Log Jam Chinking

Sashco Log Jam is stretchable chinking that seals the wide joints between your logs with the traditional look of mortar. Log Jam seals out the weather while keeping your home comfortable.
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Free Ground Shipping
We offer free shipping for all sizes of this product shipping to the Lower 48 United States. Offer does not apply to Alaska, Hawaii, and the US Territories. Free Shipping applies to this item only and not the entire order.

Sashco Log Jam Chinking seals the wide joints between your logs with the traditional look of mortar, but with much more elasticity. Log Jam is durable, easy to apply, and stretches up to 250%, even in joints up to 4 inches wide. It is guaranteed not to crack or peel away from logs and is the only chinking to hold a UL one-hour fire rating.

Features & Benefits
• Recognized as the industry standard for synthetic chinking
• Moves with your logs to create a permanently waterproof and weatherproof seal
• Exclusive 1-hour UL fire rating when applied in accordance with Fire Resistance Directory Design No. UL519
• Superior elasticity that prevents weather and insect infiltration
• Smooth, water-based formula allows for easy application and cleanup
• Stable through 5 freeze-thaw cycles
• Adheres well to most building materials

Where to Use Log Jam 
• Interior and exterior chinking joints on log and wood homes

Where Not to Use Log Jam 
• Surfaces previously coated with a waxy stain (i.e. Thompson’s Water Seal) or non-drying oil stain (i.e. WoodGuard, Q-8 Log Oil, TWP)
• Surfaces specifically designed to be non-stick (i.e. Kynar)
• Surfaces previously sealed with silicone; silicone and its residue must first be removed

Application Methods
• Ratchet caulking gun (for tubes)
• Bulk-loading caulk gun with follow plate
• Grout application bag
• Chink pump

Application Details
• Ideal application temperature range is between 50-90°F
• Ideal sealant depth is 1/2 of the joint width, but no less than 1/4" and no more than 1/2"
• Before Log Jam is applied, install a bond breaker such as backer rod, Grip Strip, or bond-breaking tape
• Clean up hands, surfaces, and equipment with water
• Log Jam forms a water-resistant skin approximately 1-4 hours after application
• It may be necessary to cover Log Jam with plastic sheeting if applied when rain is imminent
• Paintable with oil or latex stains after 1 week cure time
• Cure-through time: 3 weeks (1/2" thickness, 70°F, 50% relative humidity)
• If restoring Log Jam with chink paint, make sure the chinking has already cured

Sashco Log Jam Technical Guides
Log Jam Chinking Product Guide
Preventing Blisters in Chinking Material
Do-It-Yourself Chink Paint Formula with Log Jam Chinking
Log Jam Chinking SDS

Colors:
Buff, Dark Brown, Gray, Light Gray, Mortar White, Tan, White White, Woodtone Cedar

Sashco Technical Support
If you have questions or issues regarding the Sashco line of products, Sashco Technical Support is available at 800-767-5656.

Fundamental Chinking Application Guidelines
Proper substrate preparation and application are imperative for product longevity. Read this instruction sheet before applying any product.
1. Best results are obtained when Log Jam is applied to clean, dry, stained wood. Make certain there is compatibility between your stain and Log Jam. Log Jam has a lifetime warranty when applied with Sashco’s stains: Capture Log Stain / Cascade staining system, Transformation Stain Log & Timber and Symphony Interior Clear Coat.
2. Check the weather forecast. Finishing products are best applied in moderate weather conditions, i.e., out of direct sunlight, in dry, warm conditions.
3. Check the log surface temperature. The surface temperature should be between 40 ̊-90 ̊F (4 ̊-32 ̊C). Install a bond breaker before Log Jam is applied. Backer rod, Grip Strip, and clear packing tape all perform this function well. If Log Jam is applied over white styrene bead-board or Tyvek™ house wrap, it is best to cover the bead-board or wrinkle-free house wrap with clear packing tape (to prevent adhesion to those materials). We do not recommend the use of blue or pink extruded polystyrene board as a bond breaker.
5. Gun the chinking over the backing material. Ideal sealant depth is half of the joint width, but no less than 1/4”, nor more than 1/2”.
6. Tool Log Jam to ensure good contact with the log surfaces, especially to the upper log; this will greatly aid adhesion.
7. All chinking products may occasionally “blister”.

