Permeable setts? - Light traffic pedestrian for garden

[robinjhorn]

Hello there,

I'm looking to lay some paved areas on a current project which will only have very light traffic however my main concern is drainage.

The plan is a 2.8m dia circle with two paths of 2.3m and 5m leading onto it using 100mm granite cubes. This will have beds all around and under heavy foliage cover with one path leading to existing pavers and one to the lawn. Im going to lay 70-100mm ballast then bed down wynn edging in mortar to finish 50mm higher than the paving level to keep the beds and pavers tidy. The idea then is to lay 40mm of 'jointing sand/splitt/crushed 4mm to dust ' jointing material then the setts then joint to finish.

Now, my problem is the jointing. I want this paved area to be as permeable as possible as the edging will be bedded in mortar but am unsure as to whether the 4mm to dust 'splitt' type of aggregrate will let the water through in a 10mm gap. My only other option i can think of is to only bed and not point the wynn with mortar to allow any excess surface water to drain off between these setts to the beds. most of the site will be level but one of the paths slopes down from the lawn to the circle.

Will this drain?
Do i need kiln dried instead?

all help is very much appreciated

regards,
Robin.

[mickavalon]

Just a few of question Robin. What's 'jointing sand/splitt/crushed 4mm to dust ' jointing material, and what are "wynn edging"? Are they products local to you?
Is your ground free draining? because if not the water won't run off no matter how Permeable your Paths.
Is there nowhere to run the water at all? Is it because your edgings are higher all round?
Even a minimal fall is better than no fall, and you say that 1 path falls towards your lawn, can't you run that way?
The construction methods you describe seem a bit ott, considering your using 100mm Granite Cubes(not the most Porous of stone), I suggest you read a few of the notes on differing forms of laying Paving before you go on, that's a lot of work for a Garden path. How about just leaving some areas of Paving out and forming soak aways, topped with Gravel, you'd wouldn't need to leave many for a Path, just the odd patch, and you could still walk comfortably across the surface.

[robinjhorn]

Hi Mick, thanks for the reply;

The Wynn is the name my local brick and stone distributor gives to reclaimed setts that are a dark grey blue and smooth surfaced (dims approx 300x200x250)
The "splitt/ 4mmto dust" jointing material is referring to the terms used on paving expert to describe what i think is a grade of crushed rock that seems to me a step up in coarseness from sharp sand and i think therefore better for structure and also drainage. Ive seen people use this to lay setts on a couple of youtube vids, not sure what its called in your area tho,

Both paths run onto the circle so the water will inevitably accumulate there if anywhere, the ground seems to me to drain fine by itself and considering its not much of an area thats to be paved I'd not anticipated using any kind of soakaway as i'd figured that with so much jointing per m2 there'd be enough permeability to manage the amount of water thats likely to fall on this patch. As I said it could be an option to leave the pointing of the edging at low points to provide some form of surface spillaway if necesary but this would also be likely to get clogged with soil.

Im just concerned about using the correct aggregate to joint the cubes so as to provide enough drainage for the water to pass through the surface. What would you reccommend in this instance? I dont want to make it rigid though.

As for the construction methods I may be erring on the side of excessive but the factors I'm considering are as follows:

The garden has been up until this point almost completely wild and will continue to be after some structure has been added (paving, fencing, decking etc). The owners like spending time in the garden but not maintaining it so I'd want the paths and circle to be robust enough to be left to dilapidation and becoming overgrown/buried in debris etc.

I'd imagined that because of this and owing to the small size and unstable nature of cubes a good sub base would ensure more stability.

On that note though I'll maybe have only 50-75mm ballast instead.

thanks again for your help,

Robin

[Tony McC]

It's "Whin", not Wynn - it's a basalt found in Eastern Scotlandshire and the NE of Engerland. There's a HUGE deposit of it running north-west from Newcastle known as the "Whin Sill" but there are many other dykes and other deposits all around that area.

[mickavalon]

Geo Fix is pretty porous, and so is horticultural grit, heavy and fine enough to stay in the joints but you may get some plant growth in it, wind born weeds, maybe a bit of moss, nothing to hard to control, but knowing geo-fix you will in that to, only thats a bugger to sort.

[lutonlagerlout]

geo-%&*!!

we never mention that accursed polymeric on this forum mick
tis the devils work
LLL






:;):

[mickavalon]

I know, I know Tony, I never meant it, something was guiding me fingers, I felt all cold and shivery, and as I pressed send, I thought I heard a faint evil Laugh and a smell of sulphur. Twas old nick ee made I do it.

[mickavalon]

Robin, sorry for even mentioning Geo fix, I don't know what I was thinking(it might work though), but I feel your best bet will be really fine gravel/chippings, less than normal 10mm pea gravel, because it will be heavy enough to stay put and firm enough to stabilize the setts.
If you do not wish to do this all over, just joint the sets this way in areas where you feel water will lie, or make a feature of it and mix some areas with mortar pointing, set about 15mm below the surface, and leave some out and fill with chippings, but then cover all the joint with said chippings, and your then holding most of the Paving firm with mortar, but still allowing drainage.


Failing that, use a polymeric, but don't tell anybody I said so!!

[robinjhorn]

Hey Mick thanks for that,

I went out to the builders yard to look at some '4mm down to dust' Crushed Granite that I think will do the job fine, Its not what I'd initially imagined but it seems to be ok.

Dont fancy the ploymeric chat to be honest but thanks for breaking taboo and puttin it out there

Much appreciated guys.

[Carberry]

You want as permeable as possible but have chosen the least permeable stone? Have you thought about laying it like permeable paving or at the very least filling the joints with a complementary larger aggregate?

[Pablo]

Hi Robin I've had a good think about this and I feel that what you're proposing will look ok once completed but will quickly become the opposite. A few issues I have are that the paving will become heavily mossed and full of large weeds and because it's loosely pointed cleaning it will be impossible and once the moss and weeds are established the water will have trouble getting to the gravelbelow.You can't install this sot of paving or decking without being prepared to look after it and by the sounds of it your clients are anything but prepared for that. There's no such thing as a maintenace free garden and wild gardens actually require a significant amount of careful weeding and pruning to keep them looking wild and not out of control. Decking especially will become very hazardous on an overgrown garden and will need cleaned twice a year also if the weeds are left to gro then he whole thing will look like an unloved council house within 2 years. I think you need to have a chat with the client because when they realise in a years time how unmanagable the place is then they'll blame you and you'll not be able to salvage it. If they really want a low maintenance garden then the surfaces need to be flagged with mortar pointed joints the drainage should be good and no decking whatsoever. Also the beds need a good deep mulch of bark or gravel over membrane and the plants should be non deciduous with little or no perenials if you go down any other road and don't look after it then the only outcome is that it'll need redoing in 5 years.