Chink, Daub, Repeat. A log structure restorer discusses his craft.

Posted by | August 13, 2014

John VanArsdallPlease welcome guest author John VanArsdall. His Canjoeco Restorations of Blountville, TN specializes in meticulous, historically correct restorations of antique late 18th & early 19th century log structures. VanArsdall’s training in cultural anthropology while an undergraduate student of the University of TN, Knoxville, combined with a personal interest in history, eventually lead him to accept restoration work on historic buildings, beginning with a total restoration of an early 20th century eastern NC tobacco barn in 1989.

 

Each building has its unique nuances and complexities of difficulties to overcome. What I do requires a whole lot of adaptation in order to overcome these and involves, most of the time, a lot of patience and thought, but most of all, experience. Just changing the log’s environment by relocation, for example, changes many factors that the logs must adapt to, such as changes in humidity, sun or shade, geographic/environmental differences, and all these changes affect the logs in ways that might not be expected or predicted.

log cabin side

I use wood block chinking and traditional mix daubing primarily, because that it is the completely correct way to restore, and truly the most healthy for the well being of the structure.

The wood block chinking used by the pioneers not only added needed insulation, but also added significant structural strength to the whole building. The logs often span 25+ feet from notch to notch. With nothing in between (other than nonstructural wire), over time, gravity sags the logs. There is no upward strength supporting the length of the logs other than where they touch at the notches.

The wood blocks, then, as chinking material add structural strength, insulation, and a solid surface for the daub mix to adhere. The wood blocks also free float between the logs (not nailed to logs at all, but tightly wedged in) so that seasonal shrinking and expansion of the logs affects them very little, and if daubing does fall out, the wood shows between the logs, not rusting wire.

Modernists, rather than rely on wood block chinking, use wire mesh as foundation to apply a portland cement/mortar daub. Both the wire mesh and daub mix used do severe damage over time. Wire mesh never existed at the time the original structures were built. The methods of tacking the wire in using nails cause the daubing materials used to crack and to draw moisture in by way of the cracks. Moisture behind the cement rusts the wire, which “bleeds” onto the logs, but also rots the wood.

When I make daubing mixes, I use indigenous clay, usually found on site, and have to alter my sand to lime ratios in order to accommodate the levels of sand present in the clay used. Settlement factors affect a relocated log structure and if not reassembled properly, can damage the logs and the finished project, over time, can be compromised.

This is an example of water damage to log caused from inappropriate daubing material, specifically portland cement. Gibbs house, c. 1792, in Corryton, TN.

This is an example of water damage to log caused from inappropriate daubing material, specifically portland cement. Gibbs house, c. 1792, in Corryton, TN.

Many jobs I do are repairs to buildings that are compromised due to inappropriate or improper methods or materials used in their reconstruction. Many who are hired to “restore” these structures will also remove entire logs where only a portion of the original had damage; often replacing the entire log with a modern, recent cut replacement that changes dramatically over a couple of years as it dehydrates, shrinks, or bends to the elemenfts of nature. Very few logs require total replacement.

I skillfully splice antique replacement log parts together (authentic to the age, the hew marks, and the wood types of the original host) into the recovered solid host originals. There are so many pitfalls by errors and inexperience when moving these structures that we could write a book just on that aspect alone.

Most problems involved in moving them, or restoring them, are based on who does the job and their expertise and background. Lots has to be considered with the building’s new location: slope of terrain, drainage, protection from wind/rain/sun exposure, and orientation. Most modern contractors have no concept of these issues as pertains to log structures.

One example I am currently working on is a structure originally built c1787. I am working out and resolving many problems, but all have occurred due the reasons I expressed a moment ago: the wrong choice of builders.

When the building was relocated, it first was disassembled then stored for 8 years in a damp-proof storage building. When relocation to site took place, the building was put up on corner piers of limestone. No consideration to any of the environmental differences was considered. The property was not prepped, not sloped for water drainage, and no proper footers were dug. The lowest log on any log structure, the base plate, should be placed at 18″ above the ground to prevent water damage.

A close up of notch and crown damage that will require replacing. — in Corryton, TN.

A close up of notch and crown damage that will require replacing. — in Corryton, TN.

