Question on joinery at post, plate, and beam intersection

[mmhailey]

You know how when you have a life threatening disease, you ask for a second opinion! Well I hope maybe I can get some opinions on my proposed project.

This is a garage remodel turning a portion of it into a kitchen. The overall height of the ceiling was 12 1/2'. I intend on placing a timberframe in the kitchen space to drop the ceiling. This is a pic from overhead that I created in a drawing program I am familiar with. I wish I could figure out sketchup, but the learning curve is too steep for me right now.

The rear portion of the frame will be carried by the existing 2x6 stud wall. I am inserting studs for the plates to rest on.






My inquiry is the following. Since my plate, and beam, must meet the 8X8 post and I want the top of all 3 members to be on the same plane, I was wondering if the following joint would work?





The reason I want all timbers, to meet on one plane is so I can put the drywall ceiling in. I can't think of anything else to add, so I'll just wait for questions...  Thanks

[shinnlinger]

I guess I don't understand the question or maybe the sketch.  It looks like you are there.  You could center the tenon on the 8x8 beam and make a coresponding mortise..  You could make a haunched tenon if you are worried about enough beef on the top of the post.

[mmhailey]

I apologize I can see the confusion you might get from my sketch. I redrew it showing the tenons concealed as they would be from above.

Would you think the standard would be a 2X6 tenon size in this configuration?

As far as a haunch I had thought about that, but since the structure is only carrying itself, and simply putting in a haunch wouldn't hide any gap caused by shrinkage, I had put that aside.

[Raphael]

  I'd switch it around so the joists connected to the larger beams (running the long way and having longer tennons) and make the shorter beam sized to match the joists.  It'd look more like a traditional beam, joists and girt arrangement.
  I'd also go for wood decking (with a trap door) rather than than drywall so you've got a little storage up there (hence the longer tennons) and can crawl around on it if you ever want to change lighting, venting, etc.

[mmhailey]

I like your idea of a crawl space above. Actually there will be about 32" of space between the existing ceiling, and the tops of the new beams.  My idea was just to nail 2X4's on the flat on top of the beams and screw the drywall to them. However putting in a small access port to get to the lighting, and stove vent ducting is a very good idea. Thanks!

[witterbound]

Why not consider something fancier?  Under your design, the pegs won't really show will they?  How about dropping the 8x8 beam some?  You could then add another joist at each end for your sheet rock to tuck under, and your pegs will all show so it will look more like a timber frame.  If you kept it closer to the full height, you could pitch the timbers to form a peak and make them look like rafters, and you could add some braces because you'd have the headroom under the braces.   

[mmhailey]

On the South end that is open there will be braces. The 9 1/2' bottom of the beams, should allow sufficient headroom I believe, especially since they will be oriented over cabinetry and not a walkway.

On the North end that dies into the existing wall, my intent is to inset a full size 2X8 that would mimic the larger 8X8 beam on the opposite end.

I think my joint will show most of the pegs, except for the ones that have to dead end into the 8X8 beam. Here is a profile view.





I am still open for suggestions and comments. I will start cutting the beams later this week. I certainly intend to take pictures, and post them. This forum has certainly given me great ideas, and help!

Thak you very much for all the suggestions.

[witterbound]

Looking forward to the pictures!

[Jim_Rogers]

I would modify the joint some.
The 6x8 plate will carry more weight than the 8x8 beam due to the joists attached to it and the ceiling attached to the joists. Therefore that tenon should be a through tenon and the point where the plate reaches the post should have a shoulder or shelf for the bottom of the plate to rest on. This shelf increases the surface area of the post to support the plate.

Next the 6x8 tenon shouldn't be 2" thick it should only be 1 1/2" thick and laid out 1 1/2" off the outside face this will give the 2" tenon from the beam more depth into the post.
Also, each piece the plate and the beam should be sized down to the next smaller size by 1/2" so that they are accurate in height.
Then the 1 1/2" tenon should have a 3/4" peg and it should be 1 1/2" up from the bottom of the tenon. And the 2" tenon can have a centered 1" peg and therefore the two pegs won't hit each other as they cross, as they are at two different elevations.

Here is a top view drawing:



Here is a view of the joint from the corner:



It would be best if the post rose higher than this joint to make it stronger by full surrounding the tenons....

Jim Rogers

[mmhailey]

Jim.

