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Posted: Mon Apr 30, 2007 2:00 pm
by dmck
Hi,
I want to construct a garden path from my new decking to my shed (about 800mm Wide x 6m Long). Here’s what i plan to do, excavate the area to a depth of 150mm. Lay services for shed (waste 32mm, 15mm water supply and electrical cable). Cover with Sand to a depth of 50mm. Lay Hardcore to a depth of 50mm. Lay Sand to a depth of 35mm and use a wacker to compact. Lay Indian sandstone slabs (32mm) on top and tap into place. Finally point with mortar. My question is, am i correct in my above methods? I have never tackled anything like this before, any suggestions welcome.
Thank you.
Posted: Mon Apr 30, 2007 10:22 pm
by Rich H
If you wacker the sharp you'll never get sandstone to bed down.
I would put the layer of sand over the services to protect them (hopefully you're using armoured or conduit for the power) and a good quality membrane over that. Next use MOT to 50mm and wacker that, rather than hardcore - chances are the larger chunks could be driven down into your services. The only problem is that you only need half a ton. Some builders' merchants will supply you with half a ton loose but most won't - it's a ton or nothing!
Then lay the sandstone on a sharp sand - cement mix, semi dry (consult the pages for the recommended strength but I always use 4:1!) using a rubber mallet.
Lastly - the width. Most Indian Sandstone slabs come in size multiples of 300 or 150mm (check with your supplier to see if they're cut that size or designed to take up that measurement with the pointing gap).
The ones I buy are 300x300, 450x450, 600x300, 600x450, 600x600 & 900x600. On this basis I would size the path at 900W.
Posted: Tue May 01, 2007 10:27 am
by dmck
Rich H,
Thanks for the reply. Yes i was planning to lay sand over the services and yes i am using conduit. MOT - is that the really small stones? I have recovered the stones used in a previous path and bagged them which should be sufficent for my use. I was using hardcore as a generic term, apologies. Also good point on the width of the path, i will confirm the size of the slabs with the supplier today. Are membranes easily obtained? would they sell them in a local builders providers (i'm based in ireland) also could you recommend one? Should i screed the sand/cememnt mix and compact at all before laying the slabs? What about pointing will that still be required?
Again thanks for the reply
D
Posted: Tue May 01, 2007 7:04 pm
by Rich H
MOT forms the sub base of your paving and is critical to get right. If by 'hardcore' you mean broken-up concrete and old slabs, etc., this is not really suitable for your application as it is too 'chunky' for the depth and won't have enough fines to form a solid layer.
Tony explains all about sub-bases here: http://www.pavingexpert.com/subbase.htm
Membranes are very easily obtained. If you explain what you are doing at your local builders' merchant they will be able to show you the right one for the job.
Whatever you do, don't screed and compact the bedding layer for sandstone. Even if it feels like they're going down ok, they will end up rocking. When laying sandstone, you want the slab to compact the mix with you helping it down a little with your mallet.
Like this: http://www.pavingexpert.com/layflag1.htm#indhow
I use a spade rather than a trowel to do this but I have laid more than I recall. As a tip, add a little extra mix immediately adjacent to the neighbouring slabs as this will speed up the later pointing process no end!
Finally, you will certainly need to point them. Remember that with Indian Sandstone, the bevelled edge is down. I've relaid two patios for folks recently who've discovered they've laid them themselves upside down. Laid the right way up, this means that impacts or pressure to the edges of the slab can cause them to 'pop' off the bedding layer even when laid properly. A risk with a path, for sure. If they're properly pointed this is no longer a concern.
If you can get Romex, use that as I've heard no bad reports. Otherwise, do it the traditional way as described by Tony here:
http://www.pavingexpert.com/pointing.htm#point
Some people like to substitute one of the parts of building sand for one of sharp to give it a rustic look, but I've stopped doing that over the last couple of years as, unless you get the compaction dead right all over, it can break up in some parts over time.