Upright Groove and Tenon Corner Post options - spline vs tenon questions

[NeedsMoreToys]

I'm planning my first cabin build using vertical corner posts with a grooved vertical corner post and tenon log. I'm wondering if it matters if I were to instead groove the log also and use a spline like a 1 1/2 x 3 board instead. (Groove 1.5x1.5 in each). I see an advantage to loading the log from the side of the wall rather than dropping it down the length of an 8' post. Grooving the log would likely be easier as well. Is there a downside to this method I should know about?

I will be using "green" aspen seasoned 6-12 months. Plans are for posts at 6x6 and rectangular logs 6x8.

Other terms: "corner post", "grooved post", "post and fill", "channeled post", "poteaux sur soles", "piece-en-piece"

[DonW]

I don't know much about this construction technique you describe but a splined joint in wall openings, doors and windows,etc... is how I'm planning for restoring some conventional existing log structures I have. In principle it should be even stronger than tenon joinery. I regularly use a splined joint in my floors because among other reasons it conserves wood by not reducing the width of a board by the length of the tongue (tenon).

[NeedsMoreToys]

I'm using this style post because it allows me more flexibility in building with green or lightly seasoned logs. The logs can shrink and settle while still maintaining a tight lateral connection to each other. You can do similar by underscribing logs with saddle or dovetailed notches but that raises the difficulty level in my opinion, at least for me.  

I've seen some splines used from angle iron or T bar which may simplify it further but expensive. 

[DonW]

Expense, ok, I'd be more concerned about obvious condensation and moisture accumulation at the interface of wood to metal within the construction. Anyway wood-to-wood connection is more reliable regardless of what the engineer or inspector may think. 

[1938farmall]

DonP mentioned this idea recently from James Mitchell's book which seems to be very sensible for a 1-man build.  You say you want to slide the logs in place as you go up, but how will you insert the spline?  Short sections for every 2-3 logs or drive a long spline down from the top (tapered end) after all are stacked?

[NeedsMoreToys]

DonP mentioned this idea recently from James Mitchell's book which seems to be very sensible for a 1-man build.  You say you want to slide the logs in place as you go up, but how will you insert the spline?  Short sections for every 2-3 logs or drive a long spline down from the top (tapered end) after all are stacked?

A 2x4 spline piece per log was my plan to ensure a good fit that will allow log to settle.  Wood spline would also allow me to cut out a log that rotted in the future, in theory.

It's important each log be allowed to move independently so I think a longer spline may interfere. 

I found the link you referenced here, it was helpful. https://forestryforum.com/board/index.php?topic=108729.msg1698558#msg1698558

[Don P]

I can say that "In Theory" is a wonderful thing. I've maxxed out a 2 ton comealong on a tenoned log in a groove that it was supposed to be sliding in. When a log twists an awful lot of settling theory goes out the window, things love to bow, bind, and find every way of wreaking havoc on our best laid plans. Just stuff to be mindful of as you work.

[Hilltop366]

Thinking out loud.

I wonder how much trouble a person would get in if they figured a way to stack the logs and hold them in place then cut a grove down all the logs and install the corner post and splines?

[DonW]

This idea of piece by piece spline is a floating tenon which typically - even for this atypical application, is anchored at least in the longitudinal element. 

[NeedsMoreToys]

Thinking out loud.

I wonder how much trouble a person would get in if they figured a way to stack the logs and hold them in place then cut a grove down all the logs and install the corner post and splines?

I've seen it done that way. 

[NeedsMoreToys]

This idea of piece by piece spline is a floating tenon which typically - even for this atypical application, is anchored at least in the longitudinal element.

Do you mean it's pegged in the log to anchor it, after it's installed?  So it's no longer floating. 
(There is a log home manufacturer that uses a spline for each log that is engineered from polypropylene. It is shaped so that it draws the log in tight to the post when it is pounded in. Also as the log dries and shrinks it also draws the log/post tighter. Interesting innovation but not DIY.)
If I should peg it I would like to understand why. I assume it helps stabilize that joint. Which implies a tenon would be better. 

