Joints to use in a lintel for French doors

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Pavesa

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Hi

I have a project to install some French doors on the rear south side of my house overlooking the back yard and I'm wondering if anyone has any suggestions around my overall plan and also particularly on the kinds of joints I should use for the lumber. The house dates from about 1850 and is in a rural area and I guess in those days the back yard was just a general dumping ground so there are just 3 very small windows overlooking it, one of which is in the pantry! So, I'm wanting to convert a room on the back of the house into a sunroom by installing some French doors giving a view over the back lawn. The width of the French doors is about 6' so there are obviously structural implications as studs are going to have to be removed and I need to install a lintel to give support.

It's a 1 1/2 storey timberframe house and very solidly and heavily built. I'm showing a drawing, Picture (1),of the layout of the wall where I want to put the French doors. At each end of the wall is a heavy 4"x6" post marked A and F. Next to F is a window and to the left of this are a series of 4"x2" (genuine inches btw) studs marked B - E. The current window is between stud E and the 4"x6" post F. The window and studs D and E need to be removed to make room for the French door. Studs D and E are only about 1/2" apart and may be loadbearing, supporting the middle section of the wall and the 2nd storey of the house but I have no way of knowing. I think I have to assume they are load bearing and I should run a lintel between the structural posts A and F as I think it would be dangerous to assume that B and C would be a strong enough to take the load. Any thoughts on the concept of my plan to this point would be very helpful.

I've bought a very sturdy 4"x5" beam from a local architectural salvage firm to be a lintel across the 9' gap between A and F and I'm thinking about what kind of joints I should use to secure the lintel to the posts and to the studs. Picture (2) shows how I think the lintel (dotted lines) would fit on the wall.

I think steds A & B have fairly straightforward cross lap joints onto the lintel as shown in Picture (3).

Studs D and E need to rest securely in the lintel and Picture (4) shows how I see that working. In all cases, I'd secure the studs to the lintel either with screws or carriage bolts or maybe I should glue them?

My main uncertainty is about the joints to use to attach the ends of the lintel to the posts. The posts are obviously heavily loadbearing and the major support for the building so I'm very mindful of the need to maintain their strength. The other thing is that they're fixed in position so although a mortise and tenon joint is the obvious candidate, because the posts are fixed I wouldn't be able to move either of them to one side to insert the tenon into the mortise.

Picture (5) shows one possibility. I cut a notch 2 1/2" high and say 2" into the post and cut a corresponding tongue into the end of the lintel such that the lintel can rest in the notch in the post. Accuracy would be important (and a challenge!) to ensure that all of the notches aligned, including the notchs for the studs. I see the primary negative on this as being removing 1/3 of the 6" width of the post and weakening it.

I have some very old dense lumber from an old barn and another possibility for attaching the lintel to the posts would be bolt support pieces of this lumber to the side of the post to create a slot for the tongue of the lintel to fit in. This is shown in Picture (6). In this case, the only weakening of the post would be from having the 4 (say) bolts that fixed the support pieces. My guess is that this joint wouldn't be as strong as the cutting the notch in the post but it does avoid weakening it and it would probably be easier on accuracy as the lap joints could be cut and the tongue on the lintel could be cut and then the bolted supports could be positioned afterwards to support the tongue wherever it ends up against the posts.

I guess the other possibility would be some combination of Picture (5) and (6) cutting a notch but maybe only about (say) 3/4", ensuring the lintel was embedded in the post and supporting it with support pieces as described in Picture (6). This would minimize the weakening of the post.

I'd be grateful for any thoughts on my project. I've pulled drywall off to locate the stud and post positions so I know for sure where they are.

Thanks

Andrew

Picture_1.jpg

Picture_2.jpg

Picture_3.jpg

Picture_4.jpg

Picture_5.jpg

Picture_6.jpg
 

nealtw

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OK I got about half way thru your post.