To avoid blistering:
• Do not apply in direct sunlight.
• Protect fresh chinking from direct sunlight for 1-2 days after application with white plastic sheeting tacked over it.

Surface Preparation
• Best results are obtained when Log Jam is applied to wood that has been previously coated with a compatible and thoroughly cured stain.
• Clean the log surfaces thoroughly to remove dirt, pollen, bird droppings and other surface contaminants.
• The USDA Forest Products Laboratory and other researchers around the world have reported that surface wood exposed to sunlight for as little as 1-2 weeks can become significantly damaged and unsound, which may lead to premature adhesive failure of the stains or other coatings applied to it. It can also hurt Log Jam’s (or any chinking’s) adhesion to the surface. Once bare wood has been properly cleaned and prepped to remove unsound wood, stain should be applied as soon as possible. Follow with Log Jam chinking.
• If a stain is applied over Log Jam, it will be tinted the stain color, but will be affected differently than the surrounding wood; therefore, test appearance before wide-spread use.
• A few coatings, especially those high in wax content or non-drying oils, may interfere with adhesion, whether they are applied before or after Log Jam. We advise against using Log Jam with such products.

Cold Weather Chinking
Log Jam can be applied in cold weather by following these instructions:
1. Make sure the log surfaces are above 40 ̊F (4 ̊C). Use a surface thermometer to double-check.
2. Keep the chinking at room temperature until ready to use.
3. Make sure the logs are free of frost.
4. Tent out the walls with clear plastic sheeting and keep them warm with heaters, then apply chinking.
5. Make sure there is air circulation so moisture doesn’t form on the logs, causing a washout. Some venting up high will help with this problem.
6. Leave the tent intact day and night while chinking, and for 2 to 4 days after chinking is complete.
7. Finally, remove the plastic sheeting. This should be sufficient to let the Log Jam skin over and slowly cure. Due to cold temperatures, it will take much longer than normal for the Log Jam to fully cure, but it will be fine if left undisturbed. Warn people to avoid pushing on it for several weeks.

Methods of Application
• When using 5-gallon pails, Sashco’s Snorkler chink pump, grout bags or bulk loading guns may be used.
• When using a cartridge, cut the spout at a 45 ̊ angle to desired bead size.
• In wider joints, multiple beads may need to be run until the entire joint is filled with chinking.

Tooling
When applying Log Jam in temperatures below 70 ̊F (21 ̊C), a mixture of 1-part denatured alcohol to 2-parts water can be used for misting the chinking immediately prior to tooling. When the temperature is over 70 ̊F (21 ̊C), water alone will be sufficient.

The techniques discussed below will give an aesthetically pleasing chinking line, as well as ensure a proper seal between the Log Jam and the log surface.
• Tooling Log Jam on Round Logs: Work the material smooth with a damp foam brush, keeping a rag handy to clean up drips of water and excess Log Jam.
• Tooling Log Jam on Square Logs: Use a putty knife to strike off excess Log Jam, making the joint level with the logs. Use a damp foam brush to smooth the material, keeping a rag handy to clean up drips and wipe off excess Log Jam.

New Construction Joint Design
• An hourglass profile is the ideal type of joint design for all sealants. It allows for maximum sealant movement and favors cohesive failure (the best kind) if the movement is so extreme that failure cannot be avoided.
• Round backer rod is best, especially when substantial movement is expected, as with “green” logs.
• The chink line should be no less than 15% of the log width. For example, with 10” diameter logs, the chink joint should be about 1 1/2” wide. If you choose to apply a smaller bead, expect more chinking repairs.
• Ideal sealant depth is half of the joint width, but no less than 1/4”, nor more than 1/2”.

Restoration
• Wood should be clean and stained, as discussed in the Fundamental Chinking Application Guidelines section.
• Remove all loose mortar.
• Bond-Breaker: When using Log Jam as a restoration chinking over old mortar, cover the old mortar with clear packing tape, which provides a surface Log Jam will not stick to. When movement occurs, the Log Jam will be free to stretch.
• Tooling: Log Jam should be tooled to contact at least 1/2” of the bare wood surface on either side of the old mortar. This will ensure adequate adhesion.

