Vertical Log Cabin

Started by desdawg, December 01, 2006, 09:24:39 AM

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glenn-k

Do you get rain year round, Amanda or have to carry part year?

martyv

So is the pole barn the house and the 8X10 the bedroom?


Amanda_931

We get rain year-round--although can be pretty spotty in July and August (although on average, October is our driest month)

Tank's full right now, although I've got the roof-washer opened up so it won't freeze (that won't drain the tank, but it's annoying to replace, especially since it's my fault).  I'm supposed to have a 500 gallon tank (actually I do have a 500 gallon tank, haven't quite figured out how to hook it up).

BTW asphalt horse fence paint does not last on plastic tanks.  I was hoping.

;)

I use tank water a lot more in the summer.  Drains via garden hose.

mountainmomma

I'm itching to get started but I am having a hard time trying to figure out how to do sosmething. I am planning on felling and peeling some standing dead (beetle killed) trees for my floor joists.  We have plenty right around the cabin site. My issue comes in trying to figure out how I'll attach them to the.....what do I call them?....stringers?


In this picture, you can see the beams that I am trying to name. We have millled two sides of both of those logs flat. On the short ends of the house...we were thinking that we could actually put the vertical logs right on the beam/stringer. BUT, I was also thinking of notching those stringers to set in the floor joist logs. I don't think that I'd feel comfortable with structural integrity with all those nothces and then ALSO having a notch for the plywood spline somehow. Hmmmm...

Is it a bad idea to cut notches for the floor support logs? I was thinking about running about 4 short logs between each segment (in the same direction as those big monster logs). So,  overall that would be several notches. I don't know.....

martyv

If I understand you correctly, the two long logs are going to be the sill logs for the long side of your cabin.  And although those logs are round in the photo you have since made them flat on two sides.  

You will need to attach them in some way to your foundation beams.  If you cut very shallow notches in the bottom of your sill logs it doesn't seem that would decrease the strength too much.  Say maybe a two inch notch or less.    Now that you have cut them flat I'm not sure how thick they are.  Obviously round logs are stronger but woud be tough to work here.

A narrow kerf for the spline won't hurt too much either...especially if you glue the spline in with construction glue which I would suggest.  

Are your sill logs on the long end going to mean that your vertical logs will be shorter there than on the end because the sill logs will sit higher?  I don't think that will hurt, just wondering.


mountainmomma

Sorry. I don't think that I did the best  job of explaining myself.
The long logs have indeed been milled on two sides now. We were actually planning in attaching them to the beams with rebar pins. The short side walls would have longer logs. Yes.

The foundation beams (running width wise) are the beams I was thinking of notching for the floor joist logs. BUT, in the foundation beams that are on the outside, I see an issue. The two OUTSIDE foundation beams would not only have notches for the floor joists but would ALSO somehow have a long narrow kerf for the plywood spline.

But...as I am writing this, I'm looking back at your response and developing a new concept that I think would work. The cabin is only going ot be about 14 feet wide. Is that too far for floor joists to span? If it IS, I suppose that we could put another giant log in the middle of the two others for support and notch that too. Hmmmmm.....


martyv

Why don't you just use 2x10s or somthing like that for floor joists with hangers.  Then you could more easily insulate your floor.  

If you use logs what will be your spacing, and what will you use for floor decking?  If you use logs for joists they will likely warp and twist and the cause your floor to be uneven.  But it IS a cabin and perhaps that is what you expect.  

If you have more time than money, logs may be fine.  I agree that there may be a problem with a whole bunch of notches in that outside supporting beam.  

Maybe John will enter in here, he knows more about structural issues.

glenn-k

I don't see a problem using the logs for floor joists if you can get them straight enough to suit you.  8" logs are rated about 300 psf for the underground cabin roof.  Even at twice the span they should be well over the 40 lbs or so you are looking for on the floor.  

I don't know how big your stringers are but if large enough you could just cut a box out for the end of the joist with a chain saw -shim if not perfect.  An adze and drawknife could be useful for fine tuning.   The notch for the plywood key will be small so I wouldn't worry about it.  Pin all together with rebar.  Consider that the joist will want to rotate both stringers down inwardly so take the notches in a ways toward the center an a wide bearing area on the stringers will help stop rotation.  Are the stringers up off of the ground - If not their life will probably be pretty short, thereby ending the life of the cabin prematurely.

martyv

Good point about the joists causing the stringers down inwardly.  I had never thought of that.  I suppose that would be true with standard construction as well?


glenn-k

A bit but not as much as the joists are very near the center so there is no leverage to roll it down and the log is rounded on the bottom so will roll unless that force is counteracted by a wider flat on the foundation rocks etc.    If the beam end  is outside of the pivot point of the stringer log on the foundation it will cause the rolling force. There were some really neat pictures of Norse foundations with rather pointed or tapered short posts under the log stringers and on top of rocks if I recall - the taper made the water run off and allowed the post to dry.  May have been in a Lloyd Khan book.


mountainmomma

The foundation stringer beams are all attached to 6' deep concrete piers and are between 1' to 3' off the ground as the site slopes. All wood is OFF the ground.

Do you think that it would be a problem to notch the beams for the floor joist logs if I also use two of those beams (the outside two) for the resting site for a wall of vertical logs? I worry that the notch for the spline and the notch for the floor joist will meet up and kinda counteract each other by weakening the beam overall.

glenn-k

Silly me - I just clicked on the photo - not realizing it was a link to a big pix before - and was able to see all of that.

I don't think there would be much problem even with full size notches but you could cut the ends back as below and still have the strength of the joist in the middle while minimizing the size of the notch and getting toward the center with the load point.

