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Posted: Wed Oct 06, 2004 1:42 pm
by davidr
This site is brilliant - can you do this for all other DIY areas?!
I have two problems (well, as regards paving anyway):-
1) I want to lay a fairly narrow 23 metre path (30 inches wide, in old money). Anything wider would look odd in this narrow section of garden. I (we) like Tegula Driveset which looks best laid coursed in varying sizes. Also I wanted to use this block for the retaining edges. The path bends a fair amount so I'm into curves (who isn't?). If I lay the 160mm size as soldiers there's not enough left between them for a coursed approach to look right. It's not much better if I use the 120mm for edging. I'm just wondering if I should use something else altogether or is there a way of doing it I can't see?
2) About half of the stretch I'm covering is a bog - getting across it is one of the reasons for a path and it's at the house end of the proposed path. A hole about 15 inches, dug last February for a new tree, filled up with water almost immediately and has never been empty since. Autumn, winter and spring the lawn in this area has standing surface water. Problem is, can I lay a path across it, particularly since the moment I dig down 200mm to begin laying hardcore its likely to start filling up with water. I've read everything on the site about drainage and concluded I have to live with the problem (it's heavy clay soil, on a solid clay base about 15 inches down, with a water table around my ankles and no-one around here has solved it with soakaways).
Be very grateful for any suggestions on these two problems
Posted: Wed Oct 06, 2004 8:45 pm
by 84-1094545549
There's a few possible solutions to the path width problem. If you want to stick with the Tegula Drivesett pavers, than you might consider using the 80mm Tegula Cobbles as a soldier edge course, or even the Tegula Deco, which are 110mm squares. This would look summat like......
...which isn't too bad.
Actually, you could lay the whole path on a sand/cement screed, and do away with the need for a separate edge course. The whoole width of the path would be one big, continuous edge course, and you could use all standard teg blocks.
As for the boggy bit, I'd recommend using ageo-membrane to carry the path across the quagmire, or, again, you could use a sand/cement bed on top of the standard sub-base.
Posted: Wed Oct 06, 2004 10:34 pm
by davidr
Tony - many thanks for this. The sand/cement screed sounds like the best idea. Does this make it a rigid pavement and would the lack of flexibility cause any problems in view of the wet ground and any likely movement? What mix of sand/cement would you recommend?
Posted: Wed Oct 06, 2004 10:40 pm
by davidr
Sorry, forgot to ask - what's an ageo-membrane?
Posted: Wed Oct 06, 2004 11:03 pm
by 84-1094545549
The use of a sand and cenment bed does, technically, turn the construction into a rigid pavement, but that's neither here nor there for such a relatively narrow pathway. By the time you construct fixed edge courses, there's buggerall left in the middle - barely enough room to get the plate compactor, so a simple sand/cement bed is a simple solution. Besides, you won't be running any cars or vans over it (I hope) so the lack of flexibility is no big issue.
While you could use a relatively weak sand/cement mix for the bedding, summat like a 10:1, you need something a bit more substantial for the edge courses,say a 6:1, so you might as well use that for the lot - 6 parts of a grit sand to 1 part of cement, with NO added water. You can splash on a bit extra when you come to do the haunching, but for the bedding work, it's much easier to work with a semi-dry or moist mix.
Use of a s/c bed will not present any additional problems because of the wet ground, although you might just experience a little bit more efflorescence than would normally be expected at this time of year.
The "ageomembrane" is a simply a geo-membrane with the space missed out. :;):
There's a couple of pages dealing with geo-membranes on the main site, but the big idea is that using one such as TDP115 or Terram 1000 will prevent the sub-base material being lost into the slutch beneath.
Posted: Thu Oct 07, 2004 1:12 am
by davidr
Tony - thanks a million for your help. Laying on sand/cement and ditching the edge course would look much better on such a narrow path - although I'm not sure how easy its going to be for me (as a novice) to lay level without edge guides. By the way do I still use sand for the joints or should I be mortaring them?
Posted: Thu Oct 07, 2004 2:26 pm
by Tony at home
If you use the sand/cement bed, you can still use edge courses as level guides, but if you opt for the 'no-edge-courses' look, then use screed rails/trammel bars to guide your levelling off with the screeder board.
When it comes to consolidation, you can't use the plate compactor unless your edges are properly restrained, so you have two choices: you either find some way to restrain the edges during consolidation, or you rely on using a little rubber mallet to clonk down each of the pavers as you work your way along the path. Once the path has been consolidated, you can haunch the free edges.
If you want to use temporary restraints, you can use lengths of timber pegged into the ground. That's probably the easiest solution as they should be sturdy enough to keep the pavers in check while you rattle over them a few times with the plate compactor.
Using the rubber mallet is quite effective on these small path jobs. Kneel on the consolidated paving, have your glamorous assistant pass you the blocks as required, place them, clonk them down to level, and move on, a bit at a time. Once you've covered a few metres, check back to ensure there's no high or low blocks. It really is as simple as that!
