When it comes to mixing modern, contemporary designs with frankly absurd toughness and durability, it's hard to beat concrete when it comes to making outdoor furniture. However, while concrete can take a beating, it is not invulnerable to the elements -- the porous surface of bare concrete easily traps stains and marks which can quickly become permanent, and provides a wonderful environment for moulds and lichens to grow on. Unprotected concrete is also easily scratched and abraded, a particular concern if your furniture is on a lawn that requires mowing. 

Fortunately, a simple application of concrete sealant can protect your concrete furniture against all these threats, but there are many concrete sealants on the market and no two have exactly the same properties. With plenty of concrete outdoor furniture sold pre-sealed, its especially important to know the different properties of each sealant, and what advantages and disadvantages they bring.

Wax sealants

These sealants are based on natural beeswax or synthetic equivalents, and are the best choice if you're looking for a simple sealant you can apply yourself. One or two coats with an ordinary paintbrush is generally sufficient to seal the surface of your furniture, as the wax fills the pores of the concretes surface to repel moisture and prevent accumulation of mould and lichen. This wax coating can also give your furniture an attractive sheen.

However, wax is far from a permanent sealant, and will need to be reapplied periodically as inclement weather and exposure to sunlight wears it away. Wax is also relatively thin and provides only a thin membrane of waterproof protection, and as such provides little protection against scratches and stains.

Epoxy sealants

Epoxy sealants are based on plastic epoxy resins, and are applied in a relatively thick coat over the surface of your furniture. The epoxy dries to form a thick, thoroughly waterproof coat that provides superb protection against moisture, mould and stains. Epoxy resins even provide protection against corrosive bird guano.

However, the coat that epoxy leaves behind is highly visible, and can leave your concrete with an unpleasant plastic look and feel. In addition, it is not particularly scratch resistant, and although it is relatively resistant to sunlight constant UV exposure will eventually cause it to crack -- these cracks are unrepairable and necessitate stripping and re-coating your furniture. Epoxy sealants are also difficult to apply, and most epoxy coatings are applied professionally or prior to sale.


These coatings are also plastic-based, but have drastically different properties to their epoxy cousins. A properly applied urethane coating will protect your furniture against scratches, stains, moisture, mould and mildew in equal measure, while remaining highly resistant to wear caused by sunlight and bad weather. Urethane coatings are available in both gloss and matte versions, making them aesthetically versatile too.

However, actually applying a urethane coating is a difficult job requiring skill and experience, especially if you want a matte finish with a thin surface coating. As such, urethane sealants are almost always applied professionally, with the added costs that entails. Urethane also requires significant amounts of surface preparation to adhere to your concrete properly, further increasing costs.

Penetrating silicates

A space-age addition to the field of concrete sealants, these sophisticated sealants contain minuscule silicon crystals which solidify when the sealant is applied. These crystals effectively fill in the gaps left by the pores of your concrete, leaving a waterproof, scratch-resistant finish that is largely indistinguishable from the surface of unsealed concrete. The best thing about these sealants, however, is that they are permanent -- once dried, the silicon crystals will only wear away as the surface of the concrete itself wears away, providing decades of protection.

However, because these sealants do not form a uniform coating, they provide little protection against stains. They are also incompatible with other sealants apart from wax, and cannot be removed once applied, so you'd better be sure you want a penetrating silicate seal well before it is applied.