Slab Siding
Slab siding can pose a special challenge due to the very rapid and large amount of movement it often exhibits after being installed. This movement shows up as extreme shrinkage, bowing and twisting, and can stress sealants more than logs do. To help reduce this problem, follow these additional tips with slab siding:
1. Use only dry slab siding (19% or less moisture content level, verified with a moisture meter)
2. Install the siding with heavy screws, not nails.
3. If applying over Tyvek house wrap, make sure the Tyvek is wrinkle free and tape over it with clear packing tape.
4. If the boards are thick enough, install Half Rod backer rod with the round portion of the profile facing out. This will provide for the best joint design.

Blisters
Blisters are a common phenomenon with chinking and caulking products and are caused by a variety of things. Blisters appear as “bubbles” in the chink line and can vary widely in size. To help prevent blisters, 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:
• Pop the blister and gently push the material back into place
• 3 to 5 days later, apply a skim coat of Log Jam and tool to blend in.

Cleanup and Disposal
• Dispose of Log Jam in accordance with local regulations.
• Do not dispose of in drinking water supplies.
• Hands, surfaces and equipment may be cleaned up with water.

Product Questions

  • How do I apply the chinking if I get a 5 gallon pail?

    The main options are a bulk gun, a chink pump, or a trowel and mortar bag.  The bulk gun is the most popular of these methods.  A bulk gun is a caulk gun that be loaded as needed with caulk or chinking.  Bulk guns also have a variety of optional nozzles that can be used to change the tooling pattern.

    Bulk guns are loaded by unscrewing the cap at the end, packing the chinking inside, and screwing the cap back on. You want to avoid getting chinking on the threads of the gun, as these are very difficult to clean.  We recommend using a follow plate or a loading sleeve to make filling the bulk gun faster and cleaner. 

  • I accidentally stained my chinking and I can't scrub off the color. How can I fix this?

    Fresh stain that has dried can’t be scrubbed off. Your best option is to cover the stain.  You can either coat the affected area with a light coat of chinking or brush over it with a coat of chink paint.  Chink paint is essentially a thinned version of chinking that can be painted on as needed. Here is Sashco’s recipe for making a chink paint out of a tube of Log Jam.

  • I chinked my house 18 years ago with Log Jam. The chinking is torn away from the logs in a few places. What can I do to fix this?

    If the chinking has pulled away from the logs, then it’s likely the original chinking line was too thin and it tore when the logs moved with seasonal swelling and shrinking.  To fix this, you will need to cut out the torn chinking, install backer rod if needed, install new bond breaker tape, and re-chink the joint.  Ensure that the chinking is between ¼” to ½” thick.  Also, feather in the new chinking over the edges of the existing chinking to make a clean transition.

  • How do I keep stain off my chinking when I have to restain my home?

    The answer depends on whether there is any pigment in your stain’s topcoat when you apply a maintenance coat of stain.  The answer is easy if you are using a stain system that has a clear topcoat, such as Capture and Cascade.  The clear Cascade topcoat won't discolor the chinking if you paint or spray it over the chinking.

    If you’re applying a pigmented stain such as Transformation Log and Timber with a brush, your best option is to tape off the edges of the chinking with painter’s tape first.  If you plan to apply with a spray instead, you will want to consider covering all of the chinking with painter’s tape since it is difficult to control overspray.

  • Should I apply the chinking directly onto the wood?

    No, instead we recommend installing a bond breaker, such as backer rod or clear packing tape, between the chinking and wood to make maintenance easier.  If you apply chinking directly to the wood and need to alter it later, it can be very difficult to cleanly cut out the problem section.  If a bond breaker is installed underneath the chinking, you can simply cut the affected area at each end, which should then peel up easily.

  • When should I use chinking instead of caulk?

    Acrylic latex chinking is formulated to mimic the appearance of old-style mortar in log joints.  This means that chinking is thicker and has a heavier grit than nearly all log caulks.  Additionally, chinking colors are designed to contrast with the logs, while log caulk colors are designed to blend in with the logs. 

    Chinking is a better fit when you have a wider joint (1" or more) that would benefit from extra stiffness or when you prefer the contrasting mortar-style look of chinking.

