View Full Version : Driveway sinking and cracking.

19th Apr 2013, 12:53
If I may pick the collective knowledge of PPRuNe on finding a resolution to this problem, my driveway has started sinking and cracking in a way that can no longer be ignored.

The driveway is in itself about 50 years old and is constructed out of concrete blocks with a little lawn strip halfway down the center. Most of the concrete blocks have sunk along just one side of the driveway near my house and some of them have cracked badly on both sides. On inclement days the little lawn strip quickly gets all soggy and muddy. I have always suspected the problem was being caused by a recalcitrant neighbour whose roof guttering on the side of his house closest to us had rusted away 10 years ago, and he has put plastic tarpaulins around the base of his house to direct the water away from the foundations and towards my driveway.

So I called the house insurance company and they sent over an independent engineer to assess the driveway. He took a lot of photographs and mentioned that the soil was rather fine which tended to absorb and hold the water rather than let it run along. He considered my neighbour's roof guttering as a possible cause then he decided to play devil's advocate by suggesting there was a burst water pipe that ran under the concrete, of which I told him the water service runs along the other side of my house, and also the water meter doesn't indicate a leak. So he then suggested that there was a burst sewerage or rain water pipe that runs under the concrete, this I cannot prove or disprove as I did not build the house, whereas the neighbour's roof guttering which is rusted out all along the side of his house stands out like dogs balls.

One thing I forgot to mention to him is maybe the neighbour's house has a burst water pipe as his meter cannot be read (the water company sends him an estimation, don't ask me how he gets away with it).

The insurance company called back recently and said they won't pay out to have the driveway repaired. No details were mentioned over the phone other than our policy won't cover it and they will send a letter to us with further details within the next few days.

Is this reasonable? I don't think the driveway is mentioned in the policy, is it considered as part of "the house"? Should I pester the engineer for a copy of his report?

As for the neighbour fixing his roof guttering, that matter is in the hands of the local council who have indicated difficulty in contacting my neighbour, so much so that they are seeking a court order to enter his locked premises.

Lightning Mate
19th Apr 2013, 12:57
Do you mean concrete blocks or concrete slabs?

19th Apr 2013, 12:58
Concrete slabs. Thanks for pointing that out.

Lightning Mate
19th Apr 2013, 13:14
Then they should be laid on a concrete base which in turn should be on two to three inches of compressed hardcore, or they are liable to movement and cracking.

You say the drive was laid about fifty years ago, so it might just be ageing.

Try lifting one to see what is underneath.

19th Apr 2013, 13:18
Or who is underneath.

19th Apr 2013, 13:21
Or you could pour plaster of paris in before you lift one, and see if you get an interesting cast.
Worked in Pompei.

19th Apr 2013, 13:22
You'd better hope there isn't a sinkhole under the driveway. Is your neck of the woods geologically predisposed towards sinkholes? (limestone/karst/carbonate/salt beds?).

There may also have been previous fill such as a rubbish dump, that is now decomposing and sinking - perhaps mining activity - and even a tree stump hole that was improperly filled after tree stump removal.

19th Apr 2013, 13:30
I strongly doubt they put any base underneath them, the slabs are about 4 inches thick and the problem which started 10 years ago seems to be accelerating. Other similar houses in the street of equal vintage don't have this problem, their driveways are even and solid as was mine 10 years ago.

I'll bust one of the shallowest slabs open to see who is underneath, but only after the insurance claim is finalised.

19th Apr 2013, 13:32
50 years old and only now needing replacement? it's well past it's sell by date and I can fully understand why the insurance company won't pay out - fair wear and tear so to speak.

Whatever hard core base it had has probably been totally compressed and/or washed away. I'd bite the bullet and have it rebuilt. If they find a broken pipe or evidence the neighbour's guttering caused the problem you might then be able to claim against the insurance company or take the neighbour to court.

19th Apr 2013, 13:32
If its a sinkhole you're going to need an awful lot of plaster of paris.

You say you live in Mesopotamos. Between which two rivers are you?

that should surely be mesopotamoi.

Or do you mean you are in the middle of a river?

19th Apr 2013, 13:38
Historically, the area I believe used to be an airfield surrounded by dairy country. My house is not built on the runway but about 100m from it on very small hill.

19th Apr 2013, 13:40
Perhaps you've got a load of Spitfires down there and the crates are starting to collapse.

19th Apr 2013, 13:43
Sorry oxenos, that location is the family holiday house, of which I built that driveway myself (I do not recommend mixing 7 cubic metres of concrete, sand and aggregate by shovel alone to anyone).

This driveway is in Melbourne, Australia.

