Underfloor heating (wet) retrofit

[Mike1983]

Hi all

I'm currently getting a house extension and was considering making a change to add underfloor heating (wet / not electric) into the specification. The floor slab has not yet been cast in the extension part (approx 41sqm) but the area in the existing house I'd also like it added (approx 24sqm) has an existing slab. The extension extends the existing area mentioned above to make one large room of approx 65sqm

From what I can gather, to do this without having differening floor levels between the rooms with / without underfloor heating, I'd need to break out the existing slab and recast at the correct level.

So I guess my question is two-fold

1 - Do you think it's worth making this change?
2 - How much would I expect to be paying for sorting out the existing slabs (breaking down / recasting to a lower level? I'm based in the North West.
3 - Would you consider having the room "split"? I.E the extension part having underfloor heating with the existing part just having radiators.

I'll obviously be talking to my builder but just thought I'd get a good idea of the work myself first.

Thanks all

 

[SimonR]

I have just been through the same with my extension. My builder quoted me £4k -£6k depending on what he found to dig out the existing floor, insulate, cast the slab, put in underfloor heating and dry screed. As this was outside our budget we decided not to.

 

[Mike1983]

Thanks. What was the approximate footprint of the area?

 

[SimonR]

Thanks. What was the approximate footprint of the area?

20 of existing floor to remove and 30m2 of additional floor slab

 

[tom_nieto]

We elected to split and only have half the floor heated rather than dig up the existing. Absolutely the best move in our situation and I’m very pleased that we’ve got underfloor heating in the extension and I’m doubly pleased that we didn’t dig out our existing floor.

 

[SimonR]

I am to anal to only have half the floor heated. It would drive me insane. Hence the decision not to have it at all.

 

[Mike1983]

Are you intending on living in the house during the proposed works?

Thanks everyone. Yes I'll be intending to still live in the house whilst the work is undertaken, not having use of the rooms whilst the base is broken out wouldn't be a problem though will speak to my builders and see what they say.

 

[Mike1983]

If they pour the concrete in one go you wont have access to the house if the entire ground floor is wet, I plan on moving out the family for a few days when I replace the floors in our house

Understood thanks. I'm lucky in that regard as one of the rooms to be broken out is currently unused and the other is the kitchen (that is planned to be ripped out anyway as the extension is for a larger kitchen). Will have a temporary kitchen set up as part of the current plans.

So what's your approx quote / area you're dealing with?

Thanks

 

[UTT]

Hi all

I'm currently getting a house extension and was considering making a change to add underfloor heating (wet / not electric) into the specification. The floor slab has not yet been cast in the extension part (approx 41sqm) but the area in the existing house I'd also like it added (approx 24sqm) has an existing slab. The extension extends the existing area mentioned above to make one large room of approx 65sqm

From what I can gather, to do this without having differening floor levels between the rooms with / without underfloor heating, I'd need to break out the existing slab and recast at the correct level.

So I guess my question is two-fold

1 - Do you think it's worth making this change?
2 - How much would I expect to be paying for sorting out the existing slabs (breaking down / recasting to a lower level? I'm based in the North West.
3 - Would you consider having the room "split"? I.E the extension part having underfloor heating with the existing part just having radiators.

I'll obviously be talking to my builder but just thought I'd get a good idea of the work myself first.

Thanks all

Mike,

Polypipe overlay heavy duty system on existing floor. Basically an 18mm board straight onto existing floor, 12mm pipe within the board and 9mm ply on top.

New build/extension part get builder to put down 100mm kingspan type insulation, then ufch pipe clipped down to insulation or in plastic tray on top of insulation. Then screeded to bring FFL to roughly same level as existing plus 18mm overlay and 9mm ply......hey presto, new and existing floors at same height with no steps.

Pipe work for ufch goes back to 1 manifold (in preferably central location, i.e. Under stairs) and as both systems run on same flow rate temp of about 50/55 degree no need for separate manifold.

Jobs a good un....

 

[Bat]

We had it put in our extension and left original part of house with rads. UFH is amazing, warm kitchen tiles are simply epic. If budget and logistics restrict then I would definitely just have it in the new part. I'd love to retrofit to the rest our our house one day though.