Underfloor heating retrofit

[Roofies]

Hello
I'm looking to retrofit wet underfloor heating on the ground floor of a semi detached house. I was planning to only ideally do this in the living room and hallway, but pipes will need to be run from the boiler which is separated from the living room by the kitchen. I ideally do not want to change kitchen flooring just yet since will be looking to remodel the kitchen in a few years when I have saved up.

I was told the radiator pipes can't be used for ufh since they are too small. Options are to run the pipes under the kitchen floor (this will hence need to be dug up) or outside via the patio (the boiler is in a utility room near the back of the house).

Does this sound right? And what have people typically done and why? I don't want to wait another few years so I have the budget to remodel the kitchen before I install ufh throughout the ground floor, although I appreciate that would be easier and cheaper over all.

You could get all the pipes put in and then only connect them up properly when you get the kitchen done? They all run back to a manifold and then that connects to the boiler so you could just get the pipework and the manifold fitted and connected in later.

Running pipes externally is a really bad idea. They could freeze or get damaged

Thanks, @Geneticsbunny doesn't make sense spending all this money now and then not having functioning heating. And would mean that the radiators still stay on the walls of the living room and hallway. The idea is to paint and redecorate after ufh installed, floor changed, radiators taken off. Not sure what the going cost of a kitchen is and when I would have the budget to spend on that.

Would there be a way to run temporary pipes to the manifold from the boiler, maybe under the kitchen cabinets? Any chance you could post a floorplan or rough sketch with the boiler and kitchen units on it?

Follow up questions to this. Tagging @PigletJohn please

I have now spoken to a builder and a plumber (2 different people) about what retrofitting wet underfloor heating on my ground floor would entail. The plumber thinks that underneath the engineered wood floor lies timber floor, the builder thinks it is concrete. only the extension is new, the main house is old. I know these are guesses and we need to take one of the boards up to check, but in the meantime...

Is it easier to retrofit on a timber floor vs a concrete floor? The builder seemed to imply that he would need to dig out all the concrete to then attach insulation etc. And it would take at least 5 weeks start to finish. The plumber seems certain that it is a 2 week job on an underlying timber floor.

Is this correct? What sort of ufh system am I looking for in each case - I have read about wunda and polypipe but can't figure out suitability of either. And is the next step definitely taking a small part of the floor apart to check what lies beneath?

They are both right. If it's a concrete floor. It will need to be dug up, insulated and then relayed which will take a long time and require skips. Suspended floor method depends on what system they will be using. We have suspended spreader plates. It means the underfloor heating has a quicker response time than embedded underfloor heating and is quicker and cheaper to install. I guess it might be slightly more expensive to run than embedded pipes but as heat rises it probably doesn't make a lot of difference. I think it is also possible to put embedded underfloor heating underneath wooden flooring.
Taking a section of floor up to check underneath is a reasonable idea. You might have a mix of concrete and wooden flooring if there is some original floor and an extension so you will need to do both areas.

If it's a concrete floor, and you are not rolling in more money than you know what to do with, it's a non-starter.

I am puzzled that people who have been to your house don't know if the floors are concrete or wood. Did they jump up and down, and go outside looking for airbricks below floor level? Did they look in the cupboard under the stairs?

@PigletJohn im looking into retrofitting ufh in a 60s bungalow. Do you not think it’s worth it? I just want to be warm, all the time.

@PigletJohn and @Geneticsbunny - thank you, very helpful. Cupboard under the stairs sounds intriguing- what should I be looking for?
I did read about the jump test- will try that tomorrow. I couldn't see any air vents outside. Is that what I am looking for?

Have you got a gas boiler? Have you got wooden floors with a ventilated void beneath? How old is your house?

UFH will not make your warmer than radiators, but you may find the extra cost makes your house more beautiful, if you consider radiators to be unattractive.

Thanks. Gas boiler and concrete floors. Wasn’t planning on digging up the floors; just losing some floor to ceiling height.
But if it doesn’t work better than radiators I won’t bother! I’ll save my money for a mezzanine to pack the grandkids into.

The cupboard under the stairs often has an exposed floor, or scraps of carpet or vinyl that you can lift up to look underneath. It often has pipes or cables coming up through the floor, and you can see if they come through concrete or gaps in wood.

How old is your house?

@PigletJohn the ufh exploration started since i wanted to free up wall space - I have the most enormous radiators which severely limit furniture placement and general zoning of the living areas.
Would you have a view on how effective vertical radiators are, instead of the usual horizontal ones. These can possibly free up some horizontal space as an alternative to ufh.

Vertical ones are better for heating the ceiling, as the warm airflow comes out of the top, and rises. They more often fail to heat up properly, but I think that is probably because they are accidentally installed upside down. They have internal baffles to direct the flow of hot water inside. A wide, low radiator heats a room more evenly than a short, tall one.

If your existing radiators are not satisfactory, and you consider them to be too big, start by feeling them all over to see how hot they are. The flow pipe at one end, and the top of the radiators, should be "too hot to hold" and the return pipe and the bottom of the radiators should be "too hot to hold for long". The sides, middle and bottom of the radiators should have no cooler patches. All the radiators in the house should be equally hot within half an hour of the heating coming on, though the radiator in any room which heats up quickest or gets too warm can be adjusted to be cooler, to prevent that room heating up too fast and stealing flow that is needed in other rooms.

Modern gas boilers typically have more than enough power to heat typical houses, but there may be design or maintenance problems in the system. Heat pumps run at lower temperatures and radiators need to be bigger becsuse they are not as hot.

Why on earth would you retrofit underfloor heating with concrete floors. You’d literally have to destroy your house. It’s a bizarre plan

@bullrushes , I don't intend to install ufh if the floors are concrete - I just haven't been able to figure out whether it is or not, since 2 different worksmen had divergent opinions as to the floor.

@PigletJohn I haven't really experienced any cold patches and I do bleed the radiators regularly. Need to work out the BTU needed for the room vs what the current radiators add up to. A bay window is single glazed (others are double glazed) so I need to get that changed. One radiator is about 1.6m wide and it is permanently hidden behind a sofa because of the room layout. If ufh is a no go, I would be keen to consider vertical radiators in the living areas.

You only need to bleed them if they have "air" in them, which you will know by the top being cold.