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How to waterproof a garden shed

A shed. Roxil Wood Protection Cream has been applied and has dried. Rainwater beads off, showing the shed is waterproof.

Finishing is important when it comes to any wood restoration or upcycling project. Now that our shed is free of biological growth, it’s time to protect outdoor wood from moisture damage. Traditional wood treatments like varnishes, oils and waxes either lack protection, change or hide the look of the original wood finish or require regular maintenance. 

Traditional wood protection treatments like varnish significantly alter wood’s appearance, obscuring wood grain and adding an artificial sheen. Even worse, cracks in the physical layer of varnish can let in water, where it becomes trapped and can cause wood rot.

A wood protection treatment needs to be:

  • Hard-wearing
  • Long-lasting
  • High-performance
  • Low-maintenance

Traditional wood treatments cannot consistently tick all three boxes. Continued research and development at the Safeguard Laboratory in the field of wood protection yielded impressive results: a long-lasting silicon-based formula in water and silicone cream-based emulsions.  

To protect our shed, we’re going to show you the most optimum ways to apply both Roxil Wood Protection Cream and Roxil Wood Protection Liquid

How to prepare to waterproof a shed

Tools needed for silicone cream application

  • Synthetic hair block brush 
  • 9” paint medium pile paint roller
  • Protective gloves

Tools needed for silicone liquid application


  • Pump-action pressure sprayer
  • Brush or paint roller (as above)
  • Protective gloves
  • Protective sheet

How to choose the right tool for the job

Synthetic Hair Block Brush:

A synthetic hair block brush is typically used for precise and controlled application. Use a brush to apply silicone wood protection cream to smaller areas or detailed surfaces. It works well for getting into corners, edges, and intricate designs. Using a brush ensures an even coat and thorough coverage around overlapping cladding, the adjoining roof area and other detailing.

9″ Paint Medium Pile Paint Roller:

Ideal for wide and flat surfaces. For big sheds, home offices or long fences, using a roller can provide faster application than a brush. The medium pile on the roller helps to hold an adequate amount of the cream and distribute it evenly across the wood surface. There are many different sizes available: go smaller when you still need a faster result than a brush can handle on narrower cladding or go even bigger for massive projects with few areas of detail.

When you have a large area to cover, a short time to achieve results and demand a consistent and even application, choose silicone liquid. A thinner consistency than its cream cousin, you can use a pump-action sprayer to apply to the outdoor wood of your choice. It is especially beneficial when applying silicone wood cream on vertical surfaces like fences and shed walls. Sprays cover large areas quickly and the pressure helps ensure an even distribution of the cream. However, be cautious with overspray and protect nearby surfaces to avoid unwanted contact.

Which tool you use to apply your silicone wood protection treatment depends on the project’s size, how even its surface is and how much time you have. Each option offers varying levels of precision and control – your project will dictate the right tool for the job and may want to combine two tools. For our shed renovation project, we used a synthetic hair block brush. We’ll also show you how to use a pump-action pressure sprayer with silicone liquid.

How to choose a wood protection finish

For our shed renovation project, we used a silicone wood waterproofing cream like Roxil Wood Protection Cream. We’re also going to show how to apply a water-based silicone emulsion liquid like Roxil Wood Protection Liquid

Silicone wood emulsions protect outdoor wooden surfaces from water damage. They form a strong waterproofing barrier that prevents prevent cracking, warping, and discolouration. As waterproofing wood keeps the moisture levels low, they also prevent rot, mould and algae growth. The treated wood doesn’t get saturated with water, reducing the risk of woodworm and wood-boring beetle infestation. This makes it an ideal choice for decks, fences, outdoor furniture, and other exterior wood structures.

Unlike varnishes or finishes that create a thick, non-porous coating, silicone wood cream allows the wood to breathe. It permits moisture vapour to escape from the wood, preventing the buildup of moisture and reducing the likelihood of internal damage caused by trapped moisture.


Silicone emulsions enhance the natural beauty of the wood rather than adding a tint or sheen. They are available in both cream and liquid forms. Once dry, its finish is entirely transparent to allow the wood grain and texture to shine through.

They are generally easy to apply and don’t require extensive surface preparation compared to some varnishes. Just a simple biocidal clean will do for even the most grotty surfaces. Maintenance is incredibly easy, with touch-ups needed around once every 10 years or so. 

Silicone emulsions usually boast quick drying times, allowing you to complete your project efficiently. This is especially beneficial if you’re working on larger surfaces or have time constraints.

Silicone emulsions can be used on various wood types, including softwoods and hardwoods. It is suitable for both interior and exterior applications, making it a versatile option for protecting and enhancing the appearance of different wooden surfaces.

Get Roxil Silicone Wood Treatments from Safeguard Store

How to apply silicone wood cream with a brush

A contractor applying Roxil Wood Protection Cream on a shed with a brush. 2.
Dip & Go!
Roxil Wood Protection Cream is ready to apply right out of the tin
Roxil Wood Protection Cream application with a flat brush
See where you've applied
Roxil Wood Protection Cream goes on white for easy application
Close-up of a shed wall with Roxil Wood Protection Cream freshly applied. Still wet.
Dries to Clear
Roxil Wood Protection Cream vanishes to clear
A shed freshly applied with Roxil Wood Protection Cream. Still wet.
Long-lasting protection against the elements
Keep your wooden shed looking pristine for longer

When applying Roxil Wood Protection Cream, ensure the brush is clean, dry and in good condition. Watch out for frayed bristles – they can cause messy application and wasted product. 

