- Part 1
- As the warm weather
begins, its the time of year when we start thinking about chinking our log
homes. The first step of caulking or chinking is applying Backer Rod. The
*Log Core will take you
through a two part series of Backer Rod and Chinking. We will begin this
series with backer rods of all types.
-
-
Backer Rod
is a synthetic foam that comes in a variety of shapes and sizes from 1/4"
up to 5". The reason why Backer Rod needs to be placed in joints is that
it acts as a bond breaker, which provides a surface that chinking won't
adhere to. Eventually, the chinking will free itself from the backer and
will move with the logs as they expand or shrink. Backer Rod also serves
by adding an insulation value and reduces the amount of material needed.
-
-
Grip Strip
comes in strips
of 4' lengths. Sizes are available from 3/4" up to 5". It provides an
excellent fit with a flat working surface and is a closed cell product
that repels water. As a chinking applicator for a restoration company for
7 years in Northern Minnesota, I have found this material is the easiest
and quickest to use. No tools are necessary and it follows with the
curvature of the logs. This product really grips to the logs and stays in
place.
Tri-Rod
is another backing
material that offers a flat working surface. This is polyethylene foam
backer that is designed for round logs. It is a triangular strip and is
available in 6' lengths. It is a closed cell product also. You may need a
spray adhesive such as Touch and Seal or Foam Weld to keep it in place.
When installing the Tri-Rod around knots and curvature of the logs, the
backer must be cut out on the backside. This will keep the backer from
projecting out and will keep the chinking uniform. This does take more
time to install.
-
-
Dual Rod
can be described
as an open cell, extruded polyethylene foam. Dual Rod is extruded to leave
an impermeable shell to prevent moisture from entering the side. It is
available in a continuous length through 1-1/8"; larger sizes are
available in 6' lengths. This may be sold by the foot or case, and is
available from 3/8" to 4". Advantages of this backer are that it is very
flexible and is easy to install. Smaller sizes are offered to fit those
really tight joints. When choosing a size, the diameter should be
approximately 25% larger than the joint because of the compressibility.
Precautions to take are not to puncture or stretch during application.
This may cause out gassing. In smaller joints a blunt tool may be needed
to push backer further into the joint to allow the required amount of
chinking. This material is easier to work with for smaller size joints.
-
-
Closed Cell
backer rod is a
closed cell polyethylene round foam that also runs in a continuous length.
It is sold by the foot or by the case from 1/4” up to 4". Compared to the
Dual Rod this backer is firm, but just as easy to install. Again a blunt
tool may be needed to push backer deeper into the joint to allow the
required amount of chinking.
-
-
Open Cell
Backer Rod is easy to work with also. It is soft and compresses to fit
most size joints. This product is breathable which allows for a faster
cure, but recommended in the interior. This is because it will absorb
water. If used on the exterior, only put in the amount of open cell that
you think will get done in one day so the exposed backer will not draw in
moisture. Note: the use of a blunt tool when installing backer rod to the
exterior logs will prevent punctures to the surface of the rod and
minimize chink blistering caused by trapped water vaporizing under direct
heat from exposure to the sun.
-
- For smaller joints where
backer rod can not fit, but yet there may be a gap, a mylar tape or
strapping tape may be used. This too will serve as a bond-breaker to allow
the material to release itself from the tape and move with logs as they
settle and shrink. If applying chinking over old mortar, a bond-breaker
tape should be applied as well. Packing tape or duct tape are two examples
that will work for this situation.
-
- If the backer seems to
keep popping out, a smaller backer or a different style of backer is
needed. You should never have to nail Backer Rod to keep in place. The
most common mistake about choosing Backer Rod is that folks choose a
backer that is too big for the joint. When this happens, the backer keeps
coming out or you are left with a chinked joint that is larger than it
needs to be. I recommend to take advantage of the samples we have to try
different styles and sizes. Keep in mind that you may require a number of
different styles and sizes for your particular project.
*Backer Rod and Chinking Part 1
(courtesy of Denise Carlson, Schroeder Log Home Supply) and Part 2
(courtesy of Debbie Bassett, Sashco Products) are from past issues of
Log Core, our quarterly newsletter available through our
website.
|
|
- Part 2
- Chinking a log home is
not a difficult process. Once you get over the awkwardness of learning how
to “gun the product” onto the logs and then get the “feel” of tooling the
product you will pick up speed and find satisfaction in having a part in
finishing your home. This article covers the basics of how to chink a log
home, but before starting your project in earnest, request and read a
data:tec sheet that goes into greater detail.
