Anchoring Commercial Sink Tops to Drywall

Quick thoughts on fastening to drywall where there are no mounting blocks within the framing. February 18, 2007

I am installing vanity tops on a commercial job. On three of the restroom tops, the outside wing support does not have a stud to screw into. Does anyone have any ideas on how to solve this problem? The top is supported on a 2x4 ledger, but their is nothing on the bottom to screw into for the wing support.

Forum Responses
(Cabinet and Millwork Installation Forum)
From contributor F:
Ideally you would remove a square section of sheetrock, install a nailer to the framing, then patch that section back over. If this is not possible, the best hollow wall anchors I have used are the one's made by Hilti. They are very beefy and you install the anchor without the bolt, unlike the old fashioned toggles. I would recommend using as many as you can reasonably fit. I think the weight rating is something like 50lbs. per anchor.

From contributor D:
Can you run a board (piece of trim or something) attached to studs, horizontally on the wall where the support meets wall?

From contributor O:
I run into this too. The best anchor in the world will not prevent the sheetrock from flexing, but usually the combination of top with ledger and well anchored end brace is solid enough. I take the position that I can install the millwork, but I can't rebuild the walls. I use expanding end toggles and plenty of construction adhesive. As far as securing the lower part of the brace, I only need a little if any anchoring as the physics of this setup place all of the pullout strain at the top.

From the original questioner:
I have two 8' three sink tops that I am going to make a horizontal support that I can screw to the studs, and anchor the supports to it, and use some liquid nail for some added backing. The third top is only 3', and since it is in the admin restroom, I think a couple of wall anchors and some adhesive will do the job.

From contributor C:
I would suggest that you use the liquid nails, and try Hilti anchors called "Toggler bolt". They will improve your life.

From contributor R:
If this is a commercial job, the contractor is usually obliged to put in blocking. If you have to do this work, you are often entitled to a change order.

From the original questioner:
There is blocking for all of the cabinetry, and the vanity tops. They missed putting in blocking for the supports. I was made aware of this when the job started, and they are willing to sign off on the use of the anchors since it was their fault.

Due to some other issues, it was decided not to rip the walls apart to put in the extra backing blocks for those particular units. This has been a great job so far, and the company is already asking me to quote two more jobs for them.

From contributor L:
Make sure you get it in writing! You are the one that will be held responsible for your installation in the future.

From the original questioner:
I already have it in writing. I took care of that the day that I found out that they had missed a few of the mounting blocks.