Commissioning Underfloor Heating Before Floor Finishes Are Laid

A typical commissioning sequence starts the heating system at a low flow temperature, low enough to avoid shocking the screed, and increases it in defined steps over a period of days. This gradual approach allows the screed to adjust dimensionally and encourages even moisture migration to the surface.

Once the system reaches its intended maximum operating temperature, a hold period is generally maintained before floor coverings are considered, followed by a controlled reduction in temperature ahead of the flooring trade arriving on site.

Many floor finishes — particularly timber, vinyl and some resins — have manufacturer limits on sub-floor temperature during adhesive curing and for a period afterwards. The heating system should be reduced to, and then held at, a level compatible with these requirements before installation and for the specified period after.

Coordinating this handover between the heating contractor, screed installer and flooring trade avoids the common scenario where a covering is laid onto a floor that is either too hot, too cold, or still actively drying, any of which can compromise the finish.

An insurance-backed product warranty, where the screed manufacturer offers one, typically depends on the heat-up sequence having followed the manufacturer's own commissioning instructions rather than an improvised schedule.

Referencing that commissioning document by name and revision in the specification avoids later ambiguity about which heat-up steps the warranty actually required.

A commissioning record only earns its keep if it travels with the floor — noting start date, each temperature step and the date coverings were cleared to begin gives the flooring trade a single reference rather than a verbal account.

Where the main contractor rather than the heating installer holds responsibility for running the system during the hold period, naming that in the programme stops a gap opening up between trades.