How to prevent your wood worktops from bowing or cupping?

Last Updated on September 13, 2024

Once you take a closer look at your wooden worktop you will see that it is made out of tight grain running along the length of the wood. It would be useful to think of the grain as a bundle of muscle, a 100% natural, breathing material, which similar to a muscle – the larger it gets, the stronger it becomes. Similar to other living materials, wood continually interacts with the temperature and humidity of its environment and undergoes micro-movements as it gradually adjusts. One of the least desirable adjustments is called bowing or cupping.

That is why, when working with wooden worktops, we need to be conscious of all possible reactions the wood can have and use the appropriate installation methods and precautionary measures to offset the undesirable reactions.

Important note: wooden worktops are unlikely to bow unless they have been stored, oiled or installed incorrectly! Please refer to our guides for additional help on those topics.

What is a bowing worktop?

Bowing worktop is a term which most often refers to the deformation of solid wood worktops across their width creating a boat-like shape.

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Why do worktops bow?

A very general answer would be the difference in acclimatization of both sides of the surface or in other words, both sides of the worktop, being exposed to different circumstances (temperature or humidity). That could be caused by a number of things and here are some of the reasons:

• Untreated bottom side and treated top side: bottom side is exposed and interacts with the humidity in the air, whilst the face of the worktop is sealed. 
• Incorrect storage: worktops are unwrapped and stacked on top of one another. The face side of the worktop has exposure to the air, whilst the bottom side is sitting on another worktop.
• Not protecting the worktop from sources of heat: if you install a worktop over a washing machine or a dishwasher without a heat protective sheet under the worktop, this will create an acclimatization difference on both sides of the worktop. Another possibility for bowing is when the worktop is positioned too close to a free-standing oven and with no end-cap installed. 

Alternatively, worktops can also bow if they have not been installed correctly:

• Necessary expansion gaps have not been left: wood worktops expand and contract whilst they are acclimatizing, during that process, you need to make sure that the necessary expansion gaps (4-5mm) are left around the worktop to allow for this expansion to take place. Otherwise, when the worktop tries to expand and the expansion gap is non-existent, the only other way for the worktop to go would be up or down – bowing. Please refer to our installation guide to learn more about expansion gaps.
• Not using the correct anchoring: When attaching the worktops to the kitchen cabinets, depending on whether the cabinets are with or without a solid top, you need to use the correct attachment method. When they are without a solid top, you need to use slotted angle brackets with expansion spacers. When the carcasses are with a solid top, you need to drill an oversized hole into the carcass and then screw the worktop with a washer. All of this gives the solid wood surface a couple of millimetres of space to contract and expand as acclimatizes. Otherwise, if the attachments do not allow for this movement this would lead to bowing.

How to prevent worktops from bowing?

• Steel T-bar Reinforcement: providing additional reinforcement and support to your worktops is one of the most obvious ways to ensure worktops always stay flat. It is a forgiving solution as it allows you to rectify your mistakes. If the worktop bows due to any of the reasons listed above, it is hard to rectify or repair. Whereas with T-bar reinforcement, because the worktop stays flat, you will always have the opportunity to rectify your mistake at a later stage (unless the worktop has cracked or split). If you are interested in learning more about T-bar reinforcements or getting a worktop with one installed, please feel free to drop us an email at [email protected] or give us a call at 01727 260688.
• Leave your worktops in their original wrapping, until installation time.
• Store your worktops on battens, in a dry room with consistent temperature – ideally as close to living conditions as possible. 
• Protect your worktop from heat sources: install heat reflective sheets on any area of the worktop which will be in the vicinity of a source of heat or cold. For example, a dishwasher, washing machine, microwave, exposed brickwork, etc. 
• Oil both sides of your worktop before installation and oil the face of your worktop regularly. Perform the water test to find out if your worktop needs further oiling. We would recommend taking advantage of our 3-coat Osmo oiling service. 
• Leave the appropriate expansion gaps around the worktop (4-5mm)
• Use slotted angle brackets to attach your worktop. 
• Maintain and care for your worktop. Please see our Care & Maintenance Guide.

What to do if the worktop is bowed?

The only way to rectify a bow is to place a significant amount of weight on it. Regardless of whether the bow is upwards or downwards, the worktop needs to be placed with the bow pointing upwards in between two pairs of battens and then weight placed on top. The process might take between 1-2 weeks, however, that does not guarantee that your worktop will return to its original shape – you might need to replace the worktops.

If the worktop has been installed, the solution is the same – worktops need to be removed and placed under a significant amount of weight.

Our Solid Wood Worktops:

Here in House of Worktops, we work with timber which has gone through a very specific manufacturing process that minimizes the probability of bowing. The entire process takes around 6-8 months from cutting down the tree to production of the product. And in order to deliver the highest quality wood worktops all the way from the forest, to your doorstep – we oversee the entire process on your behalf:

• Sawing the timber with the correct methodology to use the parts of the wood that are most suitable for wood worktop production – not all parts of the timber are. 
• Storing the wooden elements under the right circumstances for an optimal acclimatization.
• Kiln-drying the wood for over 3 months until it reaches a very stable 8% moisture rate.
• Producing the wood worktops with the highest quality, moisture resistant and food-safe certified adhesives. 
• Customizing your worktops according to your needs. 
• Providing the customer support that you need. 
• Delivering your worktops to your doorstep with our in-house 2Man Delivery Fleet.

We hope this guide has been useful for you and will provide you with the support that you need to ensure your wooden worktops can last for generations to come! Please let us know what you think about the guide and if we have missed something – you know we would love to hear from you! Below we will put the links to other guides you might find useful.

If you have any questions about anything worktop related, please do not hesitate to get in touch with us!
You can find us at 01727260688 or [email protected]
https://houseofworktops.co.uk/

Enjoy your kitchen and wood worktops! 

For additional topics please check the links below:
1) When should I re-oil my worktop?
2) Care & Maintenance Guide for Wood Worktops
3) Ultimate Worktop Comparison
4) The Ultimate Wood Worktop Installation Guide
5) Health benefits of wood worktops.
6) How to Store Wood Worktops?
7) How to Oil Your Worktops with Osmo?
8) How to apply Danish Oil on your worktop?