Wet system underfloor heating for ground-floor extensions, open-plan kitchens, and modern house transformations across SE London. Hydraulic balancing performed post-installation to guarantee even, consistent radiant heat throughout.
A wet underfloor heating installation typically spans three to six working days in a domestic property, depending on the floor area being treated, the condition of the existing subfloor, and whether structural screeding is required as part of the build-up. The timeline is established during the site visit once we have assessed the specific floor construction.
The starting point of every underfloor heating job is a thorough subfloor evaluation. The construction of the floor — whether it is a suspended timber ground floor, a solid concrete slab, or a beam-and-block extension base — determines both the pipe-laying method and the required insulation build-up depth. Insufficient insulation depth is the primary cause of poor underfloor heating performance: heat that conducts downward rather than upward into the living space wastes energy and never delivers the ambient warmth that makes UFH worthwhile.
Boiler output capacity is assessed at the same stage. Adding a wet UFH zone to an existing heating system increases the circuit's demand. An undersized boiler, or one already operating at near-capacity with the existing radiator circuit, will fail to meet the combined load. Where the existing boiler is not suitable, we identify this during the site survey and discuss the options — including whether a new boiler installation is required concurrently or whether the UFH zone can be isolated to periods when the radiator circuit is not in full demand.
The pipework is laid in a serpentine pattern within the insulation layer, with individual zone manifolds controlling flow to different areas of the floor. Pipe spacing is calculated to achieve the target surface temperature across the full zone rather than concentrating heat at the manifold end. Following installation and pressure-testing of all pipe circuits, the floor is screeded and allowed to cure before the system is commissioned.
Hydraulic balancing is performed as a final step after the screed has reached thermal equilibrium. This process equalises flow rates through each circuit so that every part of the heated floor reaches the same surface temperature. A system that is not hydraulically balanced will produce warm patches near the manifold and cooler areas at the circuit extremities — a common outcome when this step is omitted or rushed.
You describe the space — a ground-floor extension, a kitchen, or an open-plan area — and its approximate floor area. We discuss the floor construction, the existing heating system, and the intended floor finish, as these all influence the UFH specification. We book a free site visit to complete the assessment in person.
Jonathon or Jack Austin attends and assesses the existing subfloor construction, establishes the required insulation build-up depth, and evaluates whether the existing boiler can support the additional UFH zone load. A fixed-price written proposal is provided within 24 to 48 hours covering the full installation scope.
Insulation boards are laid to the specified depth across the floor area. The UFH pipework is installed in a calculated serpentine pattern with consistent spacing, fixed securely to the insulation and connected to the zone manifold. Each circuit is pressure-tested individually before the floor is closed. The manifold is connected to the boiler circuit and zone controls installed.
Where a screed build-up is required — on solid floors or beam-and-block bases — the screed is applied over the pipe array and allowed to cure to the manufacturer's specified timeline. During this period the system is run at a low temperature and gradually brought up to working temperature over several days, preventing thermal shock cracking of the screed during curing.
With the screed at thermal equilibrium, the system is commissioned and hydraulic balancing is performed across all circuits. Flow rates through each loop are adjusted until surface temperatures are consistent across the full floor area. We walk you through the zone controls and thermostat, and confirm the system is performing to specification before leaving.
Every underfloor heating proposal is a fixed price. The site assessment identifies all structural and mechanical requirements before we quote, so there are no provisional sums or mid-project revisions. Screed, manifold, and all pipework are confirmed in the written proposal before work commences.
Jack was so helpful, honest and professional and did a fantastic job. I completely trusted him — hands down the best trades company I have ever used and will be my go-to for everything from now on. I'm so glad to have found Jack and his family business. Highly recommended.
We attend, evaluate the subfloor and boiler, and provide a written fixed-price installation proposal.
We'll confirm receipt and arrange a site assessment at a time that suits you.