Building and waterproofing a pergola
Waterproofing a pergola helps protect exposed timber from rain, moisture and dirt. This guide explains how to prepare the wood, apply Woodcon and keep your garden pergola looking good for years.
A waterproof pergola starts with sound construction and the right protection for the timber. Rain, condensation and damp air can make untreated wood swell, crack, turn grey and attract algae or mildew over time.
Woodcon is a clear wood impregnation for absorbent exterior timber such as Douglas fir, pine and spruce. It helps make the wood water- and dirt-repellent while keeping the natural grain visible. Because it penetrates into the wood rather than forming a thick surface film, it is suitable for pergolas, garden structures, fencing and outdoor furniture.
Use Woodcon on clean, dry and untreated—or fully sanded—wood. It will not repair rotten timber, open joints or structural damage, and it does not replace good drainage or a properly built roof. Applied correctly, it helps your pergola stay attractive and easier to maintain for longer.
Have it installed or built yourself?
Whether you build a pergola yourself or have it installed, choose durable timber and protect every exposed surface. Douglas fir, larch and pressure-treated softwood are popular choices, but even durable wood benefits from regular protection against rain and moisture.
Before assembly, treat cut ends, drill holes and areas that will be difficult to reach later. Once the pergola is built, check that water can drain away from posts and beams and that no timber stays in contact with wet soil. This helps prevent moisture from being trapped in the wood.
For the best result, apply Woodcon evenly with a brush, roller or low-pressure sprayer. Treat the end grain carefully, as this is where wood absorbs the most moisture.
Woodcon
- Very economical: depending on the porosity an average
1 liter is sufficient for 88 ft².
Available in 1 / 2,5 / 5 / 10 / 25 Liter.
Construction plan for your pergola
Plan the size and position of your pergola before you buy timber. Measure the area carefully and make sure the posts will stand on a stable base. Avoid placing wooden posts directly in soil or in standing water, as this greatly shortens their life.
Use suitable post supports or concrete footings to keep the wood clear of the ground. Check that the structure is level before fixing the beams and rafters. A slight fall in any roof covering helps rainwater run away instead of collecting above the timber.
Leave small gaps between roof boards or use a suitable pergola roof system where needed. Good airflow allows the wood to dry after rain and reduces the chance of damp patches, algae and mould.
Treat all cut ends, drilled holes and exposed edges with Woodcon before final assembly. These areas absorb water quickly and deserve extra attention.
Waterproofing a Pergola with Woodcon
Waterproofing a pergola with Woodcon helps protect a wooden pergola against rain, moisture and dirt. For independent guidance, see the USDA Forest Products Laboratory’s information on wood durability and protection.
Woodcon helps protect a wooden pergola against rain, moisture and dirt. Apply it to dry, absorbent wood in suitable weather conditions, ideally between 5°C and 25°C. Do not apply it when rain is expected before the product has dried.
Stir or shake the product well, then apply Woodcon evenly with a brush, roller or low-pressure sprayer. Work it into the timber without leaving puddles on the surface. Give end grain, joints, cut ends and horizontal beams an extra coat because these areas take up moisture fastest.
Allow the timber to dry fully before using the pergola. Protection can last for up to 10 years, depending on the wood type, exposure to weather and correct application. Waterproofing a pergola starts with sound construction and the right protection for the timber.
