Case Study: Underfloor Heating Retrofit in Wimborne

Most of the underfloor heating enquiries we take start the same way: someone's fed up with a freezing kitchen floor and a radiator hogging the only spare wall. This one came from a couple in Wimborne, in a 1930s semi off Leigh Road they'd been doing up room by room for years. The kitchen-diner at the back was the last big job on their list. They wanted the radiator wall back for a dresser, and they were tired of cold quarry tiles underfoot every morning.

Here's how the job went, what it cost and what we'd tell anyone in East Dorset weighing up the same thing. We've folded details from a couple of similar recent jobs into this write-up to keep our clients' homes private, but the numbers and timings are the real ones.

The brief: warm floors without digging up the kitchen

The house had a solid floor under the quarry tiles, which ruled out the cheapest option straight away. A traditional screeded underfloor heating system needs around 100mm of depth for insulation, pipe and screed, and on a solid 1930s floor that means days of breaking out concrete, skips on the drive and a real risk of disturbing the damp-proofing. Nobody wants that for one room.

So we quoted a low-profile overlay system instead. The pipework sits in pre-routed insulation panels laid on top of the existing floor, with a self-levelling compound over the top. Total build-up on this job was 22mm. That meant trimming two doors and adjusting the kitchen plinths, which we flagged at the survey stage rather than springing it on them halfway through.

Why we fitted a wet system, not electric

Electric mats are quicker to lay and make sense in a small bathroom that's heated for an hour a day. For a 26 square metre kitchen-diner that's in use morning and night, water underfloor heating wins on running cost, and it frees the room from radiators entirely. The couple's boiler had plenty of spare capacity, and there was a handy spot for the manifold in the utility room next door, so the pipe runs stayed short.

It also runs at a much lower flow temperature than radiators, so if they switch to a heat pump down the line, the heating in that room is already heat-pump-ready. That came up more than once. It's a question we're hearing on most heating jobs now.

How the four days on site went

Start to finish, our team was on site for four working days:

1. Day one: clear the room, check the floor for level, prime it and lay the insulated overlay panels.

2. Day two: lay the pipe circuits into the panels, mount the manifold in the utility room and run the flow and return back to the boiler.

3. Day three: pressure-test the circuits and leave them under pressure overnight, then wire the controls and fit the smart thermostat.

4. Day four: pour the self-levelling compound over the panels and commission the system once it's cured enough to check.

We never cover pipework that hasn't held pressure overnight. It's a small discipline that costs us half a day and has saved more floors than we can count. The tilers followed the week after, once the compound had fully cured.

What it cost

The all-in figure for this 26m² kitchen-diner was £4,680, covering design, overlay panels, pipework, manifold, controls, levelling compound and commissioning. The floor finish on top is separate, since that’s a tiling or flooring job in its own right.

As a working range for retrofit jobs around Dorset, budget £115 to £230 per square metre fitted. Where you land depends mostly on three things: how flat and sound the existing floor is, how far the manifold has to connect back to the boiler, and how many doors and thresholds need adjusting. Older properties usually sit toward the top of that range, and we’d rather tell you so now than surprise you later. Our plumbing, heating and electrical team handles the whole job in-house, so there’s no juggling separate trades.

We always survey before quoting, and the price we give after survey is the price you pay. On this job the survey picked up the door trimming and a slightly out-of-level corner, both priced in from the start.

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Thinking about warm floors before winter?

Late summer is the right time to sort this. The job needs a week or so plus curing time, and our autumn diary fills up fast once the first cold snap arrives. If you’re in Wimborne, Ferndown, Blandford or anywhere across Dorset and Hampshire, book a free survey through completebuilds.com and we’ll tell you straight whether your floors suit a retrofit and exactly what it’ll cost.