When installing underfloor heating (UFH) in a concrete slab, steel mesh reinforcement can be used not only to strengthen the slab but also as a fixing base for pipework. Attaching pipes to mesh keeps them securely in place during the pour and ensures correct spacing, depth, and layout. This approach is widely used in both domestic and commercial projects. In this guide, we explain how to properly secure underfloor heating pipes to reinforcement mesh — step-by-step — for a strong, stable installation.
Begin by installing rigid insulation across the floor area and laying the reinforcement mesh panels on top. Use mesh spacers or small concrete chairs to elevate the mesh 30–50 mm above the insulation. This ensures that when the slab is poured, concrete flows beneath the mesh as well as above, fully surrounding both steel and pipework. Overlap adjacent mesh panels by at least one square and tie them with rebar wire to prevent movement. Always check mesh level using a laser or straightedge.
Before fixing pipes, review the heating design. Each zone should have its own loop, starting and ending at the manifold. Pipe spacing is typically 100 mm or 200 mm, depending on the heat demand. Mark key reference lines directly onto the mesh using spray paint or marker tape to guide your installation. This ensures each loop stays within its assigned zone and avoids over- or under-heated areas. Check pipe run lengths to avoid exceeding maximum circuit distances (typically 80–100 m).
Begin uncoiling the pipe from the manifold location, laying it according to your planned zones. Fix the pipe to the mesh using plastic cable ties or specialist UFH wire clips at intervals of 300–500 mm. Make sure each tie is tight enough to prevent movement, but not so tight that it compresses the pipe. Avoid overtensioning, especially on bends. Ties should be UV-resistant and compatible with concrete to prevent long-term degradation. Keep fixings consistent to maintain clean pipe loops and reliable coverage.
As you work across the mesh, use the grid squares as visual guides to keep pipe spacing even. This not only helps with heating efficiency but also simplifies later screeding or concrete work. On curves or tight bends, reduce spacing slightly to maintain even coverage. Recheck spacing frequently as pipe tension can shift layout subtly. It’s common to double-check with a measuring tape every few rows, especially on larger pours or where multiple installers are working in tandem.
Pipes should never cross over one another on the mesh. If layout constraints make this difficult, adjust loop shapes or reroute in open areas. Compression or contact between pipes can cause heat concentration and increase risk of air locks. Maintain gentle bends with no kinking — especially around corners or returns — and ensure every loop remains on a single plane. This makes the final pour cleaner and keeps slab integrity high.
Once all pipe runs are secured, the system should be filled and pressure-tested in line with manufacturer requirements. Typically this involves pressurising the loops to 3–5 bar and leaving it for 24 hours to check for leaks. Pipes should be under pressure during the concrete pour, so any potential damage or displacement is immediately visible. This step also helps maintain pipe shape and rigidity during pouring, preventing floating or shifting under the weight of wet concrete.
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