FAQ

How does one choose the correct sealer?
Choosing the correct sealer is often a personal choice based on a combination of aesthetics and functionality. In most cases only a few options are available for each type of floor or tile type based on the surface porosity. In the case of polished marble only a repellent like Stoneshield Marble & Granite Sealer should be used as all resin based sealers will leave a plastic surface layer affecting the marble’s appearance. Consult the sealer selection chart for the correct options.

What is the difference between a sealer and a repellent or impregnator?
Generally repellents are liquid silicone, silane or siloxane type products. (Scotch-Guard for stone). They penetrate completely with no visible change or surface film. Repellents are generally the only option for polished, low porosity surfaces like porcelain, marble, limestone and granite. Nearly all wall cladding is sealed using water or solvent based repellents. Repellents are very effective against water ingress on exterior bricks, stone and cladding. (Stoneshield Wall-Cladding-Sealer ). Repellants are less effective on horizontal surfaces like floors, due to there capabilities. Repellents offer stain resistance but no surface protection against wear & tear. The advantage of repellents is that they cannot “peel” and are not affected by negative water pressure.

Sealers are resin based systems that dry forming a “skin”. These types of sealers offer effective results for both stain resistance, aesthetic improvement and surface protection. Sealers are normally selected where surface protection is required (Stoneshield Quarri-Seal®, Stoneshield Cement-Sealer™) as in the case of slate or oxided cement, where the surface is soft and the colour is often walked off. These types of sealer offer a combination of surface penetration and surface build depending on how many coats are applied.

Where ease of cleaning is a factor in the case of natural sandstone, ( here the surface is textured ) a resin type sealer helps to cover the texture making cleaning easier. ( Stoneshield Paving-Sealer )

When should one use a sealer?
Sealers are selected for most floor surfaces from concrete and cement floors to natural stone floors and walls. Sealers are selected either for protection against dirt, pollution, acid rain, moisture etc or for protection from wear and tear and staining. Slate requires sealing for surface protection and colour retention. ( Stoneshield Quarri-Seal® ) Sandstone requires sealing for ease of cleaning ( Stoneshield Paving Sealer ). Terracotta requires sealing for aesthetic reasons and stain resistance.

When should one use a repellent sealer?
Generally repellents are liquid silicone, silane or siloxane type products. (Scotch-Guard for stone). They penetrate completely with no visible change or surface film. Repellents are generally the only option for polished, low porosity surfaces like porcelain, marble, limestone and granite.(Stoneshield Natural-look™, Stoneshield Marble, Granite & Travertine Sealer, Stoneshield Colour-Enhancer™)

Nearly all wall cladding is sealed using water or solvent based repellents. Repellents are very effective against water ingress on exterior bricks, stone and cladding. (Stoneshield Wall-Cladding-Sealer, Stoneshield Colour-Enhancer™ ). The advantage of repellents is that they cannot “peel” and are not affected by negative water pressure.

Why do resin type sealers peel?
In most cases a resin based sealer peels when a combination of moisture from below is forced to the surface by direct sunlight or surface heat too quickly causing the sealer to peel through water pressure. Sealers do not peel naturally, there has to be pressure from below or from behind the sealer to cause the sealer to peel. Peeling sealers will always look like dry, flaking skin. This is because the sealer has de-bonded from the surface.

The moisture or water pressure generally occurs for the following reasons –
1. Insufficient time was allowed for the floor or wall surface to dry out prior to sealing.
a. Either the floor or wall had too much moisture from the initial installation prior to sealing.
b. Insufficient time allowed between washing and sealing.

2. Water or moisture is penetrating the surface from above or below.
a. This can be moisture from rising damp caused by the lack of DPC ( plastic water proofing membrane under the concrete slab )
b. Water penetrating through cracked grouting. This is very common.
c. Water entering the slab or wall from poor waterproofing along junctions or parapets.

How does one tell if the surface is now correctly sealed?
For new installations: After 2 – 4 hours (depending on type of sealer) place a few water droplets on to various areas. If the water droplets are absorbed the surface will require an additional coat of sealer. On existing surfaces: wet the entire area in question. If the flooring material absorbs water in patches or darkens in patches the floor will require re-sealing. Stripping before re-sealing may be required, if a uniform final finish is required.

What are self shine polishes for?
Self-shine polishes are liquid polishes that dry to a shine without having to be polished. Their intended purpose is an easy to apply protective surface layer for regular maintenance.

If one wants to apply a coating to a ceramic tile what can be applied?
The only products that can be applied are self-shine or matt polymer polishes. Although they may adhere they will require frequent re-application. Try Stoneshield Protect & Shine™ or Stoneshield Surface-Protector Matt™.

What is the difference between water based sealers and solvent based sealers?
The water or solvent is the “carrier” used to dissolve or transport the different sealer resins. It is therefore possible for an acrylic sealer, silane or siloxane repellent to be either solvent or water based. Generally solvent based resin systems tend to penetrate better than water-based systems but will darken the tile surface. Solvent based resin type products (Stoneshield Quarri-Seal®, Stoneshield Cement-Sealer™) provide better long term results than water-based products (Stoneshield H2O).

This is because solvent based resin sealers penetrate better than water based sealers. Quality is determined by the type of polymer or resin, not by the carrier. The exception is repellents where there is no real difference between water based and solvent based repellents or sealers. In cases where the stone is very dense (granite) then solvent based repellents are considerably better. In cases where the surface is very porous (face bricks) water-based repellents offer much better results. This is due to the fact that porosity and penetration need to be matched. If the surface is too porous then too much penetration results in poor results.

