Water Damaged Plaster

After a lot of water exposure to a building, regardless of the source of the water, the building must be dried out thoroughly before any kind of restoration can be done. One of the materials that exist in a lot of building is plaster so it is necessary to be aware of the kind of restoration that is required for water damaged plaster.

The good news if you’ve got plaster walls is that plaster can be dried out much more readily than other common wall surfaces such as sheetrock. Exactly ho much better it dries will depend on the plaster mix that was used when making the wall, the amount of water it has been exposed to and where in the wall the greatest damage has occurred.

If the damage to the plaster has come from clean rainwater it should be possible to save the wall. The first step I s to drain the water from the wall cavity by removing the baseboard and drilling holes in the plaster just above the floor. A word of warning here, use a cordless or battery drill when performing this task.

Remove any wet insulation from within the wall cavity. You want to ensure that the wall cavity has dried thoroughly. To speed up the drying process, open windows and doors to promote good airflow or if that’s not possible bring in fans to circulate the air.

Clean down the walls to remove any water stains and you can consider using a weak solution of Clorox and water to inhibit or remove any early stages of mold growth.

When water damages plaster it causes bubbles in the surface due to the way the lime reacts to the water. This may either be minor damage or it can involve the entire plaster coat that can then crumble away. All of the water damaged plaster should be removed and this can be done with a putty knife or a paint scraper. If the plaster surface has become too hard for the putty knife it may be necessary to use a hammer and chisel to scrape back the hard shell that has formed.

If the wall surface is painted you will have to test it to find out whether it has survived the damage. If it peels off easily when scraped with a putty knife it should be removed back until you reach a point where the paint won’t come off easily.

Once you have scraped back to undamaged plaster you can then prepare the surface and replace the plaster that has been removed with a setting-type joint compound. After refilling the plaster and letting it harden, sand it back until it is smooth and then add another layer of the compound, applying it in a direction that is perpendicular to the way it was applied with the first coat. Repeat the sanding process ensuring that the wall is completely smooth. Clean off the plaster dust and then coat the surface with a primer-sealer before painting over the patched up area.