Keeping your home warm / heating / energy crisis / insulation etc

(And for @Rich_G)
I did a fair bit of research online and unfortunately I don’t have the links but the new government guidelines are a good place to start
https://assets.publishing.service.gov.uk/media/614b30aad3bf7f718a54c0be/iwi-guidance.pdf

I found out that there were guidelines suggesting that you had to insulate to a certain level and just adding a few mm while not technically illegal was frowned upon but there was also a reasonable approach of realising that doing every surface was not always possible or practical.
So I went for 65mm as that was giving a significant gain and at a point that any further increase was into the law of diminishing returns.

Can only really offer advice if you doing something similar with insulated plasterboard but my tips would be:
Do not use dot/dab plasterboard adhesive as the number of fixings per board is 3x as many as using foam adhesive ( Cersasit CT84) you only need 3 per board and the foam is easy to use and far easier to get a seal round the edge and in a grid to stop interstitial moisture.
Use intumescent sealant on the board edges towards the face and the foam for the back.
It’s a 2 man job even with cutting the boards in half for ease of use, we did them in halves and started at the top half and used a dead man/brute force to hold in place while somebody drives the fixings in but the adhesive works quickly so the dead man was free to use on the next board by the time it was cut and scribed to fit.
I Used Ancon Insofast fixings, they work well but be really careful to not overdrive them through the plasterboard. they are only there to stop the boards falling off in a fire and blocking your exit but take pictures of the installation and keep receipts as they are needed for your new EPC and as proof of following guidelines.
buy a sureform as it’s the most useful tool for shaping the edges to get a good fit.
Ask somebody how! we took half a day to cut some boards in half do lots of measuring, work out the wrong method (fixing a batten to wall and resting a board on it) and get half a board on the wall. Things got a lot quicker after that once we had a system going.

Our walls were mostly cavity so damp was not an issue and the one solid wall was tile faced on the outside so no issue there either, no rising damp as we are on the 6th floor.
I did leave the concrete corner pillars uninsulated and they are a cold bridge but not to the extent they are dripping with condensation, the windowsills are also very cold to touch, the window reveals were not insulated either as the narrowness of the steel windows meant an expensive and above my pay grade job of cutting into concrete and masonry.
The secondary glazing meant the colder uninsulated side of the reveal is between the 2 windows and the insulation is on the warm side which helps a bit.

Not sure what i would do with a solid wall though, probably a totally different method/product/approach.

some pics:

6 Attachments

Most new windows are thermally broken, a look at the sectional PDF will likely show you how well.
I guess the bigger issue is how well the cavity closures are fixed and were decent quality ones used? don’t look at the shonky build/snagging new build accounts on instagram/TikTok..

Thank you, very helpful!

Do you remember how deep the foam adhesive layer ended up once the boards were up and fixed?

Would have only been a few mm, would probably spread/compress better than dot/dab PB adhesive.
Boards were 72.5mm so 65mm insulation/12mm board and then a 3mm skim.

Yes the cable is colder, I think the insulation further from it is squashed in and where the cable is, is just kind of loosely hovering over it with a gap where the cable comes off a beam which is what's letting the cold flow in and around it

Not sure how much of a pain extension the roof (rather, just the tiles) a but would be.

As to removing render - why bother? And you certainly wouldn't need to render over the insulation in lime. And good luck finding someone that can do lime render and insulation.

If it's inside you want, you would have to account for where the vapour boundary would land - you could end up with everything condensating between the insulation and outer wall.

Stud walls with air gaps would mitigate that, but you'd lose space.

“ And good luck finding someone that can do lime render and insulation.”
Friends of mine are self building a hempcrete house, has membrane free walls/breathable with very thick insulation. The base is not concrete but some kind of waste cinder product.
They got messed around for a year by one of the only people who was doing hemp/lime render at the time and then covid came along, it’s only now getting near completion!?

This is super useful guidance thanks! So it’s as “straightforward” as foam on the backing, sealant round the edges and then fixings.

We’re cavity wall as well and may get cavity wall insulation but I do feel adding internal insulation will really help regardless and don’t might the loss of space at all.

In Scotland, freezing house / walls and a 5 year old who wants to be in our bed every night as she’s cold.

Thanks for this write up

Are there downsides to smart meters that don't involve a deep state big tech conspiracy theory?

