Dealing With Dampness

Damp homes can cause health problems for the people who live in them, and they are more difficult to heat. It is important to try to identify the causes of the dampness and correct them.  If a home is insulated, ventilated and adequately heated but dampness and mould growth continue, it is likely that moisture is coming from damp ground beneath the floor, from rainwater leaking into the home, or from leaks in plumbing.

Surface water

If there is surface water around the house then clear or create drainage channels.

Ventilation

Good cross-ventilation under the home reduces the build-up of damp air beneath a floor.  Ensure that items stored under the home are not obstructing air flow and remove any vegetation and soil that block the vents.

Cover the ground

Cover the ground under the house with polythene to reduce the amount of moisture released into the sub-floor space.

Roof space moisture

If you have a water tank in the roof space, fit it with a  tight lid.  Vents from the bathroom and kitchen must be ducted to the outside of the home and not into the roof space.

Leaks and other causes

Check that guttering and down pipes are working properly and repair any leaking plumbing.  Deterioration of the roofing or deterioration of windows and doors and damaged wall cladding may all result in water penetration and lead to problems with dampness.

Portions of this fact sheet were sourced from BRANZ Bulletin 379 "Preventing Moisture Problems in Existing Buildings"  
www.branz.org.nz

© Asthma and Respiratory Foundation of New Zealand (Inc.) 2005 Photocopy permission granted