Large-format slabs — 120 × 120 cm, 160 × 320 cm and beyond — create almost seamless surfaces, highly sought after in Marrakech's contemporary villas. Installing them demands a perfectly flat, laser-checked substrate, the right back-buttered adhesive, suction cups and a joint-levelling system. On a poorly prepared substrate, lippage appears that cannot be corrected afterwards.
- Formats
- 120×120, 160×320 cm and larger
- Materials
- Marble, porcelain, engineered stone
- Advantage
- Continuous surface, very few joints
- Key requirement
- Substrate flat to ±2 mm, laser-set
- Uses
- Floors, bathroom walls, façades
The appeal of a continuous surface
A 120 cm slab covers an entire shower wall with no intermediate joint. On a floor, a few large slabs replace dozens of tiles, cutting joint lines and giving that sense of solid stone cut from one block. In a villa bathroom we favour large-format 120 cm slab walls — the client rejects small-format zellige there precisely for this continuity.
Substrate preparation is everything
Large format forgives no flatness defect: a 3 mm dip under a 3-metre slab creates visible lippage and a risk of fracture. The substrate is therefore levelled, then checked with a laser across the whole surface before laying. Bathroom walls receive a cement-mortar scratch coat — never gypsum, which cannot hold up to moisture — and no pipework is left exposed.
The installation technique
Full back-buttering as standard (adhesive on both substrate and slab back), cross-combing to expel air, suction cups for handling, and a joint-levelling system (clips and wedges) to guarantee a perfectly flush surface between slabs. Bedding is done with a rubber mallet and vibrating trowel for the largest formats. The result: even, flush joints of 1.5 to 2 mm.
Only if the old substrate is perfectly bonded, sound and re-levelled. When in doubt, we strip it and start on a fresh substrate — large format won't tolerate a questionable base.
