Types of Damp
There are three main types of damp, each with different causes and treatment approaches:
Rising Damp
Moisture rises from the ground into walls through capillary action, typically when the damp-proof course (DPC) is defective, bridged, or absent. It usually presents as a tide mark up to about 1 metre high on internal walls.
Treatment cost: £1,500–£5,000+ depending on extent.
Penetrating Damp
Water enters through the building fabric — leaking roofs, defective pointing, cracked render, failed flashings, or blocked gutters. It creates damp patches, staining, and deterioration often linked to specific external defects.
Treatment cost: Varies widely — from £200 for gutter repairs to £5,000+ for re-pointing or roof work.
Condensation
The most common type. Warm moist air meets cold surfaces, causing water droplets and eventual mould growth. Often worst in bathrooms, kitchens, and poorly ventilated rooms. Usually a lifestyle and ventilation issue rather than a structural defect.
Treatment cost: £200–£1,000 for ventilation improvements.
What Does a Survey Check for Damp?
During a survey, your chartered surveyor will:
- Use a professional moisture meter to test walls and floors
- Identify patterns of dampness — location, extent, and likely source
- Assess external factors — gutters, pointing, roofing, ground levels
- Check for mould, staining, tide marks, and peeling decorations
- Recommend further investigation or specialist testing where needed
Should You Buy a House With Damp?
It depends on the type and severity:
- Condensation: Usually manageable with better ventilation — rarely a reason to walk away
- Penetrating damp: Often fixable by addressing the external defect — factor repair costs into your offer
- Rising damp: More serious but treatable — get specialist quotes and negotiate accordingly
- Extensive, long-standing damp: May indicate deeper structural problems — commission a Level 3 Building Survey for full investigation
Beware of "Damp Proofing" Sales Tactics
The damp treatment industry has a reputation for over-diagnosis. Many companies offer free surveys that conveniently recommend expensive treatment. An independent chartered surveyor has no financial incentive to recommend unnecessary work — our role is to give you honest, evidence-based advice.