Frequently Asked Questions
Sub-floor Preparation & Screeds
How long do fast-track cementitious screeds need to dry before floor coverings can be installed?
Fast-track screeds dry significantly quicker than standard sand/cement mixes. Depending on the product formulation, they can accept ceramic tiles in as little as 4 hours and resilient floor coverings (such as LVT or vinyl) within 24 hours, regardless of thickness.
Can latex-based self-levelling compounds be applied over residual adhesive dampness or moisture-sensitive subfloors?
Yes, specific latex-based smoothing compounds are formulated to be moisture-tolerant. They can be applied directly over damp concrete or pre-existing adhesive residues (including bitumen) prior to laying a damp-proof membrane.
What is the maximum residual moisture level allowed before a Liquid Damp Proof Membrane (DPM) must be installed?
A surface-applied epoxy or synthetic liquid DPM is required when the relative humidity (RH) of the concrete or screed subfloor exceeds 75% RH (or up to 98% RH depending on the specific membrane formulation).
Why is priming necessary before applying a self-levelling compound or tile adhesive?
Priming controls subfloor absorbency, prevents pin-holing caused by air escaping from porous substrates, improves adhesion and strengthens soft or dusty surfaces prior to compound or adhesive application.
Tile & Stone Adhesives
How soon can tiles be walked on or grouted after using a fast-setting cementitious adhesive?
Fast-setting tile adhesives typically allow light foot traffic and grouting within 2 to 3 hours at standard room temperature (20°C).
What type of adhesive is recommended for installing extra-large format porcelain tiles?
Extra-large format tiles require a flexible, polymer-modified cementitious adhesive (typically classified as S1 or S2 under EN 12004) with high initial grab and extended open time to ensure full coverage and prevent debonding.
Can green or newly laid concrete screeds be tiled immediately?
Specialised flexible adhesives and uncoupling matting systems allow tiling onto green screeds as soon as they are walkable, bypassing the standard 28-day curing period for concrete.
Which adhesive should be used in environments exposed to high heat, such as underfloor heating systems?
Adhesives with high flexibility classifications (S1 or S2) and strong thermal movement tolerance must be used over heated subfloors to accommodate expansion and contraction.
Grouts, Silicones & Care Products
How do flexible tile grouts prevent cracking in timber floors or heated floor systems?
Flexible grouts contain specialised polymer additives that allow slight movement and absorption of stress without cracking or losing adhesion to the tile edges.
What type of grout or sealant is suitable for natural stone tiles prone to staining?
Natural stone requires non-staining, rapid-setting flexible grouts and neutral-cure silicone sealants to prevent oil or moisture bleeding into the porous edges of the stone.
What is the benefit of using epoxy grout over standard cement-based grout in commercial kitchens?
Epoxy grouts provide 100% stain resistance, total waterproof protection and high chemical resistance against harsh cleaning detergents, fats and acids common in commercial kitchens.
Water-proofing & Wet-rooms
Is liquid waterproofing required behind tiles in domestic bathrooms and wet-room showers?
Under building standards (such as BS 5385-4), background substrates in wet areas prone to frequent splashing must be protected with a liquid tanking membrane or waterproof building board before tiling to prevent structural water damage.
How fast can a liquid tanking membrane be tiled over once applied?
Rapid-drying liquid waterproofing membranes generally cure within 2 to 4 hours, after which ceramic or porcelain tiles can be fixed directly onto the surface.
What are waterproof building boards used for in wet-room construction?
Waterproof extruded polystyrene (XPS) boards act as structural, thermally insulating and 100% waterproof substrates for walls and floors, replacing traditional plasterboard or plywood in wet environments.
Floor-covering & Resilient Adhesives
Which adhesive type prevents Luxury Vinyl Tiles (LVT) from expanding or shrinking in sunlit conservatory areas?
High-temperature fiber-reinforced adhesives or heavy-duty polyurethane/epoxy adhesives are designed to lock vinyl tiles in place and prevent dimensional changes caused by direct sunlight and heat spikes.
What is a pressure-sensitive adhesive and where is it used?
Pressure-sensitive adhesives remain permanently tacky, allowing long working times for installing vinyl, LVT and carpet tiles without the risk of immediate film formation or loss of adhesion.
Structural Concrete Repairs & Renders
What type of mortar is required for repairing damaged concrete balcony edges or structural pillars?
Polymer-modified cementitious (PCC) repair mortars—often fiber-reinforced—are designed for high-strength structural repairs, providing resistance to freeze-thaw cycles and carbonation.
How fast do rapid-setting patch repair mortars harden?
Rapid-setting repair mortars can achieve high compressive strength within 30 to 60 minutes, allowing smoothing or covering layers to be applied on the same day.
Industrial Flooring Systems & Uncoupling
What are industrial cementitious concrete toppings used for?
Industrial self-smoothing concrete toppings provide high-abrasion-resistant wearing surfaces designed to withstand heavy forklift traffic, impact and chemical exposure in warehouses and manufacturing facilities.
What is the function of an uncoupling membrane under tiled floors?
An uncoupling membrane neutralises lateral shear stresses between the subfloor and tile layer caused by thermal expansion, structural drying, or minor substrate movement, preventing tiles from cracking or tenting.