The Brew Cabin

I have installed a dry laid slate patio off our sunporch. There is a roughly 1 foot drop off at the far edge of the patio, and I am experiencing a great deal of erosion off the bedding layer when it rains. I am using edging strips around the patio, but they are obviously no good. I am aware that I have probably done something wrong in setting the patio out in the first place. What suggestions are there for someone of my 'limited' ability?

Edging strips - what are these? Are they just pieces of slate laid 'on end' or are they some form of pre-fabricated item that might be used to edge a lawn or similar?

The correct consctruction for this type of job would be to use a flag-on-edge type construction, or even a dwarf wall, to retain the 300mm (12" ) uplift and prevent any erosion of the bedding layer....



...now, if you have a 300mm uplift that is basically just bedding, then you need to contain it in some way. This could be as simple as laying more slate over the exposed bedding, but laying it on a full mortar bed, so that nothing can escape, if you know what I mean, or it could require you to take up the outer courses of the paving and re-construct a shown in the image above.

If you can get me a photo of the problem, I should be able to suggest a suitable remedial strategy.

Edging strips are flexible plastic strips that are spiked down to prevent the slate from 'creeping'. You can then landscape over them with either sod or something else.
I will try to post a photograph within the next couple of days. thank you very much for the assistance so far.

I know the sort of thing you mean - I have reservations about just how suitable these 'strips' are for retaining paving. If it were a flat patio, then I wouldn't be too worried, but using them as a retainer for 300mm or so of uplifted paving seems a bit excessive to me.

Okay, I have finally taken some pictures of the patio problem I am having. I will send the images to the email address listed in this website's help page.
As you will see, I am getting a certain amount of base layer runoff from under the edge of the flagstone patio I have laid. I would like to avoid using cement as a solution to this problem if possible. I am wondering if i can solve the problem by filling more soil into the bordering garden box, and/or installing some sort of edging stone.

Okay, I am trying this again, but here is the link to view my patio images:
http://members19.clubphoto.com/bob736691/1471454/owner-0c7d.phtml
Thank you

I've re-posted the most relevant photo for you....




...The best way to cure this problem would be to lift and relay the outermost course of paving (or even the 2 outermost courses) on a cement-bound bed. That means mixing a small quantity of cement (10%) with the sand bedding that you've used, so that it binds together the sand bedding and prevents it being washed out from beneath the paving.

However, you don't want to use cement, so that makes it more or a problem. If you used a vertical edging, as shown earlier in this thread, you'd need concrete to retain the edging, and I'm not sure whether your dislike of cement extends to the use of concrete well below ground level. If not, you could adapt the vertical edging shown in my sketch above, and lay it so that the top of the edging abutted the paving, rather than sat beneath it, if you know what I mean. (See below)

However, if you really, really, really want to use a cement-free option, then the best method I can think of would be to use a separation membrane that retains the bedding beneath the paving something like the right-hand option on this sketch....



....personally, the cement-bound bedding option would be my favourite. It's simple, it's cheap and it will work. The edging is a lot more work, but would solve the problem, whereas the membrane is a lot of work and uncertain results.