Depth Of Sub Base

[gibbsy09]

Hi I'm going to do a 3.6m x 3.6m patio, I'll be using, new paving, but nothing fancy just plain 600mm x 50mm, with a mortar base of 40mm.

So what depth should my sub base be, I'm reading that the standard should be 75mm, just wondering though could I get away with 50mm, it isn't soft soil, and fairly untouched, apart from me digging out the weeds, there's
lots of stones all sizes in the soil as well so I'm going to separate them and use as part of the sub base, though I will use proper mot type 1 as well, just trying to save on sub base if I can maybe squeeze by with just a tonne, or would the stones I have not mix well with the mot type 1, none are larger than roughly 40mm, and I would toss any bigger ones, eg wouldn't compact the same, or is a stone a stone lol,Thanks

 

[Mike13]

I had a 4.5x3.5m shed to put up I worked out that as it was a free draining soil I could make it easier to do the base with a bunch of 1m deep piers using a 6" auger, I needed about 17 or so holes, but instead of 6 tonnes of base, I only needed to mix 1 tonne or so of piers. The reason for deep piers is to go below any potential frost line in a cold winter.

I then used composite beams under the bearer timbers to help keep it dry -- be warned they chew through jigsaw blades with melting the plastic and the aluminium fragments in them. But much lighter and quicker to lay.

 

[gibbsy09]

I had a 4.5x3.5m shed to put up I worked out that as it was a free draining soil I could make it easier to do the base with a bunch of 1m deep piers using a 6" auger, I needed about 17 or so holes, but instead of 6 tonnes of base, I only needed to mix 1 tonne or so of piers. The reason for deep piers is to go below any potential frost line in a cold winter.

I then used composite beams under the bearer timbers to help keep it dry -- be warned they chew through jigsaw blades with melting the plastic and the aluminium fragments in them. But much lighter and quicker to lay.

Hi never heard of piers what is it, Thanks.

 

[Mike13]

You use one of these :

https://d18hmorleaqjq7.cloudfront.net/products/Stihl%206%20Inches%20Auger%20Bit%20for%20BT%20230/1584175747771earth%20augerbit%20230.jpg

To put a hole at each corner, and then work out the best spacing each way to get holes about 6" across and about a meter deep, you need them about 2' apart or so.
I used a manual one, had to reach down to get the larger stones out as it would jam on those, but still easier than mixing several tonnes of concrete.

 

[gibbsy09]

Thanks but I'm not mixing concrete, it's a hardcore sub base for a patio