Building an extension to a driveway

[securespark]

I have searched for this topic, and can't find anything.

I have an existing concrete drive (long & narrow) and want to widen it at the front with an additional area approx 15 x 8 feet. The area is currently laid to lawn.

How far do I dig down, what depth of which material do I use and how thick should the concrete be that tops it off?

In short, a lot to ask, but how do I build this thing?

 

[masona]

If you want the surface of the concrete to be level with the surrounding, remove soil to the same depth of the concrete driveway. If it's for a car you will need 100mm thick, a path 75mm thick. If the soil is soft or loose, first put down a layer of rubble or stones and then compact with sledgehammer or roller (I don't mean your Rolls Royce), removing extra soil to allow for this and use approx 75mm of rubble, rejects or hardcore. If there are only occasional soft spots in an otherwise firm base, make these up with well compacted rubble.
If you are laying fresh concrete on a cracked base, break this up and compact otherwise it will almost certainty crack or scale.
When the base is ready, set up the formwork (a frame to hold the concrete in place while it is hardening). I would use 100mm x 25mm timber with the width equal to the intended depth of the slab. Cheap timber or old floorboards are suitable.Make some wooden pegs approx 300-450mm long driven into the ground, remember to set the forms on one side slightly lower than the other side for a slight slope for drainage. Leave no gaps between boards, otherwise concrete may flow out. The forms must be rigid to take the pressure of compacted concrete.
Tamp the concrete with heavy plank (a handle on each side make life easier) Depending on top finish you want I use a stiff brush upside down very gently just before it dried off and finish off with a edge float.
100mm concrete - 20mm ballast + cement, 4:1 ratio

 

[securespark]

Cheers Mason!