Independent assessment required

[Kalozo]

I had a patio laid last June – I provided Natural Paving 900x600 sandstone slabs and a local contractor installed.

Immediately after the work was finished, slabs started to become loose. These were re-laid. The problem continued and in September the contractor lifted and re-laid the entire patio.

At the beginning of April this year when we started to use the patio again, there were loose slabs and the jointing has cracked around the edges of the slabs.

The loose slabs range from visible rockers to others that you can hear knocking on the mortar bed when you step on them. This is a different sound to hollows.

The contractor denies that the slabs are loose and has offered to remove pointing, pour in slurry and repoint.

Some photos of when contractor lifted a couple of the loose slabs and examples of cracking and knocking:
https://drive.google.com/open?id=0BxVRB489TM8eUU85aERuY1B6QUU
https://drive.google.com/open?id=0BxVRB489TM8edl9wSkc2T2R4MmM
https://drive.google.com/open?id=0BxVRB489TM8edG9yR05yY3F2b0U
https://drive.google.com/open?id=0BxVRB489TM8eX3VQWi1taGhSVjQ

If the slabs are loose or knocking I believe they need to be lifted and re-laid.

Any advice would be much appreciated.

Also, is there somebody on the forum that would be able to provide an independent assessment/act as an expert witness in the Bedford area.

[BenM]

Answered your PM with some advice on how I dealt with my build issues.

Any expert reports done before a case will be to your benefit to detail the issues with the work. Detail them yourself for now then get an 'independent' expert witness if/when you get to court.

[dig dug dan]

The good news is, he has laid them on a full bed.
the bad news is no bond bridge has been used, hence why they lift easily.
also, what sand did he use?

[Kalozo]

Many thanks to Ben...

The first time they were laid it was sharp sand. I am not completely sure what was used second time. Do you think the sand might be wrong?

The contractor has confirmed in writing that 4:1 mix rather than Natural Paving's recommended 6:1 mix.

Would the stronger mix make a difference?

[lutonlagerlout]

it looks like soft sand to me
obviously not the best adhesion
LLL