Wednesday, March 27, 2013

A Cracking Easter: To of all you with cracked houses... read on, you're not alone.

How many of you have house cracks opening up all over the place? Gen has been worrying about the place in Parkside she and Tom have just bought, and our offices have cracks bigger than I've seen in years.

If you're worried about paving cracks, wall cracks and gaps opening up all over the place, you’re not alone.

You fill them up and when it rains, the cracks close up and spew out all that filler you just put in.

Large areas of South Australian soils are reactive to moisture, including some of our most prestige suburbs. Classic areas like Maylands, Goodwood, and the North East. With the big dry, the reactive clays that many homes sit on are shrinking and putting solid structures under immense pressure, resulting in cracks and wall movement at levels not seen in years.

Wet clay soil expands, dry clay soil contracts. This process of wetting up, and then drying out is what causes all the building issues. The game plan is to keep moisture content as even as possible over the entire area of the house structure. 

Old houses were built without all the modern engineering. They have survived in no small part due to the bulk of those old building materials, especially true of the grand old stone Villas.

So what should you do?

Some builders would suggest stabilising the moisture content by use of impervious perimeter paving. This approach evens out, and slows the drying out/wetting up of the soil around the home and assists in creating soil stability. Other techniques include the installation of a drip watering system around the house. Once again, this is an attempt to control and regulate the moisture content of the soil, which results in soil stability.

In the old days where cracking and movement was severe, builders installed bracing, and in later years utilised underpinning.

Wall braces can be found on endless old Villas, and usually are seen in the form of railway tracks (railway irons) running vertically up the external walls and connected through the roof or walls with a solid steel rod, bolted each side. Look around at Villas in suburbs like Goodwood, Parkside, Unley and the like... these railway iron braces are everywhere.

In more recent times, underpinning became popular. This is a process where soil beneath a footing (the base of the house) is dug out and concrete is pumped in under the house footing. Although underpinning is not usually visible (it's all underground), if it were it would look a little like the root of a tooth as a block of concrete.

However, underpinning has not enjoyed the popularity of when it was first introduced as the entire "balance" of the house footing can be thrown out. Making one side or corner more stable without underpinning the entire house can do more harm than good and needs expert advice.

In regards to the railways irons, I have known of buyers who have cut these rods, only to discover that they were doing an amazing job holding the entire building together... whoops, bad idea to cut these, best to just leave them alone!

Modern buildings enjoy completely different footing designs and will rarely have the cracks and issues of the old character homes. 

How do you fix it?

Modern fillers are amazing. Cosmetically, the latest paints and fillers can withstand a lot of movement. Often badly cracked walls are cosmetically sorted utilising Gyprock walls placed on battens, which are glued or stapled to the walls. The battens allow the wall to move behind, the Gyprock remains stable.

Structurally fixing these issues is a different story. Engineers qualified in this speciality area are needed. Expect a combination of some form of soil moisture stabilisation, some form of underpinning, and some recommendations on cosmetic treatments. Call Archicentre for advice or your engineer.

Modern structures utilise control joints extensively, and these too can be recommended by engineers even with old structures. Retro fitting is common and as their name suggest, is merely "controlling" where the movement occurs, rather than stopping it. More often than not the solution to your cracking is one of management; it is not an easy task to actually fix the problem completely with an existing structure.

So enjoy a cracking Easter, the rain will come, the walls will close.

Don't forget if you have a SmartTV with 3D, check out our world first property videos in 3D, log onto YouTube, search Toop3D. And if you're down at the Fleurieu over the Easter break, make sure you visit our open inspections - we have 28 over the long weekend! There's some very, very good buying to be done along the South Coast.

Remember, when it's time to get serious, it's time to get Team Toop. 

Anthony Toop

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