Supporting a large floating corner desk

[Stephen McBride]

Hi all! Thank you again for all of the help so far with my projects. You have all been a great resource and super knowledgable.

My next project is going to be an office desk and my biggest concern is stability. My initial thought is to build a frame out of 2x3 that the plywood top will rest on. My question comes in that I want the desk to be 22-24" deep and each side will be 72" wide on the wall. Both ends will be free and not spanning a wall.

Is it enough to use structural screws to fasten the frame to the wall with a desktop that is this deep with no support on the ends?

I'd like to avoid cutting into the drywall for this if at all possible. I'd like to use 1/2" plywood as the top and then 1/8" hardboard underneath to keep weight down. I would also be putting a 1x frame around the outside of it with one, maybe two, drawers on one of the sides.

Would there be a preferable wood to help the build support of the frame?

Thanks in advance!

[Paul F Franklin]

There's no way I would trust screws through the frame to properly support the desktop with no side panels or legs. There could be a tremendous amount of levering force on the top just from the weight of the top and the "stuff" on the desktop, let alone the forces if someone leaned on it or, heaven forbid, tried to sit on it.

I think you need to plan to open some of the sheetrock and install steel floating countertop support brackets, at least two on each of the L sections. Short of legs or end panels, that's the only way I would trust it stay solidly attached. I wouldn't even install any brackets that bear on the sheetrock; it will just crumble over time. They need to be solidly attached to framing. Sheetrock repair isn't that hard.

[Jamie Buxton]

I'm not clear about your design. Are you saying that the desk is L-shaped, with each arm six feet long, and the entire six feet of both arms will be supported at the walls? Furthermore, each arm is 24" deep or so. I'd say you have enough support to keep the desk surface from falling down. However, if the surface is only 5/8" thick, it will definitely bend down at the unsupported edges. Look into brackets like these from Fastcap to support the ends, and maybe in the middle. https://www.fastcap.com/product/speedbrace?cat=4

[chuck van dyck]

If I understand correctly, you will need at minimum to remove the drywall and attach directly to the studs. If steel studs, you also need to tie the studs together with blocking. Even is 2x studs I’d still recommend strapping with a 2x10 or something.
Drywall will compress which causes movement, that movement will grow and grow.

[johnny means]

If the desk top is solid enough, you'll be fine. Everything but the very far corners will essentially be suspended between the walls. For this to work thw top needs to be pretty much monolithic.

[Stephen McBride]

There's no way I would trust screws through the frame to properly support the desktop with no side panels or legs. There could be a tremendous amount of levering force on the top just from the weight of the top and the "stuff" on the desktop, let alone the forces if someone leaned on it or, heaven forbid, tried to sit on it.

I think you need to plan to open some of the sheetrock and install steel floating countertop support brackets, at least two on each of the L sections. Short of legs or end panels, that's the only way I would trust it stay solidly attached. I wouldn't even install any brackets that bear on the sheetrock; it will just crumble over time. They need to be solidly attached to framing. Sheetrock repair isn't that hard.

Yeah, I was looking into countertop brackets. This is what I was looking at, do they seem right? https://ironsupports.com/products/fl...p-wall-bracket

If I understand correctly, you will need at minimum to remove the drywall and attach directly to the studs. If steel studs, you also need to tie the studs together with blocking. Even is 2x studs I’d still recommend strapping with a 2x10 or something.
Drywall will compress which causes movement, that movement will grow and grow.

I haven't done strapping before. Do you add it at the same height as the desk along its whole width?

If the desk top is solid enough, you'll be fine. Everything but the very far corners will essentially be suspended between the walls. For this to work thw top needs to be pretty much monolithic.

The design I based my idea off of was made of pretty solid walnut, with this being plywood + frame, I'm not sure "monolithic" is how I'd describe it

Thanks everyone!

[Jamie Buxton]

Yeah, I was looking into countertop brackets. This is what I was looking at, do they seem right? https://ironsupports.com/products/fl...p-wall-bracket

Those do require removal of the drywall and replacing it after installation. The FastCap one I linked to above does not.

