Insulating concrete floor.

[robinbanks]

If you work on the floor (at 71 years old? Good show!) I'd perhaps consider putting money at those interlocking high density foam panels; thick ones like gyms and martial arts studios use..

 

[Deluks]

Is the existing floor the finished floor height? How much space do you have to play with? Increasing floor height will affect door openings and may create step downs into adjoining rooms.

 

[Bella b]

Its a Cornish Unit built around 1950 so remediation is when the Cornish prefab units are replaced with brick for structural integrity. The rot around the windows was due to leaking leadwork, the whole lot was repaired by roofer during the new roof going up with the new windows,and its all up to building regs insulation wise, its a hip roof not a dormer .
No definitely not fit when I bought it, but neighbours said the windows hadn't been opened in three years and now after new roof etc, new ceilings upstairs, it is absolutley dry now so I want to insuate the downstairs concrete floor as I will be working in there for long periods. I bought it off a housing association , my second project like this , and there is no damp anywhere now after my first wet winter, obviously I keep it well ventilated. I have spent much time planning the work as a whole and prioritising but all the major repair has been done I'm just getting ready for second fix electrics. Did you know there is a desperate housing shortage in UK? So the project is to test what can be achieved on a modest budget if most of the non specialised labour done by the owner. It is tragic that so many similar properties are either left rented out but miserably cold and damp when they can be brought back to pleasant homes, or demolished ,albeit with some time consuming roof replacement and upper windows but that was the major cost , followed by rewiring. Most of the artisans who have been here acknowledge that the house was well built in the beginning, probably better than some built a few years ago.

 

[Bella b]

Is the existing floor the finished floor height? How much space do you have to play with? Increasing floor height will affect door openings and may create step downs into adjoining rooms.

Yes this is my dilemma, I am going to rehang the door the other way,so will have to take it off, and modify the threshold to accomodate the levels .I know there are restrictions about raising the floor too much where a bottom step of staircase meets the floor, so think a threshold with a gentle gradient will be required. The room opens onto a 1m2 hallway with the staircase leading from it so height is a consideration which is why I went down the thin foil wormhole. In fact I have found someone to do most of the floor installation .
I wouldn't have that much height but am now deciding about insulation panels and still open to more reports about the foil or VPM to minimise cold bridging at perimeter. Whatever I do it will definitely be warmer but yes I want to get as much benefit from height available and £££ available. The OSB3 TG is 18mm, I'm thinking 20mm PIR boards under that . Half the room will have vinyl sheet flooring as a wet art space , the rest is carpet as my textile work mostly done on the floor. The PIR (possibly by ProWarm) needs to be fixed with adhesive but this is better than drilling into the sound concrete floor and possibly through damp proof layer under it.
So after all that I think 50mm max including OSB

 

[cdbe]

One of the best things you can get for this situation is this stuff:

Unfortunately it's not technically designed for the purpose - its made for roof decks. If laid on a flat concrete floor it's Incredibly rigid.

In terms of your project - it's quite common for councils and HA's to sell off substandard homes because they can't economically upgrade them with their ridiculous red tape and overpriced contracts, in Liverpool and Manchester you could buy houses for £1 if you undertook to bring them up to a minimum standard by yourself - a great idea that should be done a lot more.

 

[Deluks]

One of the best things you can get for this situation is this stuff:

View attachment 393448

Unfortunately it's not technically designed for the purpose - its made for roof decks. If laid on a flat concrete floor it's Incredibly rigid.

I thought same, but budget wise it doesn't compare with buying the bits separately.
25mm PIR and 12mm ply came to mind, but doesn't have the benefit of t&g unless biscuits are used or a slotted equivalent.

 

[robinbanks]

Whatever I do it will definitely be warmer

(It will if you don't use multifoil - you can use PIR for a perimeter too)

Have you considered installing UFH work area?

too much where a bottom step of staircase meets the floor

Come up an entire step? How much headroom have you got elsewhere?

 

[Bella b]

I thought same, but budget wise it doesn't compare with buying the bits separately.
25mm PIR and 12mm ply came to mind, but doesn't have the benefit of t&g unless biscuits are used or a slotted equivalent.

I thought same, but budget wise it doesn't compare with buying the bits separately.
25mm PIR and 12mm ply came to mind, but doesn't have the benefit of t&g unless biscuits are used or a slotted equi

(It will if you don't use multifoil - you can use PIR for a perimeter too)

Have you considered installing UFH work area?


Come up an entire step? How much headroom have you got elsewhere?

