How to Stain Outdoor Wood for Durability (Revised
by Lawrence Winterburn
Our clients are always
shocked when we tell them that they can stain a deck and make it last a
few years before it needs maintenance. Many
people assume that our work is made of composite wood, rather than
milled timber. Truth is, all our work is wood, mostly red and white
cedar and many of the decks and pergolas you see on our site were
photographed years after the first stain application.
The following is our HOW TO
guide to applying exterior stain to cedar decks, timber
pergolas, fences and any other garden structures made of wood. We are
satisfied with telling you how to apply the stain, but also why
exterior stain fails.
Choosing a good Exterior Stain:
Canada has banned high VOC
exterior stain. I really don't care why, but high VOC coatings tend to
last longer in the elements. High VOC coatings can still be used for
concrete finishes and many paints, but these formulations are now
banned for deck stain across the country. The current Canadian
made offerings that we have tried since the ban came into effect a
couple of years ago don't last as well as the old alkyd stains we used
to get 5 years of durability from.
you live in Canada, my advice is, and it pains me to say it--Buy
American Made High VOC coatings like Flood or Superdeck. Many are sold
here, and none are made here, and the US is still producing it. It is
the most similar formulation to the old oil based Benjamin Moore that
used to work so well.
general, paint lasts
longer than stain, however it deteriorates and marks on horizontal
surfaces. Solid stain lasts longer than semi-transparent in general
terms. There are many different companies which make numerous products
with benefits and drawbacks to all of them. Generally a good
choice of stain will contain plenty of pigment for UV protection, a
mildewcide and fungicide and be oil based.
Often price has little to do
with quality of stain--though, if you want to spring for an epoxy
marine finish at a couple of hundred per gallon, you might notice a
difference in durability. Generally good stain ranges between $35 and
70$/gallon in Canada, 25% less in the US.
Our Solutions to Peeling Stain:
Plants absorb and store
moisture and nutrients in the root structure then draw them up the stem
as required. Trees are simply just a large plant which means that
lumber is that stem sliced up. Think of a redwood tree 150’ in height
drawing moisture from the roots and feeding it to the branches. The
larger the species, the longer the cells, and, the greater the suction
created of moisture through the end grain. This means wood has a
natural tendency to draw moisture into the end grains and expand as
they do so.
Seal the end grains too.
As a plant is dehydrated,
it shrinks. Trees, being large plants behave in exactly the same way.
In fact, if a tree is left whole after cutting, they will tend to
develop cracks to the center, larger in the outer grain, smaller in the
center grain. If you have ever noticed a fence post, which is cracking
all 4 sides, that indicates that the core of the tree is in the center
of the timber. That core of the tree’s closest route for the crack is
to each flat surface of the post.
Seal all 4 sides as well as the ends to stabilize moisture
If you cut a timber seal the end again during assembly.
During the planing process
(smoothing of wood), superheated sap and sawdust is forced
the surface of the wood. This “mill glaze” is similar to glass and
stain will not penetrate it. You can see the mill glaze if you look at
the surface of the wood from an angle and the surface is shiny or glass
Before applying stain, sand all surfaces with 80 grit
sandpaper to open up
the cells of the wood to accept the stain.
Rollers will lay stain on fast, however, it won’t get the
stain into the pores. Apply stain with a roller but give it the once
over with a brush. Brush everything in 2 directions for maximum
penetration. If the stain is a thick consistency, dilute the stain you
use for the first coat a little, to help it enter the pores more
Back Brush with a paint brush after
applying the stain.
6: Stack your
lumber with 1 or 2” spacers between layers, boards 1” away from each
other. Plug a couple of fans in, and open the garage door a crack. Dry
the lumber for a couple of weeks before you sand it to remove
the lumber first -- and keep it dry until the stain is applied.
tend to fade over time. Vertical surfaces will weather at different
rates than horizontals. If you have decided to re-stain only part of
your deck, you may find it is now 2 different colors. This is
particularly true when it comes to semi-transparent coatings.
Consider staining the deck surface in semi, and use a
solid color on the verticals, (paint or stain). When it comes time to
re-coat the horizontal surfaces, you won’t have to do the verticals as
made of chemicals and compounds that are mixed. They all require
stirring prior to application. Direct sunlight can cause the materials
in the stain to separate, which will cause poor results. Often humidity
or moisture will cause the stain to contaminate. If it is too warm or
too cold stains often will give poor results.
your stain on a warm, dry, overcast day for best
need moisture to
live. At the time of harvesting trees have a high moisture content.
During the production and finishing the timbers lose some moisture, but
only kiln drying will get most of the moisture
out of the wood. Your
typical lumber is about 18-22% moisture content. Kiln dried typically
has about 5-8%. Before drying, that moisture resides in the pores of
the wood, where you want the stain to be.
That moisture, when it
freezes, will expand and release the stain from the
Dry the lumber first,
or source kiln dried lumber for your project.
How long should a stain job
If you follow the
guide above, 2-3 years on horizontals due to wear from foot traffic and
other factors. 4-7 years on verticals. If you just slap the stain on
after the structure is built, you may get a year or two before it peels
choosing stain color, are there any guidelines?
We like to borrow
colors from the exterior of the house. Trim colours for rails, (to
imitate a wainscoting), floor colors for the deck (often semi
transparent to make it an extension of the floor in the house).
Can I use
a spray gun or rig to apply the stain?
but just be careful you don’t spray your neighbor’s car, house,
children…and run a brush over the whole board end to end twice to help
photos of the finest decks in the world (click here)
plans for Pergolas (click here)
For information about our
Architectural Design Service