raising the height for new patio

[deanpaddock]

Hi
I have excavated out my patio but have had to dig out quite a lot of old loose tarmac to get to solid ground. Now i have dug out it is around 150mm to low for the edge course once i have 50mm edge block + 50mm concrete bed near the house and 50mm edge block + 100mm concrete bed at garden edge.

My question is how to raise the ground level to lay my edge on, so the top of the edge will be at the correct height.

Also once I get my edging done what is the best to do for the sub base and bedding. I was going to fill the base with hardcore and then compact, then add 50mm of type 1 then 40mm of sand/cement bedding. Do i need the type 1????

Please advise

Thanks

[84-1093879891]

Don't be messing about with non-specific "hardcore" - use DTp1 or DTp2 or 50mm Crusher Run material. It only costs a few quid more and it's money well spent, whereas using "hardcore" can often end in tears as it contains too many voids, which allow settlement of over-lying layers which, in turn, results in settlement.

[deanpaddock]

Thanks for the advice.
What about raising the height of the patio edges before filling in the middle. Do I have to build a small retaining wall and then lay the edging on top, then fill in with my sub base, bedding then paving?

Do I need to haunch the edges that arnt against the house wall. One edge will be next to the lawn and one next to an eventual block paved drive. I am unsure of what size hauch as I dont want a concrete edge between patio / lawn and patio / drive

Thanks

[84-1093879891]

You don't need to mess about creating different levels for the sides and then the infill - just prepare your sub-base to one, uniform level, and then lay your edge courses and the rest of the paving.

You don't need to 'haunch' edge courses laid against a wall, as there's nowhere for them to go, anyway. However, edge courses adjacent to lawns or non-existent driveways really do need to be haunched or the paving will not last more than a few months.

The haunch at the lawn edge can be kept low, as shown on the numerous drawing on the main website, and then the turf simply sits on top of it, and no-one need ever know there is concrete down there. As for the edges that will be up against the eventual driveway, well, they need to be firm and sound until you get around to laying the driveway, at which time, they can be yanked out to make way for the driveway paving.

[deanpaddock]

Hi
Thanks for the advice. Because the lawn edge is too low there would be no retaining edge for the sub base. Ive sent you an email with a diagram showing this. When laying the edging on the subbase at the lawn edge, there is nothing to retain the upper part of the subbase. Once the patio is in I will be filling in the garden to make it level with the patio.

Thanks

[84-1093879891]

Here's the drawing you sent to me...



...the mistake you're making is in thinking that the sub-base stops at the back edge of the edge course haunching, when, in fact, the sub-base can extend beyond that point and feather-out naturally so that no retainer is required. This is known as 'spread' and it is shown on most of the drawing on the block paving pages.

Here's a slightly amended version of a drawing from the Edge Courses page....



...which shows how the sub-base can be extended and 'spread' beyond the edge of the pavement and then 'buried' when you come to doing the garden.

[deanpaddock]

Thanks, thanks, thanks

Thats great. I see now

Thanks very much

Dean