Use normal jointing sand, as you would for proper flexible construction. With the plate compactor, that will rattle the sand into the joints, but with the individually-clonked method, you need to brush in the sand and rely on topiing it up every now an again over the next 2-3 weeks.
Posted: Sun Oct 10, 2004 12:39 am
by davidr
Many thanks again. Need to stop thinking about the job and get on with it now! Anyone know where I can get these steel road pins for marking out?
Posted: Sun Oct 10, 2004 1:13 pm
by Tony McC
You don't need steel road pins. They're handy, if you have them or if you're a contractor, but for a one-off DIY job, you can manage just as well with garden canes or bits of stick.
If you really want to use steel pins, get a 6m length of 12mm mild steel rebar from a local steel reinforcement company, and ask them to chop it into ten 600mm lengths. It might cost you as much as a tenner!
Genuine steel road pins, which are around 1200mm in length, can be bought from a Contractors Merchant or Tool Supplier such as Greenham Trading or Parker merchanting for around 1.20 a piece.
Posted: Mon Oct 11, 2004 7:31 pm
by davidr
Thanks again Tony.
I've decided the original path width was too narrow to do anything worth doing so I'm going to make it wider - just over 1m. Current thinking is I will edge it with Tegula Deco, as you suggest, but will use all 160sq Drivesett Tegula blocks set in a diamond pattern. I'm not sure if this is do-able or not as the path is all curve. One large radius of about 6m bends into a reverse radius of about 3m. I'm not sure this diamond pattern will flow with the curves without having to open up too much to go round. Any thoughts on this?
Just read your clay paver section and its tempting to go for these as, instinctively, I'm not fond of concrete and it's tendency to fade over time. But cost is an issue and don't see any clay in 'sett' style or in a subtle/mellow/aged look that is similar to Drivesett options (especially 'Traditional').
Pretty soon will have to stop changing my mind and get on with it!
Posted: Tue Oct 12, 2004 11:58 am
by Tony McC
You'll struggle to 'swing' a diamond layout around those curves without doing a lot of trimming or creating open joints. You could consider maintaining the diamond layout, but how good it would look depends on the actual shape of the path.
You can get sett-like clays - have a look at Baggeridge: they have quite a selection, and they also have tumbled clays which are great for a garden path. I have clay cobbles for my curving garden paths, and I'd be loathe to swap them for anything else.
Posted: Sat Oct 16, 2004 11:54 pm
by davidr
I'm back! Made a start by digging out 23m strip ready for hardcore but found a real sinking bog at one end. It's about a metre long and you really sink into it a long way. Tried a pgeo-membrane over it and about 5 inches of crusher run rammed in but no luck.
It would be like trying to pave a soft mattress. So have dug it out again and dropped a 3'x2'x2" old slab over it and repacked the hardcore over that. Feels solid in the middle if you stand on the slab (although some sensation of floating on a raft!) but edges still very spongy about 6" either side as slab doesn't fully cover width of strip. Can't really think of any other solution. Hoping a strong concrete bedding will hold up the edging paving. Any thoughts?
Posted: Sun Oct 17, 2004 4:11 pm
by Tony McC
I don't like that full flag being in there - if that moves, the whole bloody area moves with it!
When you get odd patches like this where the ground is just bloody impossible, you need to use soil stabilisation techniques, which is just a techy sounding term for flinging a bit of cement in with the crap that's there to stiffen it up. The trick is not to use a lot of cement, just sufficient to bind the soil and make it less mushy. Once you've worked in the cement and re-compacted, cover it with your geo-membrane. It may still be wobbling like a jelly at this point, but it will soon stiffen up, and there's no need to wait before moving on to the next step...
... you can now lay a capping layer over the stabilised sub-grade, and again, a sprinkling of cement (not more than 10%) with the backfill material will help control any residual mushiness. Sand/Gravel ballast, 75mm crusher run or DTp1 are good materials to use for the capping layer.
Once all that's in and compacted, you should be able to construct a normal, flexible, cement-free sub-base and carry on paving as though there was never a bog there at all! 
Posted: Sun Oct 17, 2004 5:31 pm
by Nigel Walker
Tony
Seen a small write up in Professional Builder the other month.
There was a product that you could apply to soil to stiffen it up (as you put it !!) It was not cement.
They said it was used on large road jobs. It meant that instead of digging out, carting away and bringing in decent in-fill. They could mix this stuff with the crappy soil and it would turn it into quality sub-grade material.
Have you heard of this. Sorry I cant remember any names.
I think the reason it was being used was to prevent lots of waste being dumped in landfill sites etc and also to re-cycle existing material.
If this is in use, would it be possible to buy it on a small scale and use it on domestic work ?
What do you think
Nigel
Posted: Sun Oct 17, 2004 7:15 pm
by Tony McC
I don't often get to read Professional Builder but I'll see if I can track down that issue.
Of the top of me head, I wonder if it was a PFA (Pulverised Fly Ash)? This stuff has many similarities with cement, but is much cheaper, is a waste product, and has been used in large scale soil-stabilisation projects in the past.