Yes, moisture can pass through plaster because it is inherently porous. Plaster acts like a breathable sponge that absorbs water vapor from the air and releases it. However, liquid water or excessive humidity can cause long-term softening, cracking, and mold growth if the moisture source is not addressed.
When plaster walls are exposed to water, the porous nature of the material allows moisture to be absorbed. Over time, the moisture weakens the plaster, causing it to crumble, crack, and bubble. Water stains may also become visible, further compromising the aesthetic appeal of the walls.
You need to ensure that the plaster is dry thoroughly before further decorating. If you don't, it could damage the plaster, causing cracks and brittleness because of excess damp. Plaster generally takes around three to five days to dry fully. It will turn from a brown colour to pale pink.
Understanding Water-Damaged Plasterboard
Once water gets into the material, it soaks it up like a sponge. It weakens, swells, and stains, and it can even break or sag over time. Plasterboard doesn't bounce back as solid plaster does when it gets wet. That's why repairs often mean replacing the damaged portion.
In a lot of cases, you can simply hack back to the original masonry and re-render and re-plaster the damp wall with a water-resistant render. This will keep any residual moisture in the wall and stop it from passing through to new finishes whilst allowing the wall to dry out naturally.
Direct warm air at small damp patches to lift off surface moisture and condensation. Run a dehumidifier to remove excess moisture and address the issue of moist air. Improve ventilation by opening windows so that you have plenty of fresh air.
There are a number of things that can indicate penetrating damp: The presence of dark spots on the exterior wall of your property. Salt efflorescence takes the form of a white, powdery substance caused by water ingress. Damage to exterior walls, including cracked bricks and crumbling mortar.
The best condition for allowing your newly plastered walls/ceiling to dry is to provide some ventilation by opening a couple of windows slightly. You can put the heating on, however, we recommend you keep this at a low temperature for a number of days after the plastering is completed.
Plaster is less porous than drywall but can still support mold if moisture is present. Common causes include leaks, high humidity, and poor ventilation. Prompt moisture control and professional remediation are essential.
Drywall can begin to grow mold in just 24 to 48 hours when exposed to moisture. Because drywall is extremely porous and backed by organic paper, it creates an ideal environment for mold spores to germinate quickly once wet.
Plaster may feel dry to the touch in 48 hours but not fully cured. Plaster drying time depends on the thickness of the layers. Complete curing typically takes 1-2 weeks for thin coats and up to 4 weeks for thicker layers.
Can Damp Plaster Be Saved? Damp plaster is, unfortunately, often beyond saving. This means that in the event your property has succumbed to a form of damp that has affected your plaster that more often than not, your plaster will need to be removed (otherwise known as 'hacked off') and reapplied.
Common mistakes in this step are not cleaning the surface properly, not removing dust or old paint, and ignoring cracks and holes. Before you start on a plastering job, you have to make sure that the surfaces you're working on are thoroughly clean. This is to make sure that the plaster adheres properly to the surface.
Plaster is rarely used in modern construction primarily because drywall (gypsum board) is faster, significantly cheaper, and easier to install. While plaster is highly durable and offers better soundproofing and fire resistance, traditional multi-coat plastering requires highly skilled labor and lengthy drying times, making it inefficient for modern housing demands.
Damp walls can be caused by various types of damp, from rising and penetrating damp, to condensation problems. Sometimes damp walls are caused by appliances such as washing machines or dishwashers failing, or from internal plumbing problems.
Plaster itself is inorganic and non-porous, making it highly resistant to mold. However, mold can and frequently does grow on painted plaster surfaces when dirt, organic debris, or condensation are present. Mold also often grows on the organic backing materials (like wood lath) hidden behind the plaster.
Yes, drywall can survive getting a little wet if it dries quickly (within 24–48 hours) and does not swell, soften, or grow mold. Small, localized wet spots that remain rigid can typically be dried and repainted, but if the drywall is sagging, soft, or damaged, it should be removed to avoid structural weakness.
Mold toxicity (or mycotoxin illness) occurs when you are exposed to mold spores that produce toxic byproducts. These symptoms can mimic other conditions and often range from mild respiratory irritation to severe neurological and immune responses.
To determine if mold is behind your drywall, look for surface signs like peeling paint, bubbling wallpaper, or warped drywall. Use your nose to check for a persistent musty smell. For definitive proof, use a moisture meter to find damp spots or drill a small hole to inspect the cavity.
Mold is generally at its worst from early spring through early fall (specifically July through October), peaking during the warmest and most humid months. Mold thrives in warm temperatures (60∘F to 80∘F) combined with relative humidity levels above 60%.
People choose plaster over drywall for its superior durability, better soundproofing, and smoother, more polished aesthetic. While drywall is quicker and cheaper to install, plaster provides a premium, hard-surface finish that is highly resistant to dents and is ideal for curved walls.
Remove mould from the walls with HG mould spray
You can see a clear result within 30 minutes. HG mould spray is self-acting and suitable for tiles, silicone grout and plaster. With 500 ml you can treat 2 to 3m2 wall surface and 6 to 8m2 tile grout. HG mould spray is also available as a mould remover foam spray.
Sleeping with windows open can introduce outdoor pollutants, allergens, and noise that disrupt rest. It also creates security vulnerabilities and allows pests inside. Furthermore, uncontrolled drafts can cause muscle stiffness and dry out your nasal passages.
Keep your home adequately heated
Try to keep your home suitably heated. It usually helps to have a low background temperature of at least 15 degrees in all rooms. By doing this you are less likely to have condensation dampness as the warm air holds more moisture than cold.
Germans open windows in the dead of winter for a practice called Lüften (airing out). It involves briefly opening multiple windows wide to completely exchange stale, moist indoor air with fresh, cold outdoor air. This ritual serves several practical purposes: