When reusing barn beams in a new structure, what should I do about old mortices? I was thinking about making snug fitting wood plugs to glue in place as the original tennon would have, then cross drill it and drive peg through, and finsh the plug and peg flush to the beam. I do understand that old mortices should be oriented in areas of the beam that will see lower stress where possible. Do people do this when reusing barn beams or do they do something else?

Plugging up the hole is a good start but adding a peg is probably unneccessary. Also by doing so you basically cut through the wood fibers and therefore you actually weaken the beam further.
I would recommend turning the mortises up so that they end up under compression when the beam is loaded.
If there are mortises on both sides you might have to support the beam at say midspan.

I believe that piece of wood is called a "Dutchman".

Dave

Ah yes. That is what I was thinking- plug on compression side of beam. I would not be drilling a new hole, but reusing the existing hole from the original peg that wehn through the mortice. The new peg would fill the hole to give it more strength as well as cosmetically making it not stand out so much. Thank guys.

brad,

I don't think you will be able to regain much strength by filling holes. Especially in a beam. If more strength is needed, your best bet is to get another bigger or sounder piece of wood. An engineer is a good person to have on your team if there is any doubt (and there usually is or at least should be).

Now, if you don't like the looks of the empty holes, then plug away. I personally would rather look at legacy joinery than contemporary dutchmen.

gook luck with your project,

Gabel

What is legacy joinery? trying to use existing mortices? It may be possible every now and then, but the new structure will be a very different design.

I plan to compensate for the morticed areas of the beam by upsizing the beam size to compensate. I had the plugging in mind for looks and maybe to get a small percentage of the strength back (in compression).

And I am an engineer (ME). I'll be refreshing myself in truss/statics loading analysis and stress analysis. I'll also definitely have my worked checked by another professional with this type of experience. The more cross checks the better. Being able to do much of the calculations myself will allow me to experiment with designs and get close with the minimum sizing of members.

I've plugged old beams on several projects and I like to use old tenon tips. I'll trim them off salvaged beams and save them for this use. As far as strength goes , don't rely on an old beams for support structurally ! They should be used as a decorative feature and be required to carry there own load only. Most old timbers are stronger than new sawn ones , but mortices and notches can obviously weaken the timber. When in doupt over build. There are also several methods for re-iforcing a spanning timber from above(if head room allows) to eliminate posts.

brad,

Legacy joinery is joinery from a previous life, and I didn't mean to imply that you can reuse the joinery in a new structure -- there are way too many variables to allow that to happen often. I will repeat that I think trying to regain strength by plugging old mortises is a losing proposition.

As for aesthetics, I have done it both ways -- filling the holes with carefully chosen color/grain/hewing pattern-matched dutchmen, as well as leaving the old mortises open. It's all up to the client.

Being a framer with a history problem, I like to be able to see the hand tool marks inside the old joinery myself. I can see how they did things and what tools they used, and it seems that I often see things I've never noticed before.

Tell us a little more about what your planning to build-- sounds like it will be fun.

gh

Being somewhat foreign to most of your terminologies used, I do have to ask: Why are the plugs called dutchmen?

When I do plug or "dutchman" I like to think I'm adding my own history to the pieces and it will drive someone else nuts trying to figure why that darn thing was plugged. We sometimes leave a message or coin or what not inside too. Every timber project is a mystery for someone in the future to puzzle over. Yeah why are they called dutchmen ! Gotta go my typing finger is cramping up.

ooooooo I like that...
Is it yours, Derek? Or did you do it for someone else?

