Insulating the UK’s solid wall housing stock.

[platinumsage]

Much of UK housing consists of solid wall Victorian terraces and 1930s semis. The vast majority of these will be heated by gas boilers, and replacing these with electric heating is not viable as it stands. If air source heat pumps or whatever are the solution, then all these houses need to have their walls insulated.

External insulation is about six inches thick and costs around 20K. Where houses face directly on to narrow pavements this would require some wayleave or transfer of property rights to expand onto the pavements. The alternative is internal insulation which reduces the size of rooms and is less efficient.

The only alternatives to actually doing this would be replacing natural gas with cheap green hydrogen allowing similar boilers to be used, or making electricity for heating cheap enough that people on low incomes would be able to use it to heat these properties without insulating them.

So the question is how should a program of insulation be funded, and how is it going to be achievable in a realistic timescale given how shit the smart meter rollout has been and how tight the workforce is at the moment.

 

[platinumsage]

Obviously the government has known about this for some time, there was even a subsidy scheme a few years ago but of course that was stopped:

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/476977/BIS-15-562-solid-wall-insulation-report.pdf#page19

 

[StoneRoad]

No way am I suggesting that ignoring the need for more insulation is a good idea.
However, some of the very old solid wall buildings the walls are so thick that it has a significant "U" value already.

There is also the problem of external insulation altering the appearance - which would (& to my knowledge has been) the grounds for refusal of planning permission in the case of listed buildings or those in areas with enhanced conservation status.

I'm in (just) a National Park which is also a UNESCO World Heritage Site ... getting anything passed by the planners is a nightmare. Even when it doesn't infringe any policy it still takes almost forever.

 

[maomao]

I live in an 1890s semi with single leaf brick wall and one of my neighbours has had their whole house insulated externally. Pretty sure it's not six inches thick and while it obscures the brickwork so does my pebbledash. I could get a photo later to show how unobtrusive it is.

 

[platinumsage]

I live in an 1890s semi with single leaf brick wall and one of my neighbours has had their whole house insulated externally. Pretty sure it's not six inches thick and while it obscures the brickwork so does my pebbledash. I could get a photo later to show how unobtrusive it is.

There‘s a semi on my road that’s been done where the adjoining house hasn’t. I looked for pics of similar online but couldn’t find any, so maybe i’ll try to photograph it later too. It looks about six inches.

My understanding is that the preferred option is 10cm thick insulation boards, plus the adhesive and render.

 

[Brainaddict]

I suspect the houses where it would actually block pavements is a minority issue. The biggest resistance apart from finance often seems to be aesthetic. I wonder if people would feel more ready to do it if they could get brick tile exterior to match the bricks underneath?

 

[Pickman's model]

At least Georgian and Edwardian houses, and those built under the current queen, won't require this external insulation

 

[klang]

I suspect the houses where it would actually block pavements is a minority issue. The biggest resistance apart from finance often seems to be aesthetic. I wonder if people would feel more ready to do it if they could get brick tile exterior to match the bricks underneath?

like one of those 'naked' aprons.

 

[Leafster]

I was interested to know the percentages of solid v cavity walls in the UK and have just found this published by the BRE Trust in 2020.

https://files.bregroup.com/bretrust/The-Housing-Stock-of-the-United-Kingdom_Report_BRE-Trust.pdf

I haven't had to a chance to read it yet but have pulled out some data

Of the total UK housing stock

• 69% has cavity walls
• 29% has solid walls
• 2% has "other" what ever that means

Of the housing stock with cavity walls

• 69% has some form of insulation
• 31% doesn't

Of the housing stock with solid walls

• 11% has some form of insulation
• 89% doesn't

If the figures are to be believed then it does show the extent of the problem.

 

[stavros]

In terms of how it should be funded, I wonder if there's a parallel with the concept of the NHS, state education and many other aspects of the public sector. It's broadly accepted that we all contribute financially to both, and that we all benefit, directly or indirectly, from their effective delivery. Some explaining might be required as to why there's a common interest to insulating others' properties, and there will be resistance from noisy objectors.

Is there precedent for this in any other countries? I first of all think of the Scandanavian countries, or Canada..

 

[WouldBe]

At least Georgian and Edwardian houses, and those built under the current queen, won't require this external insulation

Why? Early cavity walls aren't big enough to get sufficient insulation in and may already have inadequate insulation in which would require removing first.

It's not just the walls. Our previous 70's built property had no insulation under the floor and the floor was always freezing in winter. It also only had 4" of loft insulation.

 

[Pickman's model]

Why? Early cavity walls aren't big enough to get sufficient insulation in and may already have inadequate insulation in which would require removing first.

It's not just the walls. Our previous 70's built property had no insulation under the floor and the floor was always freezing in winter. It also only had 4" of loft insulation.

On the basis it's only 1930s and Victorian houses that need it

 

[WouldBe]

On the basis it's only 1930s and Victorian houses that need it

Clearly not. There are still a lot of prefabs that were put up after the war that are little more than a concrete shed.

Even some of the more recent builds aren't insulated adequately.

 

[Pickman's model]

Clearly not. There are still a lot of prefabs that were put up after the war that are little more than a concrete shed.

Even some of the more recent builds aren't insulated adequately.

Platinumsage has made a mistake then

 

[maomao]

The house on the left here has external insulation:

 

[andysays]

The house on the left here has external insulation:

View attachment 290307

That looks fine. I don't think anyone could seriously object to that on aesthetic grounds.

Do you know if your neighbour has done anything to insulate the walls between them and the adjacent houses, which obviously can't be done externally?

