Anyone online answer this patio sub base question now ???

3 Apr 2005
Reaction score
United Kingdom
Tuesday 6th March 13.35pm
Currently digging out 33sq mtr of soil in prep for patio sub base, aggregates and whacker getting delivered tomorrow morning.
I have had to cut into my exsisiting garden by approx 15sq mtr and with the recent weather its like a quagmire.

Upon finding this i scratched my head and thought about the problem ahead, then came up with an idea. Get the pc out and go online.At the moment the area is all dug out and has been levelled off with stakes

So, bearing in mind i'm laying hardcore then sand tomorrow, will i need to remove a little more of the squashy clay like substance thats was found when i removed the grass or dig deeper then the surrounding excavation and add a little more hardcore and then whack down ??
Its currently level with the surrounding excavations.
Sponsored Links
is your subsoil light mud or clay if mud ,your aggregate will sink leaving a unlevel surface down the road.
lay at least 8" of stone compact well , wet conditions will help compaction.
I would use stone dust a finer grade of stone instead of sand, sand will disapear into coarse stone ,compact with wacker in 4" layers for best results . after laying patio finish with stone dust 1/2" and lightly compact again ,stone dust will pack tightly like cement sand will wash away and grow weeds. good luck
better waiting till it dries out a bit. Doesnt really make a great deal of difference to the mot, as soon as you whacker it it will pull up the moisture to the surface. Weve just done one on a clay soil that was in a similar state. Waited another day and the mot was rock hard.

whats the exact construction your using?
Thanks for that,
I have removed the squishy stuff and have found the top of the clay, still a little bit of squishy soil hanging around in places, Have also banged a fork in it to aid drying out.
Thermo- How do you mean exact construction
Sponsored Links
what are you putting down and in what thickneses?
Putting down 33 sq mtr of reconstituted York stone in a random pattern.
600x600-300x300 and 600x300 all 37mm thick
Putting a 25mm mot base and 25mm sand cement dry mix.

Thermo- You said you did one the other day-- I am in two mids as to how to lay these.
I am getting conflicting opinions on how to lay them.
A- tells me to lay them straight onto compacted mot and a 5-1 sharp sand cement mix (dry)
B- tells me to lay onto compacted mot and sharp sand with a 5-1 building sand cement wet mix

I am getting 3 ton of mot and 3 ton of sharp tomorrow, whats your opinion on best way to lay. Im tending to lean towards a wet mix now.
Arghh too much time to think about it.. :rolleyes:
right. stop being confused!

Lay the mot and compact it with the whacker plate. lay it straight over the hardcore.

new wet lay the york stone on a bedding mix of 4 parts sharp, 2 parts building and 1 part cement.

point up a day or two later.

job done.

the only thing you need the sharp sand for is the wet mix. Im guessing youve not used mot before. Once down and compacted it will go very solid so you can lay the beeding mix directly on it.

A wet mix will give a very strong result and the slabs wont rock or move.
...and, given that you say you have only 25mm/1" of MOT going down, a wet bed will give you a good support bed under the slabs. Don't lay stone slabs (as opposed to concrete) on a dry bed or even worse, a sand screed, cos' they'll shift as they are not really heavy enough to bed down properly (IMHO).

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links