Can Hydraulic Cement Be Added to Latex Paint for Basement Wall Use?

Do Not Mix

• Hydraulic cement, like any cement products, requires a specific combination of water and cement mix in order to undergo the chemical reactions necessary for curing. Mixing in an additional component, such as latex paint, can only serve to reduce the effectiveness of the cement's bonding and potentially render the mixture unable to cure. This can lead to flaking, cracking and crumbling of your basement wall.

Clean the Area

• Before you apply any hydraulic cement to your basement wall, make sure the area is clean. If you are repairing a crack or a crumbling piece of wall, remove any loose chips and bits of cement first with a wire brush and pick. If possible, use compressed air to remove loose granules and bits of crumbled cement. Wear proper breathing and eye protection when working with the old cement.

Apply the Hydraulic Cement

• Mix your hydraulic cement according to the instructions on the bag. If you are repairing or replacing a large area, mix only enough cement for one small portion of the job at a time. This will help prevent the cement from beginning to cure while you are still applying it. Smooth the surface of the cement with a trowel, leveling the surface so that it blends in with the existing cement.

Before Painting

• Allow the hydraulic cement sufficient time to cure before you apply your paint. A small space heater can dry out any remaining moisture. You should also test the existing cement, not just the newly applied hydraulic cement, for moisture before you paint. To do so, tape a piece of plastic to the area you intend to paint, and leave it overnight. Check the plastic for accumulated moisture the next morning. If there are water droplets on the plastic, you will need to apply concrete sealant to the existing cement before applying the latex paint. While the new hydraulic cement will be a barrier to water, if your existing cement is not sealed, water will weaken the bond between the old and new materials. There are a number of paint products and sealants marketed for painting cement, and most are available in any home improvement store.