Page 1 of 2
Posted: Wed Feb 11, 2015 9:25 am
by jamie9090
I was wondering if you might be able to advise on making sure that my driveway conforms to the requirements for permeable surfacing?
The front garden is approximately 7.3m wide by 4.5-5m deep, pretty much level and currently mainly overgrown with grass/weeds.
I was thinking of block paving the whole thing with permeable paving but a) the sub base (4/20 or DTP3) doesn't seem to be available in small enough quantities and b) I understand it is difficult to install correctly for a DIYer (harder to compact??) is that correct? The other idea was to gravel over most of the driveway, apart from a path to the front door and a couple of planting areas, with space for just one car but presumably this would also require a permeable sub base?
Alternatively, I have tried to think of other options for SUDS drainage but considering the front garden is only max 5m long any drainage system would be relatively close to the house and a soakaway wouldn't be allowed. Are other options that you suggest on your site possible closer to the house? E.g. I could install an infiltration drain along one side of the gravel driveway - but this seems to essentially be a long soakaway - so presumably shouldn't be close to the house either?
Here is a diagram of the gravel idea here if it helps:
Any advice would be greatly appreciated,
Thanks
Posted: Wed Feb 11, 2015 9:28 am
by jamie9090
Tony McCormack:
Do you know what your sub-grade is like in terms of its permeability?
DTp3 or 4/20 isn't all that hard to obtain. The biggest problem is arsehole
Builders' Merchants not wanting to ring around and source some for you. It should be possible to get a 12-16T load delivered direct to site.
Posted: Wed Feb 11, 2015 9:32 am
by jamie9090
Thanks for getting back to me,
I have just tried registering again with the Brew Cabin and it is working now so not sure what happened last time – have now moved the question here...
I haven’t dug a trial pit but I think drainage is fairly reasonable – I’ve never noticed any puddles in the front garden and have previously dug a soakaway for a patio in the back garden which seemed to work fairly well.
I hadn’t actually realised I would need that much DTP3 – but have now seen that it needs to be a lot deeper (270-350mm) than using DTP1. As that that will probably add significantly to the workload (digging + compacting) and cost I’d like to avoid that route unless there is no other option.
Given that the driveway is only 5m long and it seems that soakaways (and ?other infiltration devices) can’t be within 5m of a building or road I’m not sure what other options I have? If I left a small planting area at the front corner of the drive (as in the picture) could I just slope the drive towards this? (does that count as a rain garden and can that be within 5m of the road/house?) Is there any option if I was to pave over the whole thing to allow space for 2 cars? e.g some sort of drainage at the sides?
Posted: Wed Feb 11, 2015 8:40 pm
by msh paving
what part of country are you MSH 
Posted: Wed Feb 11, 2015 8:46 pm
by jamie9090
Hertfordshire - near St Albans
Posted: Wed Feb 11, 2015 10:53 pm
by lutonlagerlout
hi jamie
where abouts mate?
we are working in radlett and brickett wood right now and both areas have shite ground === > clay and hoggin
permeable paving will not work
if you are in a sandy area you may have more luck but TBH its unlikely anywhere in this part of the south
LLL
Posted: Thu Feb 12, 2015 11:20 am
by jamie9090
In Sandridge ... The deepest I've dug down is about 1m when making a "soakaway" (or at least a rubble filled hole) for the patio and there certainly is a bit of clay once you get to that depth but nothing like I've seen when digging in some other gardens. I tested the soakaway at the time and the water did gradually drain away and I haven't noticed any puddling since. I also had a look at UK Soil Observatory website (http://mapapps2.bgs.ac.uk/ukso/home.html?) which describes the soil as "Sand to Sandy Loam" where the house is or "Chalky, Silty Loam" slightly further back - not sure what depth that is or how reliable it is. The main thing I noticed was lots of gravel and small rocks (which wasn't fun when digging by hand).
TBH I am slightly put off the idea of permeable paving anyway as it seems to be a bit difficult for a DIYer so will probably go for either normal block paving or gravel but wasn't sure what my drainage options were for this given that the drive is only 5m long from the house to the pavement?
Posted: Thu Feb 12, 2015 6:56 pm
by lutonlagerlout
I have built an extension in house lane not far from you and the ground is clay/hoggin
no good for permeable
depending on falls you will need a linear drain running to a soakaway classed as suitable (this in practise could mean a bucket of gravel)
cheers LLL
Posted: Thu Feb 12, 2015 7:09 pm
by jamie9090
Cheers, that's not ideal I guess but good to know!
The drive is pretty much level ... the problem is where to put a soakaway though given that the drive is only 5m from house to road?
Would I still need a drain/soakaway if I went for gravel over type 1 sub base?
Posted: Thu Feb 12, 2015 7:52 pm
by mickg
>>>>Would I still need a drain/soakaway if I went for gravel over type 1 sub base?
no the water will just go through the gravel, might not soak away like Tony has advised you but it would not be visible
we install a drainage channel across the driveway/pavement connected to a soak a way, job done move on
Posted: Thu Feb 12, 2015 9:46 pm
by jamie9090
we install a drainage channel across the driveway/pavement connected to a soak a way, job done move on
But what I am not clear on is:
a) where the soakaway goes if the drive is only 5m long (as it can't be within 5m from the house or road)?
b) where the soakaway goes if you are paving over the whole drive? Can it go under the paving??
Posted: Fri Feb 13, 2015 1:14 am
by mickg
if there are no alternatives then yes it can go under the driveway, you construct the soak a way and cap it with a concrete lid to support the weight of vehicles driving onto the new driveway
watch this video with Trevor and Claire from Marshalls constructing a driveway from start to finish including constructing a soak away
How to Lay a Block Paved Driveway
Posted: Fri Feb 13, 2015 9:29 pm
by lutonlagerlout
jamie the 5m rule is "where practicable"
what this means is get it as far as is humanly possible away
LLL
Posted: Sat Feb 14, 2015 7:47 am
by lemoncurd1702
Opinions please on the possible problems of using permeable on a clay soil.
Job I'm on at the moment is a new build and planning consent stipulated permeable paving.
The clients wanted natural stone, I said this was possible by using a soakaway which would still comply. Architect says no ground not suitable, I say in that case not suitable for permeable, architect says must be permeable, end of.
So we are laying Teg Priora. I have e-mail trail so can be absolved from any future issues, if any, but I reckon it would need to rain non-stop for a month before the water comes up through the joints.
Posted: Sat Feb 14, 2015 6:12 pm
by jamie9090
jamie the 5m rule is "where practicable"
what this means is get it as far as is humanly possible away
LLL
That makes things slightly easier then ... do you think it would be ok in a planting area at the front of the drive then? (as in the picture in the first post)