Both simple and ornate plaster surfaces are the work of master plasters applying many thin layers of carefully mixed plaster to lath. Though the level of decoration may vary greatly, water has the power to destroy the work of even the most skilled plaster craftsman.
Whether it is large quantities of water from a major roof leak, prolonged exposure to humid air, or condensation that has penetrated the lath, plaster invariably will be damaged. It can be tough to identify if plaster damage is due to water, craftsmanship, or structural integrity of the building. There are several hallmarks of water damage that will help you identify if water is the underlying problem. By understanding the common types of water damage and knowing when to seek professional help, you have a path to restore and protect your plaster surfaces.
Common Types of Water Damaged Plaster
Understanding the types of water damage that affect plaster is key to diagnosing the issue and determining the next steps for repair. Below are the most common types and signs of water damaged plaster and what they reveal about the underlying problems.
Subtle Discoloration
Commonly found near water access points, such as around a window frame, exterior door, or ceiling corners. This slight discoloration is often seen in older houses, which are less water tight. Often with a slightly brown or yellow hue, this discoloration can be noted on both plaster and any wall coverings placed over affected plaster, such as wallpaper or fabric.
Subtle discoloration may also be accompanied by a faint musty smell, indicating moisture that hasn’t fully dried. Using a moisture meter in these areas can help confirm if excess moisture is present, even if the discoloration appears dry. Regular inspections of these areas during rainy seasons can help detect early signs of water intrusion.
Drip/Streaking Stains on Paint
These elongated drip-like stains, usually with irregular borders, have a distinctly water-like appearance. They most commonly form where the wall meets the ceiling or on the plasterwork under a window. Usually the root cause of these stains is a leak(s) from the outside or a regular drip leak from plumbing. Prior to replacing the plaster work, the building envelope should be secured and the interior compartment of the wall treated for possible micro-organism growth.
Efflorescence
These are the salt deposits left behind when water permeates masonry, such as concrete blocks, brick, stone, and stucco. While these white or green crystalline salt structures are not hazardous to your health, they are an early warning sign that water is seeping into the building and may be indicative of a potentially larger water problem. Simply removing the salt buildup will not treat the underlying problem and an expert should be consulted to determine the scope of the damage and what potential damage might occur if left untreated. Over time, water can be wicked up from foundation masonry (or inward from exterior stone walls) and damage any plaster applied to it.
Flaking Paint
Paint and water are insoluble and an easy way to identify if plaster is water damaged is looking for flaking paint or air bubbles that burst and flake. Unlike flaking plaster, paint will flake with minimal exposure to water, while plaster often needs to get wet and re-dry before flaking occurs. If paint starts to flake or bubble, feel the plaster underneath the area; often it might feel damp or wet. If you are experiencing something similar, call a professional—do not paint over or try to re-plaster the area.
Mold and Micro-Organism Proliferation
Mold and other micro-organisms can pose serious health risks. If mold or mildew has formed on plaster it is usually the result of prolonged dampness, or repeated leaks. A professional must be called to thoroughly remove and treat both the plaster and the internal wall structure. Do not attempt to bleach or remove the growth, as it may not be the most effective method to treat the area. Additionally, it is important to identify the cause of any leaks and correct it prior to repairing plasterwork.
Mold growth might also be hidden within the wall cavity, especially in cases of long-term leaks. Infrared moisture detection or air quality testing can help identify hidden issues before they worsen.
Can Water Damaged Plaster Be Repaired?
Yes, water damaged plaster can often be repaired, depending on the extent of the damage. Minor issues like cracks or staining may be addressed with DIY techniques, but extensive damage, especially in historical or decorative plasterwork, may require professional intervention. The key to successful repair is addressing the underlying moisture source first, ensuring the problem doesn’t recur.
How to Know When to Call a Plaster Restoration Expert
Some situations require the expertise of a professional to ensure the repairs are done correctly and the plaster’s integrity is maintained. You should call a plaster restoration expert if:
- The damage is extensive: Large areas of sagging, bulging, or crumbling plaster indicate structural issues that require professional attention.
- The plaster is part of a historical building: Plaster restoration in historical settings demands specialized techniques and materials to preserve the building’s character.
- There is mold or mildew: Mold growth from prolonged moisture exposure requires professional remediation to ensure it doesn’t return.
- The plaster has intricate decorative elements: Replicating ornate plasterwork is a skilled craft that requires an experienced artisan.
- You’re unsure about the underlying cause: If the source of moisture or extent of damage isn’t clear, an expert can assess the situation and recommend the best course of action.
Plaster restoration specialists have the tools, knowledge, and experience to repair water damaged plaster effectively, ensuring the problem doesn’t recur and the aesthetic quality of the plasterwork is restored.
Addressing Water Damaged Plaster
Water damaged plaster isn’t just a cosmetic issue—it can pose risks to both your health and the structural integrity of a building. Addressing the root cause of the damage, whether it’s a leak, poor ventilation, or rising moisture, is essential before beginning any repairs. While minor damage can often be repaired with some time and effort, severe cases—especially those involving mold, structural issues, or ornate plasterwork—are best left to professionals.
With the right approach and expertise, water damaged plaster can be restored to its original beauty, preserving both its function and aesthetic appeal for years to come.
If you are in need of plaster restoration or repair services, please contact John Canning & Co.