How long will the sealer last?
There are so many different types of sealers and so many different types of tiles with so many variables that it is very difficult to answer. Each sealer label should indicate the expected life expectancy. Sealers last from about 1 year to 15 years, again depending on circumstances, type of surface, cleaning methods and traffic.

Why are repellents unable to stop surface wear and etching from acids on marble, travertine and limestone?
Repellents like Stoneshield Marble, Granite & Travertine Sealer and Stoneshield Natural-Look™ are silane, siloxane repellent products which do not form a “skin” or surface layer. They are designed to penetrate the surface and protect from within by repelling water and stains. Their primary function is stain resistance and water repellency and therefore they cannot stop wear and tear and surface damage. Resin based sealer will be required to provide protection against surface wear and tear. Stoneshield has options available. Refer to the sealer selection chart for options.

Why do the tiles have to be dry before sealing?
The tiles should be dry for three main reasons:
1. All solvent based sealers will be affected by water during the curing period which may result in the sealer turning white or not drying correctly due to chemical interference. Water and solvents are not compatible and do not mix.
2. Most sealers are designed to penetrate and if the surface body is full of water, then penetration of product will be poor or impossible.
3. If the surface is not completely dry when sealed then the residual water will need to escape after sealing, causing the sealer to peel.

Why do sealers take longer to dry in cold weather?
Most sealers dry by means of water or solvent evaporation. In cold weather the evaporation process is slowed down considerably thereby slowing or extending the drying or curing time of the sealer. A sealer that dries in 1 hour at 25c may take 4 hours at 16c. Most sealers should not be applied below 16c as sealer performance may be affected.

Why does one have to wait after laying new porous tile before sealing?
The moisture from the tile adhesive and the underlying cement floor or screed needs to evaporate. Sealing newly laid tiles immediately after installation will trap this moisture possibly leading to irreversible “picture framing” or water staining. The sealer will most certainly “peel” due to water pressure as the moisture moves to the surface.

What causes picture framing?
Picture framing is mainly caused when using resin based sealers for two different reasons with the same result.
1. Sealing of the tiles too quickly after laying entraps moisture. This moisture will generally migrate to the centre of the tiles which is drier than the edges, carrying impurities causing staining.
2. Sealing of the grout and tile before the grout has dried out sufficiently will result in the moisture migrating into the tile, carrying impurities as it cannot evaporate, causing staining.

Can one apply a repellent over a sealer?
The general rule is no. In extreme circumstances professional contractors apply repellents over sealers to boost the oil and or water repelling properties of the sealer. This is done where the surface is too porous for a repellent only and a combination of the two products properties are required.

Can one apply a sealer over a repellent?
In most cases the tile surface should be well scrubbed two to three times with a product like Stoneshield Wax-Off™ which should remove sufficient product from the surface to allow a sealer to adhere. In most cases only solvent based sealer can be used to re-seal.

Should one pre-seal porous tiles before laying?
1. Pre-sealing should only be done if the tiles are of such a nature that grout staining is probable. Examples are unfilled travertine, porous terracotta & cement tiles that cannot be acid washed.
2. Pre-sealing should be done when the tiles are acid sensitive and grout removal with an acid based cleaner is not possible. Examples are polished limestone, marble and travertine as well as cement tiles and polished terrazzo.
3. Pre-sealing should be done in the case of wall tiling where cleaning with an acid based cleaner may not be possible. Examples are where carpets, wood or marble floors are already installed.
4. Pre-sealing should be done for wall cladding where access may be difficult and costly later and where the stone will most likely not require cleaning after installation.

Why can’t one use any cleaner on a sealed surface?
Most sealers will be affected by strong acid and alkaline cleaners over extended periods. To prolong the life of the sealer a neutral detergent specifically formulated for everyday cleaning should be used. Use Stoneshield’s range of Pure-Nature™ cleaners.

Why should you neutralize after acid washing prior to sealing?
All sealers require surfaces that are neutral in PH. Most sealers will be affected by acidic surfaces. Any acid left active will cause the tile surface to become acidic which intern will affect the drying and curing of the sealer, possibly leading to sealer failure.

How does one remove the factory applied wax from porcelain tiles?
Most porcelain tiles have a factory applied wax which will need removing prior to sealing. Use Stoneshield X-treme-Clean™ or Stoneshield Wax-off™ to remove the wax coating prior to sealing.

Should one seal an industrial concrete floors?
Industrial concrete floors are prone to dusting and staining. Concrete floors whether industrial, commercial or domestic should be sealed to prevent dusting, staining and wear & tear (Stoneshield Industrial Concrete Sealer, Stoneshield Premium-Plus™, Stoneshield Concrete Densifier – Lithium). All these sealer have different characteristics and provide different results.

What are the best sealers for oxided concrete screeds?
Oxided cement or concrete screeds exhibit the same characteristics as concrete floors and will require sealing to prevent dusting, staining and wear & tear. Because oxided cement screeds are mostly used commercially and residentially they tend to be installed for aesthetic purposes. For this reason alone sealing is required to maintain the initial required aesthetic. Here only UV stable, non-yellowing sealers are suitable (Stoneshield Premium-Plus™, Stoneshield Cement-Sealer™