Let,s start over. What you have is balloon framed house. They did all kinds of things when building these houses, some for good reason and some for convenience of material available.
You don't have to and probably shouldn't follow their lead with fancy joints and methods.
In newer housed we have benefit of platform framing to make it easier to understand and work on.
The studs in your house are full length, so they directly support the floor above and the roof.
So first you calculate the load from above, do the floor joists or ceiling joists or rafters land or attach to these studs.
Or is there a center support for the ridge beam in the attic landing directly above this planned cut out.

You would treat the corner post as a king stud.
The header for a single door is 5" longer than the door is wide, 2 inches to allow for the frame of the door and 3" to allow for a jack stud on each side to hold up the header.
For a double 2' 6" door or bigger you add 9" to the header 2' for the frame 6" for 2 jacks on each side and 1" for the strip of wood they put between the two doors.
In normal conditions with nothing more extreme than the floor ,and ceiling and rafters above the engineers would not call for anything more than a 2 ply 2x10 header up to about 8 ft long.
You may be able to calculate weights and loads and come up with something less but with out an engineer I would want to just use the double 2x10.
 

Pavesa

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Hi NealTW

thanks very much for the thoughts. I'll work through what you've drawn to my attention and get back!

Andrew
 

nealtw

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These are for a better understanding of balloon framing

[ame]https://www.youtube.com/watch?v=5SiYkNaEPOo[/ame]
[ame]https://www.youtube.com/watch?v=PIiVOJpWuUY&ebc=ANyPxKq19ki1AKIoB3byfzQKkQ5KBKrWLopW2QMjiDbXMawV6oLukzpXgnHiQT0aTHphSfiaJyS144NI7eX1o1SY_aP5jkHFZw[/ame]
 

Snoonyb

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Hi

I have a project to install some French doors on the rear south side of my house overlooking the back yard and I'm wondering if anyone has any suggestions around my overall plan and also particularly on the kinds of joints I should use for the lumber. The house dates from about 1850 and is in a rural area and I guess in those days the back yard was just a general dumping ground so there are just 3 very small windows overlooking it, one of which is in the pantry! So, I'm wanting to convert a room on the back of the house into a sunroom by installing some French doors giving a view over the back lawn. The width of the French doors is about 6' so there are obviously structural implications as studs are going to have to be removed and I need to install a lintel to give support.

It's a 1 1/2 storey timberframe house and very solidly and heavily built. I'm showing a drawing, Picture (1),of the layout of the wall where I want to put the French doors. At each end of the wall is a heavy 4"x6" post marked A and F. Next to F is a window and to the left of this are a series of 4"x2" (genuine inches btw) studs marked B - E. The current window is between stud E and the 4"x6" post F. The window and studs D and E need to be removed to make room for the French door. Studs D and E are only about 1/2" apart and may be loadbearing, supporting the middle section of the wall and the 2nd storey of the house but I have no way of knowing. I think I have to assume they are load bearing and I should run a lintel between the structural posts A and F as I think it would be dangerous to assume that B and C would be a strong enough to take the load. Any thoughts on the concept of my plan to this point would be very helpful.

I've bought a very sturdy 4"x5" beam from a local architectural salvage firm to be a lintel across the 9' gap between A and F and I'm thinking about what kind of joints I should use to secure the lintel to the posts and to the studs. Picture (2) shows how I think the lintel (dotted lines) would fit on the wall.

I think steds A & B have fairly straightforward cross lap joints onto the lintel as shown in Picture (3).

Studs D and E need to rest securely in the lintel and Picture (4) shows how I see that working. In all cases, I'd secure the studs to the lintel either with screws or carriage bolts or maybe I should glue them?

My main uncertainty is about the joints to use to attach the ends of the lintel to the posts. The posts are obviously heavily loadbearing and the major support for the building so I'm very mindful of the need to maintain their strength. The other thing is that they're fixed in position so although a mortise and tenon joint is the obvious candidate, because the posts are fixed I wouldn't be able to move either of them to one side to insert the tenon into the mortise.