I am designing a house, my house. I am a newbie to Timber framing, but before you jump on me let me say that I am an ME and have artistic ability. I have managed many large projects and am accustomed to the kind of work large projects entail. Now here's where you'll probably jump on me...
I am planning my house to entail one large great room that is (at present) 40X46. This great room is sub divided into 6 spaces - 6 16X16 foot rooms at the four corners, 2 14X16 rooms in the center on each side and a central hall that is 7 feet wide the lengh of the room(46ft). when I say room or hall, I don't mean there are any interior walls. The center of the room has 4 posts that create the so called division of the rooms(also necessary to support the weight of the 2 center bents). They are really just spaces that will each be used for something different. The room will also be used for family holiday parties. We typically have 40-60 guests. The ceiling in the center is 18feet. The roof is broken and from 18 feet up is a bonus room with 7 foot knee walls(if you can call them knee walls). The peak of the roof ends up at 32 feet. The bonus room is 15 feet wide and 46 feet long(can be divided). Breaking up the roof with the bonus room allows for 16 foot roof rafters on the lean to's and 12 foot on the bonus room.
The point of this structure is to have one large room on one level for family get togethers and so that activities are done in one area - living room with TV, Office, kids play area...what what ever else is decided. One level so there is not constant going up an down stairs - let kids do that, when I'm old, I want only 1 level living.
This structure looks like a tall barn with lean to on each side. The outside lean to walls are 10ft. I am just in the creative stages of this structure now. I am also looking at doing a basement whereby large concrete cylindrical piers will rise from the basement floor to the main floor providing support for the posts. I envision coating all of the concrete as well as cladding the peirs in wood from floor to ceiling much like an oak barrel with steel bands. The posts and beams will be grand too. Attached to this grand structure will be another timber frame where the roof is 90 degrees to the 1st structure. This will hold the large kitchen, bathrooms, master bedroom on 1st floor, kids bedrooms upstairs, Mud room, foyer. I'm not sure if this will house the garage or if it will connect to the garage/shop. I already have a Steel I beam frame workshop ready to assemble(which will be assembled first on the site).
I can dream big can't I? The grand hall will be framed with very large recliamed clear non-barn beams, the bonus room above will likely use reclaimed barn beams, and the living space attached to the grand hall will as of now use reclaimed barn beams.
This is the initial thinking. It will likely be revised as I'm still sketching it up and working out details. I'm not ready to post pics yet, but will in the future.
Some have called me nuts, but then had to take it back when I did what I said I was going to do...

Brad,

I like the way your thinking big. With a structure that big have you considered using an extant barn. Browse some of these "Project Tours" to see both a barn transformed into a house and a "new" structure crafted out of old timbers.
http://www.lanoueinc.com/project_tours.html

I look forward to hearing more about your project.

PS - I hope this link comes through.

sounds like a great project.
keep us posted.

gh

In due time sir, in due time. I'm starting with the ultimate fantasy layout and then doing some cost estimating(already done some rough calcs) to determine what is really feasable and then looking for ways to save money or cut costs. I don't want to be stuck with a lot of house and not be able to afford to finish it or furnish it either. In the mean time I'm going to keep my eye out for a nice doctor to marry
The way to achieve big things is to dream big and have the will to make it happen. What was it that Jesse James the bike builder said.. "I like to bite off just a little bit more than I think we can do".
Alright, alright..here's the first sketch of the first end bent. A couple beams and braces are still missing from this pic, but it shows the idea of the layout. One square equals one foot. Bonus room is on top. All area below bonus room is open (no floors or walls). The doorway frame is shown. In the middle two bents, the main posts are set further inboard in line with the doorway posts.

BB: One thing jumps out at me right away, and that's the top rafter pair. There's nothing tieing the rafter feet together. Since the roof pitch is less than 12/12, the outward rafter thrust will be greater than the roof load. In your case, the center posts will experience a large bending force right where the shed rafters come in. Also, the joint where those posts join to the upper tie beam is in a great deal of tension. You'll have to do the math to see if your post is big enough to handle the bending, and the joint is tough enough to handle the tension. CB.

Daiku's right ,neat design but looks weak up top. That be a good place for a hammer beam truss. If you're gonna dream dream big. Collar ties would probably work to.

It also looks to be about 10ft. taller than our local zoning would allow. Something to check out before investing a lot of energy on your design.

Yep, as I mentioned, there are a few things missing from this drawing. I didn't draw in the tie beam between those upper rafters, but did realize I need it there. Like it said, it's just rough first sketch and needs refinement and adjustment. Maybe I posted it too early, but I figured you all would want to get an idea of what I was thinking about. I do welcome all of your comments though as I'm sure others will see something I miss.
As far as zoning, don't know the rules yet, but It's going to be out in the country. When I get a design I like in a few weeks, I'll start looking into county building codes etc.

Brad,
It's the 21st century. Thanks to managed care, most doctors make only a little more than timber framers. Go for a lawyer

What is going to be in the upper part of the center structure?

It seems really high unless you are planning on having a third floor. It looks almost 3 times as tall as it is wide through the center. If theres a second floor in there that would help, but if you have any open to above areas from the first floor they might tend to resemble and elevator shaft.

You could keep your peak that high is thats the look you want and lower your control points (change your roof pitch) That would help lower the exterior walls and solve some of the structural problems already mentioned.