New member - stuck for what to do next to warm the house

[Russdl]

On 06/07/2023 at 07:41, Dave Jones said:

the spray mist aerogell stuff on old housing stock could be a game changer

Not so sure about game changing for ‘old stock’ because as they say, it doesn’t fill holes it seals leaks so holes would have to be found and filled first but thanks for sharing that video, the first I’ve ever seen or heard of such a system, a brilliant idea. 

[Sparrowhawk]

I took off a wooden cavity closer by the bay this morning. Turns out it's not just the bricks in the bay that are soft it's the whole wall. Think the render is holding the wall up!

 

A generous gap was left between the UPVC frame and brickwork, plugged with mortar(?). Look out for the daylight below!

 

 

Lucky to have foam here, it's missing for most of the rest. The mortar-filled gap is over 2cm wide at this point.

 

 

 

The out of focus bit is where the face of a brick has disappeared.

 

To get a nice straight edge to the window opening they didn't cut cinder blocks to fit. Oh no, they took small ones, lined up the edge and left a couple of inch gap to the next block... covering it with plaster in the room.

 

 

Despite the strong breeze blowing through and out of the cavity, it smells a bit - damp I think.

 

I've temporarily stuffed HelloFresh insulation in the cavity. My plan had been to shove 100mm PIR in as a cavity closer but the brickwork is too uneven for a 100mm sheet to fit. Will rockwool do the job as well?

 

And between the window and brickwork where there's the mortar and a little old foam: best to fill this entirely with foam, or does it need something more solid like chunks of PIR too?

Edited September 23, 2023 by Sparrowhawk

[TonyT]

Cables. Run in the cavity too, man that’s rough

[Sparrowhawk]

21 minutes ago, TonyT said:

Cables. Run in the cavity too, man that’s rough

I know. Thought it was only one room we needed to get rewired for cavity wall insulation but no...

 

How does a "normal" house get its cables from the fuse board downstairs to upstairs? A wide chase above the fuse board, through the ceiling, then fan out under the floor?

[TonyT]

Could be Through the floor joists then up a wall/partition, or just up

the wall but clipped/adequately supported through their length

[Sparrowhawk]

Penetrations. I've set a new record this week.

 

Not counting joist ends (I can poke a twig into the cavity round most of them) there's 7 penetrations into the cavity in 1.2m. And 5 penetrations through the ceiling to the room below, which houses the boiler and fusebox.

 

Rewring TBD later. Plan is to fill the gaps or coat the entire damn section of brickwork with something - mortar? plaster? - and then use Blowerproof to seal round the joists. I'm not taping this lot.

 

Happy weekend everyone!

 

 

 

Edited September 29, 2023 by Sparrowhawk

[TonyT]

https://www.uksealants.co.uk/illbruck-fm330-air-tight-expanding-foam-gun-grade.html?gclid=EAIaIQobChMIrYbPjcDQgQMVlMPtCh0MVQRaEAAYAiAAEgKHefD_BwE
 

 

buy shares in the company.

 

I have a storage heater on a smart plug to set a timed schedule, it also lets you see energy etc. helps keep a background heat.

 

 

[jayc89]

1 hour ago, Sparrowhawk said:

Penetrations. I've set a new record this week.

 

Not counting joist ends (I can poke a twig into the cavity round most of them) there's 7 penetrations into the cavity in 1.2m. And 5 penetrations through the ceiling to the room below, which houses the boiler and fusebox.

 

Rewring TBD later. Plan is to fill the gaps or coat the entire damn section of brickwork with something - mortar? plaster? - and then use Blowerproof to seal round the joists. I'm not taping this lot.

 

Happy weekend everyone!

 

 

 

 

I have a solid wall construction and I'm packing the gaps and brickwork in the void with lime mortar.

Edited September 29, 2023 by jayc89

[marshian]

Really good thread this is - I don't envy what you need to do - Ground floor of my house was a suspended chipboard floor with a very well ventilated 2-3 ft crawl space 56m2 of 75mm Kingspan PIR and 3 months work crawling thro a small hole in the floor one of the rooms had it all insulated but a job I never want to do again.

 

I do like your blower set up may have to look at doing that for my house

[GP41]

@Sparrowhawk Great thread. I've just read through it, start to finish.  It's certainly made me feel better about what we've taken on.  Lots of great ideas.  It looks like it's some time since you've posted.  I do hope you were able to get to a better place - quite a challenge.

[Sparrowhawk]

Thanks for the reminder @GP41! I'd switched to posting individual threads in the topic forums so it's time for an update covering the past 18 months.

 

We finally got the new central heating and hot water system installed in May 2024, done by a fabulous Heat Geek trained installer. As @MikeSharp01 said on page 1 it makes a big difference and for the first winter since we moved in we've been warm and kept the house consistently at 19C+  

 

Electricity usage is down (no oil filled radiators needed) but gas usage (CH/HW only) is slightly up. But as we're stripped back to suspended wood floors with gaps between planks so it's going to drop from here onwards. Heating has also fixed the book lice and mold mite infestations in the house, and we run a dehumidifier once a day to keep on top of the humidity.

 

Living in and working from the house you're renovating (with clients coming in 3 mornings a week) is a recipe for disaster excruciatingly slow progress. That's my excuse and I'm sticking to it anyhow, got nothing to do with me overthinking, trying to treat a house like a precision mechanical instrument (tolerences >1mm? Oh the shame), procrastinating or being a perfectionist, oh no. But I am having great fun learning new skills, my SDS+ drill is my new favourite toy, bonding plaster is great to work with, and the hypotheses I've had turn out to be right more than 50% of the time.

