Technical Info >> Sealing Concrete Pavers - Advantages / Disadvantages ?

Sealing Concrete Pavers - Advantages / Disadvantages ?

Smart Precast does not actively push our paving customers into sealing the Smart paver range - as we appreciate the beauty of concrete that ages and matures naturally. However, if you want concrete paving to remain fresh, new looking, pristine and your paving is at risk of becoming stained or marked from leaf tannins, berry stains or oils from BBQ activity, consideration can be given to protecting the paving surface with a sealer.

Sealers are applied to concrete for a number of reasons; firstly protection, water proofing, hygiene and enhancement of the colour (it will appear wet looking). Concrete will dust with age and you have the possibility of efflorescence What is Efflorescence PDF affecting the colour clarity. This masking is often wrongly referred to as fading. Unsealed concrete will mark and stain and sealing will make cleaning and maintenance easier.

The paving is typically allowed to mature for at least several months to allow any ‘release agent oil residue ‘ to disappear before being sealed. Concrete surfaces should be clean, sound and free from dust, oil, grease and loosely adhering particles or other contaminants before sealing – otherwise over time the sealer will fail and flake away from the surface of the concrete. Therefore all weak surface laitance must be removed.

There are a wide number of cleaners (acidic), acidic neutralisers and sealants available for concrete, each used and recommended for a particular situation. Smart Precast are not experts in sealing so it is recommended that our customers seek the expert advice from a sealer supplier – who will recommend a sealer system specific to your unique situation.

Please note that a concrete sealer is applied in three separate coats, and due the sealers limited lifespan will need to be stripped off and the costly process carried out again. Dependant on natural wear and tear, the quality of the original application and sealer - this may need to be done every three to four years.

Also note that cleaning the concrete surface before sealing will change the appearance of the concrete surface (etching will occur) and the sealing of the concrete paving will change the visual colour appearance (colouration darkens as if wet). Sealing concrete paving also applies a skin to the surface of the concrete, which can make the concrete slippery when wet or grimy. Therefore, consideration will need to be given when selecting a non-slip additive to add to the sealant on application.

The sealer must be applied evenly and consistantly so as to avoid streaky marks or spots stains as pictured.

In an external situation the sealed concrete can display patchiness or spotting when it gets wet. This is evident especially in a ground situation (dry grind) and in cases where the finish is very open or due to bad workmanship, the surface is not closed up. Grinding removes the top of the concrete and will expose small pinholes in the surface. The spotting is caused by water ingress through the sides of these holes. The sealers are not fillers and will not completely coat the hole. What tends to happen is that when they get wet, the water is absorbed through the sides and it then migrates upwards, giving a darker appearance around the hole. Over time this does lessen.

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Concrete Sealer Spillage