Thanks for the drawing, that really helps me.

reference your "It would be best if the post rose higher than this joint to make it stronger by full surrounding the tenons...."

Do you think 6" above the tenons would be sufficient?

[Jim_Rogers]

Jim.

Do you think 6" above the tenons would be sufficient?

Yes that would be good, the more the merrier.....

[Raphael]

I was going to suggest an 8x10 beam and dropping the top of the tennons down 2" to preserve solid wood at the top of the post.

Some questions:
Can you drive the corner pegs given this is going inside an existing structure?
Of course if it's jambed tightly into the corner of a room those pegs will be superflous.

But most importantly can you assemble this design in the space?
Have you got enough play to insert those long through tennons into the post and jocky the other end onto your blocking?  If not you may need to go for something more stacked with the beams landing on top of the posts.

And can you spread the beams apart once it's caged by your existing framing?
This will effect the design of your joists.

[mmhailey]

All good questions Raphael.

I have decided to let the top of the post rise 6-10 inches above the joint, and incorporate Jim's suggestion. I'll have to come up with some sort of carving, decoration, etc; on this small area , to make this look right I believe.

I have plenty of room for the assembly. I have given this quite a bit of thought, but I'll post some pics when I get to that point.

I am at a standstill now, waiting on a sick electrician to get over the crud! I can't get my timbers inside to start cutting till he finishes his rough-in.

[mmhailey]

Electricians finished their rough-in, so a friend and I carried the beams inside to start work. The beams are much better dimensioned and straighter than either of us expected. A little planing and their ready to start cutting.

Here is the kitchen that the the frame will be in. The two plates will tie into the wall with the window.





Here are the timbers for the front. two posts, and the horizontal beam

[ljmathias]

Nice timbers- good job getting it all spruced up for the show.  And interesting project: sounds like the kind of thing that could keep a timber framer busy during down seasons (like the one we'll be having for the next couple of years): renovations vs new construction.  That's what's saving my son's livelihood right now: very little of the new residential plumbing which is easy and fast compared to renovation/remodeling work that is dirty, slow and full of adjustments and adaptations.  The former is more mindless, the latter more creative and satisfying in many ways.

Lj

[mmhailey]

I promised pictures, so here goes.

Here are the Posts, and the beam.





Here are the two plates with the thru tenons cut. Thanks Jim for that suggestion. They will indeed be much stronger utilizing your idea.




Here is the post, and the plate being test fitted. The inset/shoulder is 3/4"





Here are the rafters being test fitted.









I am going to add some embellishments this next week, and erect it next weekend, if I can get the manpower. It has been a fun project, lots and lots of planning, to make a timber frame in an existing structure. Hopefully next I can get some pics of the raising.  Again thanks for every ones suggestions, and help.

[mmhailey]

Well this project is pretty much down to the finishing.

Here we are ready to start erecting the frame





To make it fit within an existing wall, lot lot lot of measuring and pre-planning. The amazing part always for me, is when the tenons actually hit the mortise, and the post is plumb.

















What did I learn?

1: MeasureMeasureMeasureMeasureMeasureMeasure 23 times. Then have someone you trust Measure.

2: Wood is a living thing. It will give to certain extent, but eventually you better have made the right measurement, or the wood is going to show you who is boss!

3. Hemlock ( especially wet Alaskan Hemlock) is Heavy! I am thinking Spruce might be in my next project!

4. Cut your joints to a 32nd of an inch, because when they are assembled, and showing, that 32nd looks a "LOT" bigger.

Thanks for every ones help. Comments, and criticisms are always appreciated.

[mmhailey]

 Ceiling joists installed today. Time to put up the chisel, and start rocking!

Raphael I took your suggestion, and will leave the area above the joists, as a crawl space accessible from the adjoining pantry. You always need more storage.

[Jim_Rogers]

Looks good.....

[Stephen1]

Nice!!! thanks for the pictures,

[mmhailey]

Just an update, and a few new picture uploads. When I got the sheet rock up, and decided to trim I looked at different profiles, widths, and embellishments to edge the timbers where they touched the sheetrock. I am using a Craftsman trim
throughout, so thought just a 3/4" square of the same hemlock worked OK.

[beenthere]

mm
That looks very good.

[mmhailey]

In answer to your question. This is what I infilled above the frame, in the drop ceiling. 4 species random widths. Only real money trees here. Red, Yellow cedar, hemlock, and spruce.