Moisture and insects are the two most damaging elements to logs and the water issues near the foundation must be accounted for in the building’s new location. Water damage attracts insects that do rapid and permanent damage to logs. That’s why portland cement and wire mesh, as well as other modern materials, should never be used to “chink” the logs, either. It traps moisture, rots the logs, attracts insects, and in a few short years the building is rotting down from the inside out.

In restoration work, too, one of the first things I have to establish is the building’s foundation; is it on “sleeper” logs (logs in contact with the earth), is it on rock piers, solid rock walls? I have to determine log height above the ground, water runoff, and the slope & grade of the terrain it rests upon. Then correct the issues as needed for on site work to progress. When relocating, all those issues are first considered.

Often, when relocating the buildings, the tendency is to first try and make the sill plates—the base logs—positioned to be as level as possible. Well, though that may be important, when the top plate is placed and fixed, unless just out of good luck, it most often will not be level.

The various logs, their notches, and the factors of the new terrain significantly affect the result of the roof being level at the building’s top. Though the base plates are all level, the roof may not be.

Often, after the top plates are in place, the roof trusses are put on, the roof then gets covered and when finished—‘Whoa!’—it is discovered to be out of square, out of plumb, not level. Too, as the building settles, the roof then becomes even more out of level.

There are ways to address these issues beforehand by knowing what to expect and by making simple adaptions in the reconstruction process that allow for the finished project to end as all level, plumb, and square (within reason). Sometimes the situation appears nominal and inconsequential at first but the water run off from the roof is a huge consideration when being level matters.

Before removing the portland cement, there was no apparent problem or evidence of log damage. This is the rot found in the interstice after the cement was removed and is as a direct result of the inappropriate daubing material used. — in Corryton, TN.

Before removing the portland cement, there was no apparent problem or evidence of log damage. This is the rot found in the interstice after the cement was removed and is as a direct result of the inappropriate daubing material used. — in Corryton, TN.

Period roofs are almost always shake shingle (metal roofs did not exist until the turn of 20th century). Water running down shake shingle roofs must not run sideways, as it will run under the shakes, or be allowed to pour off like a waterfall at the low end of the roof due to it being out of level. Water should not run over the walls, either; the roof drip line has to extend far enough over to properly allow run off.

Too often, modern roofers do not recognize the reason wide overhangs of roof lines were used or needed in these old structures. When relocating these buildings, a modern roofing contractor most often gets hired, builds a new “modern” design, and though made to look like it belongs, because of the contractor’s lack of experience with proper shake shingling of the old way, major long term problems develop.

The one building I am in process of “fixing” has these same issues, especially with it’s roof as I describe, as well as drainage and landscape issues that will need to be remedied. All this is mostly due to the wrong “builder” being first involved.

Another big mistake that occurs in relocation of these structures is that the logs have many checks and cracks in their surface. Too often people think that those need to be filled and will daub them with cement, or fill with epoxy. This, too, is a huge mistake, causing rapid damage to the logs. In regard to filling checks, cracks, and crevices: there’s no need to. The fillers that are commonly used, portland cement, modern mortar, plastics, epoxy, etc all trap water and force moisture into the logs, thus accelerating rot.

The natural checks, cracks, and crevices are most often not through & through the log, and as long as run off of water is properly remedied, they pose no harm to the life of the log and actually add much character. With traditional chinking & daubing, the very important main ingredients in the mix combine hydrated lime with clay. Along with the correct ratios of the proper sand used, both of these materials draw water moisture out of the adjacent log wood and wick the moisture, which then evaporates quickly into the air.

Removing a rotted section of log from the Nicholas Gibbs house (circa 1793) without displacing or affecting any of the surrounding logs, and replacing it with a section of 150+ year old matching log that was recovered from another log structure originally located ~ 50 miles from this site.

Removing a rotted section of log from the Nicholas Gibbs house (circa 1793) without displacing or affecting any of the surrounding logs, and replacing it with a section of 150+ year old matching log that was recovered from another log structure originally located ~ 50 miles from this site.

