Joined: Jan. 2020
||Posted: 14 Jan. 2020,00:38
DIYer here laying ~36m^2 of boggo Marshalls block paving in Cambridge (mostly) using Tony's excellent advice. (except when it comes to carrying on regardless of it pushing it down)
Background first then two questions!
Postcode is CB4. The first 4 feet are clay. Proper sticky compacted clay that's liquid in winter (like walking on the the dried surface of cold porridge and you can sink bricks into it with your feet) and concrete in summer (when doing the fenceposts I used an Aldi kango hammer for the first foot)
After 4-5 feet you hit a sand/gravel layer that drains ok. Kid brother also lives in CB4 and block paved his 50 m^2 (courtyard) back garden by dropping a 1 m^3 soakaway in the middle sat on the sand/gravel layer then paving over the top of it and this works fine. I've copied this with an overflow to the drains so I'm happy that once at finished level it should drain ok.
Unfortunately the heavens opened in October, it hasn't really stopped since (we usually get ~50 mm/month but it's been >100 mm/month for the pas 5 months), and I didn't get to finished levels before it started.
- Excavated 250 mm of compacted clay (previously there were PCC flags "laid" directly onto the soil and these sank relatively evenly...until the water board can along and dug a 2 m^3 hole in the front garden to fit a meter)
- Terram T1000 textile (if you don't put this the rocks just sink into the clay porridge and the fines come to the surface in winter)
- 18 tonnes of crusher run compacted to refusal in 75 mm layers; nominally 150 mm thick compacted but where it sank (I hired a Wacker DPU3050He from Speedy and knocked seven bells out of it) it might be nearer 230 mm
- Soldier course laid on 100 mm of concrete against pavement to the front is the front edge edge. Solider course laid on 100 m of concrete against concrete fenceposts with concrete gravel boards is one side (public footpath). Solider course laid on 100 mm of concrete against wooden fenceposts / haunching is the other side (neighbour). Line drain set in 150 mm of concrete plus a solider course sat on ~30 mm of concrete on top of the 150line drain concrete is the back edge.
- 1:60 fall in both directions; line drain along the back edge nearest the house; to a gooey bit of garden to get some shrubs etc later.
I was ready to screed, started spreading the sharp/grit sand, then the day job got busy, the heavens opened, and the whole bloody lot is very, very, wet.
The crusher run was "40 mm to dust" concrete, bricks, and mortar. I've wacked the living daylights out of it and that wacker was more than capable of turning any protruding brick into more dust or bashing any protruding lump of concrete into the surrounding bricks/mortar until they became dust.
It's stable (and was a bugger to scrape down any high spots) but isn't exactly free draining. I've now compounded the issue by (1) adding the line drain/edge courses that prevent runoff into the garden and (2) starting to spread the sand (had to move it because of where it had been dropped, and had the bad idea of putting it into its final position)
So now I have a bowl with some sharp sand soup in it. Put a couple of blocks on this and whack them with a hammer and lump of wood and it settles very easily with water oozing out of the joints. Shovel it into a bucket and "drop" the bucket on the ground a few times and it settles down with the top surface just water.
Where I'd like to start the paving (downhill edge nearer the line drain) is wetter than where I'd like to finish.
What should I do next given that I've done an oopsie?
- spread it, wait a bit, lay anyway
- pile it up in a big heap, wait a bit, then shovel from the top and try to lay in sections
Second question is easier!
There's a water meter in the driveway. I'd like to set the cover and an edge course around it in concrete so that if it sinks (hopefully it shouldn't - I excavated a deep cone around the water meter and backfilled first with weak concrete mix then with some layers of crush before the texitle went down) the whole assembly sinks evenly.
What patten do you suggest around this drain cover? My edge elsewhere course is solider course. All the blocks are charcoal colour. (SWMBO hates brindle and charcoal or brindle were the only ones on offer at Travis Perkins...)
It's all clay up top and wet
View towards road you can see tight surface and wetter its towards the house/drain edge. The far end wasn't wacked at the time because the sand got delivered onto it whilst I was out
High spots scraped down again ready for me to make the mistake with sand and whack the last bit. Note water meter surround poking up:
Dunno what pattern to use around this drain. The other 4 edges are simple solider course:
Also this is super easy to use for what it's worth: