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How to Repair a Precast Concrete Wall

- May 17, 2018 -

How to Repair a Precast Concrete Wall

If there are cracks, holes, or delamination in the precast concrete walls in your garage or basement, you can repair them to make it as good as when you were new. Follow the process outlined below to repair the precast concrete walls.

Step 1: Clean and prepare the area

Grind the fine cracks in the precast concrete and the area around the holes with coarse sandpaper. Use 50-80 grit. Remove dirt, dirt and white minerals from the concrete.

Wipe the area around the crevice or hole with a damp cloth and keep it moist for a few hours. This will prevent the dry concrete from absorbing the moisture in the Portland cement slurry when applied.

Step 2: Portland cement slurry

In a metal bucket, mix Portland cement with water to form a thick layer of smooth grout. Stir continuously with a metal paddle to prevent agglomeration.

Fill fine cracks with Portland grout on a t knife. Use a t shank tip to fully fill the grout into any hole. Squeeze the cement slurry into cracks and crack edges. Smooth the mortar with the flat side of the t knife.

Step 3: Start the curing process

Allow grout to dry for 2 to 3 hours. Cover the repaired area with a large plastic film and stick it with tape. For 5 days a day, moisten the repaired area with a small amount of water and cover it again. Apply a silane-based sealant to the repaired area with a synthetic bristle paint brush and apply a silane-based sealant a few inches around it.

Step 4: Repair larger concrete holes in precast concrete

Use cold chisels and hammers to enlarge the cracks or holes under the surface. This will help the concrete binder and the new concrete mixture penetrate and mix with the old concrete. Mix enough ready-mixed concrete with water to fill holes or cracks and apply quickly. Press the concrete mixture into the hole and use a spatula handle to crack it and evenly apply it to the surface. Follow the instructions in Step 5 to cure the repair point and then seal with a silane-based waterproof sealant.

Step 5: Repair unstable precast concrete walls

If you need to repair large holes or redo hairline crack repairs, these may be signs of structural problems such as warping or shifting. Nails made of carbon fiber and KevlarTM can be used to re-stabilize and reinforce the walls. These unique staples remove the wall load from the damaged area. The staples will be cemented with a new layer of concrete and sealed with a silane sealant. Contact a company that specializes in structural repairs to complete this task.