Fixing basin thought tile, dot and dab into blockwork with restrictions

[justbigboned]

Hello all,

Hoping someone may have ideas or advice for my situation.

I need to fix a basin to the wall. There is no pedestal but it is 40% supported on the underside by an oak plinth which is fixed to some battening used for boxing in. The plinth is solid.

I have considered several possible solutions as follows, but I wanted to see if anyone more knowledgeable had a different opinion.

1. Corefix 120mm. Unfortunately these only allow for a maximum fixture depth of 30mm which rules them out.

2. Frame screws/plug 160mm/5.5mm screw. These allow a fixing into the blockwork, but there is no access to screw them in. Could possibly use right angled screwdriver? May not have sufficient strength being 5.5mm screws at 10mm hole diameter. Also leaves the problem of supporting the screw through the basin ceramic to avoid issues there. The basin fixing kit came with support washers which accommodate M8.

3. M10 80mm wall plug in conjunction with 160mm M8 wood to metal dowel. This would give 40mm into blockwork and leave 40mm of machine thread showing to accept the nut. I'm a little concerned about downward pressure on the tiles if the basin is full as the plinth supports under half of the depth of the basin. Wood to metal dowel link: https://www.tcfixings.co.uk/product...urniture-dowels-with-t25-torx-drive-bzp/15846

If anyone has other ideas, input or suggestions, I'd be grateful.

Situation is as follows, basin not to scale. From left, blockwork, void, 12.5m PB, adhesive, porcelain tile. Blockwork to face of tile is 40mm.

 

[blup]

Concrete screw with bolt head that you can turn with ratchet spanner, essyfix from SF are good value A steel tube, maybe from the corefix kit, to prevent the pb collapsing. The oak plinth properly fitted should bear a lot of the weight. Consider removing plasterboard and infilling the void with ply and reboarding if in doubt about any of the fixings

 

[justbigboned]

Concrete screw with bolt head that you can turn with ratchet spanner, essyfix from SF are good value A steel tube, maybe from the corefix kit, to prevent the pb collapsing. The oak plinth properly fitted should bear a lot of the weight. Consider removing plasterboard and infilling the void with ply and reboarding if in doubt about any of the fixings

blurp thank you for your post. I read it but then got back into the job and forgot to thank you. Concrete screws are a good shout but I wasn't sure how well they would do in the blockwork as it's pretty poor stuff that we have.

In the end, we worked out that we could just about get away with the longest plug that fischer make, at 80mm. We got that in and ordered some wood to metal dowels that would make it through the basin and provide enough thread. Next size down would have been too short! Corefix were also too short in terms of allowed depth of fixture. Bit of a nightmare all around this job, mainly due to the design of the sink. We had to do the job twice as the first sink had a poorly cast waste outlet and the bottle trap ended up sitting at a 15 degree angle.

Anyway, the final result of all the faffing was that it's very secure, especially with the oak plinth taking half of the weight.