Girts and Window Framing

[Brian_Weekley]

I'm getting ready to start cutting my girts and associated framing for windows (4x4s).  I'm attaching the girts into the 8x8 posts using 2" tenons with 2" offset.  However, for the general framing around the window, I'm debating on the proper tenon sizes to use.  Following the standard rules, tenons in 4x4's would normally be 1" wide with a 1" offset.  However, this seems small to me strength-wise.  For the vertical studs that attach into the plate, I was thinking to keep the same 2" tenons with 2" offset like the girt-post attachments (so the mortise width and spacing remains in line with the brace mortises).   For the headers and sills attached to the window studs, I was thinking of using slightly larger 1 ½" tenons with 1 ½" offset.  I assume this is probably fine.

Of course I'm probably making this more difficult or complicated than necessary.  In fact, many might just choose to just nail the framing together instead of using mortise and tenon for the window framing.  Just seeking input to do it "correctly"...

I've attached some drawings below showing what I'm talking about...

Thanks, Brian

[clww]

Silly me....I thought it read "GRITS".

[Brian_Weekley]

Mmm Mmm.  Just checked though...there are quite a few topics on "Grits" posted in the Forestry Forum Food category! :P

[tyb525]

Hey, you're from CT, you ain't suppose to like grits! ;D

[jPell]

I'm a newbee but why couldn't you just go with a 2" M&T centered on your 4x4s which would give you 1" shoulders? Does it matter for them to be in line with your brace joints? I can see getting the joints closer to the middle of the posts/beams on the braces for strength but just wondering how much that would matter on the girt grit framing.

[maineframer]

Brian,

I would recommend that for the girts you use 2" barefaced tenons 2" off the face. If you are pegging these i would make them 3" long and peg with a 3/4" peg.
As far as the window framing goes I would use the same as above on the vertical pieces and 1 1/2" off the face 1 1/2" tenons for the horizontal members.

[jander3]

On 3 x 5 girts I used 1.5" tenons that were 1.5" off the reference face.  Worked fine.   For 4 x 4s I agree with mainefarmer.

[Jim_Rogers]

.... why couldn't you just go with a 2" M&T centered on your 4x4s which would give you 1" shoulders?

One reason is that it is a bit harder to cut. You have to have both shoulders on either side of the tenon in the same plane to meet the shoulders on the mortise.

It's easier to just cut the tenon as David has mentioned 2" off the layout face and then 2" thick making it a barefaced tenon.

One thing that helps me decide on how to cut these joints is how is it all going to go together. What I mean is, in which order.

If we look at Brian drawing we see that this is a wall. Next we have an end bent and a middle bent.
In order for this to all go together with mortise and tenon joints we have to raise the end bent. Then insert the bottom girt going to the middle bent. We'll need to hold that up until the next bent is raised. After this is being held up we can then put in the second short girt and left hand side window post. Then the window header and the window sill. We'll have to hold up the header and window sill until we put in the second window post. After the second window post is in then we'll have to hold up the other top girt going from the right hand window post to the middle bent.

Now that we have all this together. We can raise the middle bent. As it's being raised we'll have to make sure the two girts, the long bottom one and the window post to middle bent are aligned properly so that they can be inserted into the bent as it is being raised. This can be done, but it will take many hands and/or several temporary support systems.

And all the tenons and shoulders have to be exactly correct or they won't all go together.

It's easy to say that they all will, but sometimes we go to put things together and it just doesn't fit. And we have to trim something to make it all line up and go together.

If it doesn't all fit then we may have to lean out the middle bent to get it right. A wall fit-up pre-raising day would solve this problem and insure that all joints are right, all shoulder to shoulder lengths are right and all tenons fit all mortises.

After the bents are up with the window posts in, the top plate would be lowered down onto the bent posts and window posts, with the braces going to the bent post up to the plate.

I'm not completely sure of the length of this frame. But Brian has chosen to put braces from the middle bent post up to the plate. And it appears from his drawing on both sides of the middle post. These two braces aren't always needed. As we have the two end braces from the end bents up to the plate.
If there is a reason why the end bent (not shown) brace can't be there then maybe that's why Brian has put in this brace up to the plate from the middle bent.

My next concern is that all this window framing is being supported by one long girt going from bent to bent. This will probably be ok as the long girt will be supported by the vertical siding once attached. If he is using vertical siding. If he is using horizontal siding then there should be something to nail the lower pieces to, some where below the bottom girt. As none is shown, I'll assume that the plan is for vertical siding.

In order make the raising somewhat simpler I may chose to use different joinery which would allow the bents to be raised, the plate to be installed and then tip in the window posts.

To tip in the window post, I mean to have the bottom tenon cut, a barefaced 2x2 tenon and it's mortise ready. And make a simple bevel cut on the top of the window post to fit into a matching bevel cut on the underside of the plate, like this:



The above picture show how I would add a doorway or door posts to a frame after it was raised but it's the same principal.
This drawing also shows how you could simply add the window header and sill piece by cutting them with a beveled edge.
After you raise the frame with the bottom girt in place and you have set the plate on and your bottom girt is the correct height off the floor deck, you can then cut the bevel cut on the top of each window post and tip them in.
Now Brian also has a short girt going from the window post to the bent post on each side. I believe it would be possible to still tip the window post in with the short girt engaged into the bent post as well as being engaged into the window post mortise. Or you could do a bevel cut on the end of the short window post were it meets the bent post.
After both window posts are in, you would cut the window header to length. You would have one end done and just measure and fit the second end based on the actual distance between the window posts. And then slide them in from the outside.
The could be toe nailed from the outside so that the nail heads won't show from inside.
And all this can be done another day other than raising day.

