My driveway is old pavia block and I intend to replace it with gravel and increase the area to 81 sq mtrs ie double. This means the old driveway will be compacted sand and the new area is grass.
I intend to put scalpings in as a base layer with a membrane then the top layer of gravel.
Q 1. Do I have to remove the sand?
Q 2. What depth should the scalpings be.
Q 3.What type ie quality and thickness of membrane is required?
Q 4. How deep should the top layer of gravel be?
A 1. YOU COULD COMBINE/MIX THE SAND WITH THE SCALPINGS TO REDUCE THE QUANTITY OF SCALPINGS REQUIRED AND TO SAVE YOU THE JOB OF REMOVAL/DISPOSAL.
A 2. MINIMUM 4" BUT RECOMMEND 6".
( ALSO DIG OUT LAWN AND TOPSOIL TO FIRM SUB SOIL IN PREPERATION FOR EXTENSION TO DRIVE)
A 3. USE THE BEST YOU CAN AFFORD AS THIS WILL PREVENT PERRENIAL WEEDS FROM COMING UP FOR YEARS TO COME AND AID THE DRAINAGE.
A 4. I WOULD SUGGEST THAT YOU USE AN ANGULAR TYPE GRAVEL AS OPPOSED TO A ROUND TYPE, AS THIS WILL HELP WITH THE ROLLING AND DRIFTING OF THE GRAVEL WHEN THE WHEELS OF THE VEHICLE DRIVE OVER/THROUGH.
THE ANGULAR SECTIONS LOCK/COMPACT BETTER THAN THE ROUND GRAVEL SECTION WHICH TENDS TO ROLL OVER/PAST EACH OTHER.
THICKNESS DEPENDS ON TYPE OF GRAVEL USED BUT IN GENERAL A LAYER OF SOME 3"- 4".
THE BEAUTY OF GRAVEL IS, YOU CAN APPLY LITTLE AND USE DRIVE TO SEE IF IT IS SUFFICIENT AND TOPUP IF REQUIRED.