Retrofit wet UFH

[NoNameNoNumber]

We have a ~2000 build, EPC says solid concrete floor assumed, no insulation.
We’re looking to change from oil to ASHP and part of that will be pretty drastic plumbing changes. Perhaps wet UFH is the way to go. Dig up ground floor slab, insulate and add UFH. Then I saw on TikTok a company chasing the floor out to fit the tubes. Does this rely on a well insulated slab already or it it not particularly relevant?


Alternatively, we stick with no floor insulation and chase the walls/ceilings out to remove all the microbore.

Anyone dealt with a similar dilemma?

 

[NoNameNoNumber]

Thank you for the info, that would make life much less messy, the mrs wants to replace all the skirting anyway, Id need to trim all my new doors down :/
~17mm I could deal with, we only have 8’ ceilings so would certainly want as minimal as possible.

 

[NoNameNoNumber]

Have a look at my active thread at the moment in this forum. The latest pictures show my retrofit with the manifold. It's not installed yet functioning but has just been pressure tested.

I had the same issue as yourself. Rather than digging up old screed etc we retrofitted 16mm using this product.

https://www.theunderfloorheatingstore.com/products/prowarm-loflo-lite-dual-purpose-panel-16mm

The rooms we didn't install UFH; we put osb board down to bring the level up - before putting new flooring / skirting so it all run level. However this is just mainly down it being so open plan and not necessarily required.

Thanks for the info, looks like a suitable way for us to go-despite the upheaval. But to replace all of the microbore downstairs would require butchering the walls, coving anyway. and pulling floors upstairs.
Either way-it won't be pretty.

Are you on a heat pump?

 

[NoNameNoNumber]

Done a little digging
We have 25mm of polystyrene then 50mm of screed on our floors.

How bad an idea is it to just rip all that out, lay new insulation (something better than polystyrene) and screed over wet UFH
VS trying to overlay a retrofit kit.

 

[NoNameNoNumber]

Fair point… the full picture.

Oil boiler is nearing EOL. Boiler service + parts, breakdowns etc in the last 2.5 years is costing £300 a year just to keep it going and we’re told it was rubbish when new, now it’s old and rubbish I should keep a £5k pot ready for its replacement…
Next issue, 3/5 houses built have needed new oil tanks, mine is on a boundary right next to an open water source and ~2m from the house… so we’re told another 3-5k to fit a new compliant tank in the next couple of years, and I’ve gotta find somewhere else to put it…

Ergo the chats around ASHP since we have had 6.7kW PV installed on the roof.

We’re going to be having an extension to the kitchen and diner, making around 40m sq of tiled social space we just can’t run on electric UFH so this is where the real desire for wet comes in.

So if we were to leave the floor and replace all the microbore/upsize the rads, then yes we’re ASHP ready but we really would prefer some kind of heating to the porcelain floor.

 

[NoNameNoNumber]

What is the best retrofit system?

Would it still require screed over the top?

 

[NoNameNoNumber]

You know you can mill into the existing screed floor and lay your pipes into that?

https://x.com/retrorouteufh?s=21&t=D1v3GK9gMSn4AYpUgmuhNw

Or use something like Thermoskirt

We don't have enough insulation under our screed for that AFAIK.

 

[NoNameNoNumber]

I guess the fireplace has to come out?
Rebed the hearth higher up, move the mantle too?
Also new front door in first too?

Spoiler: Pics

 

[NoNameNoNumber]

should be able to check that floor complies with standards V

A quick calc suggests our floor is 0.785 W/m²K
Which looks to be some attempt at compliance circa ~2000 when it was built

 

[NoNameNoNumber]

Downstairs is approx 130 m2

Cost of channeling, manifold, pressure testing and flex seal over the pipes was almost 4k.

I was replacing a warm air fed system, so i had no pipes or rads in the house.

I’ve just given these guys a call.
16mm deep channel with 14mm pipe at 125mm centres ~ 100w/m^2
Which is 50% more than the retrofit kits. And far less complicated to fit.

I’ll send my floor plan over to them to quote up.

Thank you Paz

 

[NoNameNoNumber]

Morning Guys,

We're going down the route of machining the floor screed for ufh pipes to be laid in. I've been told the mixer will control water flow to 30ºC but looking at the LVT, we're being told it'll only take 27ºC.
Are other LVTs available that will take a little higher?

 

[NoNameNoNumber]

Levelling compound over pipes, then flooring.

 

[NoNameNoNumber]

I’ve lifted some LVT. The contact adhesive that remains, does that need to be taken up too before JK come? Any tips on doing this?