How Hot Weather
Can Affect Your Timber
And How to Prevent It
Reading Time: 4-5 minutes
If you’ve recently had timber delivered during a warm spell, it’s important to know how quickly heat and direct sunlight can affect it.
Timber is a completely natural product, which means it reacts to changes in temperature and moisture. In hot weather especially, freshly delivered timber can begin drying out far too quickly if it’s left exposed in direct sunlight. This rapid moisture loss is one of the main causes of twisting, bowing, splitting, and uneven movement.
At Dorchester Timber, we regularly speak to customers who have started a project only to find their timber has moved before installation even begins. The good news is that with a little care and proper storage, most of these issues can easily be reduced.
Why Does Timber Move?
Timber naturally contains moisture. Once it’s cut and machined, it continues adjusting to the environment around it.
When timber is left in direct sunlight or excessive heat:
- Moisture escapes too quickly
- One side can dry faster than the other
- Boards begin to shrink unevenly
- Stress builds within the timber
This can lead to:
- Twisting
- Bowing
- Surface splits and shakes
- Warping
- Uneven movement
This is especially common during hot summer days where timber is left stacked on driveways, patios, or exposed gardens for long periods.
Freshly Delivered Timber Needs Protection
One of the biggest mistakes people make is leaving timber uncovered immediately after delivery — particularly fencing, decking, CLS timber, sleepers, or sheet materials.
Even just a few hours in strong direct sunlight can start affecting some products.
The key is slowing the drying process down naturally and evenly.
How to store your new Timber delivery?
1. Keep Timber Flat
Always store timber on a flat surface where possible.
Uneven ground or unsupported boards can encourage movement over time, especially with longer lengths.
2. Keep It Off the Ground
Use bearers, battens, or spare timber underneath to allow airflow and prevent moisture being pulled from the ground.
This also helps stop water sitting underneath during changing weather conditions.
3. Cover It Loosely
A breathable sheet or tarp is ideal.
The goal is to protect the timber from direct sun and heavy rain while still allowing airflow around the stack.
4. Avoid Wrapping Tightly in Plastic
This is a very common mistake during hot weather.
Tightly wrapped plastic can trap heat and moisture, almost creating a greenhouse effect around the timber. This can actually make movement and moisture issues worse.
Different Timber Products React Differently
Some products are naturally more stable than others.
For example:
- Plywood is generally more stable due to its layered construction
- MDF performs best indoors and away from moisture
- OSB can swell at edges if exposed to excessive moisture
- Birch plywood offers excellent stability and strength for furniture and joinery work
Sheet materials should also be stored flat and properly supported to prevent sagging or bowing over time.
Don’t Panic — Some Movement Is Normal
It’s important to remember that timber is a natural material, not a manufactured plastic product.
Some degree of movement, knots, shakes, or surface splitting can naturally occur depending on:
- Weather conditions
- Storage methods
- Moisture exposure
- Installation timing
This is completely normal within timber products and part of working with a natural material.
Need Advice? Just Ask the Team
Whether you’re building a new feather edge fence, decking area, pergola, shed base, or indoor project, proper storage makes a huge difference to the final result.
We also offer free local delivery, helpful advice, and a cutting service on many sheet materials to make your project easier.
If you’re unsure about the best way to store your timber before starting your project, feel free to contact the team — we’re always happy to help.
Disclaimer: The content provided on this page is designed to serve as a general overview and should not be considered professional advice. While Dorchester Timber strives to ensure accuracy, we accept no responsibility for any outdated or inaccurate information presented here.
