Seat cut for sawed lumber on loghouse

[Rait]

Hello, i could use some advice on the rafter seat cuts. Is what i have here good enough to do seat cut to 2by6 rafter on log house. The pitch of roof is 1:1 (45 degrees), its a small sauna 9 feet by 16 feet. The red part of circle(log) will be sawed/chiseled out and also the rafter will be a screwed to log (its a shame i know...).

For me this one sounds better:


 

Than this one:


 

[Jim_Rogers]

Can you show the plate as well?

I think the first one could be difficult to cut into the rafter due to the sharp angle.

Jim Rogers

[Rait]

Thank you for quick reply, i am not too sure what you meant by plate? The rafters will sit on round log, there is no sawn timber to lay the rafters on. To cut i could do circular+hand saw. As this is such a small building (smoke sauna) there are not that many rafters to cut. With second photo, i am little worried that force that pushes rafters outward has only collar tie and screw to hold it back...

[Jim_Rogers]

Can you show the seat in the log that holds up the rafters?

Jim Rogers

[Rait]

This is the seat in the log, those are not milled (uniform) logs, so zero point is within the log (measurements for seat are about inch within the log)



  

The rafter has simply a notch


 

[Jim_Rogers]

Rait:
Ok now I can see it.
This should work ok. It will be a challenge to cut.

Could you fill out your signature more? We'd like to know where you're from and what equipment you have to work with.

Jim Rogers

[Hilltop366]

A ridge beam at the peak would eliminate outward thrust on the wall.

[Rait]

Jim Rogers - Thank you for the reassurance! Ill see next week how good i can do the cuts.

Not that sawn timber rafters are traditional here (talking about log houses) but ridges are definately not used.

[jander3]

Rait,

On my cabin, I scribed the rafers to the log.   I thought about seat cutting but in my case there is a lateral groove in the log and I figured there was not enough material to be cutting into the log. 

I measured tail to floor and scribed the rafter so that the tails all ended up at the same height.



  

 

Each rafter was scribed individually to the plate.  On the ridge I cut a flat on the top and nailed on some 2x12s so that I had a standard birds mouth to deal with.



 

Set up the rafter, measure and scribe, drop off the building to cut, put back up and screw in place took about 20 minutes per rafter. Cutting a rafter seat into the log, I gotta believe would take more time.



 

[oklalogdog]

Great looking cabin Jander3

I have a question however.  How did you keep the tops of the rafters plumb with each other.  It looks to me like the log being a different size all the way from end to end would be a night mare as far as keeping the tops of the rafters in line with each other.  I really need to know this as we are building a hand hewn log home. 

Thanks in advance!

[D L Bahler]

Do not seat the rafters into a notch on a log home. The reason for this is simple, As the logs season and age they will settle -they shrink as they dry, and also they compress where they meet. The rafter ends need to be allowed to move, unless the gable is fully framed. The pictures of log homes show a posted ridge, this is a framed gable but is really not typical of many old European styles.

The best method is to have a log gable that supports a ridge beam, rafters are hung from or spiked to this beam, then simply rest on the walls below, allowed to move up and down with the seasons. Such a system will last centuries.

[D L Bahler]

Also it is common to dress an edge of the log -we will cut an angled face along the top side of the log that follows the slope of the rafters. When this is done, the rafters can sit on this flat and will all be level.

[jander3]

To keep the rafter tops plumb, I set the rafter on the log, measured the distance from rafter top to the foundation at the tail, and then scribed the rafter the appropriate distance.  You need the log to be generally level when starting with no large high or low spots.  Each rafter had a unique scrib setting.

[Rait]

Little update on the progress. Locals suggested to do the cut 3cm (1, 1/5 inch). As you can see not all seats came out perfect but i am sure they will work just ok. It was quite time consuming (doing this kind of stuff for first time) but it is lot of fun.




 

[beenthere]

Great to see the progress you are making with the new build. Appreciate the update.  8)