Wood is made up of
microscopically small cells. The cross section of a piece of
wood viewed thru a microscope looks just like a honeycomb.
No matter where a board is cut from the tree log, it's
surface is made up of cut cells, exposed to the surface like
little "catch basins."
On an actual wooden deck, even though the cells are treated
with an ordinary deck stain or wood preservative, they are
still empty and subject to accumulated air-borne dirt and
debris, such as carbon dust from automotive traffic
(brake-pads, tires, and exhaust emissions,) dust, dirt and
tree and plant pollens.
Particles larger than the cells will be blown or washed
away; smaller particles will fall into the cell and
accumulate over time. As the cells fill, we no longer see
the color of the wood, but only the color of the combined
particles appearing to the viewer as an unattractive "grungy
gray."
Since vertical surfaces fail to trap as much soil, less
attention need be paid to maintaining the natural color of
the wood. But on decks, the problem is much greater and even
accentuated by the application of "semi-drying"
petroleum-based products, such as those with high paraffin
oil content.
Through the application of a penetrating finish of high
solid content which changes from liquid to solid when
exposed to warm air and ultra-violet light, there is little
space remaining for the soil to lodge.
Preserving and restoring the natural color of the wood,
then, is dependent on (a) getting the surface clean,
and (b) saturating the wood with a high solid finish.
Subsequent applications, over time, will continue to fill
the cells toward the 100% mark. Over-application is to be
avoided, as it will result is a "shiner" or semi-glossy
appearance. When the cells are virtually filled, there
remains little or no space for dirt to lodge, and the wood
becomes relatively maintenance-free.
For decks, fences, and siding, etc., penetrating finishes
are superior to coatings such as varnish or polyurethane,
because they do not crack, peel, or become opaque. The
application of penetrating finishes actually strengthens the
wood fibers, since the resin residual is stronger than the
cellular structure of the wood to which it is applied.
Super Seal is about the best product for wood decks you will
find, a breathable water repellant finish, that allows wood
to expand and contract naturally without peeling.
Application should be made as "often as is necessary". On
new work, apply it immediately (remembering that every board
has six surfaces exposed to the elements). A thin, second
application at the opening of the next spring season is
recommended, then every three to five years, depending on
exposure and cosmetic appearance. At all times, apply only
the amount that the wood will absorb, stretching out the
material; that is, a thin coat is better than a thick one.
Any excess (that remains shiny) after a half hour should be
carefully wiped up with a rag. |
Do-It-Yourself:
Wood Deck Repair