If using smaller log joists you could also run a center log of smaller diameter then block up under the joist with a short post.  I see you already have a row of center piers.

I don't think the spline notch will do much damage as it is small and not deep.

What are the diameters of your stringers and floor joist beams?  Just curious.

mountainmomma

Its been a long time since I've been here.
Its been hard to be excited  about our building project when the building site is till being covered in snow during the last week of March. "Sigh"
Anyway, I think that we got out floor joist issue figured out. We are, however trying to figure out if we want to use those manufactured I joists for our 2nd story floor. Anybody have any input on those things. Are they generally MORE of LESS expensive that milled lumber? What are the advantages?

We have a few other questions too. I'll keep it down to just a few at a time though.

When we're building with vertical logs and have one log up (the corner log), should we go ahead and put all the corner logs in first? Should we leave spaces for our windows and doors and then put in the small pieces after the cap logs are on? Like in this picture?


glenn-k

I guess you will end up working it out one way or the other either way you do it,  but the way shown in the picture seems easier as things will be tied together and you can just fit and spike the short pieces.

Amanda_931

Three biggish logs--corner and one each side of that makes a really strong-feeling corner.   They got temporary braces, but that may have been belt and suspenders.  

mountainmomma

Someone with building experience in Anchorage (dealing with building codes that don't exist here) has recommended that we use K bracing under the floor of our vertical log cabin. He's also recommened putting all thread between all the logs vertically. These are to provide structual integrity for high winds and earthquakes. I am sure that Anchorage has high standards for Earthquke standards since 1/2 the city fell off into the ocean in 1964.


Anybody have any input on this?

We're all FOR building a strong house that will last a long time. However, I am concerned about cost as we are building out of pocket.

mountainmomma

new vertical log cabin pic!

http://upload.wikimedia.org/wikipedia/en/7/73/Bolduc-house.jpg

Interesting place in Missouri with a hip roof. Its kind of hard to really see the walls of the house though what with the big stockade fence all the way around. :)

Here's another link in case that one doesn't work.
http://en.wikipedia.org/wiki/Image:Bolduc-house.jpg#file

JRR

#93
Being very "mature", I usually seek a quick enery-saving method of doing things.  Often my concieved methods don't work ... so read further with caution.  There is NO experience on display here!

I've never even thought much about log cabins, always seemed like a lot of "fitting/joining" work.  But if I were to try one .... Rather than use any exact method I've read about or seen, I would use a "modified vertical" scheme.  Here are the (imagined) steps and features.

1. Split all log stock length-wise into half diameter logs.  For small dia logs a table saw might work.  Cut full depth on one side and turn the log over for cutting the opposite side.  A mallet and wedge could finish what the blade couldn't quite reach.  Of couse, biggish logs will require a chainsaw or other type mill.

2. Rather than use plywood inserts, use a complete exterior plywood diaphragm.  That means, except for window and door openings, all walls include an interior plane of plywood.  Whether the walls are assembled flat and then erected .... or, the plywood temp braced and the wall assembled in the upright position ... just depends.

3. The exterior side of the plywood wall gets a lapped layer of heavy felt or roll-roofing. Half-logs are attached vertically to the covered plywood using screws or using bolts... all on-center of the half-logs.  Fitting the logs tightly together isn't that important as the felt and plywood will do all the sealing needed.  Rainwater should easily find its way "down".  Debarking isn't a structural issue anymore ... let time do the job.

4. If the logs are well dried, the interior half-logs can be placed horizontally.  This would make a very stiff wall.  However, if much shrinkage is expected and to avoid wall bowing, the interior half-logs should be placed vertically opposite their exterior counterparts.  A good upper and lower sill would be needed to keep these wall sections straight. Foam insulation and a layer of drywall, or felt, could be included under the interior half-logs in either case.
..

What say ye, ... do I get to keep my Krazy Man title?

Amanda_931

Possibly.  It sounds like an awful lot of work.

If I were going to split my logs--I think I'd put the split sides outside, fill the inside cavities with something.  Plenty of landscape screws, top (temporary) bracing, etc. holding the whole mess together.

After all the instructions for building one were for (pine tree areas of) Alaska.

(Which might be at least as warm in the winter as here.   ;) Oh, well, it sounded good! )

In one of the local buildings, the owner had two opposite sides taken off his logs, stuck those together.  I know the people who built it slightly, they didn't mention any kinds of little tenons or anything.  But even what we did felt really really solid.

Those pictures from Missouri have the logs split on at least three sides.


mountainmomma

Does anyone know anything about using all-thread in vert. log constrction?

glenn-k

I have heard of building departments requiring all types of weird things.  Last guy I heard about them messing with on a log home told them to stick their requirements where the sun didn't shine and he did it per the design or his way as per plan.

What is your reason for wanting the all thread?  It can be used for tons of things.  I still just use rebar.  All thread I may use in a special fastening or bracing situation.  Every project is different though.

mountainmomma

The all-thread would, apparently be used to tie the top plate to the sill log

mountainmomma

The all thread and Kbracing (which is apparently meant to be done between the 1st and second floors are intended to add strength for side to side motion such as that imposed by wind or earthquakes.
Have any of you heard stories about log homes being blown over in strong winds? How about toppling in earthquakes? How do they generally compare to stick frames?

I have yet ANOTHER question.....
We were working on our logs this weekend and when I was cutting our first milled log to length, I made a little booboo.

Do you think that there is a way to fix this without milling more off the log?

MountainDon

polyurethane glue?  Seems the area is going to be all hidden anyways, except for that little bit right on the end.