DETAILS

Free Ground Shipping
We offer free shipping for all sizes of this product shipping to the Lower 48 United States. Offer does not apply to Alaska, Hawaii, and the US Territories. Free Shipping applies to this item only and not the entire order.

Sashco Log Jam Chinking seals the wide joints between your logs with the traditional look of mortar, but with much more elasticity. Log Jam is durable, easy to apply, and stretches up to 250%, even in joints up to 4 inches wide. It is guaranteed not to crack or peel away from logs and is the only chinking to hold a UL one-hour fire rating.

Features & Benefits
• Recognized as the industry standard for synthetic chinking
• Moves with your logs to create a permanently waterproof and weatherproof seal
• Exclusive 1-hour UL fire rating when applied in accordance with Fire Resistance Directory Design No. UL519
• Superior elasticity that prevents weather and insect infiltration
• Smooth, water-based formula allows for easy application and cleanup
• Stable through 5 freeze-thaw cycles
• Adheres well to most building materials

Where to Use Log Jam 
• Interior and exterior chinking joints on log and wood homes

Where Not to Use Log Jam 
• Surfaces previously coated with a waxy stain (i.e. Thompson’s Water Seal) or non-drying oil stain (i.e. WoodGuard, Q-8 Log Oil, TWP)
• Surfaces specifically designed to be non-stick (i.e. Kynar)
• Surfaces previously sealed with silicone; silicone and its residue must first be removed

Application Methods
• Ratchet caulking gun (for tubes)
• Bulk-loading caulk gun with follow plate
• Grout application bag
• Chink pump

Application Details
• Ideal application temperature range is between 50-90°F
• Ideal sealant depth is 1/2 of the joint width, but no less than 1/4" and no more than 1/2"
• Before Log Jam is applied, install a bond breaker such as backer rod, Grip Strip, or bond-breaking tape
• Clean up hands, surfaces, and equipment with water
• Log Jam forms a water-resistant skin approximately 1-4 hours after application
• It may be necessary to cover Log Jam with plastic sheeting if applied when rain is imminent
• Paintable with oil or latex stains after 1 week cure time
• Cure-through time: 3 weeks (1/2" thickness, 70°F, 50% relative humidity)
• If restoring Log Jam with chink paint, make sure the chinking has already cured

Sashco Log Jam Technical Guides
Log Jam Chinking Product Guide
Preventing Blisters in Chinking Material
Do-It-Yourself Chink Paint Formula with Log Jam Chinking
Log Jam Chinking SDS

Colors:
Buff, Dark Brown, Gray, Light Gray, Mortar White, Tan, White White, Woodtone Cedar

Sashco Technical Support
If you have questions or issues regarding the Sashco line of products, Sashco Technical Support is available at 800-767-5656.

MORE INFORMATION

Fundamental Chinking Application Guidelines
Proper substrate preparation and application are imperative for product longevity. Read this instruction sheet before applying any product.
1. Best results are obtained when Log Jam is applied to clean, dry, stained wood. Make certain there is compatibility between your stain and Log Jam. Log Jam has a lifetime warranty when applied with Sashco’s stains: Capture Log Stain / Cascade staining system, Transformation Stain Log & Timber and Symphony Interior Clear Coat.
2. Check the weather forecast. Finishing products are best applied in moderate weather conditions, i.e., out of direct sunlight, in dry, warm conditions.
3. Check the log surface temperature. The surface temperature should be between 40 ̊-90 ̊F (4 ̊-32 ̊C). Install a bond breaker before Log Jam is applied. Backer rod, Grip Strip, and clear packing tape all perform this function well. If Log Jam is applied over white styrene bead-board or Tyvek™ house wrap, it is best to cover the bead-board or wrinkle-free house wrap with clear packing tape (to prevent adhesion to those materials). We do not recommend the use of blue or pink extruded polystyrene board as a bond breaker.
5. Gun the chinking over the backing material. Ideal sealant depth is half of the joint width, but no less than 1/4”, nor more than 1/2”.
6. Tool Log Jam to ensure good contact with the log surfaces, especially to the upper log; this will greatly aid adhesion.
7. All chinking products may occasionally “blister”.

