I would go for the plastic expansion anchors.
How to attach vanity tile wall.
The basin that sits on the vanity has 4 holes with which to connect it to the wall.
Watch out for pipes and electrical cables behind the wall when you drill.
Tap the wall plugs into the wall if required so that they are flush with the walls surface.
Step 3 mounting the vanity unit.
Use the stud finder to locate and clearly mark your timber wall studs these will be used to affix and stabilise your vanity unit later on.
If there are large gaps at the wall or floor attach quarter round moulding along the wall or floor edge with finishing nails.
How to attach it to a wall that has tile on it.
Carefully mark and cut your pipe holes into the back of the vanity.
Is there any problem leaving the unsealed wall behind the vanity.
Once you re through the tile use a wood bit to drill into the stud.
Place the vanity unit against the wall and use screws to secure the vanity unit in place.
I m yet to exactly line these up but 2 of the holes would line up with tiles on the outside the other 2 are near the mess.
Drill a pilot hole through the vanity back into a stud.
How to center it under the mirror and light fixture using a tape measure or a poor man s bob plumb.
These screws only need to keep the vanity against the wall.
Using the electric drill drill the holes into the wall where you have marked.
For a tile wall first use a tile bit.
If the holes are not completely lining up or you want a more secure install use wall anchors to attach the vanity to the wall.
For holes that are not in line with studs use wall anchors made for your wall type drywall plaster or tile.
Secure the cabinet with screws.
Remove the vanity unit and set it aside.
If you don t place shims here the screws pull the vanity frame rail to the wall and rack the cabinet out of square.
If the wall behind the vanity isn t flat plumb you may need to insert shims in any gaps between the back of the vanity and the wall at each stud location.
After a plumber has disconnected the plumbing remove the old vanity from the wall and dislodge any remaining sealant with the scraper selleys silicone remover will help.
Just make sure you use anchor long enough.
They won t need to bear the weight of the vanity like a wall hung cabinet needs.
Flush the heads with the tile.
Here s how to finish the installation.