Tips on painting or staining your deck

First, how often should you stain or paint your deck? That depends on a number of factors, including where your deck is located, how often you use it, and the severity of the weather in your area. 

How do I know when it’s time to paint or stain my deck?

To help you decide, inspect the deck after the snow melts. Is the existing coating peeling off? Is there any mould? Is the surface worn or discoloured? If so, it’s time for a fresh coat. Otherwise the wood will deteriorate quickly. Make sure not to skip any steps. The majority of problems with deck coatings are caused by inadequate preparation and application in unsuitable weather.

What are the ideal weather conditions for staining or painting my deck?

Check the weather forecast before applying exterior paint or stain. Unless your deck is in a shaded area, apply the coating cloudy day. Never apply stain or paint under direct sunlight. It hinders adherence and affects colour uniformity. Ambient and surface temperatures should stay between 10°C (50°F) and 32°C (90°F) for 24 hours. Deck stain should be applied when the relative humidity is between 40% and 70%. Any higher and the humidity could affect the gloss and the drying time. Drying times indicated by the manufacturer are for normal conditions: 21°C (70°F) and 40% relative humidity. They may vary in other conditions. Don’t start the work if rain, dew, or frost is expected within three days. The wood itself must also be very dry. The moisture content, which you can check with a hygrometer, must not exceed 15%.

How do I prepare the wooden surface?

The surface of your deck or balcony must be clean. Remove all stones and grains of sand. If the wood is stained, dirty, chipped, damaged, or mouldy or if the paint is peeling off, you need to remedy the problem before applying a new coat. A wide range of products are available, including cleaners, conditioners, and strippers. Ask your local retailer about them and the prep work you’ll need to do before getting started. CAA-Quebec Residential Advisory Services can also guide you through this step and the rest of the project.

Can I stain or paint over an existing coat?

It is possible to paint a surface that has been stained, but not the other way around. If there is an existing coating, take the time to check whether the new layer will adhere properly to the old one. Try the water drop test: sprinkle a few drops of water on different parts of the deck. If the water beads, you’ll need to sand the wood lightly before applying the stain or paint. If the water is absorbed quickly, you can proceed with confidence. You can also use the tape test: apply the new coating to a small, inconspicuous area and allow it to dry for 24 hours. Then press a strip of adhesive tape firmly on the freshly coated section and pull it off in a quick, firm motion. If the tape comes off clean, the coating has adhered properly and you don’t have to remove the existing coating. If the new coat sticks to the tape or the existing coat is pulled up too, you’ll have to strip or sand the entire surface. In some cases you’ll need to apply a primer. Ask a paint specialist for advice. They’ll also be able to help you pick out a paint or stain and choose the accessories you’ll need.

Which tools do I need to paint or stain my deck? 

A paintbrush is ideal for applying coatings to your deck. If you’re using an oil-based coating, choose a brush with natural fibres. For acrylic coatings, go with synthetic (nylon) fibres. You can also use a roller. But you’ll need to go over the edges with a brush to makes sure the coating permeates properly.

If possible, coat all wooden surfaces, including the end grain. The end grain absorbs moisture, causing the wood fibres to separate. This can lead to problems with the coating.

To reduce streaking, apply the stain or paint in the direction of the grain along the entire length each board, one at a time. Let the coat cure for at least 48 hours before walking on it, and wait at least 30 days before washing to allow it to harden fully. 

How do I ensure the colour is the same between paint cans?

If you need more than one can of the same colour to cover a section, make sure they’re all from the same batch. A good trick is to refill your can with fresh paint or stain after you’ve used three quarters of it and mix the two together. And don’t forget to stir the product from time to time during application.