 

[maomao]

That looks fine. I don't think anyone could seriously object to that on aesthetic grounds.

Do you know if your neighbour has done anything to insulate the walls between them and the adjacent houses, which obviously can't be done externally?

There's only one party wall because it's a semi but I don't know them or their neighbour to talk to. I know that I don't get condensation on my party wall though and it's generally not cold to touch, whereas the rest of the house is plagued by it so I reckon a lot less heat is lost that way.

 

[andysays]

There's only one party wall because it's a semi but I don't know them or their neighbour to talk to. I know that I don't get condensation on my party wall though and it's generally not cold to touch, whereas the rest of the house is plagued by it so I reckon a lot less heat is lost that way.

Yeah, I'm sure there's a lot less heat loss through party walls than through externals.

 

[what]

I was involved in a scheme called retrofit for the future some years ago. The two properties I was involved in both had issues with external insulation, one in a conservation area other with tiny pavement out front. Both went for internal insulation on front of house and external insulation on rear.
Target set was to reduce carbon emissions by 80% or more. We succeded ( monitored for 2 or 3 years) but the cost was ridiculous.

 

[maomao]

but the cost was ridiculous.

Can you quantify ridiculous?

 

[what]

Can you quantify ridiculous?

My recollection for the full refurb was something like 1.5 or 2 times the cost of demolishing and rebuilding from scratch to the same energy standards

 

[maomao]

My recollection for the full refurb was something like 1.5 or 2 times the cost of demolishing and rebuilding from scratch to the same energy standards

Fair enough but what's that in pounds? I have no idea what the actual building of a house costs. Thirty grand?

 

[what]

No its about 10 years since the project and for one of them I recall about £275k

 

[alex_]

A sensible government would - borrow a fuckload of money to fund house insulation and domestic energy saving measures, put a floor on wholesale gas and electricity prices ( which means this wouldn’t hugely increase bills ), force energy suppliers to hedge contracted customers ( which means they are protected from sudden rises ) and then when prices are low ( below the floor ) put the repayment into energy bills as the diff between market rates and the floor.

Problems with this - it doesn’t deal with rental houses, you’d need to force landlords to take part - what happens if we are entering a period of high energy prices ? ( you’d never be below the floor ). Though wind power will long term fix that for electricity.

 

[alex_]

No its about 10 years since the project and for one of them I recall about £275k

Was it Buckingham palace ?

This says up to 22k https://www.checkatrade.com/blog/cost-guides/external-wall-insulation-cost/

 

[what]

Dont forget this is not just solid wall insulation its the whole house refurbed. Triple glazed windows, roof and floor insulation, high efficiency ventilation with heat recovery etc etc.
My recollection one of the big carbon savers was getting the leakiness of the building reduced by a huge amount. This is someting you can go part way towards yourself very cheaply.

 

[what]

Was it Buckingham palace ?

This says up to 22k https://www.checkatrade.com/blog/cost-guides/external-wall-insulation-cost/

Was a 4 bed housing association house near Ally Pally

 

[teuchter]

Much of UK housing consists of solid wall Victorian terraces and 1930s semis. The vast majority of these will be heated by gas boilers, and replacing these with electric heating is not viable as it stands. If air source heat pumps or whatever are the solution, then all these houses need to have their walls insulated.

Firstly, this is not true. There are plenty of parts of the UK which don't have any gas supply, and people have been heating their solid wall houses electrically for decades.

That said, of course we should be trying to improve insulation everywhere.

I spend a fair bit of time advocating better insulation but I also agree with those who object on aesthetic grounds to attractive front facades being externally insulated. I don't want to see all of the UK's victorian and older brick built or stone built terraces converted to blank walls of stained white render.

People always want a simple answer to how we deal with insulating old housing stock but the reality is that you have to do it on a case by case basis.

It often makes sense to externally insulate the back of a house where the aesthetic/thermal balance of benefits is different. To what extent it makes sense to internally insulate the front, depends on the work that's being done. If it's a major refurb with most of the interior stripped out, then it's much more feasible to do internal insulation. It will depend also on internal features of the house (things like decorative plasterwork and so on) and whether there's a desire to keep these.

Internal insulation is more difficult to do well than external insulation, but it is possible. You do lose some internal space but it's usually perfectly possible to do it such that only a small amount is lost and the rooms remain perfectly functional.

In most cases you can significantly improve the efficiency of a typical victorian house by externally insulating the back, insulating the roof really well, replacing windows with ones that perform well thermally, maybe insulating the ground floor, and improving airtightness throughout. Potentially, using a heat recovery ventilation system. And possibly insulating the street facade fairly modestly with internal insulation.

One reason that I don't think we should be ploughing ahead and defacing all of our older housing stock's front facades is that there may well come a technological solution that allows us to use much thinner insulation than we need now. There already exists aerogel, which is currently pretty expensive but this may change.

 

[teuchter]

The house on the left here has external insulation:

View attachment 290307

It looks rubbish and will look worse in a few years when it's streaked with dirt.

Also they have not really done it properly - to do it properly you would insulate and rebuild the bay window roof and it would not have that recess detail where it meets the rendered wall which shows there's a break in the insulation at that point.

 

[maomao]

It looks rubbish and will look worse in a few years when it's streaked with dirt.

Also they have not really done it properly - to do it properly you would insulate and rebuild the bay window roof and it would not have that recess detail where it meets the rendered wall which shows there's a break in the insulation at that point.

He did it himself. He's also layed a far too heavy front garden path that causes a dip in the (tarmac) pavement leaving an almost permanent puddle over a third of it so not surprised to hear it's a bit of a botch job.