How to Seal Concrete Block Paving

How to Seal Concrete Block Paving

One of the very first things we would do is test the surface area with a product called Xylene. Very few suppliers or sellers will make you aware of this, but it is a nightmare if or when it goes wrong. This is a way of making sure that the surface area that may have been sealed before will not react with our Block Paving Sealer. We and most of the main suppliers use the same ingredients to alleviate this issue, unfortunately in this area of business, there are quite a few in for the quick buck and will sell products that are much cheaper and will cause problems. If there is a reaction, then you will see several things that could happen.

  • Chicken Skinning – This is where the sealer has reacted with the previous product, not been able to penetrate the surface thus has no binding qualities and will peel off
  • Ghosting – Again this is caused by the solvent in the sealer reacting with the previous product that may have white spirit as the main component or polyurethane for example.
  • Silvering – This is where a driveway or patio has been sealed far too often. People like to seal the surface every year because when first done it looks at its very best but over sealing on any surface can lead to a build up of the sealer coats to a point where the 3 – 4 coats previous cause a vacuum on the sealer coat on the surface of the block and pulls it of the concrete blocks thus almost leaving it as a skin. The process for sealing Concrete Block Paving is relatively simple if you keep to the guidelines. Trust our application process and you will continue to have a colourful and lovely looking driveway or patio.

It will be left with damage that is unsightly and the sealer will have to be removed which is a job that we would not like you to have to do.

After the cleaning process that I have previously written a blog, you would have first of all cleaned the surface with our Patio and Driveway Cleaner and jet washed the area afterwards.

PREPARATION AND TOOLS – The area is now cleaned and perfectly dry you will need the following items to complete the sealing process.

  • Dry Kiln Sand – This is a fine sand to replace the sand lost from the joints when cleaned and jet washed
  • Sprayer – We sell a purpose made 8 litre Low Pressure Sprayer. I am only referencing this application. We will explain more later in the blog.
  • Broom or Brush – This will be used to move the sand around the block surface to fill all the joints
  • Sealer – Our Block Paving Sealer to apply to the surface area as a one coat application

SEALING PROCESS – After all the cleaning has been done and the concrete block paving is completely dry, and the temperature of the day is right for the sealer. You need to open the bag of kiln dried sand and spread it excessively over the concrete block paving. With a brush you then move the sand all over the block paving, making sure that you fill all the joints. Don’t worry if there is a lot of sand left on the surface. Then sweep up all the extra sand and re-bag it for future use. When you have picked up as much as you can then you must make sure that all the block surface and top of joints are free from any sand residue.

Once all the sand has been removed and the day is dry, and the temperature is warm enough then open the sealer and fill the sprayer up to ¾ of its volume and screw it tight and pressurize the cylinder with 20 – 30 pumps. When this has been done then find your starting point making sure as you move along spraying the sealer you do not trap yourself in the corner. Point the sprayer nozzle at roughly 30 degrees to 45 degrees to the surface area about 12 inches – 14 inches away from the blocks. Then proceed at a allow pace applying the Block Paving Sealer evenly all over the concrete block paving.

When this is done, you will need to leave the area sealed for up to 4 hours to walk on and 24 hours to drive on. This process should last 2.5 – 3 years before the process needs to be done again.

ISSUES YOU MAY HAVE ATFER SEALING – What this section refers to are issues that can happen if the procedure is not followed to the letter. You will have no problems if you do it as it says and we will explain why:

  • Excessive Sand – I referred to the removal of the sand earlier as important that you remove all the excess from the top of the blocks and the top of the joints. If you don’t do this what can happen is that the sand is moved around on the block and the sealer will stick it to the face of the blocks and again it will either have to stay, there or the sealer removed.
  • Using only the sprayer – I mentioned earlier that I would explain this. If you read issue 2 that is what happens far too regularly with roller or brushes. It is a cheaper way of applying the sealer, but these implements have an issue where they grab the sand and spread it. At least with a sprayer whose nozzle is 14 inches above the ground and the spray is not forceful, it will move no sand at all.

AFTERCARE – There is very little you need to do with regards to aftercare. Every so often it would not be a bad idea to jet wash the surface, not too strong. This will remove moss. Algae and other loose impediments that are sat on the surface of the sealed area. Don’t worry about the sand because when you sealed the surface the Block Paving Sealer being a solvent based acrylic actually hardens the sand almost cement like and the jet wash will not remove it.

I have added several blogs bespoke to individual substrates to understand and apply the relevant sealer that substrate (Natural Stone. Indian Stone. Block Paving, Man-Made paving, Slate and Granite. Brick and Stone) needed to be used.

They are available on our website


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