Help & Advice: Understanding Wall Moisture Readings
Why Moisture Levels Matter
Too much moisture in your walls is more than just an eyesore.
It can cause:
- Mould
- Structural damage
- Health issues
Knowing what’s normal—and what isn’t—can help you act fast and avoid costly repairs.
What’s a Normal Moisture Reading?
In most UK homes, normal wall moisture sits between 12% and 15%.
In rooms like kitchens or bathrooms, it might go a little higher. But if you consistently get 16% or more, it’s time to take notice.
What Do Moisture Meter Readings Mean?
Moisture meters show the percentage of water in your walls. Here’s how to read them:
| Moisture Level (%) | Category | Condition | What To Do |
|---|---|---|---|
| 0 – 10 | Dry | Walls are dry and healthy. | No action needed. |
| 11 – 16 | Slightly Damp | Minor moisture, maybe condensation. | Improve airflow, monitor. |
| 17 – 20 | Moderately Damp | Moisture building up. | Find the source and fix it. |
| 21 – 25 | Damp | Clear signs of damp. | Act quickly to stop damage. |
| 26+ | Very Damp | Major issue – likely water ingress. | Call a professional urgently. |
High Readings in Brick Walls
Bricks are tough—but not invincible.
Normal for brick: 13%–16%
If you see 17% or higher, watch out. Causes may include:
- Penetrating damp (from outside)
- Rising damp (from the ground up)
- Poor ventilation
Left unchecked, bricks can crumble over time.
What Counts as “Damp”?
For plaster walls, anything over 20% is a serious sign.
Even 16–20% should be watched closely.
| Reading (%) | Meaning | Action |
|---|---|---|
| 16 – 20 | Early damp | Monitor & improve airflow |
| 21 – 25 | Confirmed damp | Investigate & repair |
| 26+ | Severe damp | Call a specialist |
What’s Safe for Plaster Walls?
Plaster is more sensitive than brick. Aim for 12%–15%.
High levels can cause:
- Peeling paint
- Mould
- Cracked or soft walls
How to Spot High Moisture
You don’t always need a meter to know something’s wrong. Look out for:
- Wet patches or stains
- Musty smells
- Peeling paint or bubbling wallpaper
- Cracking plaster
Still unsure? Use a moisture meter to confirm.
Why You Should Act Fast
Ignoring damp won’t make it go away. It leads to:
- Bigger repair bills
- Health risks
- Permanent wall damage
When to Call the Experts
If your readings stay above 16%, get help.
At Damp and Mould Solutions Ltd, we can:
- Pinpoint the source of moisture
- Offer long-term fixes
- Stop mould before it spreads
Need Support?
Whether you’re a homeowner, landlord or tenant, we’re here to help.
Contact us today to book a moisture survey or speak with a damp expert.
📞 Call us at 020 4542 6114
📧 Email us at [email protected]