Proper Joint Design Last month’s article briefly touched on the
reason why backer rod is needed—to serve as a bond breaker. The following
illustrations graphically depict why 2-point adhesion is so important for
the performance of any chinking or caulking product. Synthetic chinking is
formulated to be flexible, but as the drawings demonstrate it can fully
flex to absorb log movement only if a bond breaker is installed down the
center of the joint.
|
|
|
|
|
- Surface Preparation
For chinking to establish good adhesion to the logs, they must be
clean—free of dirt, pollen, uncured oils, sawdust, and other loose
materials. The surface temperature of the logs should be between 40°-90°
Fahrenheit. The liquids in the chinking “wet out the surface” of the logs
so that the chinking can establish good adhesion. If the log surface is
colder than 40° the wood pores tighten up not allowing for proper wetting
out of the surface. Conversely, when the wood temperature is higher than
90°, the liquids evaporate off too quickly, adversely affecting adhesion.
Most people like contrast in color between their chinking and their stain;
therefore, staining prior to chinking is necessary to achieve this look.
It is also easier to tool chinking if it is applied to a stained surface,
but you must be certain that the stain and chinking are compatible, and
that the stain has had sufficient cure time.
Many stains on the market contain waxes and stearates that can interfere
with adhesion of chinking and caulking. Usually, companies that
manufacture both chinking and stains make certain that their products are
compatible, and attempt to enhance their stains for even better adhesion
of their chinking and caulking products. If your chinking and stain are
manufactured by 2 different companies, call and ask if testing has been
done for compatibility and request a copy of their test results.
Application Chinking is packaged in 5-gallon pails and quart tubes,
although for larger jobs, 5-gallon pails are more economical. When using
5-gallon pails there are a number of application methods that can be used.
You can use a trowel, grout bag, bulk loading gun, or a commercial pumping
system that pumps out the chinking material in a continuous flow, making
it easier to apply.
There are a variety of different sized nozzles available in both round and
slot styles. For smaller beads, a round style nozzle works well but for
wider joints the slot style nozzles are the only way to go.
In selecting your nozzle size be aware that the depth of the bead of caulk
should be half the size of the width of the joint, but never thinner than
a 1/4” or thicker than 1/2”; i.e., for a joint 1” wide the bead depth
should be 3/8” to 1/2”.
Apply the chinking material down the center of the joint, over the backer
rod and overlapping slightly onto the surface of both logs. Only apply
enough product down the length of the log that you can reasonably tool
before it starts to skin over. As you become accustomed to tooling you
will be able to run longer beads.
Tooling There are as many tooling implements out there as there are
chinkers! I prefer the polyethylene foam brushes available in any hardware
store or lumber yard but I have seen folks tool with rubber spatulas,
paint brushes, putty knives, trowels, and even metal spatulas cut down
with wire cutters to the desired width. The secret is finding the tool
that works best for you. You will also need a pail of clean water, a
sponge, and a spray bottle filled with clean water. To speed up the
tooling process, have several foam brushes on hand. As soon as one picks
up too much chinking and starts to drag instead of gliding over the
surface, throw it into the water pail and continue on with a clean brush.
A mixture of 1 part denatured alcohol to 2 parts water can be used for
misting chinking when the temperature is over 70°. If you are working in
the sun and the chinking is skinning over too quickly, straight alcohol
can be used. When the temperature is lower than 70° the alcohol is not
necessary.
Using a damp polyethylene foam brush, holding the foam portion parallel to
the bead, gently press the bead into place. You don't want to drag the
foam brush down the bead but instead, section by section press the foam
brush against the bead. The next step is the actual tooling. Using the
spray bottle, lightly mist the chinking with water to allow the brush to
glide over the surface. Do not apply too much water, or the latex in the
chinking will run down the logs. If this happens, just wipe off with a
damp sponge or rag. The idea is to smooth out the ripples caused by
gunning, but most importantly, to feather the bead out onto the top and
bottom logs at least ” so that the chinking is tooled tightly to the log
surfaces.
Clean-up and Disposal To properly dispose of unused chinking
material, it is good practice to understand and follow all of your state
and local regulations on clean-up and disposal. Do not dispose of chinking
material in drinking water supplies. However, for easy clean-up water may
be used for cleaning hands, surfaces and equipment. Toxic solvents are not
required for chinking material clean-up.
Warning!
As you finish
your chinking and stand back to admire your work . . . ugh! Blisters!
Blisters are a phenomenon commonly found after applying chinking. They
form when moisture from the chinking accumulates in voids beneath the bead
and the heat from the sun causes the blister to appear as “bubble” in the
chinking. To avoid these blisters, use a white tarp to shield freshly
chinked walls from the sun. If this is not possible, keep a close eye on
the chinked wall for the first 24-48 hours. If a blister pops up, just
puncture a hole in the middle of it and gently push the chinking back into
place. Then after 3-5 days you can repair the blister by applying a small
portion of chinking material into the hole.
Cure Time After the chinking process is completed, allow it to cure
for one week if you will be painting over it with oil or latex paints,
total cure-through is 28 days. Just one last suggestion that I picked up
from a professional chinker: Hang a small board with several beads of the
chinking in a conspicuous area with a sign inviting people to satisfy
their need to touch. Hopefully, this will keep them from satisfying their
curiosity on the chinking courses of your home!
|
