Talk to me about cracks. . . .

[Cath]

I am looking at a property that has some cracks that I would love some feedback on. They are not huge at all as the first time I viewed the property I didn't notice. When I went back to check it out again i was paying very carefull attention to everything so they stood out to me.

It is a house that is approx 5 years old. The outside is rendered and on 2 of the windows there are small cracks coming from the corners heading out not more than about 20cm long, they are not wide enough to be able to fit anything into at all. The path around the house has come away quite a lot, I have been told come winter it will go back against the house again. The path and driveway have several cracks as well.

There is also a couple of cracks in a few spots on the skirting boards. None whatsoever on the walls or ceilings.

Now I have no idea about cracks, I know due to the extreme weather that cracks are becoming more common. I would love some feedback on what all this could potentially mean.

 

[Rob Williams]

Don't suppose you took some pics? Cracks are a visual more than a descriptive thing

 

[Cath]

nope, that would have been helpfull hey!

 

[Rolf Latham]

much depends too on what burb you are talking about

Many of the sydney suburbs that have the Wianamatta Shale in between the Sydney Sandstone have quite reactive soils, and often it doesnt matter how much reo or piering you do, there will still be some movement

ta
rolf

 

[Pa1nter]

House was probably built using waffle pod.

http://www.scdcs.com.au/Wafffle-Pods.html

The house tends to float around.
The footpath around the side is not pinned to the house slab therefore is separate and can drop and fall quite a lot.

I have seen a few problems with this system with pipes popping out of the floors up to 150mm and then disappearing under the floor a month later.

I'm sure someone else more qualified can explain it better.
Personally I would like to know why they use this system

 

[Cath]

House was probably built using waffle pod.

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The house tends to float around.
The footpath around the side is not pinned to the house slab therefore is separate and can drop and fall quite a lot.

This sounds exactly what it could be, the path was literally not touching the building at all in some parts. There was also this black foam kind of stuff in between the house and path.

 

[battler]

There was also this black foam kind of stuff in between the house and path.

This is normal to allow for some expansion and movement.

I am curious as to why a 5 year old house is rendered, is it brick or rendered over cement sheet?

Sometimes cracked brick houses have been rendered to hide cracks.

 

[ianvestor]

A small crack in 5-year-old building may lead to very large crack 10 years later because 5 years might not be long enough for the ground to settle, but a small crack in a 25-year-old building is probably already as big as it's ever going to get.

Also, a really heavy downpour can be the trigger for new cracks (again, it's usually the ground movement that does it).

 

[voodoo]

Hi Cath,

pictures would tell a better story but I would not be to worried about a few minor cracks. Concrete does expand and shrink and that is probably why it has moved away from the wall in the hotter drier weather.

You said that the cracks run from the corners of the windows. That is a common place for concrete to crack as concrete finds a weak spot and induces a crack across that location. Next time your out and about find a concrete slab that goes down both sides of a house or shed and 99% of the time there will be a crack running from that corner out into the slab, that corner has induced that crack.That is why concrete slabs are cut or joints put in to control the cracking so they dont just crack any where.

Cracks may also appear on the surface of a path or slab if it goes off to quickly, especially on a hot windy day the surface dries out and these are called shrinkage cracks. They usually run along the slab in one direction and are about 100 to 200mm long. It just means the concrete went off too fast on a hot day...

I hope this helps you,

good luck,

 

[Propertunity]

There was also this black foam kind of stuff in between the house and path.

That is a bitumenised expansion joint - to allow for expansion & contraction with temperature changes.

 

[Propertunity]

Personally I would like to know why they use this system

A couple of reasons:
1. It uses less concrete & reo - so it is cheaper
2. It is supposedly stronger - like an upsidedown egg carton is stronger than just a flat piece of cardboard
3. The airpockets underneath are supposed to act like insulation - less heat loss through the slab - but personally I think this one is clutching at straws.

We live in a place on a waffle slab and the paths around the hose have 'pulled away' buy a pinky finger width. This is my own 'rule of thumb' (please excuse the mixed metaphor) if you can fit your pinky finger into it - in a house wall - it is too big - smaller than that I'd keep an eye on it but no cause to panic. This is especially so since we had a drought for many years and this caused much cracking - now followed by normal rains so they are moving again.

Archicentre has a good article about causes and effects:
http://www.archicentre.com.au/survival_kit/cracking_brick.pdf

 

[MTR]

I am looking at a property that has some cracks that I would love some feedback on. They are not huge at all as the first time I viewed the property I didn't notice. When I went back to check it out again i was paying very carefull attention to everything so they stood out to me.

It is a house that is approx 5 years old. The outside is rendered and on 2 of the windows there are small cracks coming from the corners heading out not more than about 20cm long, they are not wide enough to be able to fit anything into at all. The path around the house has come away quite a lot, I have been told come winter it will go back against the house again. The path and driveway have several cracks as well.

There is also a couple of cracks in a few spots on the skirting boards. None whatsoever on the walls or ceilings.


Now I have no idea about cracks, I know due to the extreme weather that cracks are becoming more common. I would love some feedback on what all this could potentially mean.

Hi Catch

We had major cracks in an old property we purchased, we had archicentre check it out. They were excellent.

It was water damage, limestone footings had rolled out. We fixed the problem and monitored the situation.

This is what was interesting, archi advised us to use a glass perspect over part of the crack, if the glass cracked the building was obviously still moving. Did my head in for a while, but that glass never cracked.

Anyway, sorry to deviate, even if it seems minor if you are going to lose sleep over this issue get someone out, not worth taking the risk.

Cheers, MTR

 

[Cath]

I am curious as to why a 5 year old house is rendered, is it brick or rendered over cement sheet?

It is brick, and I almost certain it would have been made like that when it was originally built. There is 3 in the same street that are the same so going to guess this was a popular choice with the particular builder 5 or so years ago?

Cracks may also appear on the surface of a path or slab if it goes off to quickly, especially on a hot windy day the surface dries out and these are called shrinkage cracks. They usually run along the slab in one direction and are about 100 to 200mm long. It just means the concrete went off too fast on a hot day...
I hope this helps you,

Thank you it did.

That is a bitumenised expansion joint - to allow for expansion & contraction with temperature changes.

I thought this was probably the case, feel a bit silly for mentioning it now.
That article was really really helpful.

We had major cracks in an old property we purchased, we had archicentre check it out. They were excellent.

It was water damage, limestone footings had rolled out. We fixed the problem and monitored the situation.

This is what was interesting, archi advised us to use a glass perspect over part of the crack, if the glass cracked the building was obviously still moving. Did my head in for a while, but that glass never cracked.

Anyway, sorry to deviate, even if it seems minor if you are going to lose sleep over this issue get someone out, not worth taking the risk.

Cheers, MTR

Interesting about the glass. So it may or may not be a huge problem and to someone like me that has no idea it is just best to get someone out to have a look. By reading everything everyone posted I am going to take a guess that it's most likely not a huge issue however I will definitely get someone out if I take it any further.