BLOG - Glues, grouts and use of trims
Tiles need to be bonded to the substrate with an appropriate product that will provide:
- suitable bond,
- flexibility to absorb movement,
- ease of use,
- conformity to Australian Standards
Most floor-appropriate adhesives are cement-based. They are either plain, polymer-modified and or rubber modified. These are available in a one-part (mix with water) or a 2-part (cement based powder to mix with latex liquid).
- Cement based glues, non-polymer modified, are generally only used externally to lay concrete pavers.
- Cement based adhesives, polymer modified, and/or rubber modified are used for indoor and outdoor areas (where substrates and tiles are fit for purpose) to provide maximum flexibility to absorb movement, both thermal and material contraction. It should be noted that the rubber crumb in rubber-modified is there to extend the coverage of the adhesive - it DOES NOT make the adhesive flexible. The polymer additives create the flexibility.
- The two-part cement-based adhesives are used when maximum bond-strength is a priority.
- Dry mastic adhesives are cement-based adhesives with similar properties to mastic adhesives e.g. non-slip, non-slump.
- Mastic adhesives are synthetic resin-based adhesives with superior non-slip, non-slump properties used predominantly for wall tiles in internal areas.
SPECIAL NOTES ON ADHESIVES:
- It is extremely important that you use the correct waterproofing membranes under tiles. Moisture cured polyurethane waterproofing membranes are NOT for use under tiles. Tile adhesive manufacturers will not guarantee bond to any of these membranes.
- The pre-mixed "mastic" adhesives are generally NOT suitable for use on floors or over waterproofing membranes.
- The addition of polymer is extremely important externally and in submerged areas (e.g. interiors of pools). You should never use an adhesive without polymer in these areas
To ensure that you have the correct product for the job, ensure that you consult data sheets on individual products and if in any doubt consult tile shop staff.
Grouts are predominantly designed to fill the joint required between tiles. This joint has several purposes, being to allow for slight movement and expansion/contraction of tiles as well as to accommodate tile size variation (particularly in pressed edge tiles).
This is separate to expansion joints which are required at certain intervals (see Australian Standards) and are a flexible joint using silicone or a manufactured rubberised infill (installed during laying).
These joints can be turned into a feature by using a wider joint and / or using a contrasting colour. Conversely they can be semi-hidden by using a colour that matches the tile colour.
There are essentially three types of grouts:
- -Sanded grouts are used for wide joints, generally above 3mm, including exterior use. In situations where larger random-sized pieces of stone are used, a standard sand and cement mortar mix is still often used in extremely large joints.
- -Flexible (Fine) grouts are used for small joints, generally up to 3mm, and wall joints. NOTE: White grout is generally a superfine and is NOT appropriate for floors at any time. White is too soft and will not wear well on floors, apart from the inherent problems with keeping it clean. Black grouts can also be a problem if used in an area with direct sunlight. They can fade in direct UV light.
Cement grout manufacture has improved over the years and now most have anti-bacterial properties to reduce mould growth.
- -Epoxy grout is a two part, non-porous grout which will provide superior performance for most joints. It is created by a chemical reaction between 2 separate parts and is generally only used for commercial kitchen areas, due to its high cost and use difficulties. This being said, there have been great advances in epoxy grout technologies and there are now some water-based epoxies that are almost as easy to use as a cement-based grout. It is often suggested to use these in kitchen splashbacks and small areas with high probability of staining. Epoxy can be used in areas where white & black grouts cannot be used.
**Please note that the standard grouts carried and used by tilers are light grey or neutral for the floors and white for the walls. If you require other colours it is advisable to specify this to your tiler, or buy them at the time you purchase your tiles to ensure you get the product and colour you require.
Trims are used in tiling like architraves, cornice and skirtings are used in building. They hide joints, and protect edges. Trims can be used:
- -as part of waterproofing,
- -as transitions from different substrate levels,
- -as edge protection where tiling stops, but the tiles sit proud of their surrounds,
- -on external corners, both horizontal and vertical (including around niches).
Trims come in coloured plastics, mill finish (plain) aluminium, matt or bright silver aluminium, brushed finish aluminium, brass, stainless steel, and powder coated coloured aluminium. Not all trims will be in stock on the shelves at your preferred supplier, so order trims with your tiles to ensure everything is ready when required.
Each product has its unique characteristics and we have been very general in our approach, it is therefore recommended that you speak to the experts on tile flooring at Complete Tiles & Stone to further confirm the appropriate product and finished look for you.
And most of all...enjoy the whole experience!