Larsen SLC1550 Rapid Set Pro is one of the UK's most popular self-levelling compounds — and the questions we get asked about it at the counter are always the same. Here are the answers, straight from the datasheet and years of selling it to Coventry's tilers.
How long does SLC1550 take to dry?
Light foot traffic: 2–4 hours. That's the rapid-set advantage — you can walk on it the same morning you pour it. For overlaying with tile, LVT, vinyl or carpet, allow 1–3 days depending on pour depth, temperature and site conditions. Deeper pours toward the 50mm end of its range need longer; a thin 3–5mm skim in a warm room is ready sooner. When in doubt, check moisture before fixing.
How much does a bag cover?
A 20kg bag covers approximately 1m² at 10mm depth. At a more typical 3–5mm levelling pour, expect around 2–3m² per bag. The maths: bags = area (m²) × average depth (mm) ÷ 10, plus 10% wastage — or skip the maths and use our levelling compound calculator.
What depth can it be poured?
3mm to 50mm in a single application — unusually deep for a one-part compound, which is why it suits fast-track renovation work where floors are badly out.
Can you use SLC1550 on wooden floors?
Yes, with preparation. It's fibre-reinforced and flexible, which makes it suitable for rigid, well-fixed timber substrates — secure loose boards, overlay if needed and prime first. For particularly lively timber floors, a two-part latex compound like Larsen LLC206 NA is the belt-and-braces choice.
Is it suitable for underfloor heating?
Yes — SLC1550 is suitable for use over UFH systems. Keep the heating switched off while pouring and during initial cure, then recommission gradually per the heating manufacturer's guidance.
Can you tile straight over it?
Yes. Once cured it's an ideal flat base for porcelain, ceramic and stone — it is an underlayment though, not a wearing surface, so it must always be covered with a floor finish.
Key specs at a glance
- Single-part — just add water; protein-free
- 3–50mm in one pour; fibre-reinforced
- Light foot traffic 2–4 hours; overlay 1–3 days
- BS EN 13813 CT-C25-F7; UFH-compatible
- Coverage ≈ 1m² per 20kg bag at 10mm
Where to buy Larsen SLC1550
Ark Tiles stocks SLC1550 in single 20kg bags, 24 and 48-bag pallet deals (the full pallet ships free), with same-day collection from our Coventry showroom. Questions? Call 0330 520 1804.
0 comments