When you look at this bare frame:



And the drawing of this frame:



You'll see that in the drawing are a lot of window posts, sills and headers that haven't been installed yet.
In this frame most of these will be toe nailed from the outside so that they won't show.

I hope this has helped you to understand how you can do window posts and other "girts".....

Jim Rogers

[PaAnkerbalken]

Jim,
   Instead of cutting the bevel cut on top of the door post, could you cut a half lap instead or would that take out too much wood?

[Brian_Weekley]

Thanks for all of your feedback.  Your comments reassured me to go with the 2" barefaced tenons and "Snaff/Snaff" (1 ½"/1 ½") for the header/sill connections with the vertical studs.

I'm not completely sure of the length of this frame. But Brian has chosen to put braces from the middle bent post up to the plate.

My bays are 10 feet wide.  Just thought I'd add braces to the center post for some added rigidity.

My next concern is that all this window framing is being supported by one long girt going from bent to bent. This will probably be ok as the long girt will be supported by the vertical siding once attached.

Yes, vertical siding will be used so that will support the girt along its length.


I was originally considering placing an upper girt higher.  The problem is that the girt would intersect with the braces (wouldn't have been a problem if I had a taller structure).  I thought about using half-lap joints between the girt and braces at these intersections, but I thought this would be a little more tricky to get a nice fit.  In addition, I didn't really want another joint adjacent to the tie beam connections in the posts.  However on the end wall in Jim's drawing (not the photo), he shows an upper girt tied directly into the braces.  I hadn't considered that, but that could be another option.  That way, I could have the vertical window studs tied directly between the upper and lower girts and not have to mortise them into the top plate.

Thanks, BW

[grweldon]

Great illustrations Jim.  Pictures and drawings do it for me!  How big is the shed you are showing?

[witterbound]

You must be a man with a lot of free time to do all of this for windows.  I'm sorry, I haven't been tracking your project.  Will all of this be visable from the inside so you can see an appreciate the 13 mortises, 13 tenons, and 13 joints you're going to have to fit up for this one window?   If so, I can see why you might want to do this.  Otherwise, it's just a huge time commitment to do all the joinery, it seems to me, for something you'll never see.  Back in the day, was it traditional for timber frames to have windows done this way?

[Jim_Rogers]

Back in the day, was it traditional for timber frames to have windows done this way?

That is a good question. I'll ask Jack Sobon when I see him on the 23rd.....

Jim Rogers

[Rooster]

You must be a man with a lot of free time to do all of this for windows.  I'm sorry, I haven't been tracking your project.  Will all of this be visable from the inside so you can see an appreciate the 13 mortises, 13 tenons, and 13 joints you're going to have to fit up for this one window?   If so, I can see why you might want to do this.  Otherwise, it's just a huge time commitment to do all the joinery, it seems to me, for something you'll never see.  Back in the day, was it traditional for timber frames to have windows done this way?

I'd have to say that I also follow WB's thought process... he likes to put things "down on the bottom shelf...so that you can grasp it"  ;) :D ;D ;D
 
With all the historic frames that I have seen or worked on in the midwest, I have never seen 4x4 door or window frames with M&T joints.  On occasion I will see 4x6 (flat) joined to 6x6s, but most 4x4 are nailed and sometimes have a shallow housing to help with the butt-joint.

Historic barns in Wisconsin were not timber-framed as a purist art-form built to deny the use of steel/iron fasteners.  They were built in a way that would yeilded the largest interior space, support a large roof system, using the most available materials to create a useful building for the family business...aka "farm"  So I would not get caught up in the "no nails" idea of building...so use your trunnels for the structural part of your frame...and nails for the "added framing elements".

I now release you of all guilt associated with using fasteners in your frame...because I'm telling you, that if they had what we have now (fasteners), they would have used them.  ;)

Rooster

[Brian_Weekley]

Witterbound telling it like it is.  I appreciate that.  No, don't have a lot of spare time, but when I come home from my day job, I find it very therapeutic to cut some timbers.  Therefore, the opportunity to cut some extra mortise and tenons doesn't bother me.  Besides, I've never been known to do things the easy way!  In fact, my wife keeps asking me if she will live to see the final product...

Rooster, or do I dare reveal your true identity—Dr. Manfred C. Roosterhaüser III, world famous clinical psychologist.  I almost shot Coca Cola out of my nose when I read your last paragraph.  Yes, doctor, your diagnosis is accurate.  I am suffering from "No nail syndrome".  Was it that obvious?  Is there a cure?   :D

Seriously, being this is my first timber frame, I guess I like the challenge of using mortise/tenon/pegs and avoiding nails where possible. I kind of viewed using nails as "cheating".  Practicality wise, maybe I should be a little more flexible...

Thanks, Brian

[Jim_Rogers]

Although you mentioned you saw my drawing with a girt between two braces, which I drew with two tenons and pegged off, we discarded this idea as being too complex to cut and install.

We decided that we'd just cut the girt ends on an angle and toe nail them up into the bottom of the braces now that the frame has been raised.

Back in 2001 I photographed the raising of a frame at the Hancock Shaker Village that the students of Jack Sobon's workshop cut.
It was a chicken coop building. One of the braces in this frame went from the sills up to the posts. And there had to be nailers along the wall for the siding.
Jack snapped a chalk line across the building matching the mortise height for the bevel cut. Then fit the nailer to the line and cut it off with a hand saw.
He then toe nailed it in from the outside.
I have proof:



You can see the blue chalk line, under his hand, and the first nail he just drove in below that, the black dot in the shadow. You can't see his other hand which has the hammer in it.

Jack is the one in the straw hat.

This is allowed and we don't/won't hold it against you.

But you don't have to tell anyone you did it if it doesn't show........

Jim Rogers