Cupped oak worktop

[DIYlover402]

Hello

I recently purchased an oak worktop, pre oiled and with the cut outs pre-cut.

Unfortunately only after installing the hob I've realised the worktop is not perfectly flat, in fact it is very slightly convex on the top from the front to the back. The hob therefore isn't flush at the back/ front which is bound to continually collect crud and has generally disappointed me.

I wanted to know:
(A) if there any established ways to fix this? I tried putting 10kg kettle bells on it based upon some Googling but this hasn't done anything.
(B) whether the worktop fabricators' suggestion that oiling the installed worktop (i e. just the topside) with many more coats would work. I would have guessed this would just make the worktop more convex if anything.

The fabricator also suggested that I had caused the cupping by not storing the be worktop flat (instead I stored on edge indoors but I can't see how this would cause cupping like this). They also sent me the spare cut out timber (unoiled) which looks to have exactly the same cupping.

Thank you

 

[big-all]

how was it stored and for how long ??
was it stored flat on the floor or propped on a wall ??
how long has it been in ??
is the kitchen warm and dry??
it may be damp or bent to that shape by leaning and settle down over time

 

[Notch7]

Hello

I recently purchased an oak worktop, pre oiled and with the cut outs pre-cut.

Unfortunately only after installing the hob I've realised the worktop is not perfectly flat, in fact it is very slightly convex on the top from the front to the back. The hob therefore isn't flush at the back/ front which is bound to continually collect crud and has generally disappointed me.

I wanted to know:
(A) if there any established ways to fix this? I tried putting 10kg kettle bells on it based upon some Googling but this hasn't done anything.
(B) whether the worktop fabricators' suggestion that oiling the installed worktop (i e. just the topside) with many more coats would work. I would have guessed this would just make the worktop more convex if anything.

The fabricator also suggested that I had caused the cupping by not storing the be worktop flat (instead I stored on edge indoors but I can't see how this would cause cupping like this). They also sent me the spare cut out timber (unoiled) which looks to have exactly the same cupping.

Thank you

If I understand the top surface is convex, ie the top bulges up in the middle?

You need to get some heat on the worktop - mostly aimed around the middle. - you might be able to fix a fan heater so it blows down over the top.

don’t get it really hot, just get it warm. After about 12 to 24 hours it will go flat.

basically the convex side has taken on a bit of moisture and expanded.

 

[DIYlover402]

Stored for a week on with its long edge on the floor but held vertical rather than 'leaning' (that's why I didn't think it would bend either way), stored in the kitchen kept at same temperature and dryness as any normal kitchen. Noticed the cupping after oiling it about a week after installing but thinking it was always cupped since the cut out has the same shape despite no oil and not stored the same as the worktop on receipt.

Any idea if fixable?

 

[Deleted member 174758]

(A) if there any established ways to fix this? I tried putting 10kg kettle bells on it based upon some Googling but this hasn't done anything.

You could try applying some extra weight to it - I'm thinking more in the region of 100 to 200kg. but even then it may not work.

(B) whether the worktop fabricators' suggestion that oiling the installed worktop (i e. just the topside) with many more coats would work. I would have guessed this would just make the worktop more convex if anything.

And I think that I'd have to agree with you there.

The fabricator also suggested that I had caused the cupping by not storing the be worktop flat (instead I stored on edge indoors but I can't see how this would cause cupping like this).

That was the wrong way to store it. Solid timber worktops should always be stored flat, in an area with reasonable air flow, and raised off the floor on softwood "stickers" (2 x 2in untreated pine). This is to ensure that movement doesn't happen. TBH when I've fitted solid wood worktops I've got the cabinets in then had the worktop delivered and done my own cut-outs before installing. That way I can check if the top is flat before I install it and if so get it onto tha cabs before it can warp or cup...

The cupping is probably a combination of two things - it was certainly stored incorrectly and has most likely taken on more moisture from the atmosphere on one side that the other, causing the slightly damper side to swell a little.

Secondly the staves themselves may also be at fault, so any chance of an end grain photograph from, say, the sink cut-out (and/or the cut-out) which might help identity whether or no there is an issue? If the staves aren't extremely stable making the cut-outs can accellerate cupping by removing stresses locally to the cut-out, but the fact that the cut-out has also cupped isn't positive, either. As an aside, as a bit of PR I always used to to make-up at least one cutting board from a sink or hob cut-out for my clients. Generally went down well with the lady of the house

Lastly, just how convex is the top? Is it 2mm? 5mm? 10mm? As a chippy I'd think in terms of taking 2 to 3mm of cup out with a combination of a trying plane, a jack plane and a belt sander. I've done that enough times with solid wood bar tops (in posh pub/restaurants, etc) to know that I can take up to maybe 5mm out without it being all that noticeable, although it may require some extra packing underneath. the heat approach has never been feasible for me due to working environment, etc. Again, a photo would be a help

 

[big-all]

how much are we talking ??
5mm at the back and front compared to the middle or more ??

 

[DIYlover402]

Thanks everyone for the help and suggestions.

We are talking about 2-3mm difference in level from the middle of the worktop to the front and back edges... Is that within typical tolerances? Only my AEG hob doesn't seem to have any ability to conform to a slightly curved surface / any fixings to pull it down tighter onto the top.

See attached pics

 

[Deleted member 174758]

Well, fortunately it isn't as terrible as all that. TBH I think the suppliers coiuld have done a bit better, but now it is in maybe the best thing would be to deal with it in situ. I think that can be taken out with a combination of trying plane, jack plane and belt sander by a competent joiner. I've dealt with worse. How is it fixed to the units? Buttons or some other way?

 

[DIYlover402]

It's screwed to some existing IKEA cabinets which have slotted holes (slotted perpendicular to length of worktop which is what supplier recommended) and just supports it at the front and back edges so should in theory have the freedom to uncup in situ.

 

[Deleted member 174758]

It may settle down in use, but i somehow doubt it. The slotted holes are to allow the wood do move in service (natural wood expands and contracts - chipboard/MFC don't so you need to take this into account). At least it isn't the installation adding to your problems