Modern Chinking

Modern chinking sealant material, typically acrylic, is designed to remain flexible after it cures, allowing it to stretch and compress without breaking as logs expand, contract and twist. It comes in tubes so that it can be applied with a heavy-duty caulking gun. In fact, modern chinking is a wide band of caulk chemically designed for durable exposure to weather.

Chinking is manufactured in a number of textures and colors, usually formulated to either give the appearance of old-style mortar-based chinking or to blend closely with wood.

It’s also designed to be resistant to damage from Ultra Violet (UV) radiation, which can be a problem with long-term exposure to sunlight.

Antique hay barns, identifiable by the spaces left between logs to allow hay to dry and keep cool. The barn on the left was built in 1861. The small barn in the photo on the right has been turned into a studio and the spaces between logs filled with modern chinking.       (Note the mis-aligned log at mid-window indicating the lack of a spline)

MODERN CHINKING CONSIDERATIONS

Many defective applications are not visible until they fail and confirmation of proper chinking methods connected with these conditions should be disclaimed by inspectors in the report and explained verbally to the client.

• Two-point adhesion- To allow maximum flexibility, chinking should be adhered to both upper and lower logs, but should have a middle section of uniform thickness which is free floating- not bonded to wood. This is usually achieved by installing foam backer rod or plastic tape into the joint between logs before chinking is applied. Proper application may be difficult to verify visually.
• Blistering- Improper backing materials such as colored foam boards or extruded polystyrene can cause blistering. Excessive moisture in the logs can also cause blistering.
• Telescoping- poor backer material installation can show through once the chinking has cured.
• Thin application- Chinking applied too thinly will tear. This is sometimes a problem where round backer rod has been used. A good rule of thumb is 3/8” minimum thickness. This is often difficult to confirm. Tears less than a foot long can be caulked. Tears exceeding one foot should have chinking cut out and replaced.
• Inadequate bead width- A good rule of thumb for the width of the chinking bead is 1/6 of the log diameter. An 8” log diameter would be calculated like this (8 ÷ 6 = 1.3”   (1  5/16 in. wide chinking bead). A home with significantly smaller beads throughout should be brought to the client’s attention with a recommendation for a specialist evaluation.
• Incompatible finishes- Some adhesion failures can be caused by the application of chinking to a log finish with which it’s not compatible. Logs with oily or waxy surfaces do not allow for a good bond with chinking sealants. Inspectors need not give reasons for adhesion failures, but only state that they exist, and recommend a specialist evaluation or repair by a qualified contractor.
• Tooling- Tooling the chinking bead compresses it to the wood surface and helps ensure a good bond at the bead edges where the chinking is thinnest. Untooled chinking should be called to the client’s attention as possibly shortening the lifespan of the chinking system.
• New chinking bonded to existing mortar- Although it’s not recommended, new chinking applied over existing mortar is not in itself a defect. However, a bond-breaker such as plastic tape must be applied to existing mortar and areas of missing mortar must have a backing material installed. Both these conditions will be difficult for inspectors to verify and are one more reason to disclaim hidden chinking conditions.

The following disclaimer should be reviewed by an inspector’s attorney and included in homes with chinking installed…

CHINKING CONDITIONS

                                                           Courtesy of Permachink Inc.

The two photos above show chinking stretching to acommodate widening of a check.

The photo to the right shows the proper method of installing modern chinking.

The tearing in the photo below was caused by shifting of the lower log.

                                                                      Both photos above courtesy of Permachink Inc.

Courtesy of Permachink Inc.

Blisters from application in hot, direct sunlight                                           Chinking applied over Tyvek

Courtesy of Permachink Inc.

       This sagging chinking was applied too thickly.           Chinking was applied to an overly wet surface.

The chinking shown to the right was applied too thinly and has torn.

                                                            Courtesy of Permachink Inc.