Just had our patio extended, but after a couple of wet days there is a
> significant puddle of standing water in the middle. Obviuosly the guys
> that did it didn't quite get the levels right but the slabs were laid on
> wet mix so extremely diificult to take up again.
> What do you think of drilling one or two holes through the grouting (?) at
> the lowest parts to let water drain below a little. Would this weaken /
> destabilise the sub surface ?
> Thanks
A couple of holes will fill up quickly with detritus and block. Suggest you get the builders back to fix their error. If this isn't an option, I would drill out enough slabs to install a small gully (150mm dia) use a fence hole borer hired from hss to create a 2 to 3 foot deep hole, install drain with a length of 110mm plastic pipe on bottom so water going into gully top has to travel to bottom of pipe. May be worth filling pipe with 10mm pea shingle to within about 100mm of surface.
BUT best option is to get them back to do it right.
Al