To avoid blistering:
• Do not apply in direct sunlight.
• Protect fresh chinking from direct sunlight for 1-2 days after application with white plastic sheeting tacked over it.

Surface Preparation
• Best results are obtained when Log Jam is applied to wood that has been previously coated with a compatible and thoroughly cured stain.
• Clean the log surfaces thoroughly to remove dirt, pollen, bird droppings and other surface contaminants.
• The USDA Forest Products Laboratory and other researchers around the world have reported that surface wood exposed to sunlight for as little as 1-2 weeks can become significantly damaged and unsound, which may lead to premature adhesive failure of the stains or other coatings applied to it. It can also hurt Log Jam’s (or any chinking’s) adhesion to the surface. Once bare wood has been properly cleaned and prepped to remove unsound wood, stain should be applied as soon as possible. Follow with Log Jam chinking.
• If a stain is applied over Log Jam, it will be tinted the stain color, but will be affected differently than the surrounding wood; therefore, test appearance before wide-spread use.
• A few coatings, especially those high in wax content or non-drying oils, may interfere with adhesion, whether they are applied before or after Log Jam. We advise against using Log Jam with such products.

Cold Weather Chinking
Log Jam can be applied in cold weather by following these instructions:
1. Make sure the log surfaces are above 40 ̊F (4 ̊C). Use a surface thermometer to double-check.
2. Keep the chinking at room temperature until ready to use.
3. Make sure the logs are free of frost.
4. Tent out the walls with clear plastic sheeting and keep them warm with heaters, then apply chinking.
5. Make sure there is air circulation so moisture doesn’t form on the logs, causing a washout. Some venting up high will help with this problem.
6. Leave the tent intact day and night while chinking, and for 2 to 4 days after chinking is complete.
7. Finally, remove the plastic sheeting. This should be sufficient to let the Log Jam skin over and slowly cure. Due to cold temperatures, it will take much longer than normal for the Log Jam to fully cure, but it will be fine if left undisturbed. Warn people to avoid pushing on it for several weeks.

Methods of Application
• When using 5-gallon pails, Sashco’s Snorkler chink pump, grout bags or bulk loading guns may be used.
• When using a cartridge, cut the spout at a 45 ̊ angle to desired bead size.
• In wider joints, multiple beads may need to be run until the entire joint is filled with chinking.

Tooling
When applying Log Jam in temperatures below 70 ̊F (21 ̊C), a mixture of 1-part denatured alcohol to 2-parts water can be used for misting the chinking immediately prior to tooling. When the temperature is over 70 ̊F (21 ̊C), water alone will be sufficient.

The techniques discussed below will give an aesthetically pleasing chinking line, as well as ensure a proper seal between the Log Jam and the log surface.
• Tooling Log Jam on Round Logs: Work the material smooth with a damp foam brush, keeping a rag handy to clean up drips of water and excess Log Jam.
• Tooling Log Jam on Square Logs: Use a putty knife to strike off excess Log Jam, making the joint level with the logs. Use a damp foam brush to smooth the material, keeping a rag handy to clean up drips and wipe off excess Log Jam.

New Construction Joint Design
• An hourglass profile is the ideal type of joint design for all sealants. It allows for maximum sealant movement and favors cohesive failure (the best kind) if the movement is so extreme that failure cannot be avoided.
• Round backer rod is best, especially when substantial movement is expected, as with “green” logs.
• The chink line should be no less than 15% of the log width. For example, with 10” diameter logs, the chink joint should be about 1 1/2” wide. If you choose to apply a smaller bead, expect more chinking repairs.
• Ideal sealant depth is half of the joint width, but no less than 1/4”, nor more than 1/2”.

Restoration
• Wood should be clean and stained, as discussed in the Fundamental Chinking Application Guidelines section.
• Remove all loose mortar.
• Bond-Breaker: When using Log Jam as a restoration chinking over old mortar, cover the old mortar with clear packing tape, which provides a surface Log Jam will not stick to. When movement occurs, the Log Jam will be free to stretch.
• Tooling: Log Jam should be tooled to contact at least 1/2” of the bare wood surface on either side of the old mortar. This will ensure adequate adhesion.