19th Apr 2013, 13:44
My money's on a filled tree stump hole that is subsiding. Cows generally kill trees eventually by continually rubbing against them. Dead trees are usually bulldozed out - before that they were pulled over by wire rope via the winches on steam traction engines - and before that, they were burnt out.

Tree roots that are burnt out leave holes to fill. If the ground compaction was inadequate (as most driveways are) before the concrete was laid, the ground will continue to subside for decades.

19th Apr 2013, 13:49
If it is an old rotting tree stump from the days when trees were big and plentyful (remember them), would you reckon the insurance company would cough up?

19th Apr 2013, 13:56
Do you know of the old saying - "a snowflakes chance in Hell?" :) :{

Lightning Mate
19th Apr 2013, 14:04
Do you know when the airfield was decommissioned?

19th Apr 2013, 14:06
Oh well, I guess I better start ordering the concrete, sand, aggregate and a shovel.

Oh the pain Dr Smith.

Lon More
19th Apr 2013, 14:06
oxenos, I had the same thought. Now we know where the missing PPRuNeRs went

19th Apr 2013, 14:09
Stop piling so much beer in the back of the ute.

19th Apr 2013, 14:12
LM, I recall being told it was used during WWII but I don't know for what role. It was decommissioned shortly afterwards. The area was big on dairy farming with the lords living further inner city and these parts referred to as "the swill", it could even have been a rich persons private strip.

19th Apr 2013, 14:14
a rich persons private strip.

They're twenty quid in the bars around here. :E

19th Apr 2013, 14:15
Do you have main drainage or could that area be part of a soakaway that has, er, soaked away over the years?

Lightning Mate
19th Apr 2013, 14:23
Was it Monomeith Park Airfield ?

19th Apr 2013, 14:27
Irish pal of mine in Liverpool (just been on phone) could sort it, tar mac 55mm and rolled. He'll give you a guarantee for ten years.300 all in including Vat.


19th Apr 2013, 14:38
Dunno nothing about the stormwater drainage and where they installed those pipes, chances are they run along the side of the house but at which end? Maybe the insurance assessor can access the local council's engineering drawings on the storm water network.

LM, Monomeith Park Airfield is about 50 miles South East from us. We are located about 2 kilometres South East of Caulfield racetrack, Melbourne (which I now refer to as the swill). I've got a hunch that one of the street names carries the old airfield's name. I'll have to pop into the council's library one day and dig through some of their reference books.

19th Apr 2013, 14:48
Thanks Daz, bitumen driveways doesn't do it for me, especially on hot days (we had a stinker of 10 days over 40 C in "mild" Melbourne last month). And the transportation costs :eek:

19th Apr 2013, 15:32
Ahh, sorr, we'll fix dat for yees in no toime at all, at all....see we've been layin' tarmac on dat motorway over dere and we've got some left over :p

19th Apr 2013, 15:37

20 pound? that's pricey. Scunthorpe you can get the strip plus extras for 50p!

19th Apr 2013, 15:41
Why not tell them on Aviation Mystery and Neuralga that you might just have Spitfires under your drive? In no time at all someone will have dug it all out for you and all you've got to do it fill it in with some hard core. (or get dazdaz's friend to do it )

19th Apr 2013, 15:55
I could tell them thar be Spitfires in a crate under this driveway, but the place looks nothing like Thialand...afterwards may be a different story.

But seeing they are aviation history and nostalgia maybe they can explain to me why the cost of hiring a simple Tigermoth has gone through the roof.

19th Apr 2013, 16:22
If you keep flying their Tiger Moths into roofs, it could be the insurance that is making hiring them expensive.

19th Apr 2013, 16:35
Move. Right now. There's no good will come of it; witness Hatfield:

http://farm9.static.flickr.com/8238/8483557366_6198fc197e.jpg (http://www.google.co.uk/url?sa=i&rct=j&q=hatfield+colliery+landslip&source=images&cd=&cad=rja&docid=OE6GyOyEGelK6M&tbnid=jlahlMyUn1V9AM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.flickriver.com%2Fphotos%2Ftags%2Fhatfie ldcolliery%2Finteresting%2F&ei=JXJxUYCsJsaikQXX_IGoBw&bvm=bv.45373924,d.dGI&psig=AFQjCNHxqkoxUUulpRaQSxJkVGwfroDKJg&ust=1366475507140027)

19th Apr 2013, 17:15
Cattletruck, nothing lasts for ever (not even the bosoms of ladies depicted in Slasher's posts), and I think 50 years is a pretty good lifetime. You are going to have to bite the bullet and have it all up, put in a new foundation of some sort, possibly drainage if justified, and then relaid.

Bitter news I know but closing one's eyes to sagging and slumping doesn't help (even more so with driveways).

19th Apr 2013, 18:04

I think that you should move.