 

Planning for MVHR has been a massive time sink. We don't need MVHR but we're on a clifftop by the sea where it's breezy on a calm day and windy the rest of the time, and what we really don't need is extractor fan sized holes in the walls and trickle vents in the windows. Wind washing is real, and removing the two extractor fans downstairs and sealing up their holes has made a noticable difference to heat retention on windy days. And this is with gaps in the floor and leaking windows.

 

Back to MVHR, and ducts here are difficult to route due to extensions, and it became an obsession to see if I could work out how to make them fit and be concealed and within the thermal envelope. I've had far too many 3am wakeups drawing diagrams in my mind but victory is mine, and with the compromises of 75mm duct and one run in the (cold) loft I have it planned out - and promptly lost my enthusiasm because I'd solved it hadn't I and the fun bit was over... The first duct run is in and whether we actually buy a MVHR and fit it, it's there and ready. A big shout-out to @Gus Potter for his help on whether I could take a chunk out of a cavity wall to run ducts through. Just got to pluck up the courage to cut a 10x30cm slot now!

 

I'm slowly adding underfloor insulation in the hallway. Another of those that's been excruciatingly slow because to begin with I spent ages trying to work out how to fit it in an airtight way under existing stud walls built on top of the floorboards. Eventually pragmatism won through and I'm fitting it where I can and will put an airtight membrane over the top of everything and taped to the walls before we lay a new floor on top. Anything else is too much hassle.

 

Sound proofing is my nemesis and no matter what I do the downstairs toilet remains... a place for exhibitionists. Ditto airborne sound from ground floor to first floor in certain rooms. I've sealed the perimeters with airtight sealant, added glassfibre between the joists and made sure the floor is tight. And we can still have a conversation with barely raised voices. Next stop is overboarding the ceiling, and then resilient bars if required.

 

We need to replace windows this year so we can get the house replastered. After dreaming of triple glazing, we got stupid quotes from Norrsken (£35k) and Nordan (£25k) for 4 windows, 2 bays, a front door and 2 narrow sets of patio doors and my piss-poor negotiating skills didn't get them to shift much, it's back to UPVC 2G. My questions about airtightness, corrosion resistance and whole-window U values rub double glazing salesmen up the wrong way so I am procrastinating about getting any more in because it's a painful process.

 

Best purchase of 2024? One of these: https://www.bosch-professional.com/gb/en/products/gde-162-1600A001G8 which when connected to my dust extractor lets me drill anywhere in the house without making a mess.

Edited March 18 by Sparrowhawk

[GP41]

Honestly, the parallels with where we are are amazing.  Admittedly, I think you are starting with a bigger challenge, but the procrastination and perfectionism are real.  The 3AM "how on earth can I get ducting through there" moments have been all too frequent - we're in the middle of backtracking from 'being sold' a solution involving rigid steel ducting run through a cold loft, told it will be ok to "just put it under the insulation" to now looking at a semi-rigid radial solution with ducting largely within the envelope. 

 

I'm currently walking into our living room several times a day to give it a good dose of deliberation as I try to work out how to install underfloor insulation to the suspended floor (how many times can I read the EBS guidance document), how to extend under the floorin the adjacent room that is covered in Amtico that we are not planning to remove, what to do with a false wall that contains an old pocket door that we know is a cause of unwanted airflow but that will be a massive disruption to remove.  

 

And in parallel with that and whilst waiting on the ASHP/MVHR pricing to come through, gluttons for punishment, we've started the process of getting window quotes.  We've started with Norrsken, based on recommendations here and their commitment to taking end-to-end responsibility; after seeing your figure I'm thinking there's a lot we can do with our current uPVC 2G and a decent can of foam...  

 

And the arrival of MVHR is going to put pressure on progressing the airtightness work.

 

It'll all be worth it though. 😊

[Iceverge]

On 18/03/2025 at 19:49, Sparrowhawk said:

Back to MVHR, and ducts here are difficult to route due to extensions,

 

I'm semi convinced that a unit just dumping air into a hall or large room and extracting from somewhere else would work so long as you opened internal doors occasionally. Air mixes pretty well. 

 

On 18/03/2025 at 19:49, Sparrowhawk said:

Sound proofing is my nemesis and no matter what I do the downstairs toilet remains... a place for exhibitionists. Ditto airborne sound from ground floor to first floor in certain rooms. I've sealed the perimeters with airtight sealant, added glassfibre between the joists and made sure the floor is tight. And we can still have a conversation with barely raised voices. Next stop is overboarding the ceiling, and then resilient bars if required.

 

For airborne noise air pathways are key. Do you have any stud walls routing up to the floor void? 

 

Then add mass. Doesn't matter where it goes really, above, below, between, all gravy. Sand above the plasterboard would do the same thing as expensive mass loaded vinyl.

On 18/03/2025 at 19:49, Sparrowhawk said:

We need to replace windows this year so we can get the house replastered. After dreaming of triple glazing, we got stupid quotes from Norrsken (£35k) and Nordan (£25k) for 4 windows, 2 bays, a front door and 2 narrow sets of patio doors and my piss-poor negotiating skills didn't get them to shift much, it's back to UPVC 2G. My questions about airtightness, corrosion resistance and whole-window U values rub double glazing salesmen up the wrong way so I am procrastinating about getting any more in because it's a painful process.

 

Don't loose hope. A good company will turn up. I'm a big fan of quality uPVC. If it was twice the price more people would use it . 3G is good but quality sealing and latches are far more important. 

 

Great thread and well done on the work. Keep us posted.