Slab Siding
Slab siding can pose a special challenge due to the very rapid and large amount of movement it often exhibits after being installed. This movement shows up as extreme shrinkage, bowing and twisting, and can stress sealants more than logs do. To help reduce this problem, follow these additional tips with slab siding:
1. Use only dry slab siding (19% or less moisture content level, verified with a moisture meter)
2. Install the siding with heavy screws, not nails.
3. If applying over Tyvek house wrap, make sure the Tyvek is wrinkle free and tape over it with clear packing tape.
4. If the boards are thick enough, install Half Rod backer rod with the round portion of the profile facing out. This will provide for the best joint design.

Blisters
Blisters are a common phenomenon with chinking and caulking products and are caused by a variety of things. Blisters appear as “bubbles” in the chink line and can vary widely in size. To help prevent blisters, 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:
• Pop the blister and gently push the material back into place
• 3 to 5 days later, apply a skim coat of Log Jam and tool to blend in.

Cleanup and Disposal
• Dispose of Log Jam in accordance with local regulations.
• Do not dispose of in drinking water supplies.
• Hands, surfaces and equipment may be cleaned up with water.

REVIEWS
PRODUCT QUESTIONS

Product Questions

  • How do I apply the chinking if I get a 5 gallon pail?

    The main options are a bulk gun, a chink pump, or a trowel and mortar bag.  The bulk gun is the most popular of these methods.  A bulk gun is a caulk gun that be loaded as needed with caulk or chinking.  Bulk guns also have a variety of optional nozzles that can be used to change the tooling pattern.

    Bulk guns are loaded by unscrewing the cap at the end, packing the chinking inside, and screwing the cap back on. You want to avoid getting chinking on the threads of the gun, as these are very difficult to clean.  We recommend using a follow plate or a loading sleeve to make filling the bulk gun faster and cleaner. 

  • I accidentally stained my chinking and I can't scrub off the color. How can I fix this?

    Fresh stain that has dried can’t be scrubbed off. Your best option is to cover the stain.  You can either coat the affected area with a light coat of chinking or brush over it with a coat of chink paint.  Chink paint is essentially a thinned version of chinking that can be painted on as needed. Here is Sashco’s recipe for making a chink paint out of a tube of Log Jam.

  • I chinked my house 18 years ago with Log Jam. The chinking is torn away from the logs in a few places. What can I do to fix this?

    If the chinking has pulled away from the logs, then it’s likely the original chinking line was too thin and it tore when the logs moved with seasonal swelling and shrinking.  To fix this, you will need to cut out the torn chinking, install backer rod if needed, install new bond breaker tape, and re-chink the joint.  Ensure that the chinking is between ¼” to ½” thick.  Also, feather in the new chinking over the edges of the existing chinking to make a clean transition.

  • How do I keep stain off my chinking when I have to restain my home?

    The answer depends on whether there is any pigment in your stain’s topcoat when you apply a maintenance coat of stain.  The answer is easy if you are using a stain system that has a clear topcoat, such as Capture and Cascade.  The clear Cascade topcoat won't discolor the chinking if you paint or spray it over the chinking.

    If you’re applying a pigmented stain such as Transformation Log and Timber with a brush, your best option is to tape off the edges of the chinking with painter’s tape first.  If you plan to apply with a spray instead, you will want to consider covering all of the chinking with painter’s tape since it is difficult to control overspray.

  • Should I apply the chinking directly onto the wood?

    No, instead we recommend installing a bond breaker, such as backer rod or clear packing tape, between the chinking and wood to make maintenance easier.  If you apply chinking directly to the wood and need to alter it later, it can be very difficult to cleanly cut out the problem section.  If a bond breaker is installed underneath the chinking, you can simply cut the affected area at each end, which should then peel up easily.

  • When should I use chinking instead of caulk?

    Acrylic latex chinking is formulated to mimic the appearance of old-style mortar in log joints.  This means that chinking is thicker and has a heavier grit than nearly all log caulks.  Additionally, chinking colors are designed to contrast with the logs, while log caulk colors are designed to blend in with the logs. 

    Chinking is a better fit when you have a wider joint (1" or more) that would benefit from extra stiffness or when you prefer the contrasting mortar-style look of chinking.