WHAT'S YOUR CALL ON THIS?
Is This Rising Damp? How Concerned Would You Be?
Original PostHomeowner88 (New Member)Posted 3 days ago
Noticed this patch in the corner of our bedroom.Worse in winter and there’s mould at times.Moisture meter reads high on the wall.Is this condensation, penetrating damp or rising damp?What would you check first?
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5 Replies To This Topic
Top Comment -
🧠 DampDiagnoser (Top Contributor)
I’d lean towards condensation here — especially if it’s on an external corner or near a kitchen/bathroom.
What often happens is warm, moisture-heavy air (from cooking, showers, even breathing) hits a colder surface and condenses into water. :contentReference
Corners, window reveals and wall/floor junctions are classic cold spots (thermal bridges), so they attract condensation and can look exactly like penetrating or rising damp.
Moisture meters can confuse things as well — they only tell you there’s moisture present, not where it’s coming from.
--How I’d actually diagnose this (step-by-step):
1. Take comparative moisture readings
- Skirting level
- Mid wall
- Higher up
👉 If readings are similar across the wall → more likely condensation
👉 If high reading low down then gets drier the higher you go → possibly rising damp
2. Check humidity (this is key)
- Use a hygrometer for a few days. Take reading before and after you use the kitchen or the shower.
- If it spikes above ~60%, condensation becomes very likely
High indoor humidity is one of the main drivers of condensation problems.
3. Use a thermal camera (best tool for this)**
- Scan the corner vs the rest of the wall
- Look for colder patches
👉 Random Cold spot could mean penetrating damp (from outside in) called a thermal bridge → condensation risk
Cold bridges create lower surface temperatures where moisture condenses and mould forms.
- Is this room used for drying clothes?
- Kitchen nearby?
- Extractor fan working?
- Windows / trickle vents used?
Condensation is very common in areas with moisture generation like kitchens and poorly ventilated rooms.
**5. Rule out external causes (don’t skip this)**
- Gutters / downpipes
- Window seals
- Cracks in render
- Air bricks blocked
Verdict:
I’d say condensation caused by living factors is most likely here** — but confirm it with readings and temperature checks before doing any treatment.
Don’t jump straight to damp-proofing — wrong diagnosis = wasted money.
👷 BuilderBob (Site Pro)
Posted 3 days agoI’d look at condensation first.Cold external corner + worse in winter + a bit of mould usually points that way.Check ventilation and room humidity before assuming damp coming through the wall.👍 5
🛠 PlasterPro (Trades Member)
Posted 3 days agoMoisture meter readings on plaster can be misleading.Take readings low down, mid wall and higher up — the pattern tells you more than one high reading.One reading doesn’t prove rising damp.👍 4
🌡 ThermalTech (Building Surveyor)
Posted 3 days ago
I’d get a thermal camera on that.
If that corner is colder than surrounding wall, you may have a cold bridge causing condensation.
A thermal scan would show that straight away.
🏚 HeritageRenovator (Renovation Expert)
Posted 3 days ago
People jump to rising damp too quickly.
I’d rule out cold spots, blocked air movement and outside defects first.
Check gutters, pointing, window seals and air bricks.
👍 6
🏠 OldHouseDIY (Member)
Posted 3 days ago
Had something similar.
Thought it was rising damp — turned out a leaking downpipe was soaking the wall behind the render.
Patch dried out once fixed.
👍 5