1840's Barn meeting current code

This is my first post, so thanks in advance for the assistance.

I have an opportunity to purchase an 1840's timberframe barn in Ontario. It is a 30 X 40 feet, with 4 bents. The cross beams clear the entire 30 foot span with no posts. The beams are 12 X 12 pine. There is also a "Swing beam" that is 19 inches high in the middle and tapers to 12 inches on the end.

I'm not sure I've given enough information, but my question is how would this design meet current requirements. We are looking to move the barn to Alberta, it would have a metal roof, but I don't have details on the pitch or truss design. The current design has 10X12inch purlins (spelling?).

Thanks.

I'd like to see some pics of that 30 foot clear span and the configuration that does it. First question is, are you trying to turn it into a home? I assume someone told you it "wouldn't meet code". Specifically what aspect are we talking about? Snow load? Structural? Electrical? Heating effeciency? If you're turning it into a home, a certified engineer in your county should analize the design to determine if the structure is sufficient for the snow loac for your area, the live loads you will add for second or third floors etc. If there is a problem, they can suggest ways to add to the structure to meet those requirements. Hopefully if they are good and experienced with timberframe (find and pay someone who is) they can do it so the additions are subtle, or fit in with the style of the frame. If by pass code they meant the specific condition of the timbers, they can be inspected and graded if necessary, and any sub-par components replaced, or damaged components replaced. Sil timbers in barns are not typically reused due to their proximity to the ground and moisture. The bottoms of post can be cut and the height shortened, or a repair to the post made. Perhaps the person could have meant that the height of the barn would not be allowed where you planned to re-erect it? In towns there are often height limits in residential areas. You definitely need to ask more questions and gather more information. Barn frames have been reclaimed and used many times.

Thanks for your response. I'll try to clarify. My concern is that I like the idea of a 30 foot clear span with no supporting beams. However, I'm concerned about meeting snow loads. The frame I'm looking at was raised in 1880 and put on a block foundation. The condition of the timbers are in perfect condition thanks to some additions on the side of the barn that made the walls "interior" walls.

I am looking at adding a second floor to a portion of the frame for a master beadroom / loft.

I'll try to get some pictures this weekend and some better measurements.

Thanks for your insights.

Welcome RCB,

Not to familiar with Canada and their provinces and such. are we on the same latitude from its original home to the new one? First thoughts and (in my opinion) if their is no decay and it has been standing since 1840.... put it back together and work around it. it has worked this far.

By the way if a structure has been standing from 1840 and it doesn't meet current requirements than the current requirements are bogus (in my opinion).

p.s. yes purlins

p.p.s. what is a swing beam?

p.p.p.s if you can somehow propose that you are extending the life of something old, you might find a loophole to shoot down "current" requirements.

hi, was reading again. 10X12 purlins?! is this right and if it is what are the size of the principal rafters they are joined to?

There is a compelling logic in your question: if it's stood for 170 years, what could codes possibly have to say that is meaningful?

My cautions would include; changes in the weather, and in the use of the structure, and deterioration of foundation and timber over time. (We say a major, major change in the snow loads in NH a few years back; new numbers developed from 50 years of observation.)

All this sidesteps any notion of life-safety-health codes that the revitalized structure might reasonably be expected to meet.

Here in Live Free or Die New Hampshire, a fellow can reasonably expect to be able to build any old thing for his own use, but still be properly held to modern standards when building something for public use or sale to strangers.

It sounds like a beautiful barn. 10x12 purlins? Principal purlins with common rafters? We will see.


Tim

Some current requirements are bogus, but... if the use of a structure changes there is good reason to look it over. I've been in one barn who's broken beams were being supported by the feed bunks. I doubt in a conversion those would be there. After looking through a barn on a property a friend moved to I told him to stay out and to keep his boys out. Although it had stood for over a century it collapsed within the year. I've worked on several old homes that had joists that were well overspanned. Two I can think of were downright scary. They had stood for over a century and the angels were getting tired of flapping. We live considerably heavier now than we used to and with different serviveability tolerances. None of those sound like this barn but a critical eye is money well spent.

