Exterior Wood Staining Guide


Proper surface preparation is the key to any successful project. Coatings require a clean, sound surface free of dirt, dust, grease, mildew, loose wood fibres and mill glaze. Briskly sand all surfaces with 60 to 80 grit sandpaper or chemically clean & brighten with a biodegradable solution. Your stain will last up to 60% longer and it won’t peel.

Always clean your deck, WITH SOAP, before you sand it. If you are recoating an existing finish, the surface still needs to be cleaned with a Wood Cleaner to remove dirt, pollen, mildew and barbeque grease. Water alone will not remove these contaminants.

A simple “water bead test” should be performed to ensure absorption. Sprinkle a few drops of water on your surface – if the water quickly soaks in – the surface should be safe to finish.

Take a few moments to read the instructions on the product. Every product has some unique application guidelines which should be adhered to. Some stains require the second coat to be applied “wet-on-wet”, this information is important if you want good results.


If moisture is visible, or it has rained or been recently washed, the wood is too wet to stain. Allow at least 2 days of dry weather before staining. Some exceptions apply, ask an expert about information on “wet wood friendly” products.

Hot surface temperatures force stains and coatings to dry before they penetrate. This is the number one cause of product failure and peeling on exterior finishing projects.

Excessive film thickness can limit the coatings ability to breathe resulting in premature coating failure. This rule DOES NOT APPLY to wood stains made by Sansin, these products require a flood coat or application to the point of refusal.


Regardless of the product used, if the surface is not prepared properly and the wrong application method is used, it could peel. Make sure you prepare by following the application guidelines supplied by the manufacturer.

New wood always has mill glaze, and mill glaze will cause poor adhesion and blotchy results. Horizontal walking surfaces are most prone to peeling, a mechanical “Orbital” sander should be used with a 60 – 80 grit sandpaper. Your time is worth more than the daily fee at the local rental store, and it takes less than an hour to sand a large deck with this equipment.

A roller should never be used to apply wood stain unless the product is being “back brushed” immediately. Rollers tend to lay the product on top of the wood, rather than working it into the grain. Roller application also results in a patchy application pattern, as it deposits an uneven amount of product across the surface.

Over applying wood stain will often result in a peeling product. A coating that is too thick compromises the stains flexibility and breathability, and almost always results in peeling and cracking.

If it is warmer than 25 degrees Celsius outside or the surface is hot to the touch, the stain will “flash dry” and will not penetrate the wood deeply or adhere to the previous coat of stain. As previously mentioned, this is the number one cause of stain failure. For best results, plan your working times around the exposure of your home and always stop staining once the surface begins to feel hot.