Joined: April 2017
||Posted: 13 April 2017,22:02
Hi, Iím a layman and would really appreciate some advice from folk experienced in laying flags about a paving job gone wrong.
We have had approx. 50 sq m of granite flags from a well-known supplier laid as part of a building project Ė by a recommended builder claiming to be highly experienced in paving work. This was completed in November 2016.
The patio is split into 2 roughly equal sections, one at the top of an earth bank (being laid to lawn) and the other on top of a raised section with a small retaining wall and a short flight of steps.
The ground was prepared by excavating and putting down a decent depth of type 1 MoT, whickered down, and then slabs laid on a full bed of sand and cement.
Iíve looked at some of the excellent information on this site based on which Iím concerned about the following issues:
* None of the slabs seem to be bonded to the cement bed (thereís a hollow sound when theyíre tapped). Where theyíre retained by soil they seem to be staying put, but the slabs at the free edge and on the steps have all come loose and are shifting. This is quite dangerous, particularly when using the steps and treading near the edge causes the slabs to flip up underfoot.
* The cement around the edges of the wall / steps is crumbling and falling out. Iíve lifted one of the loose slabs on the steps and can see that the bottom of the slab is completely clean (no cement bonded to it). The cement under it is soft and crumbles in my fingers.
* It looks like the cement has been mixed entirely with soft builders sand and not sharp sand or a mixture.
* There are a couple of slabs rocking underfoot and having lifted one there are voids at the corners where thereís no sand / cement supporting
* The resin based pointing is sinking in a number of places, like it hasnít been compacted properly or there are voids underneath that its dropping into. Obviously itís also wrecked where the slabs have moved.
* We have water pooling in a couple of places where the patio isnít draining properly because the slabs donít look to have been laid with an even fall.
Iíve attached some photos that hopefully help to visualize and illustrate some of the above.
My main concerns are that the cement isnít bonded to the slabs Ė and from the info on this site they should have used a bond bridge / SBR slurry to prime the slabs which I donít believe they did. Also at least some of the mortar is no good and needs sorting out, is the stuff that looks to have set properly also no good because of the sand used?
I am going to have to agree a course of action with the builders and need to go in with a view of what needs to happen to put the job right. Iím really hoping itís not as bad as having to lift and relay the lot , but I do want the job done right so it will last and if thatís what it takes then thatís what will have to happen. I also need to take a call on whether they are competent to tackle any rework or I should look elsewhere to get the job finished properly, since the problems with their work so far have left me concerned about their competence to do this job.
The whole thing has been a real headache / source of stress and there is no doubt going to be more to come before itís all sorted.
Any views / advice would be very much appreciated.
Many thanks, Phil
Link to photo album