Checking dry screed and underfloor heating compatibility before starting
Identifying the type of underfloor heating (electric, hydraulic) and its constraints
Start by confirming whether your underfloor heating is electric (cables, mesh) or hydraulic (pipes). Hydraulic systems generally require better heat diffusion and careful controls, with a limited surface temperature. Also check the compatibility of the dry screed build-up: boards, insulation, any diffuser plates. It must be validated by the manufacturer for use with underfloor heating. To go further on installation and sizing constraints, see our article on underfloor heating pipe spacing for low-temperature systems.
Checking the flatness, moisture and load-bearing capacity of the existing substrate
Dry screed doesn't fix everything. Check with a 2 m straightedge, treat dips and remove hard high points. On the moisture side, the substrate must stay properly dry to avoid swelling and levelling issues in the boards. In renovation, check the floor's load-bearing capacity (timber, slab) and the absence of deflection.
Planning ahead for thicknesses: finished level, door thresholds and ceiling height
Before installing, do a thickness study. Insulation, network, boards, covering. The goal is a finished level consistent with thresholds, doors and skirting boards. If ceiling height is tight, favour thin solutions and secure the connections with neighbouring rooms.
Choosing a dry screed suited to renovation: materials, performance, uses
Comparing board and granulate systems: weight, installation, zero drying time
In renovation, dry screed comes as floor boards (fibre-reinforced gypsum, wood panels) laid on a flat substrate, or as boards over levelling granulate (expanded clay, perlite) when the floor is uneven. With granulate, you gain levelling capacity and room for network runs, at the cost of a bit more thickness and load. Either way, the installation is clean and drying time is zero. You can move straight on to the covering.
Targeting the right thermal resistance: impact on underfloor heating efficiency
For underfloor heating, look for a low-insulating system. Thermal resistance that's too high restricts heat diffusion and forces the water temperature up. Do the calculation including boards, underlay and covering. Also validate compatibility with the allowable temperature and the manufacturer's requirements.
Planning for acoustics and stability: resilient strips, decoupling, joints
Comfort comes from the details. Lay resilient strips around the perimeter to avoid acoustic bridges. Plan for decoupling on timber or cracked substrates, and expansion joints at thresholds and long runs. In double-layer systems, stagger the boards and take care with bonding and fixing for lasting stability. To go further on requirements and solutions, see our article on acoustic insulation of intermediate floors.
Installing dry screed over underfloor heating: key steps on site
Installing the insulation and vapour barrier depending on the substrate: points to watch in renovation
On a concrete slab, timber floor or old tiling, check flatness and load-bearing capacity. Lay a continuous vapour barrier, turned up at the perimeter, then insulation compatible with the load. In renovation, treat special points and keep a dry substrate to avoid swelling.
Installing the underfloor heating: pipe spacing, fixings, no-heat zones and testing
Lay out the underfloor heating pipes or cables at the spacing set during sizing, often 10 to 20 cm. Fix them without crushing the insulation. Leave unheated zones under fixed furniture and around penetrations. Before closing up, carry out the tests and pressurisation. Keep the circuit under test during installation.
Laying the dry screed: levelling compound if needed, layout, bonding/screwing, edge treatment
If flatness isn't quite there, a suitable levelling compound sets everything square. Lay the dry screed boards in a staggered pattern. Bond or screw depending on the system, without touching the pipes. At the edges, plan a resilient strip and an expansion gap. Finish with a clean perimeter joint.
Ensuring performance and avoiding failures: common mistakes and checks
Avoiding thermal bridges and noise: insulation continuity and decoupling
On underfloor heating, the slightest break in the insulation or a forgotten perimeter strip costs you in comfort and call-backs. Aim for perfect continuity of the insulation, treat the edges, check the thermal breaks if included, and keep the screed decoupled from walls and partitions to limit noise.
Managing expansion: fractioning joints and door thresholds
The screed moves. Without suitable joints, cracks often appear at thresholds. Plan fractioning joints based on surface area and geometry, follow the substrate's existing joints, and take care at door thresholds with a continuous profile or joint. Check before pouring, with a dimensioned plan and supporting photos.
Validating the heat-up: heating protocol, readings and traceability
Heating up isn't a by-feel test. Run a gradual protocol after the prescribed drying time, in stages, then step back down. Note the flow and return temperatures, the pressure, and keep a written record. Simple traceability secures handover and warranties.
Pricing and site framework in 2026: technical arguments and client expectations
Assessing the overall cost in renovation: materials, installation time, substrate preparation
In renovation, the quote hinges on the overall cost, not just the price of the kit. Count removal, disposal, levelling, insulation, connections and commissioning. Also allow for "invisible" time: protection, threshold rework, and a moisture check before closing up.
Justifying the lightweight solution: allowable load, shorter timelines, occupied dwelling
A dry underfloor heating solution stands on facts. Less added load than a traditional screed, little water on site, so shorter timelines and fewer hazards. It's often the right choice on an upper floor, and when the dwelling stays occupied.
Coordinating the underfloor heating trade and the floor covering: tile, wood, resilient flooring
State the covering clearly right from the quote. Tile, wood or resilient flooring don't share the same thermal resistance, nor the same adhesives, underlays and expansion gaps. Aligning thicknesses, heating temperatures and phasing avoids rework and secures the warranty.
Key figures
30 to 50 kg/m²
Dry screed weight
100 to 150 kg/m²
Liquid screed weight
5 to 8 cm
Total thickness
Frequently asked questions
You can point your clients toward MaPrimeRénov' (amounts vary with income), CEE energy-saving certificates, and often a reduced 5.5% VAT rate if the work overall improves energy performance. Incentives generally require eligible products and installation by an RGE-certified company when the scheme requires it. Remember to have eligibility validated before signing, and keep technical datasheets and detailed invoices.
Louis Airy
COO of Argile