No, I haven't got too much headroom , but I think I can make it work just around 50mm height. The original floor covering (removed by seller as filthy) must have had some height so the extra should be doable. I 'm not having UFH , I'm eligible for energy upgrade but not with UFH only radiators, mysteriously. For the perimeter PIR do you put that behind the skirting?

 

[Bella b]

I thought same, but budget wise it doesn't compare with buying the bits separately.
25mm PIR and 12mm ply came to mind, but doesn't have the benefit of t&g unless biscuits are used or a slotted equivalent.

I think I'll

One of the best things you can get for this situation is this stuff:

View attachment 393448

Unfortunately it's not technically designed for the purpose - its made for roof decks. If laid on a flat concrete floor it's Incredibly rigid.

In terms of your project - it's quite common for councils and HA's to sell off substandard homes because they can't economically upgrade them with their ridiculous red tape and overpriced contracts, in Liverpool and Manchester you could buy houses for £1 if you undertook to bring them up to a minimum standard by yourself - a great idea that should be done a lot more.

Yes lots of young people could do it if they didn't mind roughing it for a bit , but even though my house was cheap (its in SW,so not as cheap as some areas,but the mould and doggy filth saved me £1000's on price) most young people can't afford the deposit . I have raised this blind spot at housing seminars with MP's present they don't want to think outside the box just build on more greenfield land . No wonder UK is broke and homelessness out of control. A family are renting the other one I did and sold, although it was 19thC cottage with roof caved in at beginning

 

[gehngus]

It was around the beginning of this century when regs started going potty with u-values, r-values and insulation and the necessity to vaxuum test a building to ensure it was air tight. Then not long after realised moisture was a massive issue so add trickle vents, heat recovery systems to replace moisture air with fresh air and emphasised the importance of air flow.
The Victoria's figured this out over 100 years earlier.
So the buildings most likley to have moisture over the last 150 years are between 1998 and 2005.
Then we have cavity walls. Cavity to stop the water and moisture being filled with beads or shredded paper or expanding foam.
What a mess that caused.
Then they decided to reverse the regs that said "No polystyrene in buildings. It's a fire risk" into "cover the outside with 100mm polystyrene. We all know how that went.

You just couldn't write it.

Anyway. I have used the multi layer foil and special things. It was called something super-9, then super-11 then something else.

It was designed to save thickness or save head space etc.
I mean when every mm counts why use 100mm insulation when you can use 9mm insulation?
Installation was asked follows:
Surface - 50mm batton - super-9 - 50mm batton - surface.

It had to be done this way because the u-value was achieved due to it's reflectability.

It ended up being slightly thicker than insulation and a lot more hassle.

I wouldn't have thought it could be installed in a floor, and if this is now the case I no idea why you would have to fix it to the concrete floor and presumably screw through the dpc?

More madness i say.

 

[endecotp]

when every mm counts why use 100mm insulation when you can use 9mm insulation?

Because the idea that 9mm of snake-oil insulation is as good as 100mm of real insulation is false.

 

[robinbanks]

why use 100mm insulation when you can use 9mm insulation?

It had to be done this way because the u-value was achieved due to it's reflectability.

No. Very little of the heat of the plasterboard leaves in a radiant fashion, so there is precious little to reflect

mean when every mm counts why use 100mm insulation when you can use 9mm insulation?
Installation was asked follows:
Surface - 50mm batton - super-9 - 50mm batton - surface.

50mm + 9mm + 50mm is 109mm

If every mm counts, why use 109mm of crap insulation when you can use 100mm of decent insulation

And installing the snakerfoil would have taken longer with all that detailing

I'm sure you see the lunacy in it and your post is actually making a point of it being a terrible idea, but it kinda comes across as endorsing it. It shouldn't be endorsed

The Victoria's figured this out over 100 years earlier.

No, they just built crappy, draughty houses, then lit massive bonfires inside them to try and keep warm, shoving huge amounts of heat and pollutants up the chimney, choking everyone in the district and sowing the seeds for the legacy we're now trying to walk back with climate change targets

But if it helps you sleep at night, keep drinking that koolaid!

 

[Bella b]

This is an interesting discussion . I've got about a week to decide what to do but this has definitely given me lots of information . There is so much conflicting information from experts and suppliers . About the cladding, I stayed in a grotty hostel in the same London borough and sent them photos of dangerous electrics. They replied and asked me what I'd had for breakfast!!! They only did food poisoning for hotels, it seemed.