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Posted: Fri Dec 10, 2010 4:15 pm
by weejack
Hello All,
I had a new driveway laid a couple of months ago. We have just had 10 days of horrendous weather, snow, ice and temperatures of -15 degrees.
The snow is now melting and most of the jointing sand between my paving stones has disappeared and many of the blocks have sunk or are moving.
I have a five year written guarantee from the contractor but it has a disclaimer on it with regard to severe weather.
Any advice would be much appreciated.
Posted: Fri Dec 10, 2010 4:32 pm
by lutonlagerlout
a photo would be handy jack
where are you?
LLL
Posted: Fri Dec 10, 2010 4:41 pm
by weejack
Hi LLL,
I'm in Glasgow - I will take some photographs tomorrow ( it's dark up here now!)
How do you get photos onto the website - sorry, I am new on here mate.
Posted: Fri Dec 10, 2010 7:48 pm
by jonsey24
I am suffering a similar scenario with my newly laid path, with the snow and ice some of the joints that used to contain sand are now depleted and require topping up.
Also do you get some settlement with a newly laid path after a short period of time? what i mean by this is where i park the car appears to have settled slightly more than where no car is parked, it hasnt troughed or caused major sinking it just looks slightly lower.
When the path was laid it contained 150mm MOT with 30 - 40m sand then 60mm block work, at each stage of the laying process it was compacted with an industrial sized wacker plate that took 3 adults to lift i am just concerned that the settlement may get worse and eventually dip and sag can anyone ease my worries
Posted: Sat Dec 11, 2010 1:01 pm
by weejack
Hello again folks,
My drive looks worse this morning - individual blocks sunk about 20mm, and large undulations across the whole thing - I think I might need to lift the whole lot and start again, and that's about 80 square metres !:(
Posted: Sat Dec 11, 2010 1:18 pm
by Bob_A
weejack wrote:I have a five year written guarantee from the contractor but it has a disclaimer on it with regard to severe weather.
Can I ask the professionals on here whether that is normal practice.
Posted: Sat Dec 11, 2010 5:54 pm
by GDFC
Ours is now starting to show these signs, been down for 9 months and all was well now the snow is melting I notice a lot of the sand has been washed away which now leaves some blocks moving, also a lot of water is coming up from the edges of some blocks when you stand on it, even begining to think some areas are also dipping.
Posted: Sat Dec 11, 2010 6:29 pm
by weejack
Hi GDFC,
I know absolutely nothing about this stuff - that's why I employed a contractor . I happened to chance upon this website, and there's obviously plenty of professional guys who regularly give opinions and information gratis - much appreciated.
I suppose my real question is this - can two weeks of really severe weather wreck a new driveway ? or have I just had a duff job ?
Posted: Sat Dec 11, 2010 6:34 pm
by colordrives
sounds like a bad case of frost heave, what kind of screed material did you use. can you lift a few blocks and take some decent photos?
Posted: Sat Dec 11, 2010 6:37 pm
by Dave_L
Severe weather always shows up the driveways that haven't been dug out enough/enough subase put down/properly compacted.
It's what we always say when we see a man with a small excavator and a cpl of skips digging out a driveway we've quoted for........
Punters more often than not always look at the bottom right hand corner and NOT the specification......this is more often than not my parting words when I leave a survey job. Make sure you are comparing comparable jobs!
I'm not saying this is what has happened at the OP's address but I have my suspicions.
And no, we don't always get it right :rock:
Posted: Sat Dec 11, 2010 7:26 pm
by rab1
My neighbours path lift lifted about 6 inches at points last year, It was laid on top of clay with a bedding layer of sharp sand and cement and he wondered what went wrong. ???
Posted: Sun Dec 12, 2010 11:21 am
by Tony McC
There has been more frost heave over the past couple of weeks than there was in the snow of last winter and this is because we have had much lower temperatures over an extended period, which allows the frost to penetrate deeper.
In theory, when a pavement is constructed from even layers of homogeneous materials, the whole lots rises then falls as one. This bit here heaves by 20mm and that bit over there heaves by 20mm. When the thaw comes, the whole pavement settles to the same degree. In theory.
When we see significant lips and trips within a pavement, it is most often due to a variation in the sub-layer. Walking down to the Post Office last Thursday with my grand-daughter, I noticed that a bitmac surfaced service trench in the footpath, cut 7 years ago to accommodate the cabling for new traffic signals outside the school, had heaved by 15-20mm, whereas the rest of the footpath seemed unaffected. There was a pronounced trip formed along the longitudinal joint between old and new. (Naturally, I didn;t have a camera with me to photo this phenomenon 
)
The older part of the path, constructed in the 60s, was laid over a mixture of slum-clearance brick rubble and boiler ash, two aggregates we had no shortage of in Lancashire at that time, while the new trench was backfilled with Type1 limestone. After 7 years, it would be fairly safe to assume that compaction and settlement was complete, but it must be the case that the newer limestone sub-base hold a greater water content than the ash/rubble mix, and so when the frost penetrates the 75mm of blacktop, the limestone expands more.
So: the point of all this is that, if there is significant lips and trips in a newly constructed pavement, it suggests that there is some significant variation in the sub-layers. On a pavement that is only a couple of weeks old, this could be something as simple as some parts of the laying course being wetter than other when laid and a fortnight hasn't been long enough for the moisture content to even itself out.
On 3 month + pavements, I'd hazard a guess that it's a significant variation in sub-layer thickness that is the cause. If some parts of the pavement have 25mm of laying course sand and others have 75mm, the potential for water retention is worryingly variable.
The remedy is to leave it for now. There's no point in trying to put right frost heave damage that may well re-occur later this week, or next month, or February. leave it until the Spring, then start by simply running a plate compactor over the lot once we're in a warmer period. See how much of the unevenness can be "ironed out" with the plate, and if there are still significant high spots, then it's probably a case of lift and re-lay.
The beauty of a segmental pavement, such as block paving, is that problems such as frost heave are fairly easy (and cheap) to rectify. Spare a thought for those poor sods, like the lady in Rotherham I spoke to this week, who have seen their expensive decorative concrete heave and crack in the recent freeze. You can't repair a crack like that - at least not invisibly.
Posted: Mon Dec 13, 2010 8:00 am
by weejack
Thanks very much Tony - I'll take your advice .
Thanks also to all who posted - great site now bookmarked .
Posted: Mon Dec 13, 2010 4:37 pm
by GDFC
Thanks for this advice, we will be in touch with the marshalls approved installer soon with our issue but will make sure no further action is taken until March/April
Interesting to know that I was given a 3 years guarantee by the installer however on checking Marshalls website I notice they offer a 5 yr guarantee for installtion defects and a 10 yrs for material, for a small fee. Spoke to Marshalls about this guarantee and they say it has to have been taking out within 28 days of installtion.....doesnt tell me that anywhere on their website, feeling short changed at the moment.