loss to the best extent.

Thanks again for all the good advice.