log end construction

[john hass]

hows this for an idea??  build a timber frame then infill with log ends without all the grout and work and expense. then paper the outside and a layer of 1/2 inch or thicker insulation and using a nail gun, nail on siding to the out side. using a nail gun would not move the log pieces like hand nailing. then sheet rock- why would any one want sheet rock?, then nail on boards on the inside for finish. this would be fast and cheap i believe. john hass

[beenthere]

Interesting idea.
Do you have some description of the materials you suggest?
Like paper ??
log ends ??
insulation ??
sheet rock ??  outside ?
boards  ??

Am wondering, why no grout?

[Ron Wenrich]

You would have to mill the log ends so that the thickness wouldn't waver too much, or you'll have bumps in the walls.  Plus you would have open areas between the log ends that wouldn't have as much insulation, and become susceptible to drafts.  But, I'm no builder.

[Kansas]

Just remember this. Owning what I call a log home (6x6 cedar dry cants, t&g) one thing I am sure of. Wood has lousy insulation properties. In retrospect, if I had it to do over again, I think the log home look, coupled with 2x6 and insulation, would have been better. Cheap is not always better when you are trying to heat and cool it.

[Axe Handle Hound]

If you're going to bury the log ends inside a finished wall you could just spray foam insulate the voids between them. 

[D L Bahler]

no, you cannot spray insulate the voids.

This will work for a time, but the foam will cause moisture to condense on wood surfaces and hold it there, causing the wood to rot quickly.

Spray foam should never be used in direct contact with wood, it is just inviting disaster.

[drobertson]

Not sure how correct this is, but when doing our basement 15 years ago, the concrete man said to stud the walls and leave a dead air space.  My dear uncle Pat said I should have put in insulation, he said the paint will come off the sheet rock,  no signs of anything wrong with the dead air, very cool in the summer, nice and warm during the winter months,   no sign of mold, or moisture of any kind. 

[Axe Handle Hound]

no, you cannot spray insulate the voids.

This will work for a time, but the foam will cause moisture to condense on wood surfaces and hold it there, causing the wood to rot quickly.

Spray foam should never be used in direct contact with wood, it is just inviting disaster.

Not sure i understand why this is taboo.  Based on every stick frame, hewn log, and round log house I've seen over the years it appears I can put mortar, foam backer rod, plastic sheeting, and/or spray foam in contact with the logs/studs and it meets building code.  Other than the mortar, none of those materials really has any moisture transfer properties so why is spray foam between log ends not acceptable? 

[D L Bahler]

This has nothing to do with building codes. Building codes should not nor can they ever possibly be your only guide to what is good building practice.

And you actually gave the answer in your own question, that these materials have no moisture transfer properties.

Wood absorbs, emits, and transfers moisture depending on it own moisture content relative with that of the environment around it. Manmade materials, however, do not share this property. Plastic foam cannot tranfer moisture, nor can portland cement. The result of this is that any moisture contained in the wood or traveling through it will tend to condense into liquid at the point where it can no longer travel as vapor, which will invariably be at the point where you have a membrane of plastic, cement, or other such impervious material. Portland cement and plastics both cause sweating, this is a known porblem in the repair of old buildings, where for example the use of portland cement as chinking in an old delicate log cabin causes the dramatic acceleration of the rotting already occurring in the wood. The same affect occurs in new construction, though it may take a few years before you realize it.

To reiterate, you are using a material with NO transfer properties in contact with a material that readily absorbs and transfers moisture, and always contains a certain amount of suspended water. These materials serve to trap the water.

The alternative is to use materials that do not trap moisture, such as lime, clay (clay is hygroscopic, and if properly applied to a wood surface will actually prevent rotting) and cob, to name only a few. Natural insulation such as mineral wool also is good.

Insulating the cavities in a basement wall can be problematic for a different reason. The air is highly saturated with water, and fiberglass insulation very readily absorbs that water. Even if it is not noticeably wet, it may have a high enough water content to harbor dangerous molds. 

[Ron Wenrich]

The moisture transfer is something that might be considered.  The vessels in wood run lengthwise and moisture could move along those vessels much more easily.  I guess you could coat the ends to prevent it.  But, wood used in studs, siding or the like have vessels running parallel to the use, and don't transfer moisture nearly as well. 

To me, it seems like this method would be more labor intensive, and wouldn't give you as good of a R value in the wall as the more modern products. 

[Draco]

The alternative is to use materials that do not trap moisture, such as lime, clay (clay is hygroscopic, and if properly applied to a wood surface will actually prevent rotting) and cob, to name only a few. Natural insulation such as mineral wool also is good.

"Mineral wool products can hold large quantities of water and air that aid root growth and nutrient uptake in hydroponics; their fibrous nature also provides a good mechanical structure to hold the plant stable."

If you are concerned about moisture in contact with wood, mineral wool would be a terrible choice if there is any chance of it getting wet.  It gets wet and stays wet for a LONG time.

While Portland cement alone could trap moisture, the nature of the material(s) are going to create small cracks and air spaces between the wood and cement.  This allows any moisture to evaporate quickly, if it gets in.  Foam and man made chinking products trap any moisture that gets in.

[D L Bahler]

Personal experience and observation, as well as the wise words from people who have done this for many years, have led me to my observations about Portland cement, and moisture that gets into those spaces does not get away quickly.

This is the very reason why the building code requires that only treated wood can be used in contact with concrete, as portland cement is proven to accelerate the decay of untreated wood. 

The only chinking material that I really feel safe using is that which has been used and proven its effectiveness in diverse climates for a very long time, natural materials such as cob, lime cement, etc.

Mineral wool is an alternative to fiberglass or cellulose, which similarly trap moisture and hold it there. But the thing of these materials is they trap moisture and HOLD it, not deposit it on wood surfaces.

[john hass]

the idea of no mortar is to save all that time and money, and give you wall thickness which = thermal mass.

paper would be 10 # felt, then the styrofoam sheets. inside could see pine boards nailed on in any pattern.

i have also seen osb board used in place of sheetrock then stuccoed over and painted, but i am trying to get away from the chemicals

that is the reason for boards for wall covering. i also hate the idea of not being able to hang a picture or anything into sheetrock.

  john hass