Building carport on existing block paving

[sealtt]

In front of our house we have a reasonably large block paving area - concrete base, with cement between the blocks - total 100mm depth approx.

We have been given planning permission to build a good sized carport, around 30sqm internal area. Total weight is approx 1500kg and is spread over 8 legs.

We are near to TPO'd trees, so to do any foundations work we would need to pay a tree consultant to oversee the work which could end up costing a fortune. A contractor has suggested we could just use metal brackets to fix the carport legs directly to the block paving base?

Any thoughts on that? Or any alternatives to digging out the block paving to pour concrete pads. The supplier specifies a 200mm pad for each leg. Is there anything that could be mounted on the surface?

[ColinM50]

I'd be tempted to remove the blocks where the carport legs are going to be then dig down using a hired two stroke two man arbor drill thingy for two feet or so or until I can't get down any further, fill with postcrete and work from there

https://www.hss.com/hire/p/post-hole-borer-manual

[sealtt]

[sealtt]

ColinM50 said:

I'd be tempted to remove the blocks where the carport legs are going to be then dig down using a hired two stroke two man arbor drill thingy for two feet or so or until I can't get down any further, fill with postcrete and work from there

https://www.hss.com/hire/p/post-hole-borer-manual

Probably best, do it properly

[barryrs]

Could you cast a raised reinforced strip along the edge using the sub-base of the block paving and some formwork?

I would negate the need to dig but would take some effort to make it look attractive.

[ColinM50]

Looking at your pics, can't you put the posts in where the soil is rather than disturb the paving?

[sealtt]

[sealtt]

On one side we could have built in the exposed ground, but on the other side it's on top of the crazy paving area, as the hard standing covers the whole area as you can see above.

So our new idea is to cut the 8 holes in the hard standing with a grinder, get the tree consultant in and watch as holes are dug as per planning requirements, then fit a concrete block in each of the holes to mount the legs on. Connect legs to blocks with metal brackets.

Ideally increase the 200mm depth to 300mm or 400mm for peace of mind, though planning was only for 200mm depth as per supplier spec.