How to prime concrete before painting

When priming a concrete floor we recommend priming with Floorseal Stabilising Solution. This guide explains how to prime concrete floors before painting, plus how to carry out any work required before priming.

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How to prime a concrete floor

Apply a single coat of Floorseal Stabilising Solution to your floor with a masonry roller. The floor must be dry and free from obvious loose material. If the concrete is new you must remove laitance (if any is present).

Laitance is a soft crumbly layered of lime and/or aggregates which, if present, will be visible on the surface. Laitance is typically caused by an over watered concrete or perhaps rainwater damage during curing.

There are a variety of reasons which cause laitance, they all manifest as a soft layer on the surface of the concrete. Laitance should be removed before priming with Floorseal Stabilising Solution.

Removing laitance

Laitance removal can be undertaken with an acidic solution such as Floorseal Cement & Grout Haze Remover diluted at 1:2 (1 part concentrate to 2 parts water). Apply to the surface, allow it to react and then remove by rinsing with clean water.

Another method of removing laitance would be to use a diamond grinding machine fitted with suitable abrasives.

Etching power floated concrete

To etch the surface of concrete prior to priming & painting we recommend using Floorseal Cement & Grout haze Remover. This product will etch the surface when applied at a ratio of 1:2 – One part product to two parts water. Always rinse well after etching concrete floors.

Application of Stabilising Solution

Once the surface is dry, free from laitance & has been etched (if required), apply a single coat of Floorseal Stabilising Solution. Apply with a short pile masonry roller. After the primer has been applied allow the floor to dry, a minimum of 4 hours drying time is required.

All signs of damp must have disappeared before painting. The longer the floor has to dry the better, particularly in low temperatures. The application of primers in low temperatures will usually extend drying times. However, the introduction of ventilation and heat will reduce drying times.

Apply Floorseal Stabilising Solution with a short pile masonry roller. A brush can also be used to apply the primer when treating small areas. For very porous concretes or screeds, a low-pressure pump-up sprayer is also a suitable method of application. Always try to apply the primer in a thin even layer.

Floorseal Stabilising Solution will penetrate the surface of the concrete or screed, improving the adhesion of paints.

In conclusion

Floorseal Stabilising Solution should be applied in a single coat to concrete floors or screeds to prime the surface before painting. Prepare the surface by removing laitance from concrete (if present). You may wish to etch the surface of power floated floors prior to priming.

Ensure all surfaces are completely dry before applying  Floorseal Stabilising Solution and the primer is fully dry before painting.

Further information

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 The information included in this article is not exhaustive. If you need further information please contact Floorseal on (01484) 861461 or email us info@floorseal.co.uk our web address is www.floorseal.co.uk.