When it comes to treating rising damp or penetrating damp in your property, having a damp proof course installed is only part of the solution. While this treatment addresses the source of the problem, many homeowners overlook a crucial follow-up step: replastering the affected walls.
Let us explain why replastering after damp proofing is so important, and what can happen if you skip this vital stage.
What Happens During Damp Proofing?
Damp proofing typically involves installing a damp proof course (DPC), such as a chemical injection, to prevent moisture from rising through the walls. This stops further moisture ingress but it does not repair the damage that the damp has already caused.
Over time, damp causes plaster to become salty, brittle, and contaminated. These salts are hygroscopic, meaning they attract moisture from the air, which can cause ongoing damp issues even after the original source of moisture has been treated.
Why Replastering Is So Important
Removes Salt-Contaminated Plaster
Damp brings with it ground salts that get trapped in the plaster. These salts continue to absorb moisture from the atmosphere, creating persistent patches of damp even after the wall has dried out. If the contaminated plaster isn’t removed, the wall can’t fully recover.
Prevents Damp from Reappearing
Without replastering, the old salts can create the illusion that the damp treatment has failed. In reality, it’s the plaster that’s the problem, not the DPC. By replastering with a salt-resistant render or plaster, you eliminate the risk of this happening.
Provides a Fresh, Dry Finish
Replastering ensures your walls are clean, smooth, and dry ready for decorating. Skipping this step can leave you with stained, crumbling walls that are unsightly and impossible to paint or wallpaper effectively.
Protects Interior Air Quality
Damp and salt-laden plaster can contribute to poor air quality, especially in enclosed spaces. Replastering removes these contaminants and creates a healthier indoor environment.
Restores Structural Integrity
Long-term damp can weaken plaster, leading to cracks and crumbling. Replastering not only improves the look of your walls but also restores their strength and durability.
What Type of Plaster Should Be Used?
After damp proofing, it’s important to use a salt-resistant plaster or renovating plaster. These plasters are specially formulated to prevent salt migration and ensure moisture does not reappear at the surface.
Some professionals also use a waterproof render base coat, often with additives like SBR (Styrene Butadiene Rubber), followed by a breathable finish. Always ensure the materials used are compatible with the damp proofing system installed.
Damp proofing is an essential step in protecting your home from moisture damage but it’s only half the battle. Replastering is the key to making your damp treatment effective in the long term. Without it, you risk recurring damp patches, ruined décor, and even a failed damp proof course.
If you’ve recently had damp proofing installed or are considering it make sure you speak to a qualified contractor about replastering options. It’s an investment in your property’s future and your peace of mind.
