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

I did ours using:

• Expanding foam tape externally between window frame and aperture (black stuff on a roll, not spray foam)
  
• Full fill of cavity/gap with Illbruck FM330 airtightness spray foam
  
• Tescon Vana airtightness tape to seal internal edges of window frames to internal reveals
  
• 20mm PIR pieces cut to fit snugly around all 4 sides of reveal, also taped along both edges
  
• Solido airtightness tape to finish the final edges and corners of window frame to PIR pieces. The corners need a special tape cutting detail to prevent pinholes forming
  
  

Seems a bit overkill now that I’m typing it out, but didn’t take too long and might as well do it correctly.

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IMO the trouble is that 'good' is quite hard to discern.

They might be punctual, polite, neat and well priced but it doesn't mean they've done a good job.

Would suggest a read of this https://www.thepebbletrust.org/wp-content/uploads/2023/08/230814_SRG-ed2_Digital-V2_compressed.pdf

To help inform what it is you're asking for because insulating floors and lofts in older buildings in particular needs to be done sensitively to avoid problems with moisture/damp/mold.

Thanks! This is really useful.

Thanks - yeah I completely agree, nervousness about damp / breathability problems is one of the reasons I'd want this done by a pro / based on good advice. Will read that doc and see how it lines up with what I've read before

also - what quantities did you use? I have 5 windows and 2 doors to do. Obviously sizes will differ but even ballpark...

No idea tbh, but I got through shit tons of the Tescon Vana tape, which is a complete bump. It can't be difficult to calculate what you'd need, if you know the dimensions of everything.

I since found a much cheaper alternative airtightness tape: PHS Argo plus

Builder has suggested using ventilation tape (which is literally a fraction of the cost) instead of formal airtightness tape.

Hard to argue with logic that it would work fine given it's design to make ventilation systems airtight...

Is it a bad idea?

The silver stuff? I expect the glue will fail in the short term and it’ll all peel away eventually. If I was closing something up permanently under plasterboard etc I’d want to know it’s gonna be fine for 20+ years.

If something is under plaster board, and its tight fitted how is it gonna peel off?!

If you've got airflow in your roof - and you should - it will be at a pressure and it will find its way through failing tape to where it's not supposed to be going.

Do not do this. As others have said, the adhesive will quickly fail.

Builder has suggested using ventilation tape (which is literally a fraction of the cost) instead of formal airtightness tape.

Why? What savings are we taking about, it can't be that much in comparison to what you're spending on windows?

I wouldn't do it, that's not the place to be skimping imo.

Not sure if this is quite the right place, but…

We want to switch our vented hot water tank to unvented, fed by a condensing boiler, but with the option to heat using electric immersion too. We also want it to have the capacity to be fed via solar in the future (in case that requires something different to mains fed immersion).

Are there any brands we should be looking at/avoiding? There seems to be quite a range of prices, from about £650 to £1200 or so. What makes some better than others?

How did you find this? (Just curious). It's great. Thanks for sharing.

It’s been linked here a few times, I know I had a copy saved, possibly @dbr linked it?

Boxes of Dupont acrylic airtight tape can be found on eBay for ~£100, so £10-£15 each.

As others have said, ventilation tape isn't up to the job...

I re-posted from here a while ago, such a good resource but I can’t claim to have found it

Might have been me as I did a lot of research for retrofit insulation, what I didn’t save was the blog with all the guidelines for internal insulation with the calculations simplified and best practice.
Was a useful resource.

I’ve just used this detail for insulating suspended timber floors downstairs. I was keen to get it right as we’re having UFH, so really wanted to ensure that the insulation wouldn’t cause problems with damp down the road. Any repairs would become a massive undertaking. This seemed to tick all the boxes, using the hemp insulation was a dream
Compared to PIR. https://www.ecologicalbuildingsystems.com/post/best-practice-approach-insulating-suspended-timber-floors

a mate of mine who knows one of the authors sent it to me a few years back. I have the paper version now too.

Oh nice - did you do it yourself or get someone in? How much work was it?

This is something I want to do in our place over the next year or so as part of upgrading electrics and heating.

We want to sand and refinish the floors too, but have no experience of doing something like this and am unclear as to the order of going about the works. Lift the boards to sort the electrics/pipe work that run underneath first, then insulate, relay floor and replace any boards that haven’t survived before sanding and finishing?

I find working out which things will get fucked by other trades helps decide ordering questions.

Don't finish your boards until every thing else is done tbh

1. Lift boards
   
2. Cry when most of them disintegrate
   
3. ££ on new boards, pile them up everywhere making your house unusable
   
4. Cry when you're greeted with hench piles of rubble filling all the floor voids
   
5. Hire labourers and 3x skips to remove rubble
   
6. Find broken/blocked airbricks, ££ to replace
   
7. ... ?
   
8. Toasty floor
   

Looks about right
Currently on step 2 and step 3