HOW do you ensure you have the right leveller for your contract flooring job? Whether a floor is to be finished with tiles, resilient flooring, carpet or any other covering, achieving a level subfloor is critical to a successful outcome.
Any newly-laid or existing substrate is likely to need levelling with the use of a self-levelling compound to ensure there is the lowest possible height variance in the floor. The leveller acts as an intermediate layer, on to which the finished floorcovering can be laid.
Concrete must be at least six weeks old before floorcoverings are laid. This drying period allows movement caused by drying shrinkage to take place. The floor should be clean, dry and free from dust or contaminants which could act as a release agent and prevent the adhesive from bonding to the concrete.
Preparation requirements differ depending upon the substrate. Cement/sand screeds, anhydrite screeds, chipboard or existing tiled surfaces all require different priming/sealing regimes before they are suitable for levelling.
Says Norcros Adhesives: ‘When levelling impervious substrates such as existing tile finishes, Norcros Key Bond Gritted Primer should first be applied. This is a ready-to-use, low emission, film-forming, fast-drying modified styrene acrylic copolymer dispersion primer which is designed for use directly on to dense, non-absorbent smooth surfaces and epoxy and PU-based primers.
‘Once dry, the primer provides a rough textured key onto which levelling compounds and adhesives can form a strong bond.’
Norcros Adhesives says it offers one of the widest range of levellers available on the market. The latest addition to its range is reportedly already proving very popular in the contract flooring sector. Norcros Pro AF Low Prep Self Smoothing Levelling Compound is described as an ammonia- and latex-free, 2-part levelling compound. It’s suitable for use on most substrates without need for priming.
It’s been formulated for use over old adhesive residues including bitumen, historically a problematic material to bond to. There’s no need to prime or remove firmly bonded residues. This greatly reduces the time usually required for preparation of the substrate to be levelled.
Says the company: ‘Norcros Pro 30 Fast Track Levelling Compound is one of the most environmentally friendly products in this market, containing recycled crushed glass, which replaces quarried sand. It’s a flexible, single-part leveller which is suitable for use from featheredge to 30mm in a single application, without the need for additional aggregate. It’s ready to tile after just 45 minutes, and can receive impervious floorcoverings after 90 minutes, allowing early foot traffic and fast-track tile fixing.’
The product is said to be suitable for levelling various substrates, including:
- cement:sand screed
- flooring-grade asphalt
- existing quarry and vinyl tiles
- overlaid timber floors
The company says Norcros Pro 30 Fast Track Eco is also suitable for encapsulating under-tile heating mats and cables, protecting the heating elements during the tile-fixing process as well as providing a level surface for the provision of a floorcovering. It’s said to be suitable for use on timber floors which have been overlaid with 15-18mm WBP or marine-grade plywood. It comes in a 20kg pack.
‘One important technical innovation from Norcros Adhesives has been the development of Reinforced Polymer Technology (RPT). The main benefit gained from the incorporation of RPT is that the polymer strands give reinforced flexural and bond strength, in addition to providing improved crack bridging, anti-shrinkage and thermal ageing properties.’
The company adds: ‘RPT technology is incorporated into Norcros Pro 50 Levelling Compound. This is a single part, fibre-reinforced self-smoothing floor underlayment, suitable for use from 3mm to 50mm in one application without the need for additional granite chippings. It’s ideal for levelling a variety of substrates including concrete, screed, flooring grade asphalt, terrazzo and quarry and vinyl tiles. It can be used with undertile heating mats and on overlaid timber floors.’
Norcros Pro 10 Levelling Compound is described as a single part polymer modified self-smoothing floor levelling compound. It’s said to be suitable for levelling various substrates including concrete, cement: sand screed, flooring grade asphalt, terrazzo and existing quarry and vinyl tiles. Norcros says it’s ideal for use with undertile heating mats where it may be used to cover the wired elements, providing a level substrate to tile to and also protecting the heating elements during the fixing process.
Continues Norcros: ‘Its excellent levelling and flow properties make it ideal for preparing sub floors prior to fixing ceramic, porcelain or natural stone tiles. It has a setting time of three hours permitting early foot traffic and fast track tile fixing. The product is designed to be used up to 10mm thick in one coat, or with the addition of single size granite chippings up to 20mm.’
Alternatively Norcros 2-Part Levelling Compound may be used from feather edge to 10mm in one application without the need for additional granite chippings. The product is reportedly suitable for levelling various substrates including concrete, screed, flooring grade asphalt, terrazzo and existing quarry and vinyl tiles.
Says Norcros: ‘It’s ideal for use with undertile heating mats to encapsulate the wired elements, providing a level substrate to tile to and also protecting the heating elements during the fixing process. The product is also suitable for use on timber floors overlaid with marine grade plywood.
The levelling and flow properties of Norcros 2-Part Levelling Compound make it ideal for preparing sub floors prior to fixing ceramic or natural stone tiles or soft floorcoverings such as carpet, vinyl, and timber. It has a setting time of three hours at 20deg C permitting early foot traffic.’
Ceramic and porcelain floor tiles may be fixed after three hours. Soft floorcoverings may be fixed after 12 hours and natural stone after 48 hours.
Completing the range is Norcros Pro 10+ Levelling Compound. This is a pumpable polymer-modified cementitious single part floor leveller, suitable for use up to 10mm in one application, ready for laying ceramic or porcelain tiles after about three hours. Natural stone tiles and soft floor coverings such as carpet, vinyl and timber can reportedly be laid after about 24 hours.