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Cleaning and Sealing Block Paving
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Over time the surface of concrete block paving can fade and turn dull, stain from spillages and grime, and attract moss and weeds, but it is possible to clean the surface and restore it, almost to its original condition.

Cleaning and sealing block paving can be a DIY job but the strongest cleaning and sealing materials are only available to professional contractors.

Tools are available at most DIY stores which make removing moss and weeds from between the joints in block paving much easier and depending on location and aspect, this may need to be done once or twice a year.

There are also many proprietary products for cleaning and sealing block paving and although this can be a DIY project, there are a number of contractors who will be happy carry out the job for you.

As with all DIY jobs though, it will obviously cost more to pay a specialist to cleaning and sealing block paving driveways or patios but the upside is that they should have the proper tools for the job and often have access to more effective cleaning and sealing solutions. They should also take less time to do the job and save you from back ache in the meantime.

Rotary cleaner used to clean block paving
Cleaning and Sealing Block Paving - Applying sealer to block paving
Applying sealer to block paving

Basic cleaning of block paving

The block paved surface can be regularly cleaned with a brush and pressure washer which should remove grime, moss and algae.

Most oil stains can be removed by applying a mild detergent, brushing with a soft scrubbing brush and then rinsing. More stubborn oil stains will require a proprietary cleaner.

One which we can recommend is supplied by Resiblock™, one of the world’s leading sealant manufacturers, and goes by the name of Resiblock OR™ (oil remover).

Rejuvenating block paving driveways and patio areas

Although basic cleaning and sealing block paving surfaces can be carried out several times a year, for a longer lasting rejuvenation of the blocks they will need to be properly cleaned and sealed.

There are several different types of sealant available but for the most part they can be divided into water-based emulsions and urethane based sealants. Sealants are also available to provide a matt or glossy, wet-look finish.

If you decide on a gloss finish, we would recommend that you see a few driveways with that finish before finally deciding as you will probably change your mind.

Water-based sealants are typically inexpensive, need applying every year or two and can be no more than a colour enhancer. Urethane sealants penetrate the surface of the blocks to repel oils, prevent staining and virtually eliminate the growth of weeds.

They also bond the grains of sand in the joints not only to the sides of the blocks but also to each other, helping to hold the sand in place and the blocks firmly in place. Urethane sealants also last much longer but are more expensive.

Cleaning and Sealing Block Paving - Buff coloured block paving before and after cleaning
Buff coloured block paving before and after cleaning
Cleaning and Sealing Block Paving
Cleaning and Sealing Block Paving

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Block paving should be completely clean and dry prior to sealing

Before sealing a block paved driveway or patio area however, the surface should be thoroughly cleaned of all grime, moss, algae, lichens (with a fungicidal wash) and oil, otherwise these will be sealed in.

The surface should also be clear of any efflorescence; the dusty white powder which can form on the surface.

Cleaning can be carried out with a brush and pressure hose but a contractor would be more likely to use a rotary flat surface cleaner which will not only be more effective, but should be quicker to complete the job.

At this point, any damaged or badly stained blocks can be replaced. Prior to sealing, the joints between the blocks should be re-filled with kiln-dried or silica sand and then swept clean. The area should also be completely dry.

Applying block paving sealant

Every sealant will have its own application instructions, which should be followed carefully for the best results, and some require more than one coat of sealant. Most sealants however, are supplied in drums and the transparent liquid can be applied on to the surface of the blocks with a sprayer unit, a roller or be painted on with a brush.

Sometimes it is a combination of these as a paint brush is often required to apply sealant in areas which are difficult to access. The block paved surface should not be used until the sealant is completely dry and this can be tested by scraping out 5 mm to 10 mm of the sand in a joint – if the sand below is dry, the blocks will be.

Finally, some driveway and patio surface sealants claim to be suitable for all paving types but we feel that what is best for concrete block paving will not necessarily suit clay paving, tarmacadam or pattern imprinted concrete.

Care should be taken when choosing a sealant for your block paved driveway or patio as specific sealants have specific jobs but the best, generally more expensive products will invariably provide the best results.