I have an area that I am going to slab with different sizes of slabs.
It is only to be used as a patio, with no heavy traffic. I am being told different advice, as to what sub base to use, if any.
Some say just compact the soil, and add a thin layer of sand to level the site, then dabs of mortar to bed the slabs.
Others say dig down 6 ins, apply hardcore, then compact, layer of sharp sand to level, then dabs of mortor to bed the slabs.
Just what can I get away with ??? but to do a decent job.
Everything you could want to know:-
My father always maintains that no one ever "Lays Slabs" - you lift them more times than you lay them!
Mungo :-)
Just helped lay a paviour driveway (bricks). About 4" of harcore well compacted, then about 1" of sand vibrated down, then the paviours. Paviours vibrated down with kiln dried sand on top. This is to take cars. So for you, if the soil has been undisturbed, dig down to the level you want taking into acount the depth of the slabs. Then lay some sharp sand, or a weak cement sand mix (1:9 ish), then lay the slabs on top. Use some kiln dried sand (from Wickes etc.) and brush it into the joints, Can add some cement to the kiln dried sand if you want but brush it in then water it a bit. You could also lay some garden matting under the slabs to prevent weeds growing, or dose the soil with weed killer (apparantly strong salt solution does just a good a job).
I laid mine on a full hardcore base with about 3" of 7:1 sand cement over and cement grouted joints. Still got a little cracking. Don't use dobs. You WILL get loose stones.
You can get away with sharp sand straight onto the ground with the slabs straight on top but they may move a little over a period of time. My whole patio is like this but the ground underneath is also quite solid.
Thirded! Brilliant site, absolutely brilliant.
I am a bit non plus now.
Some people say bed with a weak mix 1 to 10, now its 1 to 20
Maybe I am wrongh but I would have thought 1 to 20 was to weak. As good as useless.
Can somebody put me right. ???
Do a mix anywhere between 1:10 & 1:20. It does not matter a lot.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required