Fitted desk top advice please

[NDRiley]

I'm currently designing a desk to fit an unusually shaped room. The back edge of the desk will be scribed to, fitted to and supported by the the wall on four sides (see sketch of plan view attached). The front edge will be a stretched "S". The top will be solid oak - probably around 40mm thick but maybe a bit less. I would prefer to make the top in one piece by joining a number of boards shown by the dotted lines in the sketch. I like the idea that the curves and left and right ends will show end grain to contrast with the front edge.

The length of the desk at its longest point is approx 2400mm and it is 680mm deep. In addition to fixings and support from the wall it will sit on and be screwed down to two drawer units, one at each end. I'm also intending to add a number of intermediate cleats running front to back in sliding dovetails to keep the top flat.

Any thoughts? In particular I have three queries/concerns:

1: Movement in the right hand corner could be an issue if not allowed for. I could leave an expansion gap along the right hand wall and hide it with an upstand but would welcome any other suggestions.
2: The short grain on the last board on the right could also be an issue. I'm assuming it will be supported/protected by the adjacent wall once installed - but maybe I'm wrong?
2: The span of the desk top between the drawer units will be approx 1300mm. Any thoughts on whether this is likely to need additional support? I don't want to use a traditional rail but could recess a T section of stainless steel or aluminium into the underside.

Many thanks

 

[Oddbod70]

Thats 50 or 60kg of desk. I don‘t think its going to deflect even a mm over 1.3 m.!

You could have movement at both ends, the right pulling away and the left pushing in. I’m not sure it will be too bad, but an upstand or length of moulding would be the normal way.

on 40mm oak I dont think it be worrying about short grain.

 

[Cabinetman]

Hi, this is a bit of déjà vu, if you put Behomoth into the search button (top right) the one I did will come up. Well I certainly don’t think you need the bracing underneath in dovetail grooves. When you are joining all the boards together you will see on mine that I used stopped tongues this helped enormously with the cleaning up of the top after it was glued, The planks were alternated so that the cups and bridges as I call them, on the end grain helped mitigate movement. In your typical British house the movement across that top will be negligible I wouldn’t worry too much about it, ( provided you use kilndried timber) as I see it the biggest problem is getting an accurate template of the shape inside those 4 walls, I would want it to fit perfectly without any up stands if it was me.
I worried about the joint in my L-shaped top and like you I wondered about putting an inset stainless steel reinforcer, it turned out it was totally unnecessary as I believe it is on yours, 40 mm oak across that short distance isn’t going to go anywhere at all, even if sat on.
Very best of luck with it, feel free to message me if you need to. Ian

 

[Oddbod70]

Excellent advice (as always) from Ian (Cabinetman).

 

[Cabinetman]

What was that song in the 70s, mutual appreciation society. I think it’s probably used as glue on here, but nothing wrong with that.

 

[NDRiley]

Hi, this is a bit of déjà vu, if you put Behomoth into the search button (top right) the one I did will come up. Well I certainly don’t think you need the bracing underneath in dovetail grooves. When you are joining all the boards together you will see on mine that I used stopped tongues this helped enormously with the cleaning up of the top after it was glued, The planks were alternated so that the cups and bridges as I call them, on the end grain helped mitigate movement. In your typical British house the movement across that top will be negligible I wouldn’t worry too much about it, ( provided you use kilndried timber) as I see it the biggest problem is getting an accurate template of the shape inside those 4 walls, I would want it to fit perfectly without any up stands if it was me.
I worried about the joint in my L-shaped top and like you I wondered about putting an inset stainless steel reinforcer, it turned out it was totally unnecessary as I believe it is on yours, 40 mm oak across that short distance isn’t going to go anywhere at all, even if sat on.
Very best of luck with it, feel free to message me if you need to. Ian

Hi Ian, many thanks for your advice - very much appreciated. I've also just been looking at your Behomoth for inspiration. What a fantastic project! That is a beautiful piece of work and thanks for taking the time to share such useful intel.

I feel more confident in my design now. As you say getting the shape accurate will be critical. Luckily my clients also bought into that so I'm currently in the process of making a full size mock up with MDF which I will take to their house and fit - and can then use as a template for the real thing. Definitely required as the house is very old and nothing is square or straight! I've also mocked up the under desk drawer units to make sure the proportions work and the desk is useable in the way the client wants.

I like your idea of stopped splines. I don't have a spindle moulder but do have a domino so will probably use that for alignment of the boards.

Thanks also for the offer of further advice - I will shout if I get stuck!

Norris

 

[NDRiley]

Thats 50 or 60kg of desk. I don‘t think its going to deflect even a mm over 1.3 m.!

You could have movement at both ends, the right pulling away and the left pushing in. I’m not sure it will be too bad, but an upstand or length of moulding would be the normal way.

on 40mm oak I dont think it be worrying about short grain.

Many thanks for that Oddbod, much appreacited. Thanks also for your endorsement of Cabinetman's thoughts above. Sounds like its time for me to stop procrastinating and crack on!

 

[Cabinetman]

Thanks Norris, it’s good if you can get the client on board like that, some really do like to be involved and asked their opinion on shapes and edges and proportions, good that you’re checking proportions by the way. If I was doing the template I would start with stiff card to get the back to corners angles set because as you say those walls might not be parallel. Let’s hope that it’s wider at the front than the back or you won’t get that desk in!
Two long thin lats of wood are very useful for getting measurements between two things like the walls, you overlap one onto the other when both ends are touching the walls and mark them both. So much more accurate than a tape measure.
Yes dominoes would work fine, just remember to always work from the top surface.
Ian