They take up a valuable plug space.
And the mental stress of seeing your daily spend at £5 by 11am.

The cost of producing / delivering them, both in isolation and opportunity.

mental stress of seeing your daily spend at £5 by 11am.

Mostly this though, at least when they are working.

Having a smart meter doesn't force you to use the display.

My smart meter just sits outside and gets me electricity for (today) 34% below the price cap.

How? Mine seems to send messages to Eon saying just "more"

Octopus Tracker What's that, you need an Octopus referral code? And the twitter tracker to see how much you're saving each day.

who here has fixed a leaky dehumidifier? pro tips?

As to removing render - why bother?

It's often shit, and ugly, and stops solid walls from breathing. There's no way we're keeping the current stuff we've got on the front of our place.

And you certainly wouldn't need to render over the insulation in lime.

I've lost track of what the original scenario @apc was asking about, but they might if they have a house built before the 1930's. It's quite common to need to render over external insulation and if your house has solid brick walls you need to use something breathable.

To reinforce what you said about EWI vs IWI and the risks of condensation and damp: Yes EWI is more expensive and harder to fit, but if you don't get IWI exactly right you can easily end up with a damp or mouldy house.

With proper EWI you get higher heat flow through the wall which helps it dry out. Walls often dry towards the interior, so if you stick impervious/non-breathable insulation on the inside you end up with damper walls and any timber in those walls will also be in a damper environment.

IWI does the opposite - it lowers heat flow through the wall, reducing its ability to dry, which means you're more reliant on external finishes keeping the rain out of the walls (whereas a proper EWI system will include something that does this, then any moisture in the walls is free to move into the interior of the building, which might sound like a bad thing, but isn't). This is true even if you install a properly detailed, breathable system using hygroscopic insulation with good capillarity.

Hempcrete is great stuff, would love to use it in our place but we won't need much concrete and not sure it would make sense...

Smart meters are a conspiracy by big energy. They're meant to save energy but you have to plug the monitor in so they actually use more, plus what's powering all that smart gubbins? More energy!

THINK ABOUT IT SHEEPLE

Re: rendering - if you're covering the outside with insulating panels, the notion of walls breathing is somewhat moot.

Saying that, I'd probably remove it, because I hate it.

Re: rendering the insulation - yes, but just not with lime. That would be a bit pointless, no? You've just chucked up a bunch of pretty impermeable panels, and you choose a fiddly, expensive, hard to find the trades, medium to cover it, whose sole advantage is that it is breathable, and should go on solid walls.

if you're covering the outside with insulating panels, the notion of walls breathing is somewhat moot

No because the panels can (and IMO should, for as building with solid walls) be breathable.

I'm pretty sure we're going to use wood fibre panels, which tick all the boxes of being breathable, hygroscopic and have good capillarity, but also sequester carbon.

If you then do render them you need a breathable render, like lime, but as we're cladding our place with viroc cement boards, my current understanding is that we shouldn't need to render.

It's usually because some fluff has got in it and blocked a pipe / water run somewhere.

Tries your patience though with the 15 million screws required to get in to the blasted thing.

Yes EWI is more expensive and harder to fit

It should be vastly superior to IWI. IWI seems bonkers to me. Eats space, requires loads of disruption, almost guaranteed to cause condensation where you don't want it and mould, does nothing for the exterior.

No because the panels can (and IMO should, for as building with solid walls) be breathable.

This is correct. You aren't going to clad a single skin property with celotex for example.

"IWI seems bonkers to me”
Depends on the property. a 6th floor flat that’s not listed but has restrictions on its exterior including windows, the options were do nothing or insulate internally.
“disruption” not when it’s done as part of a refurb in an empty flat.
“Eats space” we lost 75mm off 2 walls in bedrooms and 75mm off one wall in a 6m long lounge/diner, the gains far outweighed any loss of space.
“guaranteed to cause condensation/mould” now you are just trolling, most of the flat is cavity wall and in good condition seep vents in the cavity are there for a reason IWS or not. the one single skin wall is tile faced so not breathable.

Each case/property is different, i would do it again if the property was suitable.
A shitty built victorian terrace with solid walls and a bit of slate for a damp course would be a different proposition, but then I wouldn’t ever buy one as I prefer being warm and not paying a fortune to do so.