How to Treat Wood for Outdoor Use?

The preservation of wood in the outdoors is really important to any homeowner whether for the fence, patio, gazebo, shed, or deck. If there's no proper protection, it can have serious effects from salts, sun, rain, pests, moisture, or frost. It has a bad effect on the appearance and stability of lumber structures.

Although all wooden creation does not last forever, by observing to a few basic precautions can prevent his or her investment from the normal toils of element exposure. Following this guide will give you some the basic fundamentals for the preservation of the exterior wood. These fundamentals if followed will ensure a long-lasting and functionality of your lumber-based structures.

Choose the Best Type of Wood

You should plan accordingly as your shed, fence, deck, etc. will always face the effects of the wind, rain, sun, and temperature and a threat from molds, or insects. But if you’re not really sure what are the greatest hazards in your specific location, it is better to consult with the professionals at your local lumberyard.

There are different types of wood and all of them are not the same when it comes to the quality of wood and how to treat them. For example, reclaimed wood must first be cleaned, sanded prepped for 1 coat of anti-termites and ideally 3 coats of varnish.  New wood you buy from the DIY store might already be treated against termites, so you just need to add 2 coats of varnish. A tip here: Spraying will get you better results than painting.  

Always choose among the varieties resistant to the adverse effects of pests, moisture, fading, and warping. The better option would be the heartwood rather than sapwood. Heartwood is older, darker, and innermost wood of a tree. Try to ask your local lumberyard for an example of heartwood and sapwood so you can differentiate the two types of wood.

Best species includes Cedar, Cyprus, and Redwood. Avoid bad types such as Firs, Pine, Poplar, Hemlock, Gum, Ash, and Pine. And be sure that the wood has been fully dried to avoid post-purchase shrinkage. If you notice an indication that the wood may be green, do not buy it to save yourself from a headache it will bring to you.

Right now, the most common type of outdoor wood being used is treated, pin, and fir.

Despite the fact that treated wood is much cheaper and readily available then untreated Cedar or Redwood, it still has some drawbacks

Aside from the fact that it’s a little bit pricey, the wood tends to get an unnatural hue (green sheen) as the effect of the chemicals during its treatment process, although this hue can be dyed out eventually. But in the recent years, health concerns about the safety of chemicals have increased.

You should choose any of the following species: Douglas Fir, and Pine. Although these species are not suggested as an untreated lumber, Fir and Pine are used widely and recommended if they went to a pressure treatment. This treatment will extremely increase their resistance to rot and moisture. Avoid species such as Poplar, Hemlock, and Gum.

Be aware that pressure treated wood come in two types – the ground contact and the above ground. First is the above ground, use ground contact lumber for any part of your deck, shed, etc. that will be in direct contact with the below ground.

Avoiding Decay

Outdoor wood will always get a serious exposure to the elements whether on a fence, shed, garden furniture, or deck. These elements can cause decay and decay can lead to destruction. Let’s say that you have chosen the best wood available for the work, the next thing you should do is to install a proper drainage system for your structure and add preservatives to the wood.

  • Drainage: Standing Water is the Enemy!

Treating your lumber with water-repellent is only semi-permanent. Make sure to avoid puddles and pools, otherwise, it’s a total exposure to dampness.

For roofs, there should be a proper installation of the gutter systems, shingling, tarring, and gradient implementation which help water the water run away from the shed, gazebo, or greenhouse.

For fences, decks, and other wooden structures look for alternatives of encouraging drainage like a gap between deck floor planking but still maintaining the aesthetic of the structure.

  • Preservation: Apply a Brush or Spray Treatment

Again, it’s good to reiterative that pressure treatment is always the best for effectiveness. Even though the cost is high and may not be good to expect that the entire structure consists of pressure treated lumber, but make sure that all load-bearing pieces such as beams, posts, joints, and all ground-contact pieces will be treated with full pressure.

Keep in mind that only non-pressure wood treatments can be applied at home. Spray or brushed solutions are the most common treatment for the various non-pressure options.


Now, it’s finally time to talk about the finishes and there are two main varieties. It’s the Natural and Unnatural.

  • Natural - If you’re using an expensive wood like redwood, this will be the finish used. With pigments from transparent to semi-colored, these stains are created for the enhancement than overpowering wood’s natural beauty. But for the best results, reapply a natural finish every one to two years.

  • Unnatural - When constructing anything from cheap lumber like plywood or pine, preserving its natural beauty isn’t a high priority. But, it’s totally fine if you’re planning to use unnatural finish. It may not last longer than the natural, but it’s better used to improve the aesthetics of whatever you’re building because of its heavy pigment.

Exterior-paint is the most common unnatural finish used on outdoor wood. To get great results, you need to apply at least two coats of primer. Make sure that the first coat has completely dried before applying the second coat. Once done with the primer, add the third coat of paint, but you can now apply whatever color you preferred for the exterior finish. If done properly, you’ll get an unnatural finish that has the rock-solid longevity that will last for five to eight years.

In conclusion, to treat wood for outdoor use, always remember that proper wood preservation is always the key.  These three keys that you must remember are choosing the lumber for your projects, best treatment selection, and finding a finish that’s best for the needs and aesthetic of the wood.