Retrofitting water based underfloor heating

[Loueytb3]

Can you do it? I know electric underfloor heating can be retrofitted but it's expensive to run in a large area. We previously had water based underfloor heating put in an extension but the pipes were embedded into the concrete when it was built. We are (hopefully) moving to a house where we are going to do the kitchen diner and wondered about putting in water based underfloor heating. I can see that there are low profile systems now but I have no idea if they are any good. Does anyone have any experience of these systems?

Part of our wet system was retro fitted. It’s possible. It just costs to dig out the floor and make sure the levels are correct afterwards. I love the underfloor heating though.

We have a low profile system across a new extension (easy) and existing space hard.

The actual system installation was easy and it's very effective. However the builder was having kittens over getting the floor heights the same after having to chisel out a bit. So you'll need your builder to be up for it, factor in extra dust, skips, time and top levelling screed (maybe latex) to get it ready.

Yes, you can, with either a concrete or a wood subfloor. But it is pricy to fit because you have to insulate under the floor so the heat goes up and getting the levels right is a faff.

I'm pretty sure it's a concrete subfloor.

Roughly how expensive is it to dig out the floor? We need to get builders in to knock a wall out and put a beam in so in theory I can get them to do it all at the same time. I just can't work out whether it's worth it to put the underfloor heating in. We will be renting until it's finished but we need to factor in putting a new kitchen as well and we don't want to be paying rent + mortgage for too long.

is it a concrete floor or a wooden floor with void under?

We got this done in September. Our house was built in early 1950's and has a concrete floors. The builders didn't need to level the floor as it was already even. They put some insulation down, I think, and a polystyrene boards in which the ufh is embedded. We have an engineered wooden floor on top of it. It works beautifully and the whole downstairs feels much warmer and more comfortable then before it was installed.

We had a low profile water underfloor heating put in on our existing floor during a renovation. We had a 1980's extension which consisted of 3 rooms knocked through together to make one big kitchen. They took the tiles up, in one section and carpet in the other. From memory I think they did level it. It was polypipe (other brands available) it seemed very new to most builders I spoke to 2 years ago. It is specifically designed for refurbishments and new builds with the floor already done and doesn't require the floor to be dug out. It works beautifully underneath our stone floor and in the longer term much cheaper to run than electric.

Ooh MammaAgata that sounds just like the sort of thing we need. How long did it take to do?

The floor is engineered wood in the dining area and tiles in the kitchen (see pic). As far as I know the subfloor is concrete. We would be replacing the floor throughout regardless. The wall between the rooms is going.

Hi Louey, we basically rebuilt the 3 rooms and made into 1 big room - it's hard to explain but it was a shoddy 1980's extension attached to our house with a glass linkway. We made the glass linkway part of the room and properly roofed it etc, so the whole project took about 4 mths, from memory the floor part of the this was about 3-4 days. I would start contacting builders for quotes, but be mindful of them not knowing about the type of options available in lay on UFH heating systems (lay on an existing floor). If you google polypipe you can see the spec and where to use it etc. Its perfect for a renovation project. I am not a builder though! I only offer this advice from my own experience.

I'm using polypipe overlay too in my new kitchen/extension, some existing concrete floor, some new. The builders have said they will latex it to level it and then lay the polypipe. Looks pretty straightforward from the website, the plumber is unsure about it though as he hasn't used it before.