How to seal interior natural stone floors

This article explains how to seal a natural stone floor with one of the three Floorseal products typically used.

There are other Floorseal products which you may find useful, but the products discussed are suitable for most projects.

The sealer you ultimately select depends on the following factors:

• Whether you wish to retain a totally unaltered appearance?
• Do you wish to colour enhance the surface?
• Is a sheen required or not?
• The type of stone and its age i.e. a newly laid floor or a historic older installation.
• Do you need to dustproof the surface (a minor issue with floors).

If you wish to view the product pages of any of the sealers mentioned in this article, please click the product title highlighted in blue. There is other information at the foot of the page regarding user guides and other how to guides.  

1. Sealing with Floorseal Natural Stone Sealer Breathe

This product is an invisible breathable impregnating sealer which does not form a film, lacquer or skin. It can be applied to any porous natural stone like sandstone, limestone, clay-based tile, concrete, or porous pointing material. Natural Stone Sealer Breathe is water-based, solvent and VOCs free, low odour and dries rapidly. Apply twice, approximately 40 minutes to an hour apart, removing any excess after each application.

This impregnating sealer can be applied to any new, or older, existing porous natural stone slab or paver and it resists water and oil-based staining.

Natural Stone Sealer Breathe is fully breathable, so suitable for any situation where moisture vapour transmission is required, examples include old floors where no damp proof membrane (DPM) is present or newly laid surfaces where moisture vapour transfer is still occurring.

As Natural Stone Sealer Breathe is an impregnator, it will not alter the appearance of natural stone. For that reason, the sealer can be described as ‘matt finish’. This product could also be described as having ‘no finish’ as the sealing polymers become meshed into the pores of the stone, leaving a natural, unaltered finish.

This sub-surface sealer is not a surface sealant, so will not create a sheen. Therefore, it is the most natural way to seal any natural stone and as such it is suitable for listed buildings.

The types of stone this sealer is best suited for are:

• Indian, York, Kandla grey and monotone plain grey sandstones.
• Slate where a totally unaltered finish is required.
• Honed surfaces such as limestone, travertine, marble, concretes and porous granite.
• Porous brick and natural stone where altering appearance is not required.
• Natural stone where breathability is required.

This sealer can also be used as a pre-grout sealer (after fixing) & could also be applied to the slab’s prior/after laying. It is compatible with sand & cement mortar and lime pointing.

2. Sealing with Floorseal Stone & Tile Sealer Satin

Stone & Tile Sealer Satin is a topical sealer; it dries on the surface to create a subtle satin finish which is semi-breathable. As a by-product, it will slightly deepen the colour of certain surfaces.

This satin finish sealer is water-based, low odour, VOC free and dries rapidly. Apply the first coat, followed by a 2nd coat approximately one hour later. You can build the sealer up in further coats to increase the level of sheen. This product resists water & oil-based staining.

Apply in thin coats with a roller, brush, or microfibre flat mop or cloth this ensures no puddling or pooling can occur. We have found application via microfibre systems (cloths or flat mops) produces optimal results.

The types of material this sealer is best suited for are:

• Porous surfaces like sandstone, slates (including Indian & Chinese slate), York stone, clay-based materials i.e. tiles & bricks.
• Porous stone or tile that requires dustproofing/surfaces that appear dusty and chalky.
• Interior black limestone.
• Surfaces which would benefit from a low sheen.
• Normally, we do not recommend that it is applied to pale (newer) limestones or polished stone.

We do not recommend using this sealer in wet areas like bathrooms/shower cubicles. This product should not be used as a pre-grout sealer. It is compatible with sand & cement mortar and lime pointing.

3. Sealing with Floorseal Flagstone Sealer

Flagstone Sealer is a semi-breathable topical sealer; it partially dries on the surface to create a subtle silk finish. It will significantly deepen the colour of natural stone & other porous surfaces. This product resists water & oil-based staining, UV light and moisture clouding.

This topical sealer is solvent-based, relatively low odour & dries rapidly. Apply the first coat, followed by a 2nd coat approximately one hour later.

Apply in thin coats with a roller, paint pad or brush, this ensures no puddling or pooling can occur. The sealer can also be applied using a microfibre cloth or mop.

The types of material this sealer is best suited for are:

• Porous surfaces like general sandstone, York stone, Indian sandstone, slates and clay-based tiles & bricks.
• Surfaces which require strong colour enhancement.
• Any porous stone or tile that requires dustproofing.
• Normally we do not recommend applying to pale limestones or polished stone.

We do not recommend using this sealer in wet areas like bathrooms/shower cubicles. This product should not be used as a pre-grout sealer. It is compatible with sand & cement mortar and lime pointing.   

In conclusion

We have three sealing options for achieving the correct interior natural stone treatment, depending on the finish you want and your stone type:

Natural Stone Sealer Breathe – A breathable water-based sealer that resists water & oil-based staining. It does not change the appearance of the surface it is applied to. Once sealed, the surface still retains an unaltered natural finish. It is to be applied twice with all excess product removed after each application. Suitable for new or older surfaces (possibly in listed buildings) which may not have a damp-proof membrane (DPM). Suited to sandstones, general flagstones, pale limestones and other porous surfaces.

Stone & Tile Sealer Satin – A water-based semi-breathable topical sealer which creates a sheen and may slightly deepen colours. This product should be applied twice and can be applied in further coats to increase sheen. Often used on sandstone, slate or brick flooring but can be used on a stone surface that is dusty or chalky. We do not recommend application to pale limestone and highly polished stone.

Flagstone Sealer – A solvent-based topical sealer which creates a silk finish and significantly deepens colour. This product should be applied twice. Often used on sandstone, slate or brick flooring but can be used on a porous surface which are dusty or chalky and would benefit from colour enhancing. We do not recommend application to pale limestone or highly polished stone.

Further information

Please Click Here to view all of our products & accessories for cleaning and sealing natural stone floors. This includes our handy ‘how to’ guides & user guides for cleaning & sealing natural stone floors.

Please note there are other products which can be used on your interior floors which may also be suitable. We stock sample sizes of our sealing products; these are available from the individual product pages under the select size options.

The information contained within this article is not exhaustive. If you need further information please contact Floorseal or email Info@floorseal.co.uk