Liquid Screed & Underfloor Heating Guide
Is liquid flow screed compatible with underfloor heating?
Yes — liquid flow screed is the best screed choice for underfloor heating. Its self-compacting nature fully encapsulates UFH pipework with no air gaps, delivering excellent thermal conductivity and faster, more even heat transfer than traditional sand-cement screeds.
What are the key installation points for UFH?
UFH must be installed by a competent engineer before screed goes down — see our preparation guide for the full pre-pour checklist. Pipework spacing matches the heat source specification; manifolds are positioned for service access; the whole system is pressure-tested and balanced prior to pour. Once the screed encapsulates the pipes, alterations are not practical.
- Recommended screed cover over pipework: 40–50 mm
- Minimum cover above the pipes: 30 mm
- Pressure test before pour — keep system pressurised during pour
- Expansion joints between different heating zones and at door thresholds
- Commission heating no sooner than 7 days after pour
How is the heating commissioned after the pour?
From day 7 after pour, set the flow temperature to 20–25°C and hold for 3 days. Then increase in 5°C steps to maximum operating temperature (never exceed 55°C for screed). Hold at max for a further 7 days. This force-dries the screed and proves the system. See our drying times guide for the full commissioning schedule and when floor finishes can be applied.
How fast does underfloor heating respond?
Modern UFH systems with intelligent controls pre-programme heat-up times so the property is at temperature when needed. The controls learn your patterns over time. The thermal mass of liquid screed means slow but very even heat delivery — ideal for steady occupancy, less ideal for short bursts.
Can I retrofit underfloor heating during a refurbishment?
Yes. There are UFH systems for every floor construction — screed, fully floating timber, battened or joisted floors, acoustic build-ups. We design the right system for your specific build-up and can extend it later. Get the design right from the start to save money over the life of the system.
I have a joisted timber floor — can I have UFH?
Yes. Spreader-plate systems sit between floor joists and deliver heat through the existing floor deck, no screed required. Output is lower than a screed-encapsulated system but more than enough for normal residential heat loss. We design and install both types.