The lime also uses the carbon from the water to chemically convert the hydrated lime in the mix back into becoming limestone, over time. Anything else put between the log’s cracks, splits, crevices, or in the interstice spaces between the logs, forces water into the wood, holds moisture and causes rot.

Chemical insecticides should never be used! The elements used to make these products cause chemical damage to the wood, often discoloring it, or leaching out over time to damage the wood. Get the logs off the ground, away from moisture, use the correct building materials and the bugs will leave on their own. The foundation site should be properly prepped, sloped or drained to keep moisture away and there is where proper ground treatments against termites, etc, should be applied…not on the logs themselves… where it serves no real value.

Power washing logs as means to clean them? …not good.

There is much involved… as you might garner.

All the many log structures I’ve done are in either east Tennessee or in southwest Virginia. I am working on several now. One is being relocated next week to Stoney Creek, near Elizabethton to be reassembled and completed at the Brooks House, a former home of President Andrew Johnson’s daughter.

I am in process of working on the Woodland Hall, c 1855, a reclamation and restoration project in Glade Spring, VA.  I also will be doing the chinking & daubing and trim restoration in Abingdon, VA on the Breckenridge House, c1769. It is in limbo waiting to be disassembled and relocated to the historic “Muster Grounds” but requires a class B VA contractor’s license to get it moved.

Here's a wide angle view of the newly installed portico roof on the Gibbs house.

Here’s a wide angle view of the newly installed portico roof on the Gibbs house.

9 Responses

  • […] out this article about historically accurate log structure […]

  • Maureen Flannery says:

    Have you any suggestions for the foundation of a hundred year old log cabin with pine floor being moved only 8 miles from it original site in Wyoming.
    it will be moved whole by a house mover.
    We would appreciate any advice you can give

  • Heather says:

    We bought some land in NC with a 2 story hand hewn cabin & we are considering a restoration project. We would like to restore it where it sits. There is sinking on one side due to rot/insect damage. Once that is repaired, would you recommend removing all existing chinking & re-apply or just loose chinking & patch? Also, would you share the recipe for chinking?

  • Donnie says:

    A mixture of Portland cement, masonry sand, and masonry lime isn’t good for chinking?

  • Scott Lewis says:

    I am building an 8×8′ log smoke house on concrete blocks. I have taken my time. My gap between logs is from 1 1/4″ to zero. I live in South East Texas in Polk county and was wondering if you would be kind enough to send me the Chink mix recipe you think is best for this area of East Texas. If old time mix i have plenty of clay i can use from red clay to grey gumbo clay.
    Thank you Scott Lewis

  • Tom Kass says:

    Always amazes me how long “primative” last. It makes sense. I have seen first hand how a mortice, tenon and peg will look as new after 150 years while interior nailed joints even with iron nails sweat, rust and then the rust decays the wood ( I think chemically). I switched to galvanized nails inside after seeing same. I am not surprised at all portland cement ( a good water barrier ) will trap and puddle the moisture the bugs and molds need to wreck things. A few years ago I went through about 3 set’s of quick set locks in a decade and decided just to put the 100 year old door lock back figuring it lasted a hundred years and probably will last 100 years more. It should be against building codes to put wood within 16 inches of the ground: it’s just an invitation for termites to destroy your house. Not a matter of if but when.

  • Lori Adams says:

    What recipe for chinking interior walls? We used red clay (we are in Va) and lime for exterior with some sandy topsoil mixed in but we would like something lighter for the interior.

  • Craig Berg says:

    What is the formula/recipe you use for chinking? I recently attempted to use a clay mix of 2 parts powdered clay from property, 1 part clean wood ash and 1/2 part granulated cattle salt as the binder. When this mix dried it cracked and flaked off easily. After I removed this chinking I returned the next day after a foggy night and while the surrounding logs were dry in appearance, the area where the clay chinking was removed was very damp with atmospheric moisture. Please advise. This cabin is in northern Minnesota 40 miles South of Duluth. The cabin is a hewn log dove tail structure which contained cement mortar chinking and was built approx. 1920. I am currently restoring it and at present the chinking is a real problem for me.

  • I am interested in learning the chinking and daubing techniques used in 1834. Any suggestions as to whom I can contact for a hands on lesson. Not a video. Real life.

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