[Leo Graywacz]

As long as the ends are supported with brackets, wood triangle or something going down to the floor it should be fine. Make sure the corner of the desktop is sturdy so it is self supporting.

[Kevin Jenness]

I would recommend using 3/4" plywood. It will allow for a more substantial joint in the corner and be stiffer. 1/8" hardboard will add nothing but weight to 1/2" ply. Biscuits or Dominos and zipbolts will tie the sections together flush. If you want to avoid visible means of support you will have to invest a lot more work into torsion boxes. I have used metal brackets in situations like this over drywall without a problem.

[Michael Burnside]

Those do require removal of the drywall and replacing it after installation. The FastCap one I linked to above does not.

Thanks for that link Jamie, those look pretty cool and might be useful for a project I have coming up. That notch in the back might be a slick way of creating a concealed cable management system.

OP, I have used the ones you linked, but as Jamie suggests, you'll need to cut a hole in the drywall and screw them into studs. Ideally these are installed before drywall is installed, but it's not the end of the world if they aren't. It just might mean you need to clean-up the wall first, unless whatever you're securing can hide the holes. I will say they work very well. I built a floating media console below my TV that is probably 175-200 lbs when loaded with a sound-bar and accessories. 4 brackets around 16-24" OC hold without issue.

[Stephen McBride]

Those do require removal of the drywall and replacing it after installation. The FastCap one I linked to above does not.

Spoke with the boss (wife) and since the original floating idea was my own and we really don't want to cut up the walls that much I'm going to look into a combination of what you linked supporting the length and corner and some legs like these [https://www.amazon.com/gp/product/B0...sc_act_image_2] at the end. Thanks for the rec!

I would recommend using 3/4" plywood. It will allow for a more substantial joint in the corner and be stiffer. 1/8" hardboard will add nothing but weight to 1/2" ply. Biscuits or Dominos and zipbolts will tie the sections together flush. If you want to avoid visible means of support you will have to invest a lot more work into torsion boxes. I have used metal brackets in situations like this over drywall without a problem.

Since the initial idea was 100% floating, the hardboard was to just cover the bottom so you wouldn't see the frame underneath. I think I'm going to do a hybrid and mount the frame to the wall but adding legs plus something like the braces linked above.

[Cameron Wood]

As an aside, 22" -24" is shallow for a functional desk- why 30" or more is standard.

Make sure that will work for you.

[Jim Becker]

Regardless of how you support the desktop, any components that attach directly to the wall (cleats, brackets, etc.) really should go on the framing and not just have fasteners going through the drywall. Gypsum will collapse when you get enough pressure on it. One technique to help with this is to cut out horizontal strips of drywall and replace with 1/2" plywood at the fastening points and then do mud work over that plywood so it "disappears". You get the structural support of the plywood right on the framing without taking away from the look of the wall if you want your desk support structure to minimally impact the actual wall.

[Stephen McBride]

As an aside, 22" -24" is shallow for a functional desk- why 30" or more is standard.

Make sure that will work for you.

The office is also an additional spare room. 24" depth is the max to still accommodate a full size blow up mattress.

Regardless of how you support the desktop, any components that attach directly to the wall (cleats, brackets, etc.) really should go on the framing and not just have fasteners going through the drywall. Gypsum will collapse when you get enough pressure on it. One technique to help with this is to cut out horizontal strips of drywall and replace with 1/2" plywood at the fastening points and then do mud work over that plywood so it "disappears". You get the structural support of the plywood right on the framing without taking away from the look of the wall if you want your desk support structure to minimally impact the actual wall.

Great idea. Thanks!

[Jamie Buxton]

30” deep may be a traditional size, but is no longer. 24” is much more common. I’ve even built them shallower. Consider a desk with a flat-screen monitor, a keyboard, and a mouse. That works easily on 24”, and even on less.