When is a crack not a crack? When it’s a concern. Ok, not a great piece of humour, ironically a little like cracker humour, if you’ll forgive the pun.
Joking aside, cracks in our world (of property) are worth understanding – many a deal has turned out to be a poor one because the buyer either didn’t spot the cracks or, if they did spot them, didn’t understand their significance.
Conversely, many a good deal has fallen through because the buyer thought the cracks they found were more serious than they actually were.
Here’s the reality. Not every large crack is dangerous; not every small crack is innocent or inconsequential.
The problem with cracks is that understanding them only comes with experience. There are many causes of cracks (technically we could call them ‘structural failure’), and many times a crack can be caused for multiple reasons meaning there are almost endless permutations of causes!
That’s why, if in doubt, call upon a surveyor (preferably a building surveyor, although a general practice surveyor who specialises in surveys will also be able to help – and yes, preferably RICS qualified or similar) or a structural engineer. Structural engineers really know their stuff and as a young surveyor I was always in awe of them.
Whether a crack is serious or not will depend on:
- The cause of the crack in the first place (goes without saying but needs to be said)
- The method of construction of the wall or member in which the crack is found
- The type of materials used
That’s why it’s entirely possible to find a crack so large you can stick your hand through it but still conclude that there is no danger structurally, whereas an identical crack, in a situation involving a different method of construction, or different materials, or both, might have you making arrangements for emergency shoring to support the affected wall.
Consequently it’s is very difficult to give blanket advice on why a crack might be present, and whether it’s significant.
Having said that, here are the three main causes of cracks in walls that I have found over the years, based purely upon my experience.
Number one – drainage problems.
I’ve lost count of how many times I’ve found cracking near the corner of a property and, lo and behold, there’s a downpipe coming down from the roof gutters and feeding either into a hopper or directly through the soil surface into the drain run. Or a soakaway. If it’s into the drains chances are there’s a leak and the surrounding soil, including that beneath the foundations, has washed away and the foundations have dropped. If there’s a soakaway, there’s even more chance that any sand and gravel used has long gone, with the same effect – soil under the foundations has also washed away. When the foundations drop, the walls will drop, and cracks will form.
Number two – the presence of trees.
These don’t need to be large trees, small trees can be a problem if they are of the right type and close enough. Also, the trees don’t need to be close – large trees can have root systems that spread for thirty meters or more in all directions. The roots can either get into the foundations or, more commonly, suck the soil dry below foundations causing foundations to drop, and cracks in walls above.
Number three – Dry weather
The summer of 1976 was famous for being one of the hottest on record, and also for the record numbers of calls to insurance companies as home owners reported subsidence claims. Clay sub soils, like those in London and the south east, were particularly affected as the clay dried out. As the clay dried due to the water table diminishing due to lack of rain, foundations dropped. When foundations drop, cracks appear in the walls above. Yes, rain is a good thing if you live in a house, it helps to keep the house standing! Bet you’d never thought of that before!
And, of course, add trees, large and small, into the mix with dry weather and the problems compound.
There are many other reasons why cracks appear. It could be down to construction. I remember as a young surveyor in Wimbledon being taught by my very experienced boss that there was a street where the Victorian builder had erected rows of terraced houses which had ridiculously shallow foundations of a foot or so which had been packed with hay and the brick walls build laid direct onto the hay (by comparison, today, the foundations would be 3 or 4 feet deep and filled with concrete). When the hay rotted, the houses settled, evidenced by cracking to the brickwork. If you’re wondering, yes, those same houses are still standing some 150 years after they were built, and I expect the residents are none the wiser.
And I was also issued with a map which showed where every bomb dropped by the Luftwaffe (German air force in world war two) had exploded. Why? Because the shocks and tremors often resulted in cracking in houses several streets away.
Which brings me to an important point. Many times what looks like a ‘serious’ crack is ‘historic’, and the cause stopped having an impact decades, or longer, ago. The settlement has settled down, and the moving has ceased.
For this reason cracks can look ‘old’; and experienced eyes can see the edges of the crack are weathered, and the crack is full of dust and dirt. This is not a new fresh crack which would cause concern.
Oh, and I have to mention uPVC windows. How often do you see cracking over replacement windows? Very often. Why? Often because the old timber windows were part of the structural support for the brickwork over, but the new uPVC windows just aren’t made for that. Replacement windows need lintels. And that’s another reason why you want your replacement windows installed by a FENSA registered contractor so they are done properly (or inspected and signed-off by Building Control from the local council if they are not fitted by a FENSA registered contractor). In older properties the windows might have had lintels, but the lintels were timber, and have now rotten – that, too, can cause cracking of brickwork over, and the lintels will need to be replaced.
Anyway, the moral of the story is, just because there’s a crack doesn’t mean there’s a problem, but if you don’t know, then do get advice. If there is a serious problem, and the property requires under-pinning (where new foundations are dug and filled below the existing foundations) it could cost you a small fortune.
If you are interested in property construction and defects, and if you are investing in property, or thinking of investing in property, you should be, you might be interested to know I have rewritten and updated my best selling eBook 63 Common Defects in Investment Property and How to Spot Them, which is as it says on the tin. It won’t make you into a surveyor over night, but it’ll give you a much better idea of what you need to be looking out for, where you need to be looking for it, and why it’s significant. To be forewarned is to be forearmed, and all that.
Peter Jones B.Sc FRICS
Chartered Surveyor, author and property investor