Depth of sub base - hopefully in the right forum !

[Boxa]

Hi all, apologies first as I put this in the noticeboard initially, presumably the wrong place, so i will just cut & paste it here ........

Hi all, firstly would just like to say what a great website !! Anyway I'll cut to the chase - I am about to block pave the front garden so that a Black Taxi Cab (approx 1.25 Tonne) & a Transit Connect (probably about 1.5 - 1.75 tonne laden) can park on it. The size of the block paving will be approx 8.4 x 5.4 metres & my question is this ...... I have just dug down to allow for 100ml of C20 dry mix / cement - 50 ml sand & then 50 ml for the bricks. However, after a conversation with a neighbour I am doubting as to whether this will be enough, as I obviously want to avoid wheel channels along the block paving due to the vehicles being too heavy. I have surfed your site & all I can really find is a guide of 100 - 150 mls - so just wondering if you think I should go to 150 or stick to 100 ? Or maybe keep the 100 ml but place some steel reinforcing in it ??

I do have another question or 2 but don't want to milk it too much on my first visit

keep up the great site & looking forward to your advice,

Cheers, Paul.

Apologies once again,

Paul

[Tony McC]

Yes - the wrong place, so I got rid of it!

If you're intent on using a concrete sub-base, then 100mm will be adequate, BUT....

- you may need to prep the sub-grade and use a damp proof membrane beneath
- you may need a regulating flexible sub-base benath the concrete if the ground is uneven
- you MUST ensure there is some way for the laying course material to be drained

... I wouldn't waste my time with rebar, expecially if you plan to use a semi-dry mix. A better construction would be to use a 50mm slump with PP fibre reinforcement.