Technical Specifications

the extreme shrinkage of "green" logs (and thereby putting such high
stress on the sealant that it greatly exceeds its elastic capabilities).
The following suggestion will help reduce the amount of chinking
that may need to be repaired on "green" logs.
We recommend that round backer rod material be used with green
log construction. Green logs undergo not only extreme shrinkage dur-
ing the first couple of years after construction, but those portions of
the logs exposed to the interior atmosphere also experience very fast
rate of shrinkage (because of the dry, warm air generated inside dur-
ing the winter when the furnace is fired up each fall). The combina-
tion of extreme shrinkage at a fast rate greatly stresses all sealants.
And, to have the best chance of withstanding such a circumstance, it
is important to construct the chinking joint in as nearly an ideal way
as possible. Round backer rod is a key component to ideal sealant
joint design.
Slab Siding
1. Start with clean wood that has already been treated with a preser-
vative and stain compatible with Log Jam. (We recommend
PeneTreat as a preservative and either Capture/Cascade or High
Sierra Log Stain.) The coated wood should also be well cleaned
immediately before the Log Jam is applied.
2. If the structure is wrapped in Tyvek™ (or equivalent plastic
wrap), you can apply Log Jam directly to the Tyvek™, but the
Tyvek™ must be flat without wrinkles or folds or else these
inconsistencies will telegraph through the chinking.
3. If Tyvek™ is not used, you must apply a bond breaker down the
middle of the gap between the boards, i.e., mylar tape, or backer
rod. If the boards are thick enough to install backer rod, we rec-
ommend that Half Rod™ backer rod be used (with the round por-
tion of the profile facing out from the building).
4. Apply Log Jam by use of trowel, grout bag,
bulk loading gun, pre-loaded cartridges, or
commercial machinery, such as the patented
Sashco Snorkler Pump.
5. The width of the contact surface of the Log
Jam on the edges of the siding should not be
less than 3/8" (to insure good adhesion) —
and the Log Jam should be firmly tooled for
good contact with the top and bottom siding
boards.
6. Don’t forget to chink or caulk (with Log
Builder) the butt joints (where moisture could
otherwise gain entry in driving rains).
7. Refer to Sashco’s bulletin entitled "Preventing Blisters in
Chinking Material" (available free of charge by calling Sashco’s
toll-free number).
NOTE: Ideal joint design allows for the chinking to form an hour glass
shape as in the top example with the half rod backer material. Some slab
siding undergoes extreme shrinkage which can lead to some early-on
maintenance of the chinking.
Round Logs: To use a foam brush, work the material smooth
with a damp brush, keeping a rag handy to pick up drips of water
and excess Log Jam.
S q u a re Logs: Use a putty knife to strike off excess of Log Jam,
making the joint level with the logs. Use a damp foam brush to
smooth the material, keeping a rag handy to absorb drips and wipe
o ff excess Log Jam.
Not only do these techniques give an aesthetically pleasing
chinking line, they also ensure a proper seal between the Log Jam
and the log surface. These procedures are easy to
learn and will give professional results.
Clean-up and Disposal
Dispose of Log Jam in accordance with local regu-
lations. Do not dispose of in drinking water supplies.
Water may be used for cleaning hands, surfaces
and equipment. Toxic solvents are not required for
clean-up.
Warning: Blisters May Occur
Blisters are a phenomenon commonly found in the
caulking and sealant industry. They form when mois-
ture from the chinking accumulates in voids beneath
the bead and gets hot from the sun. Blisters appear as
“bubbles” in the material and vary widely in size.
Shield freshly chinked walls from the sun with
white tarps. If this cannot be done, keep a close eye
on the chinked wall for the first 24-48 hours. If a
blister begins to develop, puncture a hole in the mid-
dle of it, and gently push the material back into
place. 3-5 days later, touch-up the repaired blister
with Log Jam.
For more detailed information on blisters, please
refer to the Sashco Savvy Bulletin entitled
“Preventing Blisters in Chinking Material.” Call
Sashco for this Bulletin.
UL One Hour Fire Rating
When applied in accordance with Fire Resistance
Directory Design No. UL519. (Call The Publications
Group at 708-272-8800, extension 42612 for more
information.)
1. Wood Logs: Soft wood timbers with a minimum
diameter of 7.0 inches. The gap between the logs
shall not be greater than 2.5 inches.
2.Backer Rod: Formed polyethylene backer rod
used to fill the gap between wood logs and to pro-
vide support to the chinking material. The diame-
ter of the backer rod varies with the width of the
gap between logs. The backer rod may be mechan-
ically secured to the wood logs.
3.Joint Treatment Material: The chinking material
is applied with a caulking gun over the backer rod
and to the surface of each log adjacent to the
backer rod. The minimum thickness shall be .5
inches. The maximum may be troweled to achieve
a smooth finish and/or feather the edges.
Current Warranty:
10-Year Log Structure Warranty
When applied in accordance to this Data Tec,
Sashco Sealants warrants Log Jam for:
• Adhesion: Log Jam will not pull away from log
surfaces.
• Elasticity: Under normal log movement conditions,
Log Jam will remain elastic and will not tear, up to
100% total joint movement (±50%).
If Log Jam fails to perform as specified above
during the warranted 10-year period, Sashco Sealants