Grout & Grout Haze

Grout is used to fill the gaps (joints) between tiles and mosaics that have already been fixed in place with adhesive, forming a barrier that fills the void, seals, and reinforces it.

Traditionally, grout has been a mixture of sand and cement, which is mixed to a paste with water and pushed into the joint using a grout float. Excess grout is removed from the surface of the tile. When the grout is almost dry, tacky but still pliable, the tile surface is cleaned using a damp sponge and clean water. When the grout can’t be compressed in the joint, polishing the surface with dry soft cloth will generally remove grout haze.

Grout Haze occurs when the tile grouting process is completed without washing residual grout from the tile surface.

Grout

In modern times, Grouts and related products have been developed by Adhesive Manufacturers for specific application purposes, to improve performance. These products are specific to the Adhesive Companies in chemical composition, but can be broadly categorized:

• Sanded Grout – A sand and cement mixture, usually mixed with a coloured pigment. The sand can be course or ground depending on the purpose and desired finish. Many suppliers are now adding polymers or latex to this type of product to help bind it and give it additional water-resistant properties. These products can also contain mould resistant chemicals.
• Non-Sanded Grout – A cement-based mix with ground mineral additives, usually mixed with a coloured pigment. Has a smoother final surface and often contains polymers, latex and mould resistant chemicals.
• Epoxy Grout – Designed to be used in commercial / industrial applications that require strict hygiene and chemical and physical resistance. Epoxy is a hard durable chemical. Epoxy grout is more complicated to use, usually requiring the mixing of several components mixed in specific ratios. It has a shorter working time and binds more permanently than traditional grouts.
• Grout Additives – Available in powder or liquid formats, grout additives are designed to improve the performance or finish of the grout product, for example to improve grout adhesion and mechanical strength, or to reduce porosity and absorption.

Grouts and grout related products that are currently used in the tiling industry are blended mixtures of :

• Inorganic mineral components – For example, sand, cement, carbonate or oxides 
• Organic components – For example, polymers, latex or epoxy.

Preventing Grout Haze

In Australia there are multiple grout manufactures, each one selling a variety of grouts and grout additives to tilers. Each Product has a unique chemical composition.

To prevent Grout Haze, grouts and grout additives should always be used as directed in the Application Procedure detailed in the grout supplier’s Product Data Sheet, which are available from their website (see the links listed below)

The application process of each grout is specific to the individual product, however there are some common elements, that are designed to prevent grout haze:

• Excess Grout - Remove excess grout from the tile surface once the joint is completely filled and the grout is flush with the tile edge. A smaller quantity of grout on the tile surface is likely to make cleaning the tile easier.
• Timing the Cleaning Process – When to clean grout from a tile’s surface effectively, is time and temperature dependent. If cleaning commences too soon, before the grout has dried sufficiently, grout may be removed from the joints. If the cleaning process is delayed too long, the grout will harden on the surface and will be much more difficult to remove. Warmer conditions speed up the curing process.
• Limiting the Area Grouted Before Cleaning – Dried grout is significantly more difficult to remove, particularly when using epoxy grouts. Grouting large areas before the cleaning process begins is not recommended. Do not mix excessive amounts of grout or add additional water to the mix. When grouting mosaics and smaller tiles, work in smaller areas. Larger format tiles can be grouted in slightly larger areas. Avoid grouting in hot conditions.
• Use a Clean Sponge – Cleaning residual grout from tiles before it dries, is best achieved with a clean sponge. Clean water is imperative to wash out grout from the sponge before resuming the cleaning process. Multiple buckets, with the water changed regularly, help to reduce the grout smearing across the tile, as it is cleaned. If this smeared grout dries before it is removed, it will form a grout haze. Do not use excessive amounts of water either, when mixing or washing off grout.
• Clean the Tile Thoroughly – Removing all the grout completely from the tile in the cleaning process, before it dries, saves time overall. Residual grout will eventually need to be cleaned. The longer grout haze sits on the tile surface, gathering other dirt, the more complicated and laborious the cleaning process.

Cleaning a Tile with Grout Haze

The best prevention of grout haze is to follow the manufacturers’ Application Process. The cleaning process will depend on the grout/grout additive used and the type of tile it is applied to. Many Grout Manufacturers supply cleaning chemicals that suit their products.

Grouts contain inorganic components like sand, cement, carbonates, oxides and organic components like latex, resins and polymers. These are best cleaned by a cleaning chemical which can work on both inorganic components (acid based) and organic components (solvet based). An experienced tile cleaning professional can provide advice on a cleaning solution for removing grout haze.

Grout Manufacturers

The leading grout manufacturers provide Information on their products on their websites, including Product Data Sheets containing an Application Process and Safety Data Sheets:

1. Ardex: https://ardexaustralia.com/products_category/tile-and-stone-installation-systems/tile-grouts-tile-and-stone-installation-systems/
2. Bostic: https://www.bostik.com/australia/en_AU/markets-applications/construction/tiling-grouts/
3. Davco: https://aus.sika.com/en/construction/tile-stone-installationsystems/tile-grouts.html
4. Dribond Construction Chemicals: https://constructionchemicals.com.au/product-categories/grouts/
5. Kerakoll: https://products.kerakoll.com/en/s/mineral-and-organic-grouts
6. Mapei: https://www.mapei.com/au/en/products-and-solutions/lines/products-for-ceramics-and-stone-material?category=product-line-category-8642#fascia-colore
7. Laticrete: https://au.laticrete.com/en/our-products/tile-and-stone-installation/tile-and-stone-grouts#filterproduct_e=0&filterproduct_productsubcategories=Cementitious%20Grout
8. RLA: https://www.rlapolymers.com.au/products/?swoof=1&product_cat=grouts