Precon Products, A leading national independent supplier of construction products

How To Seal Concrete

In this guide we will go over the steps of how to seal concrete, why you need to seal concrete and a little bit about concrete sealer. If you want to know more about what concrete sealer actually is, then please take a look at our guide - Choosing A Concrete Sealer

How to seal concrete and knowing exactly what concrete sealant is may be second nature to some in the building industry. However, you may be new to the industry or you might want to brush up on your knowledge. Hopefully this article will shed some light on a process that you may require.

 

Why Do you Need To Seal Concrete

Sealing concrete is a very important task and it provides so many benefits. If your concrete surfaces are not properly sealed moisture is able to penetrate, which can lead to mould growth. Sealing concrete prohibits moisture ingress and therefore improves the surface's longevity. This longevity means concrete sealer can extend the life of your concrete by 25-30 years.

Concrete sealant protects the surface from corrosive elements, cracking and scaling. You can improve the durability of your concrete surface  and ensure they look better for longer by correctly applying concrete sealer. Maintaining the aesthetics of the concrete surface is also important and by sealing coloured concrete surfaces you can help to protect the floor’s colouring. 



When You Need To Apply Concrete Sealant 

Concrete sealer needs to be applied in dry conditions because it won’t adhere to damp concrete. It is best to check the weather before planning to apply sealer as the temperature also needs to stay above 10°C (50°F).



New Concrete Surfaces

As soon as a new concrete surface can withstand the weight of the installer most acrylic-resin concrete sealers and some penetrating sealers can be applied. However, it is advised to wait at least a month before most high-performance coatings can be applied, such as epoxies and urethanes.



Existing Concrete Surfaces

If the concrete surface is not freshly laid you will need to follow the below steps to make sure the area is properly prepared for a new coat of concrete sealer.

 

Preparing The Concrete Surface

To seal a concrete surface you will need to follow a simple process as detailed below. Essentially, you will need to prep the surface then pour a small amount of concrete sealer into a suitable container. A painting tray works best if you want to use a paint roller to apply the sealer to ensure an even distribution. Make sure you give the concrete sealer the time it needs to dry - around 12 - 24 hours is best.

 

Clean The Concrete

Make sure the surface is clean by sweeping it of all dirt and debris. You will also need to make sure that all grease, oil, mastic or paint is removed, as well as stains that can show through the new sealer. Use the correct cleaner for the substance you need to remove - use a degreaser to remove any stubborn grease. 

Once you have removed all the stains from the concrete surface, mop it with floor cleaner, sweep or vacuum the remaining debris and allow it to dry for 24 hours.

 

Repair Any Cracks In The Concrete

Any cracks or pitting should be filled at this stage to ensure a smooth finish. Apply the concrete repair to the affected area and follow the manufacturer's guidelines for application. For a strong finish that also acts as a concrete sealer use Epocrack Seal from Adomast. As an epoxy resin sealer it completely seals cracks against water ingress, with its uses including repair of concrete beams, columns, slabs, walls, etc.

 

Remove Old Concrete Sealer

You will need to remove any old concrete sealer if it has been applied previously. If you’re not sure if sealer has been used you can test it by pouring water on to the surface. If the water beads and stays on the surface then it has been sealed, however, if the water soaks into the concrete then no sealer has been applied.

If you are experienced then a sandblaster is a way to remove old sealer that does not include using any chemicals. However, in most situations a chemical stripper is the most effective way of removing the old sealer. Once you have applied a thick coat of chemical stripper you should start to see the surface bubble and crinkle. With a long-handled scraper continue to scrape the surface and remove the sludge residue. Be careful to avoid contact with the skin and remove the waste correctly. 

The last step in preparing the surface is to clean it again with trisodium phosphate (TSP) and water, such as Precon’s cleaning solvent. Dry and wait for another 24 hours before the application of the new concrete sealer.

 

Apply New Concrete Sealant

Apply the first coat of sealer with the method described earlier and wait for at least 2 hours before you apply the second coat. Allow for lots of ventilation if applying sealer in an interior environment. For strong adhesion apply the second coat at right angles to the first coat and then wait for the sealer to cure adequately. Please check the application guidelines on the product you use, but some concrete sealers can take up to 3 days to properly dry.

Author Lydia Swallow. Category Concrete Repair. First published Tue, 15 Jun 2021 12:00:00 +0100