Painting exterior wood: this is how you do it

Wooden cladding, garden fences, external doors, etc. are exposed to sun, rain, wind and temperature fluctuations day in and day out. Whether you need to repaint an old coat of paint or are painting wood for the first time, the combination of ‘wood’ and ‘outdoors’ poses its own challenges. Customers expect an aesthetically pleasing result that will last for years – despite all outdoor conditions. In this article, we explain how to achieve that long-lasting, professional result.

Wood behaves differently outdoors than indoors. UV radiation, moisture, wind and large temperature differences make wood expand and contract throughout the year, putting constant pressure on the paint layer. In addition, each wood species reacts differently to paint. A high tannin content, for example, can lead to discolouration if you don't use an appropriate primer. Or again: porous wood absorbs more paint, thus requiring more layers.

Painting wood outdoors therefore requires a specific approach and different products than painting wood indoors. In this article, you will find out how to go about it. In any case, before painting wood, it makes sense to consider these specific points of interest.

1. The right products: Zinsser Allcoat Exterior

Even more than in other paint projects, the elasticity of your primer is crucial. Zinsser Allcoat Exterior is a water-based, elastic product, ideal for painting most types of wood. This primer and top coat in one has a better elasticity than traditional lacquers or other moisture-regulating primers and will therefore not crack when the wood shrinks or expands. Allcoat Exterior also has good vapour permeability, which is important to allow the wood to breathe and avoid blistering or cracking of the paint.

Zinsser Allcoat Exterior Matt

Zinsser Allcoat Exterior Matt allows you to apply a vapour-permeable, water-repellent and elastic matte top coat.

Zinsser Allcoat Exterior Satin

Zinsser Allcoat Exterior Satin has the same properties as the matte variant, but provides a subtle gloss on the wood.

2. Preparing the substrate

Follow these steps to optimally prepare the exterior wood surface.

Step 1

Degrease the substrate

Degrease the wood with a universal degreaser or with diluted ammonia.

Step 2

Sand the substrate

Sand off loose material with a hard brush or other abrasives. Dust the surface so that it is smooth, clean, dry and dust-free.

3. Painting the substrate

Zinsser Allcoat Exterior is a primer and top coat in one. That means that you don't need to apply an additional top coat, unless you really want to or the type of wood is very porous.

Step 1

Prepare the paint

Make sure to mix Allcoat Exterior properly. This will ensure consistent colour and texture.

Step 2

Apply a first coat

Apply the first coat. This is best done with a paint brush. That coat needs to dry for at least one hour.

Step 3

Apply a second coat (optional)

If the wood is porous, apply a second coat of Allcoat Exterior. The paint will be fully cured after seven days.

Conclusion

If you need to paint wood outside, you only need one product: Zinsser Allcoat Exterior. This vapour-permeable, water-repellent and elastic primer and top coat in one was specially developed to withstand all outdoor conditions. It is weather-resistant and retains its colour excellently.