[DonW]

In one way or another, yes attached to the log. Even glued at both ends it is still called floating tenon. But I think in such a construction you and this engineering log company are entering pretty speculative territory. A better idea seems this one mentioned of minimal two or three logs to each splined section. In any case then it is actually a spline where spline principles apply. 

[1938farmall]

years ago i almost built a cabin using the Mitchell method.  he had it all worked out to where one could build walls in sections at home, then move the modules to the build site & put them in place.  my plan was to use his suggestion of building a skeleton frame of 2x4's the height of the log wall & width somewhat less than the log section being build.  the idea is to stack the logs up against the frame to get them to fit the way you want (coped or chink) and anchor them in place with screws thru the 2x4 frame.  once that is done, trim the whole unit to length with chainsaw.  then make a jig with more 2x4's to stand up at the ends of the wall to guide your saw to cut the groove.  i was thinking mount a wood block on each side of the bar to follow the "window" in the jig to cut 1 side of the groove; then follow the other side of the window to cut the other side of the groove.  you could make additional freehand cuts to waste the material in between & finish with a chisel.  the advantage of this method would be speed & accuracy of having the grooves lined up for the splines.
this same "window" jig could be re-positioned and used to groove the posts before setting them

[NeedsMoreToys]

years ago i almost built a cabin using the Mitchell method.  he had it all worked out to where one could build walls in sections at home, then move the modules to the build site & put them in place.  my plan was to use his suggestion of building a skeleton frame of 2x4's

I have thought of something similar.  This method seems perfectly setup for a jig.  However not sure you save much time vs a few quick passes with a skill saw on each log end. Grooving and chiseling each end seems like more work than a tenon. Plus I see value in cutting the log to fit individually for as tight a tolerance as possible. Regardless it's all just theory until the work starts and will adjust accordingly. 

I ordered the Mitchell book and am curious what he has to say. 

[kantuckid]

My own home, my only log build, done by myself (meaning one person in the ;D work force ) to the top of the first floor windows is how I'd do it again. And I am, but albeit much smaller off-grid cabin 20x16. My corners are dovetail this time and logs are "D" crossectional while our home is round in and out. I like the esthetics and construction details of a hewed log home and Scandinavian too but using my brain, body and materials, I'll stick with stack log. Works just fine with green logs done properly. My home is SYP from an even aged stand(CCC Camp) while the current build is EWP also green- actually their real green cause what with this weather, they are still growing in the woods! :D
Todays the first day in over a week that we can drive to our house due to ice. 
FWIW, I just graded my road and was barely able to get back up hill with my 4x4 tractor. Solid ice. Where my logs are gonna be logged from there are thousands still w/o power right now! 
Stack em up, screw em down! and decide what corners. I just don't like the splined verticles at all. You can look in some log building suppliers at jacks, all thread and springs to adjust you logs=my home has none of that, only headspace allowances. 

[Remle]

I'm planning my first cabin build using vertical corner posts with a grooved vertical corner post and tenon log. I'm wondering if it matters if I were to instead groove the log also and use a spline like a 1 1/2 x 3 board instead. (Groove 1.5x1.5 in each). I see an advantage to loading the log from the side of the wall rather than dropping it down the length of an 8' post. Grooving the log would likely be easier as well. Is there a downside to this method I should know about?

I will be using "green" aspen seasoned 6-12 months. Plans are for posts at 6x6 and rectangular logs 6x8.

Other terms: "corner post", "grooved post", "post and fill", "channeled post", "poteaux sur soles", "piece-en-piece"

The wall will shrink more than the corner post .  How do you plan to makeup for this ? I under stand from having worked with a neighbor how to work around door / window openings . He also made provisions to shorten the interior post to account for the exterior wall settlement along with interior walls. His walls are all horizontal logs, no vertical corner post .
If my memory is correct he cut the internal posts off several times over a 3 to 4 year period to keep the second floor level , probably took off 1 1/2 ", don't quote me on that figure , but I know it was to make up for the wall settlement.

[kantuckid]

I dealt only with a horizontal 4x4 trim board above my openings, not the rough frame itself which was built to remain one size. I filled my cavity with fiberglass but now days there are better ways.