Drive Foundations 2

[welding1]

I am extending my driveway using light decorative paving slabs. The drive will only have to take the weight of a light family saloon car. What foundations do I need?

The soil below the surface contains large amounts of clay. If I put down 2 to 3 inch of aggregate and then finish with a layer of building sand 2 inch deep, will that be sufficient? Or Would I be better using a dry mix of sand and cement instead plain sand?

 

[phuduhudu]

You would probably be best using a slightly thicker layer of good quality gravel fill (about 6 inches) which you should moisten and compact. The best thing for pavers is interlocking brick pavers on a dry sand bed. The brick size pavers are best as they are unlikely to break themselves. The sand bed need only be 1 inch thick and then you should sweep sand over the top into the joints and compact the pavers (you can probably do this just by driving over them). Carl Bauer

http://www.bauerconsultbotswana.com

 

[Ron]

If you use a gravel bed then a sand bedding for the pavers, be sure to put a geotextile layer between the sand and the gravel, else raveling into the gravel voids will occur.

Do not use a mixture of cement/sand/gravel as a subbase for the pavers. This will not allow free drainage from the top and can result in "pumping" or water pressure build-up beneath the pavers. Since you have clay, use a free draining coarse sand or gravel/geotextile/sand bedding.

 

[LPPE]

Rob and carlbauer said it all. What size pavers are you using? The larger the paver, the more likely to crack.

 

[phuduhudu]

Ron, I'm interested in what you say about raveling of the sand into the voids. When we do block paved roads here we always put a sand bed directly onto a gravel base and I wasn't aware there could be a problem. Maybe we have a different definition of gravel here. What we call gravel is generally a well graded material which can be compacted when moistened (the sort of material you would use as the base for a tarmac road). Carl Bauer

http://www.bauerconsultbotswana.com