Short definition
A seamless join in sheet vinyl flooring made by melting a vinyl welding rod into a routed groove between two sheets — used in wet areas and commercial fitouts.
A heat weld is a permanently fused join between two pieces of sheet vinyl. The installer routes a small V-shaped groove along the join, then runs a melted vinyl welding rod into the groove with a heat gun. Once cool, the join is monolithic — water-tight and visually almost invisible.
Heat welds are standard in wet areas (commercial bathrooms, hospital rooms, school wet areas) and in any sheet vinyl fitout where hygiene matters. The alternative — a chemically bonded cold weld — is faster but does not match the long-term durability or water resistance.
In a flooring takeoff, the heat weld decision affects two things: the linear metres of welding rod consumed (one rod metre per metre of join, plus a wastage allowance), and the labour line on the quote (heat welding is slower than laying alone). The takeoff itself does not change — area and perimeter measurements are the same — but the materials list grows by the rod count and the labour by a per-metre rate.
For vinyl plank or carpet jobs, the heat weld term does not apply: planks click-lock together and carpet seams are taped rather than welded. The term is sheet-vinyl-specific.
Worked example
A 4 × 5 m vinyl wet area with two 4 m sheets joined down the middle needs 4 linear metres of welding rod, plus 10% wastage = 4.4 m of rod on the order line.