Types of damp:

  • Rising Damp from naturally occurring ground water. This rarely occurs, but can be widespread within a property
  • Penetrating Damp caused by rainfall and construction defects
  • Water leaks from plumbing, drains or wastes
  • Hygroscopic damp from contaminated materials
  • Condensation caused by lack of ventilation and extraction

Click images to view enlarge example types of damp and damp detection tools

Penetrating damp

Rising damp

Penetrating damp

Penetrating damp

Penetrating damp

Hygroscopic Damp

Penetrating damp

Moisture meter

Condensation

Condensation

How are properties protected from damp:

  • Damp Proof course in walls
  • Damp proof membranes in floors
  • External weatherproofing: Low-porous bricks, roof felt & tiles, render, boarding, paint
  • Sealing all joints
  • Collecting and dispersing water: Gutters, downpipes, soakaways, drains
  • Air extraction: Bathrooms, Kitchens, ducted to exterior, correctly rated, humidity controlled
  • Ventilation: Under floor, cavity, trickle, positive pressure.
  • Surface drainage (rare)
  • Basement or semi-basement tanking

Damp Health Problems SurreyThe Health risks of living with damp

The Building Research Establishment report ‘Understanding Dampness’ (published 2004 ISBN 1-86081-686-X) details several health risks relating to living in a  damp environment. The most important of these is ‘respiratory allergic reactions to mould spores and the faecal capsules of the dust mites that are associated with moulds’.  The report continues ‘…some forms of mould are actually toxic’.

All mould should be regularly washed off with warm soapy water. Do not use bleaches or fungicides as dead mould is more toxic and allergenic than live mould. We offer mould remediation services working to PAS 64 guidelines which includes air and swab testing.

Signs of damp

  • Mould or fungal growth
  • Water staining
  • Damp musty smell
  • Plaster bubbling
  • Paint blistering 
  • Wallpaper delaminated
  • Ceiling sagging
  • Efflorescent salts
  • Timberwork rotting or warping
  • Carpet/underlay marked
  • Laminate floor cupped or bowed
  • Timber floor finish cupped or bowed
  • Timber floor structure affected
  • Floor or wall tiles delaminated
  • Floor or wall tiles grout stained
  • Water staining in floor voids
  • Previous Silicone DPC injection
  • Cavity wall insulation
  • Doors binding
  • Rusting plaster beads
  • Plaster beetles
  • Frost damage
  • Wall DPC (failed, bridging)
  • Floor DPM (failed, non-existent, not meeting DPC)
  • Solid wall
  • Porous bricks
  • Pointing
  • Holes in masonry 
  • Ceiling sagging
  • South or South West facing – driven rain
  • Cavity bridging (insulation, debris)
  • Cavity condensation (Interstitial condensation)
  • External ground levels above DPC
  • Render (failed and/or below DPC)
  • Plaster below DPC (bridging)
  • Cladding or tile hanging failed
  • Impervious (plastic) masonry paints
  • Roofline (gutters, downpipes, soakaways)
  • Open gullies above DPC, spilling, cracked and leaking.
  • Roof leaks, valleys, flashing
  • Unknowns (well, redundant drains, storm drain)
  • Lifestyle and high %RH and effect on dew point
  • Basement or semi basement tanking failed, inadequate, blocked
  • Window frame and sill leaks, door frame leaks
  • Attached neighbour problems
  • Party wall. Height differences (stepped construction)
  • Lack of extraction: Kitchen, Bathroom, Shower, tumble dryer
  • Lack of ventilation: Under floor, cavity, window trickle vents
  • Chimney (soot/salts, when last swept, hearth DPM, closed up no vents, not used, blocked/debris, flashing, porous bricks, no cowls, pointing, removed in loft space)