The Inspectors Perspective
Rising damp is not just a problem of medieval castles
The damper climate conditions of the past couple of years have resulted in an increase in the occurrence of rising damp in the perimeter areas of concrete floors. Prior to this, several years of dryer conditions reduced the number of properties presenting with this problem. The problem now is quite common, and can be due to a number of factors. Rising damp can lead to serious deterioration of building elements if left unchecked for an extended period.
Some indicators of rising damp can be a musty smell in carpets and closets, mould growth, drummy floor tiles, decay to the bottom edge of skirtings, external paint or render damage to the slab edge or persistent dampness to the exposed edge of the concrete slab. A good building inspector will have equipment to test for moisture and should always use this equipment when conducting a building inspection…
Decay was noticed the skirting boards during a pre purchase inspection.
The moisture meter indicates a problem to this garage floor.
Today’s building methods have progressed from the days of medieval construction and concrete floors are now constructed with a moisture barrier (plastic sheeting) under the slab. Problems can arise from one or a combination of factors including, incomplete moisture barriers (e.g. plastic collapsing into trench during concrete pour), poorly constructed concrete with increased permeability, poor site drainage, inadequate detailing and / or installation of moisture barrier to the slab edge. The latter two being quite common. Moisture can also come from other than the slab edge due to poor construction practices and building deterioration such as poorly constructed / porous masonry walls, inadequate or damaged damp proof flashing, blocked or inadequate weepholes, poor installation of brick ties, roof and wall leaks.
Rectification of construction problems can be complex matter for builders, but there are a number of recommendations that the home owner can follow to minimise the risk of rising damp problems. Most importantly, ensure there adequate falls to the soil and paths around the house to prevent water ponding or the soil becoming waterlogged. Ensure all roof areas have gutters and adequate downpipes that discharge water well away from the house and that they are kept clear of leaves etc. Consider applying a waterproofing compound to the slab edge below ground level if the plastic membrane has not been brought to the surface. Do not raise the soil too high against the building and ensure brick weepholes are kept clear and free draining.
This information is provided for general guidance only and in no way replaces the services of professional consultants.
If you have any questions or concerns about this or any other building matter, you can call David at DR Inspects Building and Pest Inspections on 0421 641 301 or contact us today.