Picture (5) shows one possibility. I cut a notch 2 1/2" high and say 2" into the post and cut a corresponding tongue into the end of the lintel such that the lintel can rest in the notch in the post. Accuracy would be important (and a challenge!) to ensure that all of the notches aligned, including the notchs for the studs. I see the primary negative on this as being removing 1/3 of the 6" width of the post and weakening it.

I have some very old dense lumber from an old barn and another possibility for attaching the lintel to the posts would be bolt support pieces of this lumber to the side of the post to create a slot for the tongue of the lintel to fit in. This is shown in Picture (6). In this case, the only weakening of the post would be from having the 4 (say) bolts that fixed the support pieces. My guess is that this joint wouldn't be as strong as the cutting the notch in the post but it does avoid weakening it and it would probably be easier on accuracy as the lap joints could be cut and the tongue on the lintel could be cut and then the bolted supports could be positioned afterwards to support the tongue wherever it ends up against the posts.

I guess the other possibility would be some combination of Picture (5) and (6) cutting a notch but maybe only about (say) 3/4", ensuring the lintel was embedded in the post and supporting it with support pieces as described in Picture (6). This would minimize the weakening of the post.

I'd be grateful for any thoughts on my project. I've pulled drywall off to locate the stud and post positions so I know for sure where they are.

Thanks

Andrew
Bafore you start this project you'll need to determine if the 2nd floor, floor joist actually bear on this wall, because if they do not, you are not off the hook, there is just another method.

If they do you can simply build a temporary wall about 18" in from the new door/wall, the full length over A & F.

If they are not then you'll need to find the distance from the new door/wall to the 2nd, 2nd floor, floor joist, and build a temp. wall there.

At the 2nd floor you'll need to determine if the ceiling joist end over the wall above the door/wall and if they do you'll need to build another temp wall there.

If they do not there will either be a ceiling joist or a 2X nailing cleat nailed to the wall as a nailer for the ceiling. Set a 2X flat to the ceiling and brace back too a 2X above the wall below.

As for the new "lintel" which in framers terms is called a header.

The general rule for determining the size of a header is 1" in height for each lineal foot of length, double when supporting a 2nd floor. So you can compose your header from multiple pieces of lumber nailed together to achieve the 4" width.

I prefer dimensional one piece headers so I would p/u a 4X10 RO, (rough sawn), and install it between A & F.

The general rule for nailing headers to king studs is 1-16D for each inch of height, so 5 nails on each side.

Neal is correct, and opening 6' and over requires double trimmers on each side ok the opening.

I have a couple of questions;

Which direction and what size are the floor joist under the door/wall floor?

Is the new door going to be a store bought prehung unit, or are you composing it?
 

mako1

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Andrew what is your location? This could have something to do with the correct answer.
 

bud16415

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The OP called his house a timber framed house not a balloon framed house and his first drawings showed big posts at the corners and filled in with studs. He also showed a lot of joinery common in timber framing. He may well have a balloon framed house and is miss describing what he has or he might have timber framed / barn construction and in that case the studs he wants to remove would play no structural role.

Before we give any specifics on something like this I think some photos need to be looked at.
 

nealtw

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That was my next question, that's why I dropped off the videos.
I have been trying to figure out what questions to ask without ripping the house apart.
 

Pavesa

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Hi Snoonyb

thanks for the information and the videos links - very interesting and useful.

I checked and the joists (3"x8") run parallel to this wall so they aren't bearing on it. Post F (King stud) is the corner of the building so there's going to be a hefty beam running running perpendicular to the wall I'm working on to support the joists.

The door is a pre-hung unit to fit in. Under where the French door is going to be is a beam running along on top of a thick stone foundation wall. I'm attaching a photo - the beam is 7.5" x 7.5".

P1010723.jpg
 

Pavesa

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I should have added that the joists under the floor (ie/ those in the basement ceiling) run parallel to the wall with the French doors.
 

nealtw

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I should have added that the joists under the floor (ie/ those in the basement ceiling) run parallel to the wall with the French doors.
We have kind of moved on to figure out just what you have.
What ever it is the sill plate you showed in the last post could be found in any style
This picture has a little of both the gable end is timber framed and the side is more like balloon frame.
So the question becomes, is there a beam at floor level or are there open bays past the floor.

