How to Make a Concrete Block Water Sealer

Intricate concrete blocks with many open spaces especially need sealing against moisture.

There are many concrete sealers available on the market that protect masonry from water and other factors that may cause it to crack, chip or otherwise deteriorate. Concrete blocks, because they are not solid, can be more vulnerable to these types of damage than poured concrete. For this reason, concrete or cinder blocks are generally sealed before use. If you prefer not to use a chemical-based sealer, there is an effective natural alternative that can give you peace of mind.

Things You'll Need

• Mineral spirits
• Linseed oil
• Plastic bucket
• Plastic spoon
• Plastic paint pan
• Paintbrush

Instructions

1. Mix together one part liquid mineral spirits and one part plain, unboiled linseed oil in a plastic bucket. Stir the liquid with a plastic spoon. Do not use any metal to contact the solution, since metal can affect chemical contents.

2. Transfer the mixture to a plastic paint pan. Do not apply sealer to concrete that is not fully cured or is at all wet.

3. Apply the sealer to the concrete blocks with a clean paintbrush. Brush the sealer on rather thinly and in straight lines, if possible. Let the sealer dry at least 24 hours and add a second coat. Wait another day before using the sealed concrete blocks.

References

• The Natural Handyman: Linseed Oil - Its Uses and Limitations
• boston.com: Your Life: Linseed oil is an ideal sealer; spiders the best insecticide