Worktop support - advice please

[Stevem]

Well, I say worktop - I'm intending to utilise a length of 40mm thick Oak kitchen worktop ( the sort made with 40mm staves ) as a desk and occasionally for my lady to use for sewing (ie will be required to support about 15kg of Bernina ).
The intended run is 2100mm, I will support both ends and rear edge with battens to walls.
Will I be able to get away with no centre support/leg ?
Thanking you for any advice , steve

 

[Sgian Dubh]

Probably best not to leave it unsupported at the front, but you could test it by sitting the worktop on top of two supports spaced roughly 2,100 mm apart (saw horses?) then apply weight, e.g., sit on it as gently or as hard as you like. If it feels a bit flexible then an intermediate support or supports should really be incorporated. There's also time dependent stress to consider: in essence, a simple beam (i.e., not fixed at the ends), carrying no load, supported only at either end will, given time, develop a sag. This is unlikely to be a significant problem in your proposed 40 mm thick oak worktop, but worth your while being aware of.

All the same, if I was designing this I'd certainly have in the back of my mind that an additional support or two might be necessary. It may be, for instance, depending upon how the two of you use the top surface, that a natural or comfortable division or divisions of labour work best, and a support (or two) in the right place reinforces the division. Slainte.

 

[Phil Pascoe]

Build or find a little drawer unit to carry the front edge minimising its span? Sewing does involve thousands of small bits and pieces.

 

[Doug71]

The sagulator thinks it's ok but that is just using it as a shelf

https://www.woodbin.com/calcs/sagulator/
If you are leaning on it you might get a bit of flexing, you could put a heavy duty shelf bracket on the wall to be sure, maybe something like this

https://www.screwfix.com/p/heavy-duty-brackets-black-500-x-300mm-2-pack/98807

 

[Fitzroy]

With a batten on the rear edge along the wall it’ll be fine.

 

[Knotty Norm]

I have done a similar thing with an Ikea wood top, a batten on the back and one side and an adjustable Ikea leg holding up the 'free' front corner. Mine is a computer and writing desk. Cheap and cheerful as well as quick to put in place, but entirely happy with it after several years in use.

 

[Stevem]

Thank you all very much for all your suggestions and input.
I rather think I'm going to go for a 'staged' approach...
As my lady is currently using a temporary desk comprising of a 2m length of regular composite laminated 40mm worktop spread over two trestles, I have, as suggested above, parked my rear end thereupon - some flex noted... ahem. However my guess is the oak will be sturdier. I'll be trying the oak next.
I'm going to try without support first, then if necessary, add a centre post or bracket as Doug71 suggests (the reviews for that are very good -esp the chap who says he used them to support two scaffold boards for his missus' make-up ).
Thanks again all. Stay Safe