BSI-033_Photo_02.jpg
 

mako1

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That's why I asked where he was located and got no response .He may have a timber framed house or could be in another country with framing we are not familiar with. Judging from his OP I sure think that's a possibility.
I would not be so quick to give him advice on a ballooned frame home assuming he's in the US.
 

nealtw

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That's why I asked where he was located and got no response .He may have a timber framed house or could be in another country with framing we are not familiar with. Judging from his OP I sure think that's a possibility.
I would not be so quick to give him advice on a ballooned frame home assuming he's in the US.
Really old houses were timber framed in North America. Balloon framing started sometime after 1800
 

Pavesa

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Hi

well, it has that sill plate at the bottom of all the walls. I think there's a beam at floor level, certainly there's no open bays into the walls running down into the basement. I haven't had reason to tear the shingles off the outside much so what's behind them is a bit of an unknown.

I'm attaching a couple of photos which might give the experienced eye some clues. The one from the rear (with the satellite dish) gives a good view of where the French doors are going. They'll be on the sunny wall to the left of the satellite dish with the guttering pipe running down it. Post (king stud) F is just the left of the small window in the picture and there is an extension to the main building beyond that. Post A is where that wall meets the L out the back. There was no insulation in the L when we moved in and I was doing prep work up in the attic and occasionally a piece of plaster would drop down the inside of the wall and it seemed to fall right down to the bottom of the first floor wall although not actually into the basement. The other photo is from the front of the house.



I hope this helps!

P1010274.jpg

P1010266.jpg
 

nealtw

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That is a nice looking house.
I don't see a problem.
When you open the wall for this job you will be able to tell if there is a beam holding up the floor or not. If that beam is right above the studs it would be timber framed and you could not do much damage by just cutting a hole for the new door.
If the floor joist is along side the studs or let into the studs you will have to support the roof while you work on the new header.

If you can get to that section of the attic and see what the top of that wall looks like and see if you can drop things into the basement, that would tell a story. and if it is open balloon framing you should plan on doing the fire stopping talked about in the videos.
 

nealtw

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If it is balloon framed you want to plan the header so it reaches far enough so the jack and king studs don't land above the basement window.
 

Pavesa

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Hi nealtw thanks for the help, it's really appreciated. I'll be opening up the wall a lot to get the beam and the French doors in so I'll give it a good examination. The videos says 1880's was in the middle of the balloon framing and this house is a bit earlier than that, it seems 1850-60.

I think you're thinking the door will be on the wall with the satellite dish but it's actually going to be on the adjacent wall, the one with the inverted yellow bucket in front of it.

In fact, the attic is rather inaccessible now as it contains about 10" of blown-in insulation. I did a lot of prep up there beforehand and the top of the walls is rather difficult to see because it's 1 1/2 storey and the walls are at the bottom of the roof slope above the upstairs bedrooms.

The L was added later as there's a concrete conduit for a small stove pipe that leads through the wall from the main house into the upstairs of the L.
 

nealtw

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Hi nealtw thanks for the help, it's really appreciated. I'll be opening up the wall a lot to get the beam and the French doors in so I'll give it a good examination. The videos says 1880's was in the middle of the balloon framing and this house is a bit earlier than that, it seems 1850-60.

I think you're thinking the door will be on the wall with the satellite dish but it's actually going to be on the adjacent wall, the one with the inverted yellow bucket in front of it.

In fact, the attic is rather inaccessible now as it contains about 10" of blown-in insulation. I did a lot of prep up there beforehand and the top of the walls is rather difficult to see because it's 1 1/2 storey and the walls are at the bottom of the roof slope above the upstairs bedrooms.

The L was added later as there's a concrete conduit for a small stove pipe that leads through the wall from the main house into the upstairs of the L.
I did have the wrong wall and I figured getting to the top of the wall was tricky so we will just wait and see, I suspect that it will look much like the framing in the last photo I posted.
 
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