Vertical cracking in bricks/mortar

[CPK]

Hi All,

Some advice will be appreciated on these cracks I've spotted on a house we are intending to buy.

The house is built into a slope, these cracks appear at two corners of an extension built in 2000.

I'm a bit concerned something serious is going on and would appreciate second opinions before getting a structural survey and pointing them to the problem. When I was taking the photos I didn't spot the difference in colour shade of the brick either side of the crack.

The crack which shows the white brickwork below does have a reasonable crack on the inside but about 1ft away from this crack. As far as I can remember the crack doesn't go through to the damp proof layer and neither crack is higher than 6ft. It just stops.

 

[terryplumb]

You should get a full structural survey. Only a full on site inspection by a suitably qualified surveyor will result in the necessary advice you need. Opinions based on a few pictures posted on here will be of no real value. If you dont want to invest in professional consultation ,and the costs incurred ,best to walk away now ,and find another property.

 

[CPK]

Hi Terryplumb. Thanks for the sage advice

Please don’t worry though!. Surveyor is booked in, he is RICS AND comes with recommendations.

However, I know there are some very knowledgable members on here who can give some good advice based on a few dodgy photos. I’d appreciate that advice (even if it’s tosh) because I can then take some of that advice, filter it out with more research where necessary, and quiz the surveyor until kingdom come on the possible issues, causes and consequences.

A few opinions on here will hopefully give weight to the surveyors findings and all will be good!

 

[terryplumb]

Ok ,never been called a sage before ,but a few choice other things !! Here is my tuppence worth ,from somebody who has bought buildings from one hundred and ten thousand square foot factory complex ,to three bedroom terraced houses. Vertical cracks in brickwork is down to movement. Will it get worse ,no one can say 100 per cent sure. Will the cracks allow moisture in ,yes they will. Can that cause damp inside ,yes it can. Will the cracks get bigger ,possibly. Can that be prevented ,yes as long as you are prepared to spend enough money. What do i do when i see such things ...walk away and buy something else. Not being interested in spending considerable amounts of money buying someone elses problem. Regards Terry.

 

[John D v2.0]

second last photo looks like someone's had a brick out higher up. but cracks opening at ground level then petering out are due to movement starting at ground level. could be as simple as shrinkage due to heating up and cooling, this can happen on a longish wall.

 

[CPK]

Thanks for all the advice.

I did spot it looked like some had a brick out, I don’t know why, there aren’t cracks top or bottom of it.

I also suspect the cracks are due to movement. Interesting comment about not knowing if/when it will get worse or not. Trouble is we don’t know how long they’ve been there.

With regards to heating/shrinking, both are at corners and the bottom one the wall is probably just 4m long.

If the price is right I’d be relaxed about paying to sort it but if it doesn’t guarantee a fix and there is a possibility it could return then we will walk away. I’m intrigued to see what the surveyor will say now!

 

[JohnD]

there seems to be a surprising amount of white salt deposits or lime at the bottom of that wall. I wonder if there is a water leak that's softened or washed away the ground under the wall footing.

I get lime deposits on my walls due to chalky groundwater, it rises up one or two bricks from ground level and never passes the dpc.

the wall glimpsed behind also has it, possibly above two courses of bricks which look darker so possibly wet.

I can't see the dpc.

IME it's often a water supply pipe under the floor.

 

[bobasd]

they are small cracks, only a few mm's typical of thermal movement cracks so not usuly significant.

however, the cracks both come near outside corners, and they are more or less mirrored inside the extn.
the extn is also on a slope.
in the second pic the mortar bed seems to have lifted indicating that perhaps the brickwork below that bed has dropped a little.

in a single story extn these things would be no big deal because they can usuly be identified an repaired for a reasonable cost.

ask the homeowner if they have certs for the extn and whn the cracks first appeared and in what order.

edit. yeah, i wondered about the white stuff?

 

[bobasd]

thers a guy comes on here whose veery good on cracks an structural stuff but not seen him for a bit?

 

[KenGMac]

CPK, good evening.

From images posted, looks like Thermal, end of a very hot summer Etc. does the wall on the left hand of the image [the one unseen in the images] face South or is it exposed to prolonged sunlight?

How long is the [unseen] wall ? is it about 4.m?

What could have occurred is that the unseen wall has been heated by the sun and expanded? depending on the brick, some brick will expand at a much higher rate than others.

OK the wall has cracked. but? they have both ends cracked in the same place, very close to the corner, and vertical, if you consider it, the [unseen] wall appears to be pushing the side walls, causing vertical crack to form in line with the expansion occurring on the wall being heated by the sun?

If you look at the width of the vertical crack, it is [reasonably] uniform in width top to bottom? the dimension from the corner to the crack is near enough the same width as the bricks on the unseen wall, again pointing to thermal expansion?

If it were to be Subsidence of the corner? then, there will have formed a diagonal crack, not vertical, and the crack will be much wider at the top of the crack diminishing near the base of the wall. Any such diagonal crack tends to be about two to three meters in length [measured along the crack] and such diagonal cracks are generally at [roughly] about 45 degrees.

Ken.

 

[CPK]

Hi Ken,
Thanks for the long and detailed reply.

The first two pics are on a west facing wall so the other side is south facing. The length of that wall is about 12m but it has an expansion joint approx 8m along. The face you can’t see is about 1m before a bay window (you can see this in background).

The other wall (white at bottom, replaced brick) is north facing and shaded. This wall is about 4m but has big windows along it, approx 50cm up. So the crack goes up the pillar which is approx 40cm wide.

I suspect that corner has sat in water and the patio doesn’t drain away properly (lots of white bricks and some faces off from frost cracking).

Assuming it is thermal cracking, what can be done to rectify it and stop it getting worse?

 

[tony1851]

It's cause by expansion of the brickwork. This can result from 2 causes; 1. thermal expansion of a long stretch of brickwork, particularly south-facing, or 2. initial expansion of the bricks soon after construction (bricks are bone dry when they come out of the kiln and if they are built in soon after manufacture, they gradually take up atmoshpheric water which causes them to expand slightly).
Whichever the cause, something has to give, and you frequently see the vertical crack at the corner, particularly where there's a short return as you have. It's almost a text-book case of the symptom, and that fact that it doesn't extend below the dpc bears this out.

 

[bobasd]

whats happened to the guy that was good on cracks an structural stuff?

 

[wessex101]

whats happened to the guy that was good on cracks an structural stuff?

Do you mean Woody? In which case he thinks ALL cracking is caused by "thermal shrinkage"

No worries though, Tony has nailed it. That is a text book example of thermal expansion cracking. Provided there is a reasonably long run of brickwork to that wall.

 

[bobasd]

i dont have any worries. if you had read the first line of my post above #8 you'd have seen i mentioned "thermal movement cracking". just saying.