Google "swing beam barn" and you'll find lots of info. Here's a couple.
http://www.howellfarm.org/farm/barns/fish_barn/lessons/anatomy%20fact%20sheet.pdf

http://www.circlerockinc.com/images/gallery/gallery-9-lg.jpg

welcome RCB:

What comes to my mind is a 40' building w/ only 4 bents... that's a large spacing of ~13' or more. Perhaps that's why it has such beefy timbers.

Of course, the steeper the roof the better it will handle any snow loads. The code requirements for rafters typically decrease as pitch increases.

Again, that's a large bent span. Perhaps even more of a consideration w/ those softwood timbers. But there's a lot to be said for the test of time.

Thanks to everyone for their comments.

Here's a link to a website that shows a picture of a similar barn to the one I'm looking at. The top right hand picture of the "1840's Moffat Barn" shows a large horizontal timber that is conciderable thicker in the middle and tapers to the end. I believe this is a "Swing Beam"

http://www.historiclumber.ca/salvage2.html

In fact the rafter and purlin system is similar to this barn as well.

I'll try to get some additional details to share. Appreciate the help.

Here's another link to a better picture of a "Swing Beam"

http://www.historiclogandtimber.com/timberimages/scotlandbarn4.jpg

I believe the name "Swing beam" was given to the beam so that you could swing a wagon being pulled by a horse around inside the barn.
If a post was there holding up the beam then there wouldn't be enough clearance to swing the wagon around.
But I could be wrong.....

To me, the problem here is the large clear span - 30' and then trying to add a second floor on it. This is an engineering problem. As you go beyond 24 feet, the stresses increase dramatically. I actually have the same problem in that I want a 30 foot clear span and second floor living space above. I haven't gotten deep enough into it yet however.
It sounds like you need to be working with an engineer to determine all of the loads that will be applied, and how much load your frame can support. As is, it probably can't support both the snow and live loads of a second floor, as that is not what it was designed for. So then you have to look at what you can do to increase it's carrying capacity. That will mean moving bents closer together, reducing the width of bays to see if is sufficient to carry the loads. If that's not good, then increased timber size and careful analysis are in order. If it comes to that, your're then going to be building a frame from scratch.

Depends, hay is not light. I do agree about span increasing stress. When a span doubles the bending moment quadruples, the span is double and the load is doubled.

Jim I have heard that as well and seen drawings depicting that, I don't know for sure, these barns typically have a drive through pair of doors, so I don't see the need to turn round, but that sure doesn't make me certain one way or the other.

So you are assuming a hay loft. He said it was a 30 foot clear span and he was PLANNING to add a second floor. To me this implies that it does not or did not have one. It's always in the details...

DonP

if your barn is anything like what is pictured in the links... do not be deterred. this is stronger than anything you could buy.

that beam is strong enough to swing a carriage. look at it.

by the way as you go beyond 1 foot the stress increases dramatically!

decreasing the spacing between bents might be a good idea, maybe not. chances are this was over "designed" based on good carpenter intuition. don't be deterred the live load of a couch, chair, dresser and a couple of people ain't that much.

Nothing can be said until the frame is disclosed....

Thanks folks. I'll try to clarify. I am looking at turning this frame into house. My question around the "code" is exactly what brad_bb mentioned in his post:

"the problem here is the large clear span - 30' and then trying to add a second floor on it. This is an engineering problem. As you go beyond 24 feet, the stresses increase dramatically. I actually have the same problem in that I want a 30 foot clear span and second floor living space above."

I appreciate everyone's input. I'll try to get some additional details in the near future.

well you can do some basic engineering calcs yourself. Although it has withstood the test of time from a snow load perspective I would not put any type of dwelling on a 30' span from what you have stated are beam sizes.

Building codes here in canuckistan state a structue needs to comply to engineering rules. New or used building!

When in doubt buy local....find someone to cut you a frame out west based upon a traditional design. By the time you are done with this project, hauling, erecting and engineering you may just be better off starting from scratch!