The exposed end grain of wood is one of the most vulnerable areas, and is often overlooked when protecting wood projects, as it isn’t front-facing and on show.
Without the optimal treatment, the wood cut ends can rapidly absorb moisture during changing weather conditions, leading to swelling, splitting, decay and long-term damage.
Using one of the best end grain wood sealers for cut ends, such as Osmo End Grain Sealing Wax, will optimally treat and seal everything from wooden decking boards to hardwood cladding with confidence.
Why Sealing End Grain Matters?
End grain is the part of wood where the fibres are most open – often due to cutting – and are typically found at the ends of planks and boards used for exterior projects such as decking, fencing, cladding and more.
When unprotected, these exposed ends or cuts act like straws, pulling in moisture far quicker than the face or edge grain.
When left untreated, end grain and cut ends tend to:
- Warp and crack due to repeated wetting and drying
- Develop mould, rot, or fungal growth
- Compromise the durability of the wood plank, deck board etc.
- Lead to repairs and replacements, even when the wood face looks ok
What Do You Seal End Grain With?
The best way to seal end grain and cut ends is with a dedicated end grain sealer that’s designed to protect these exposed areas from water and dirt penetration while allowing the wood to breathe.
Osmo End Grain Sealing Wax 5735 is a microporous timber end grain sealer developed specifically to reduce water absorption at cut ends and protect against weathering. The Clear Satin finish works with any main choice of Osmo wood coating system for optimum compatibility on every project.
The Best Wood Sealer for Cut Ends – Why Choose Osmo?
When it comes to choosing the best end grain sealer, it must be:
- A long-lasting protection coating against changing weather conditions
- Complementary to your main surface wood finish
- Easy to apply and compatible with other Osmo wood oils
- Microporous and will not flake, blister, crack or peel over time
- Safe for humans, animals and plants once dry
Osmo End Grain Sealing Wax ticks all these boxes and more.
It is suitable for all types of wood, including hardwood end grain and pressure-treated softwoods, and its Clear Satin finish blends seamlessly with any Osmo oil-based base coats and top-coats.
Whether your project is garden decking, cladding, or joinery, Osmo gives you a reliable end sealer that is built to last in demanding exterior conditions.
Will Polyurethane Seal End Grains?
Technically, yes – polyurethane can seal end grain. But for exterior applications, it is not recommended as polyurethane forms a hard, impermeable coating which can crack and trap moisture over time, leading to additional maintenance instead of long term protection.
In contrast, Osmo End Grain Sealing Wax creates a microporous layer that repels dirt and water. Microporous means it allows the wood to breathe while being protected, making it a superior exterior end grain sealer for decking, fences, cladding and other outdoor joinery.
Should You Seal Both Sides of Deck Boards?
Sealing both sides of deck boards isn’t always necessary, but along with sealing the end grain which is absolutely essential, sealing the underside of wooden decking can be highly advantageous in the long-term providing optimal protection against moisture and more.
Here’s a general guide:
End Grain
Always seal the end cuts of decking boards with End Grain Sealing Wax
Underside
Optional but highly advantageous – Osmo WR Base Coat will provide optimal protection for underside and top surface faces which is extremely water repellent and resistant to blue stain, rot and insect attack.
Top Surface
For wood decking finish with Osmo Decking-Oils for colour and protection against UV. Also, explore the full exterior product range today!
How to Treat and Seal Wood End Grain (Step-by-Step)
Sealing end grain and cut ends is easy with the right tools and products. Here’s how to do it properly using Osmo End Grain Sealing Wax.
Note: You can apply Osmo End Grain Sealing Wax either before or after applying your main Osmo wood finish and/or colour to your project.
What You Need:
- Osmo End Grain Sealing Wax
- Stirring stick
- Flat soft tip brush or lint-free cloth
Application Steps:
- Prepare the Surface: Ensure the wood is clean, dry and frost-free. Optionally, sand the cut ends smooth if necessary. A trial application is recommended, especially for unfamiliar surfaces.
- Stir the product: Osmo End Grain Sealing Wax is ready to use. Do not thin. It is essential to stir well before use.
- Apply Generously: Use a flat soft tip brush or lint-free cloth. To achieve an optimal protection for strongly absorbing end grains, we recommend applying the sealing wax two times wet-in-wet or after drying carry out a second coat.
- Non End Grain Areas: Wipe away any excess wax from other surfaces with a cloth.
- Let it Dry: Leave to dry for approx. 3–4 hours under normal conditions.
Protecting Timber from the Inside Out
A wood project is only as durable as its most vulnerable points – in most cases, this means the end grain. By using a dedicated end grain wood sealer like Osmo End Grain Sealing Wax, you can significantly increase the lifespan and appearance of your timber project investment.
Use Osmo for professionally-formulated products designed specifically for wood.
For help and advice, visit the Osmo Help Centre today or contact the expert technical team to discuss your wood project.
Go one step further by using and downloading the Osmo Recommends app. Answer a few questions about your project and receive perfect product recommendations from the experts, right at your fingertips.
Then, find you nearest Osmo Supplier online today by searching your postcode or using the interactive map.