19th Apr 2013, 19:47
Get a friend of yours to tell the cops that you have bunped off your wife and buried her there. They will have the place dug up overnight.

19th Apr 2013, 20:26
oxenos says:

In no time at all someone will have dug it all out for you and all you've got to do it fill it in with some hard core

I have some spare hard core you can have. Its under my bed.
I'll post it all under plain cover, discretion assured.
Though just how some spicy mags and vids will help is anyone's guess!

G&T ice n slice
19th Apr 2013, 21:13
pavingexpert - Paving, Drainage and Hard Landscaping Advice (http://www.pavingexpert.com/)

This is a very helpful site, put together & maintained for his own amusement but very heavily refered to & quoted throughout the hardcore do-it-yourself community; me I get a chap in to do everything if it involves lifting anything heavier than a pint.

see his own intro
Paving Expert - AJ McCormack & Son - Company Information (http://www.pavingexpert.com/ajmcinfo.htm)

It will give you a lot of background info and a lot of help


ps. it is NOT a commercial site, he makes his dosh as a consultant in the industry

Milo Minderbinder
19th Apr 2013, 22:28
50 year old concrete slabs?
and they're not broken up as a result of either traffic, frost, or concrete disease?
Sounds like a good innings. After 50 years time to replace - dig the lot out, replace with hardcore, geotextile and readymix.
While you're at it, stick some drains in leading to a soakaway to move the neighbours water

20th Apr 2013, 02:33
Thanks G&T ice n slice, that web link you provided made my posting here on JB worth its while. The site is brilliant. :ok:

G&T ice n slice
20th Apr 2013, 07:54
That's OK CattleT.

The chap who put it all together spent about 2 years flat on his back after an accident so he rather threw himself into it and it helped keep him sane.

As you say it is quite a brilliant site - literally "everything you always wanted know".

West Coast
20th Apr 2013, 15:25
Cattle truck

One thought should you end up replacing the driveway, add reebar to the replacement especially if any large vehicles are going to use the driveway. At another house I added a side section to the existing driveway to park a motorhomes on. Was told it would age much better if it had an internal structure of reebar. I'm no structural engineer, but for the handful of years after, there was no issues despite parking a very heavy vehicle on it.

Good luck

20th Apr 2013, 15:47
The loading on pavement extends to serious depth below the top levels. That's why great care is taken in preparing the sub-base (foundations) of any major roadways or runways.

In particular, when you have two loaded axles close together, the axle loading pressures (which essentially form a "pyramid" pressure zone, under the tyre contact points), overlap at depth.

Where these "pyramid" pressure zones overlap, you have a high stress zone in your sub-base, which results in sub-base deformation (sinking). Speeding and even small amounts of axle bouncing, result in increased sub-base pressures again.

In replacing the driveway, you will have to pay serious attention to compaction of the ground under the pavement, and proper drainage of same, to ensure that the ground doesn't become waterlogged and thus have its load-carrying ability reduced.

G&T's paving, drainage and landscaping website link, is indeed a very worthy link, and I have rarely seen such a comprehensive and informative site. Well done, that man. :D

G&T ice n slice
20th Apr 2013, 21:01
G&T's paving, drainage and landscaping website link, is indeed a very worthy link, and I have rarely seen such a comprehensive and informative site. Well done, that man.

no, no, it isn't my website, as anyone who knows me could tell you (a) because I am completely & utterly cack-handed and am never let anywhere near tools or sharp-edged blades and (b) I couldn't even spell HTLM never mind programme in & create stuff.

Mind you I suspect that the real creator would be amused to receive positive feedback from Australia...

21st Apr 2013, 01:23
G&T - Perhaps I should have re-worded my post. I do understand the paving info website isn't yours, and it's your mates website. When I stated, "well done that man", I was referring to your mate.

Your mate might be amused about positive feedback from Australia - but all Internet websites are accessible worldwide - and earthworks/road/driveway construction follows pretty standard procedures, worldwide.
There may be some local terminology variations, and local terrain techniques that are specific to the area - but virtually every soil type and earthworks problem is known worldwide, and experienced people know how to deal with any particular situation that arises.
In my references, I use Australian military engineering terminology and definitions, because that is where I gained a large part of my formal education.
However, these military engineering terms and definitions are usually also well-known, and transfer across to civilian useage, because the military have been at the forefront of definitions and technology in engineering for a very long time.

21st Apr 2013, 08:00
West Coast, yep re-bar is the norm now, it also prevents cracks from opening or cracked bits from lifting/sinking. I used it at the holiday house and was impressed that once I built 6 meters of driveway over there, it could hold the weight of the truck that delivered the supplies for making more.

G&T I got a feeling I'll end up buying the book to add to my technical library. :ok: