Exterior Stain on Wood DIY
How to apply stain on
exterior wood decks is a common question posed by our clients. 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 stain application. Here is a comprehensive
guide to applying exterior stain to cedar wood decks, timber
pergolas and any other garden structures made of wood. We were not
satisfied with telling you how to apply the stain, but also why
exterior stain fails.
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 in the end grain.
Solution
1:
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, you will be assured 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.
Solution
2:
Seal all 4 sides as well as the ends to stabilize moisture
content.
Solution
3:
If you cut a timber seal the end again during assembly.
During the planing process
(smoothing of wood), superheated sap and sawdust tends is forced into
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 see a shiny surface.
Solution 4:
Before applying stain, sand all surfaces with 80 grit
sandpaper to open up
the cells of the wood to accept the stain.
Solution
5:
Rollers will lay stain on fast, however it won’t get the
stain into the pores. You can apply with a roller but you should really
go over it with a brush. Thin the stain 10% to keep it workable and
enters the pores more readily.
Plants 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
Solution
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 glaze.
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.
Solution
7:
Use a good quality stain with a track record. We take
pride in recommending Para’s exterior alkyd stains for your exterior
projects. In 6 years of use, many of our projects still do not need
refinishing. Price of product does not guarantee good performance. We
have used products at double the price of Para, with dismal to fair
results.
Coatings
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 shades. This is
particularly true when it comes to semi-transparent coatings.
Solution
8:
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
well.
All stains are
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.
Solution
9:
Apply your stain on a warm, dry, overcast day for best
results.
Q&A
How long should a stain job
last?
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
off.
In
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?
Sure,
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
penetration.
For
photos of the finest decks in the world (click here)
To purchase
plans for Pergolas (click here)
For information about our
Architectural Design Service
(click here)