Lightly dip the brush into the tin. Ensure you’ve picked up a thin and even coat of cream before applying even pressure to the surface of the wood. Glide along the surface steadily to ensure a fine and uniform layer.

Silicone Emulsion Cream is thick, so go softly at first to get a feel for its unique consistency. The cream goes on a visible white layer, making it very easy to see where you’ve applied and where you have to go next. Once you’ve applied one even lump-free layer, simply watch the cream disappear into the wood. In summer, the cream will vanish to clear in around 2 hours (or 4-6 hours in winter). 

Any misapplied cream can be easily wiped away and cleaned with warm soapy water as long as it is done relatively quickly after application. Be extra careful around paintwork, plants and glass.

Brush Tips & Tricks

  • Before application ensure that the wood surface is clean, dry, and free of any dust, dirt, or previous finishes. Use a brush or a soft cloth to remove any debris or loose particles. If needed, sand the surface lightly to smooth out any rough areas or imperfections. Proper surface preparation will help the silicone wood cream adhere better and result in a more even application. Need more help? Follow our how to clean a shed guide.
  • Use smooth and even strokes. Start from one end of the wood and work your way towards the other end, applying the cream in the direction of the wood grain. This technique helps ensure that the cream is evenly distributed and absorbed by the wood. Avoid overloading the brush with too much cream to ensure a smooth and even coating.
  • Take extra care around intricate details or hard-to-reach areas, ensuring thorough coverage. Once the section is complete, move on to the next, overlapping slightly with the previously treated area to ensure a seamless finish. For high-detail areas and crevices, consider using a smaller brush to ensure full coverage.

How to apply silicone wood liquid with a pump-action sprayer

A contractor pouring Roxil Wood Protection Liquid into a pump-action pressure sprayer.
Ensure you protect grass when decanting
Pour slowly and steadily to minimise mess.
A contractor applying Roxil Wood Protection Liquid on a shed with a pump-action pressure sprayer. 4.
Roxil Wood Protection Liquid: best for wide surfaces
Pump-action sprayers provide lots of coverage, fast

A low-pressure pump-action sprayer is a little more complicated to set up than dipping a brush into the tin of cream, but the actual application is a breeze once you’re all set up. 

Safeguard recommends the Spear & Jackson 5-litre Pump Up Sprayer for all our sprayable cleaners and treatments. A pump-action sprayer is a great tool to have around the garden. It’s also perfect for quick and easy watering, especially for those with mobility issues or big gardens with large patches of flowers and vegetables.

Before using the pump-action sprayer, ensure that all foliage areas of the garden are protected and that you spray away from sensitive areas,

Ensure you prime the pump by pumping around 20-30 times. Push or twist the handle (always check the instructions that come with your specific model) to lock the pump into place. Adjust the carrying straps to fit so you can comfortably wear the tank. When you’re ready to apply, aim the wand in the direction of the wood you want to be treated. Gently pull the trigger on the wand to start the spray. Tighten your grip on the trigger to test the trajectory and get a feel for the spray. As your mind flashes back to memories of childhood water-pistol fights, carefully cover the wood with the silicone protection liquid until the entire surface is wet. Once the first coat has been applied, apply the second coat within 30 minutes. The second coat must be applied while the first coat is still wet.

Pump-Action Sprayer Tips & Tricks

  • If the spray seems weak, stop. Remove the tank from your back and pump the tank to regain water pressure. 
  • Before opening to refill, push the pressure release valve to vent the air pressure.
  • Depending on the model used, the nozzle may be adjustable for different types of flow. A thin and concentrated stream delivers a more accurate application.

Once you’ve applied two coats, let it dry. Over time, a water-repellent barrier will form. Surfaces will be shower-proof once touch-dry. Full water repellency develops over a period of one month.

If you’ve followed these steps, congratulations! Your shed or other outdoor wood is now protected against rain, spills and the complications that come from excess moisture.

Want to know more about why we waterproof wood? Check out this article.

Other general shed waterproofing tips

Shed foundation options

Ensure the shed isn’t in direct contact with the ground by building it on a wooden or concrete base. Here, we’ve built the shed on a concrete patio to maintain a barrier between the shed walls and avoid rising dampness.

You can also raise the shed off the ground by constructing a wooden base under it to prevent damp. Treat the timber with a preventative woodworm and rot solution like Soluguard Woodworm & Rot. Erecting the shed atop a wooden base allows air to circulate underneath.

Regularly check the shed roof

Unless you notice any water ingress, you should inspect your shed roof annually. Carefully check roof edges, where a felt roof is usually held down. If your shed is shingled, ensure that the shingles are tightly adhered to the 

Regularly check window and doorframes

Wood is sensitive to the atmosphere it’s in – dry conditions cause wood to lose moisture and shrink while wet conditions cause swelling. This can worsen door and window gaps – use draught excluder tape to keep seals tight and keep water from entering the shed.

Managing water runoff

Consider adding drainage to direct rain runoff from your shed roof. Without it, rain can build up into standing water around the shed. Install gutters and keep them clear to ensure water can flow freely away from your shed or into a water butt.

Insulation and Ventilation

If you spend a decent amount of time in your shed regularly, you may want to consider simple ventilation measures like static vents. Insulation is also an option – modern options like polyisocyanurate (PIR) insulation board or more traditional solutions like wool or rock wool are both efficient ways of insulating a wooden structure like a garden shed.

For more information call
01403 210204