Wooden Slab Vanity in the washroom; Safeguarding against wood movement beneath sink.

[John Pond]

Hey there, so as the title suggests I'm considering putting a wooden vanity with a top and bottom shelf in my bathroom renovation. 330916 I have concerns that the 2'' slab that I intend to use as the top surface, which would be under the sink, might swell or twist with the bathroom humidity and possibly break the connection with what I suspect is a rigid P-trap/drain. So if anyone has any ideas which to include in the design and safeguard against this problem , I'd appreciate it. Thanks

[Prashun Patel]

Drill the drain hole wider than the pipe to allow for contraction. Also, plan for movement around those legs. If it were me, I'd split the slab in the middle. That will allow you to make rigid connections to the legs, but allow for expansion inward. You'll then need to make rails between the f/r legs.

[John Pond]

Movement around the legs, in what direction? Is that what split in the middle would offset? And how would that look? Like a Nakashima butterfly joint or something? Is there a risk of the board wanting to 'pop' up towards the ceiling? The vanity I had in mind wouldn't have the front (apron I think its called?) piece like in the picture, you would just see the edge of the two inch slab. If thats the case is there something I'd need to plan for to have the same stabilizing effect as the apron?

[Dan Hulbert]

If I were to do this, I'd put the rails between the front and rear legs as suggested above and attach the top to the legs with screws through slots. Oversize the drain hole as suggested to allow for shrinkage. If you offset the drain line so the P trap is NOT perpendicular to the wall, it should be able to move enough to float with the sink and slab. The PEX for the supply lines shown in the picture is the way to go to allow them to move with the slab also.

Post a picture when you're done. I like the idea.

[Scott T Smith]

Finish all surfaces of the slab top with the same number of coats of a moisture resistant finish.

[ron david]

allow for movement around any receptacle; allow for the top to move. I don't understand (not yours) the comment about splitting the board as if it ever got wet then the moisture would run down there. and as mentioned finish app surfaces
ron