"In areas of continued drought, where water restrictions are in place, the situation is set to worsen with some owners of cracking houses wanting to sell them facing serious financial implications with a drop in the home's value."

Mr Cook said many vendors facing the cost of repairs are opting for superficial cover-ups which can leave unsuspecting buyers with hefty repair bills. Archicentre recommends a thorough structural inspection to ensure the structural integrity of the property.

"Cracking in homes has become a major issue for Archicentre architects undertaking pre-purchase inspection, design and status reports for home owners. Some homes inspected have fine hairline cracks in their plaster, whilst others have major cracks threatening the structural integrity of the building.

"We are advising people with cracks in their home to monitor them carefully and if they are not sure of the extent to get professional independent advice before they embark on expensive repairs."

Experts suggest that changes in the water content of clay-type soils cause up to 90% of all cracking problems in houses.

Mr Cook said the greatest damage occurs when trees are planted after construction. Contrary to popular belief, it is rarely the growth or uplift of the tap roots of big trees which disturb the foundations. The damage is done by the plants extracting considerable quantities of moisture from the soil, which reduces the volume of the soil, causing footings to subside in that area and cracks in the masonry to appear.

Archicentre general maintenance tips

1. Don't plant trees or allow them to exist closer to the house than their natural height, unless their roots are discouraged or contained in some way.

2. Keep the garden and lawns around the house evenly damp throughout the drier months. Don't neglect one side of the house just because nothing much grows in the area.

3. Regularly check existing drains, down-pipes, guttering and service piping to ensure no leakages occur over the life of the building.

4. If you think your house needs underpinning or other building work carried out, make sure you have an independent assessment undertaken first by an architect or engineer. Then obtain at least three quotations and make sure you have a firm written contract with the company and appropriate permits if required.

Click this link for a full list of West Australian local government areas cracking statistics.

Archicentre has a Free Cracking Information Sheet available to download from the Archicentre website at http://www.archicentre.com.au/Crackbrick08.pdf