What this work covers
Underfloor-heating pipework divides the floor into circuits and connects them to a manifold so heated water can circulate evenly. Once the screed covers the pipes, even a small fault becomes disruptive to repair, so bends, spacing, circuit labels, flow, and pressure need to be checked first.
When this work is needed
New circuits may be needed when old pipework is failing or when an extension or layout change alters the heated area. If only one room feels cool, first inspect manifold valves, circuit flow, boiler settings, and possible blockage before deciding to replace the floor system.
Decide before laying the circuits
Set the heated zones and the finished-floor build-up together.
- Rooms receiving new or retained heating and the area served by each circuit
- Manifold position, maintenance clearance, and circuit labelling
- Pipe spacing, minimum bend radius, and fixing method
- Insulation at extensions, perimeter walls, and other exposed zones
- Pressure, hold time, witness, and record required before screeding
Check in the quote
Do not assess the price by floor area alone. Check circuits, manifold work, insulation, and testing.
- Are inspection, removal, retained sections, and new pipework separated?
- Are pipe material, size, spacing, and manifold replacement or relocation stated?
- Is perimeter and extension-zone insulation included?
- Are circuit labels, flow balancing, and pressure testing included?
- Who repairs and retests a failed circuit and supplies photographs before screeding?
If you have the heating plan, manifold photographs, or a quote, I can help review the circuit layout and pressure-test scope.
What to check on site
The floor should be handed to the screeding team with every circuit identified and still under test pressure. That makes damage visible before it disappears into the slab.
- Inspect existing heating and manifold
Trace each existing circuit at the manifold, mark signs of leakage, crushing, or discolouration, and operate every valve. Confirm that any new connection remains accessible after the floor is finished before setting the replacement scope. - Install floor heating pipes
Divide the new pipework into manageable room circuits, lay it at consistent spacing, and secure it without sharp bends or overlaps. Coordinate tighter or wider zones around thresholds, extensions, and fixed furniture without exceeding the bend radius. - Pressure-test and connect boiler return
Pressurise the circuits, inspect all joints, and record the change for each loop. Keep the system under pressure during screeding so damage is detected immediately, then hand over a complete route photograph and manifold schedule.
Where problems usually start
- Kinked circuit A pipe bent too tightly or crushed can restrict flow until that floor zone no longer heats evenly.
- Manifold and valve joint A leak here can spread moisture through the floor and into adjacent finishes, so it needs close inspection under pressure.
- Missing pressure test A small leak discovered only after screeding can turn a local repair into removal of a much larger floor area.
A cool room does not by itself prove a kink or leak. Check boiler settings, manifold valves, circuit flow, floor finish, and insulation in that order.
Before screeding, keep circuit room names, manifold connections, full pipe routes, tight bends, and starting and finishing gauge readings as one record set.
Timing and records
Allow about 8 to 16 hours on site. Existing condition, extension area, manifold relocation, and pressure-hold time can change this. Screed curing and heating commissioning sit outside the pipe-laying duration.
Keep pipe material and size, circuit areas, manifold labels and valves, insulation zones, route photographs, pressure readings, repairs, and retest results.
The prepared floor before pipework and the screed after it show where each trade must protect the heating circuits.