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Posted: Sun Jan 06, 2013 8:51 pm
by jack101
Hi, i have to construct a car park approx 2000m2 andim looking for a cheaper surfacing method than tarmac. it will have a huge base of 300mm-400mm and this wont cost me much as i have the material. on top of that im planning 90mm tarmac ac20 like road base and thats costing about £15m2.
is that the cheapest option?
concrete at 100mm would cost about £9m2 but is 100mm thick enough? also i dont think conrete would look as good but im not too worried about looks.
any new product out there that would be cheaper?
it is a public car park but wont have heavy vehicles on it, just cars and vans.
thanks
Posted: Sun Jan 06, 2013 10:19 pm
by bobbi o
you could cut down the spec to 65mm depth of 10/14mm dbm.if its a single layer that would be better than AC20.
you could use a self binding gravel for the parking bays (most dobbies garden centre car parks are constructed this way)
get plenty prices.
Posted: Sun Jan 06, 2013 10:27 pm
by Tony McC
Don't forget that concrete needs movement joints and a DPM, all of which bumps up the price.
Gravel, even the self-binding variety, is the only viable cheaper option. You could go for crappy planings/arisings but they're often more trouble than they are worth.
A ground reinforcement system is a popular modern choice, but even they cost more than 10 quid/m²
I'd go with Bobbi's suggestion of 65mm thickness DBM, even 20mm dense would be adequate if looks aren't critical.
Posted: Fri Jan 11, 2013 10:28 am
by jack101
yes i looked into the plastic grid but its too expensive. had not heard of self binding gravel - will check it out. should help drainage too.
thanks
Posted: Fri Jan 11, 2013 5:57 pm
by jack101
what is the difference in performace between the ac10/ac14 vs ac20? i assume the ac20 is less smooth but is there a strength difference or flexibility difference?
the self binding gravel could save about £10k and it would look better. can we do without an edger between the self binding and tarmac?
Posted: Fri Jan 11, 2013 8:53 pm
by bobbi o
ac 20 is a basecourse, ac 14/10 is a wearing course.
ideally you lay 60mm depth of ac20 and 40mm depth of ac10/14 in 2 layers
the wearing courses are designed to withstand the shearing forces of tyres turnng on it. the base courses provide the strength to the road structure.
the number relates to the size of the aggregate.
you can get away without an edger,as your self binding gravel will be laid flush with the top of the tarmac roadways.
send a cut of the savings you've now made to Tony McC ! 
Posted: Sat Jan 12, 2013 10:44 am
by Tony McC
bobbi o wrote:send a cut of the savings you've now made to Tony McC !
Oh! I like this idea of being on a %age of all jobs on which we advise. Money for sitting on me arse! 
Posted: Sat Jan 12, 2013 11:39 am
by lutonlagerlout
like the tributes the mafia captains have to give to tony soprano :laugh:
LLL
Posted: Sat Jan 12, 2013 7:24 pm
by jack101
i suppose something will have to be laid to contain the tarmac during laying? may as well leave it in place
Posted: Sat Jan 12, 2013 7:32 pm
by jack101
on a separate point, i am required to upgrade a road which the council will adopt. the road is currently private, in use for many years and in good condition. the council asked us to core holes and provide the results. it showed an average of 150mm tarmac and between 200mm - 280mm of hardcore base.
i would have expected to be asked to add 40mm of tarmac to this but i am being asked to add 130mm!! of tarmac (90+40)
i think this is over the top, is there any way to get them to reduce this spec? i dont know what the process is but i dont think there is an appeals process.
the number of axles is very low, if a standard axle is 8200kg once per day then this road axle number will be zero or 1 (bin lorries?)
it is an access road for 36 dwellings so on an average day there maybe 150-250 cars on it?
if there was no road, they would only be looking for 170mm in total.
its nearly 3000m2 so its going to cost a fortune for every mm.
its in scotland.
thanks
Posted: Sat Jan 12, 2013 9:32 pm
by jack101
lutonlagerlout wrote:like the tributes the mafia captains have to give to tony soprano :laugh:
LLL
tony mcrano
Posted: Sat Jan 12, 2013 9:32 pm
by lutonlagerlout
jack are you a contractor,developer or subbie?
you seem to be getting a lot of big jobs in
LLL ???
Posted: Sat Jan 12, 2013 9:38 pm
by jack101
I'm the developer. [quote]
Posted: Mon Feb 11, 2013 12:29 pm
by jack101
re: self binding gravel, what is the spec of this? i have seen some online for £60 per ton!!! that would work out as expensive as tarmac.
my local builders merchant has a red granite dust that is £18 per ton but this is 6mm to dust. i think this may be a bit small and perhaps 10mm to dust would be better. im sure the quarry could supply something different if the order was big enough.
any ideas?
thanks
Posted: Mon Feb 11, 2013 6:04 pm
by henpecked
Take the over-spec tarmac on the council job and lay on your cut price car park. Everyone's a winner! :p