Base must be about 70 years old and has always had a slight crack but the last two weeks its got pretty big quickly, its not an alien trying to escape as ive had this checked out !

So what is the cause ? Worth contacting insurance company ? Garage is at end of the garden 70ft from house.

Whats the worse that can happen – topple over ?

Sinkhole?

Not built on an old cemetery is it?

??

TOOOO SLOOOWWW

boom!!!

Does look like it’s sinking on one side to me. Broken drain/ water pipe underneath? Neighbours digging tunnels? 😉

Its emanating from that heavyweight 26er.

Badgers?

Contents look a bit picture heavy to me…

Basic slab failure. Slab has been undermined at one end and the weight of the garage (is it a prefab off the slab) has broken it’s back. Base probably has little or more likely no reinforcement in it.

Badgers?

Bodgers

do you have a relative of the Moleman of Hackney living next door?

http://news.bbc.co.uk/1/hi/7348949.stm

You may have had a miner event nearby.

a sticker?

I guess you’re after a serious reply, well I’m convinced it’s got something to do with Quatermass and the Pit.

Gravity

As the body decomposes it creates a small amount of subsidence, often resulting in such a crack as pictured. Consider patio?

Most likely summer shrink/swell of the soil. The concrete has suffered brittle failure and is unlikely to have steel reinforcement if its 70 years old.

Joseph Fritzel’s English cousin extending?

paint defect

Art innit

What’s the prevailing soil type clayey (can roll moisten soil in to threads) or sandy?

Even if prdominatly clay with the age I wouldn’t expect normal shrink-swell action to suddenly be massively different to the other 70 years especially as we haven’t had record aim fall or drought conditions. Although long term attrition of movement causing voiding under the slab and progressive weaken of the slab is a possibility.

Has anything else changed in the vicinity? Added or removed trees?

Any slopes in proximity to the garage.

(Bored geotech eng watching track cycling drinking wine)

Slab looks a bit thin. Probably dry ground combined with the weight of the garage. Does the picture of the door, which is out of true with the frame, have the end closest to the right or left?

Consider your options before contacting insurance company. i.e the hassle when you have to reveal that the property or any land within 150 metres has suffered from land heave/subsidence/slip when trying to sell, and the insurance quote website falling over in shock each time you try and change insurer…

crack on the floor you say

Japanese knotweed.

Been dry lately, it’ll close up when it rains again.

Probably.

Probably water erosion has undermined the base over a long time, then more recently the slab eventually cracked under the stress hence it is now ‘settling’ relatively quickly.

One solution could be to first fix the underlying water erosion problem, and then inject mortar or polyeuethane under the base to float it back into alignment and then fix the crack using some epoxy crack sealer.

Another solution could be to knock the whole thing down and build a new garage/manshed in its place.

In any case you can try contacting the insurers just expect them to require insane amounts of paperwork and be really slow and convoluted and for it to probably cost you more than getting it rebuilt.

Fracking nearby?

Heavy rains locally?

If it’s really bothering you take the garage apart, lay new slab and rebuild.

Is it just the floor that’s cracked, any photos of the whole garage to give us an idea. I. E. Is there any other movement in walls, or doors sticking in frames.
As mentioned check drains are running free. When you put a long stick through Crack goes it hit earth?
Clear the grass by the door to eye if ground being washed away.

Garage could do with a bit of a tidy up

FunkyDunc – Member
Garage could do with a bit of a tidy up

This.

Recon’ its the shear weight of crap stored in there. Looks like something of a channel 5 program about hoarders! Do you even know whats at the back of the garage?

Sensible answer is shrink / swell or ‘heave’ of the ground under the slab. Downpipe exiting off the garage roof against the wall? cracked drain?? look at where the water is going first.

Had a similar crack in mine – as per other suggestions, you just have a basic slab base and slowly the weight of the wall and some movement means the floor loses. I was lead to believe its a fairly common failure of that kind of base.

I needed to fit a new garage door, and the structure wasn’t square, so I needed to do something about it. I managed to get the whole garage rebuilt courtesy of insurance with nice foundations for the new wall. Didn’t seem too hard to get done but wasn’t super quick; seemed to be helped a bit by the fact I’d just bought the place and the survey had failed to comment on the issue.

As above, there are some implications of doing it on insurance and I’ve not changed my insurance company since as a result!!

I’m back in the room !

Thanks for replies amusing and serious ones, I’ll go with the old base bit and weight cause.

Living 7 miles from centre of London I’ve not heard of any fracking going on and there are no major drains nearby.

Thanks for all help

Very likely your located on London Basin Geology and you have London Clay under the foundation. L.C is a high plasticity clay which suffer volumetric changes due to shrink swell. The clay has shrunk in the dry summer months and the pad has been slightly undermined by a few cm. I would leave it as it is, come winter the crack aperture will contract a bit.

7miles from London. Bloody loaded!

I would guess you probably have a tree in the vicinity, causing shrinkage.