Solid Wood Worktop Installation when bowed

[DazJWood]

We have a 40mm solid wood beech worktop fitted in our U-shaped kitchen. Two lengths and a third breakfast bar.

The kitchen and wooden worktops were bought and delivered a year ago. Due to various reasons (including my own slow DIY skills) we have only now got to the point of fitting the worktops.

The worktops were stored in the garage originally but only for around a month before they were bought inside. On unpacking they was varying bowing / twisting / cupping on all three. Not overly severe but enough to mean the butt joints would not be exactly level in place.

Due to not having the right tools (and also not having fitted solid worktops before) we employed someone to cut and fit the worktops. He has cut all the worktops to length and also the cut-outs for the sink and hob. He initially did this a week ago and agreed he would come back yesterday to tighten up the butt joints after the worktops had had chance to settle and to see if the bowing / cupping would settle. I also weighted down the high points of the worktops over the last week to see if this would allow the wood to relax back to being level.

After a week it is now evident that the worktops have improved and are not as bowed as they were initially. Yesterday our fitter came back and has siliconed the butt joints and bolted them together (should they have been PVA'd?). As there is still some twisting and bowing he used some packers under some cupboards to allow the butt joints to be bolted together. He has not screwed down any of the worktops to the cabinets as I can do that (I have the right brackets with the slots running perpendicular to the grain). Though when I do this I will be either having to put more packers in so the brackets meet the worktop or screwing in and pulling the worktop further away from where it should be.

The butt joints are sort of OK but not as tight as they could be and are slightly raised in places. The fitter suggested they could be lightly sanded to bring them level.

Whilst I sort of understood the reasoning at the time I am now not convinced that this was the best course of action. In one of the worst areas near a butt joint there is a 4mm packer. For one, the worktops are now no longer level as they are packed out differently across the level worktops. Two, surely over time the worktop will potentially move more but because the packers are in place it will mean the worktop moves further away from true not closer.

I would have thought that it would have been better to try and get the worktops back to being level again. So no packers, release the butt joints, weight down the areas that are bowing upwards and potentially where the worktops are cupping upwards screw them down at the back and then clamp the front and slowly tighten them over a few weeks to bring them true.

Is this a good course of action and if so how easy will it be to separate the already siliconed butt joints? Or has the fitter taken the best course of action with the packers and we have the best outcome we are going to get?

I have included a few photos.

I appreciate any advice! Thanks in advance!!

Daz

[Job and Knock]

The kitchen and wooden worktops were bought and delivered a year ago. Due to various reasons (including my own slow DIY skills) we have only now got to the point of fitting the worktops.

The worktops were stored in the garage originally but only for around a month before they were bought inside. On unpacking they was varying bowing / twisting / cupping on all three. Not overly severe but enough to mean the butt joints would not be exactly level in place.

I'm sure that you now realise why the advice is often given to install sooner rather than later. Part of your problem is that the timbers used in worktops is kiln-dried down to about 8 to 10% MC (moisture content) whereas outside in the UK (and the garage, whilst sheltered, is effectively outside) timber naturally dries to 16 to 20% MC in the summer months. In winter the figure in the north west, where I live, stored timber can often go up to 25% MC or more. Simply translated, once kilned timber must be stored in the same environment in which it was kilned or it will take on water and warp. Even storage in a domestic environment can cause this (assuming that you don't keep the windows closed and have your aircon set constantly throughout the year). This is what appears to have happened to your worktops.

After a week it is now evident that the worktops have improved and are not as bowed as they were initially. Yesterday our fitter came back and has siliconed the butt joints and bolted them together (should they have been PVA'd?). As there is still some twisting and bowing he used some packers under some cupboards to allow the butt joints to be bolted together.

A glued joint between long grain and end grain will never be the strongest, so it's a moot point whether or not it will be a worthwhile technique. The silicone makes sense up to a point as it will prevent wicking of water spills into the timber, but with solid tops I'd have tried to use either biscuits, loose plywood tongues or Dominos to "lock and align" the edges together as far as possible and reduce any future tendency to move. BTW this isn't essential - it's a personal preference.

The butt joints are sort of OK but not as tight as they could be and are slightly raised in places. The fitter suggested they could be lightly sanded to bring them level.

In the past on 50mm thick solid oak bar tops I've ended-up resorting to cleaning-up the discrepancies in the joints which had come from the workshop with "problems" by using a block plane and straight edge, a belt sander and finally a scraper to get an acceptable result in terms of surface level, but the faces of the joints still need to be pretty tight. One of the difficulties you face is that you will never be able to pull a solid hardwood worktop down onto a (relatively weak) chipboard carcase without risking damage to the carcase. All you can hope to do is level and pack as best you can then take to the hand tools to correct any glaring deficiencies in the top surface

...surely over time the worktop will potentially move more but because the packers are in place it will mean the worktop moves further away from true not closer.

Possibly, but highly unlikely if you seal it properly. Once the worktop is fixed down and has been sealed (underneath and on top) it will have a much reduced tendency to "settle" as you put it. You might as well face the fact that your initial poor storage plus the extended storage in the house has done irreversible damage and no amount of faffing about will "get the worktops back to being level again". It may be worth noting that when I've done worktop replacements (on existing kitchens) it has almost always been necessary to introduce packers somewhere or other because of movement and/or poor initial installation of the cabinets combined with bow, warp, etc in the worktop as it came from the factory - so packing is not unusual

Bear in mind that the fitter has probably approached this from the point of view that you will be paying him a limited amount of money for a one- or two-visit solution and he's only really done what I'd have considered doing myself. In the end I think that they don't look bad in the photos despite their imperfections. Possibly the only extra thing I would have done would have been to take moisture content readings before starting the work (in my experience few kitchen fitters have the meter to do this, though - but why should they?). If these were wildly inconsistent or too high (i.e. approaching 15 or 16%) I'd probably have refused the job and advised you to replace the tops