We have built many wood decks and railings over the years mostly from western red cedar that happens to be one of the most naturally durable and resilient woods in the world that is resistant to decay, insect and moisture damage that makes it ideal for our environment. The stability of cedar is twice that of most soft wood lumbers so it doesn't shrink, split, warp, splinter and cup nearly as much as the other softwoods.

Three main types of wood species commonly used for the Decking on west coast decks. 1) Pressure Treated Lumber (PT) derived from a mixture of softwood trees (SPF) Spruce, Pine, Fir 2) Yellow & Red Cedar. Red cedar originates from coastal rain forests where yellow cedar comes from inland areas. 3) Foreign hardwoods like Batu & Ipe come from oversees rainforests like the Amazon and Congo basin.

Pressure Treated Lumber (PT) is milled wood that has preservative pressurized around the circumference of the boards that penetrate the lumber by about 1/8". Once these boards are cut they expose untreated areas of lumber that Need to be treated onsite before assembly. Spruce, Pine, Fir (SPF) hemlock are the species of softwood lumber that is used for pressure treatment.

Main reasons we only use PT lumber for deck framing/building and not the decking or railings is that chemical off gassing will lasts 6 months to a year that delays staining processes which can cause the allready less stable SPF wood to split, warp, splinter and cup even more due to the nature of the species used. Surface toxicity may also be absorbed by hands and paws when touched by humans and pets and every time it rains small amounts may be washed into the ground water.

Most lumber available from the lumber stores is 'green lumber' (not pressure treated) that describes the fact that it hasn't been 'dried' and 'cured' in a controlled environment like kiln dried wood. All wood decking needs some sort of finish coatings to preserve, protect and stabilize the wood. Proper application methods require a relative moisture level of no more than 15% before applying the finish to seal the wood otherwise trapped moisture will cause wood rot, premature stain failure and other undesirable imperfections.

When lumber dries to fast the outer layer will dry quicker than the inner core and this is the main cause for wood to split or crack. Typically most woods take 6-18 months to fully cure depending on relative humidity, temperature, moisture under deck, diameter, sun exposure and species. Stain should always be used instead of paint for any new exterior wood and if a 'solid color' is desired a 'solid stain' or a proven product that will breath better should be used.

The undesirable traits of wood can be further reduced with kiln/pre drying and pre-staining each plank on all 4 sides to seal and protect the planks by reducing moisture absorption that causes wood to expand and contract every time that it rains or when there is high humidity. This stabilizes the planks and reduces 'nail lifting' and splitting.

The pre-stain process will extend the maintenance, appearance longevity and service life of the decking and railings that is applied before assembly because the 3 sides (other than the side you see) of the planks are not fully accessible after construction and are the areas where most of the moisture lingers.

Example: If you seal just the top of the plank and it rains, the water and the relative humidity in the air will cause the top surface to expand or swell much less than the rest of the plank causing it to cup upwards. When the plank dries to the same relative humidity as the top surface the board flattens. This constant and uneven expansion and contraction causes nails to 'Lift' and if face screws are used it may cause the boards to split along with other undesirable traits.

There are two variations of wood that can be purchased for your deck and railing project. One is called 'Tight knot' and the other is 'Clear' (clear of knots) This refers to the area of the tree where the boards were cut from. The outer layer of the tree is less valuable where knots are formed from the branches of the tree. Select Tight Knott (STK) is the grade used where the knots shouldn't fall out of the plank leaving a hole. STK has a more 'rustic' appearance as the knots are darker than the surrounding areas of the board.

Clear wood is quarter cut from the center of the tree where the vertical edge grains do not have knots and provide a more uniformed color and grain structure. Clear lumber is usually double the cost of STK lumber and offers the most lumber stability from its grain characteristics and is usually kiln dried and/or stored in a low humidity covered area. In the case of 'clear cedar' an unstained S4S 2x6 plank (Smooth 4 Sides from re-milling) is about the same cost per linear board foot as an averaged price composite deck plank. Note: Cedar is a softwood and may scratch or dent easier than composites or hardwoods.

Overseas hardwoods such as Batu or Ipe mostly come from ancient and/or unsustainable rain forests in countries where forest management is replaced by the highest bidding for the most profitable plot of forest. Most of these woods are 'clear' of knots and very dense is structure with a 9 out of 10 on the Brinell scale (similar to composite) making them the slowest re-growth forests in the world.

They have hi impact durability but minimal grain definition with low anti skid properties and requires maintenance clear coats to bring out the colors that is otherwise dull in appearance. The material costs are similar in price as the more enviromentally responsible quality composite decking products and 'Clear' cedar decking.

Common or the best way to install hardwood decking is with a jig that predrills and places the screws on the corner of the decking boards rather than the face of the boards or using a router to create groove channels that accepts hidden fasteners like composite decking installations making the installation costs the same or more than composite decking.

Some consumers may want some clarity in choosing sustainable woods (PDF 3MB) that are environmentally responsible that have been harvested from newer growth forests with re-plantation programs when shopping for wood deck components.

It is important to take finishing costs into account when comparing various Wood Deck & Railing choices. New wood deck surfacing consists of a light sanding and staining or sealing with a minimum 2 coats although 3 provides a more uniformed look when striving for a certain color tint. Wood deck maintenance with heavier sanding and min 2 coats will be required every 2-4 years depending on directional exposure to the sun and shade, species of wood, pedestrian traffic and original application procedures.

Bare wood absorbs liquids and humidity very well due to a trees ability to transfer water from roots to leaves by means of capillary action more so on the lumber ends and that is why it is imperative that sealing or treating any PT deck framing lumber where cuts have been made does not get left out during the building process which is quite common because most carpenters do not like handling the perservative and the application slows down assembly process.

As a society it may be of importance for us to remember to reward companies that truly make an effort to be sustainable and environmentally responsible by having the insight to be profitable and competitive through innovation rather than exploitation that causes irreparable damage to the necessities of human and animal life. Using appropriate woods and efficient construction practices with the best preservation methods or wood alternative for maxiumum longevity that could make all the difference in our world.