Hey all,

I have a couple of 4 bent barns that are failing in the same location: bents 2 and 3 tie beam to post connection. The pegs have failed and the walls are growing outwards as the roof sags downward. Folks who have tried repairing before I arrived have employed chains and steel cable which have stopped the progress of the failure, if only temporarily.

I have a number of great timber frame books that explain how to build new but have yet to find one that teaches how to (safely) fix old. Can anyone tell me of a title out there that addresses the subject. Is there an article in Timber Framing I have not found yet?

I'd love to craft an elegant and lasting solution for these barns. I am afraid that simply replacing the pegs is, while not disruptive to the historic fabric, a foolhardy solution as they have already proven to fail in this orientation.

I look forward to your wisdom and bibliographic references.

-Shawn

There is an article in Timber Framing on repairs. It is by Jack Sobon. He had the magazine with him last week, to show us some possibilities for our Dutch barn restoration. I don't know the issue number, but it was from 2003, if that helps. I plan on buying the TF CD, as there is so much info available in that magazine.

This book was published only a few years back and is already out of print - You could not buy it and go into the restoration business, but it is a primer on rigging and repair of timberframed barns, and is some of what you're looking for.

http://books.google.com/books?id=u2CNNwA...eFpnCyATrt9yLCA

Amazon lists it as out of print and unavailable, but at least has an image of the cover art -

http://www.amazon.com/Preserving-Old-Bar...5924&sr=1-1

Last I knew ( Last Fall when they finally opened a frame we built for them in '01 to the public ) the New Hampshire Farm Museum still had a couple of signed copies on hand, give them a call I'm sure they'd be happy to ship it to you.

http://www.farmmuseum.org/

It does sound like there is an insufficiency in the barns framing, is it just simple rafters ? With the ties doing all ? What is the GSL in your part of Michigan ?

Will,
Thanks for the tip on the book. I'll call the museum ASAP.

I don't have my copy of Jack's book "Historic American Timber Joinery" with me right now, but I recall him describing this dropped tie to post joint as common and also likely to fail.

The GSL is 90 PSF in Allegan County though the further you get from Lake Michigan that will decrease. Most of the barns I have met in Michigan feature 2" mortise and tenon joinery. One of these two barns is all white oak and the other is mixed hardwood. The posts are 8x8.

The load is carried by the 2x rafters to a scarfed top plate thence to the posts. The tie beam is in both cases about 2 feet below the plate. The only resistance to outward thrust was the pegs holding the post and tie together.

In most cases around here barns have been given many layers of roofing to bear up in addition to the snow load and farmers are loath to spend on removal and reroofing. I am not surprised these joints are failing but sure would like to find a solution to their problem.

In that vein, is there a preference out there amongst framers? Wooden repairs, steel brackets, chains, cables, ropes? I imagine it would matter if the barn was to be reused as a barn vs converted to a residence. It would surely make me nervous to live in a structure bound by steel cable but I image the cows and chickens don't mind.

-Shawn

Hey Shawn:

Some of these dropped tie-to-post connections had dovetailed or wedged tenons on the end of the tie beam, usually w/ a angled haunch cut into the post.

The dropped tie is not the best in my opinion. I've seen some barn books speak to this area/design as prone to failure.

Just a atraight tenon and a couple of pegs is really asking for trouble on this type of joint. Can you say "withdrawal?" Anyway, take another look at that particular barn and see if the tenon isn't wedged...from the outside under the sheathing if you can get to that area. Maybe it needs a new wedge (I know, too simple, right?)

Here's Sobon's book you mentioned. It's availible on the Guild's site as a PDF. Look at the dovetailed/wedged tenon (pg. 4) http://www.tfguild.org/joinery/part1.pdf


As far as guarding against future wall spread, once you get the walls back to plumb, or close, perhaps inserting some sort of ridge support is part of the overall plan? If the ridge can't sag, the walls can't spread. Maybe a number of vertical ridge supports is an option.

One should be able to view the wedge from the inside, on the top of the tie, they are through wedges. Most of the barns in my area have large staples/dogs installed to assist with this spread, I think it is helping.

Tim

Like you suggest it all depends on end use and engineering demands, we will sometimes inject even a timber system that looks out of place, so it will never be confused with original framing.

In your average utility barn I'm typically for doing the least visible and out of place looking repair that the owners budget will support, To at least try to keep it looking like it always has.

Sounds like a heavy steel strap over the of the tie, though the mortise and down the back of the post might be one way to go. But the bending issue would then return, how far is the drop ?

Introduction of a canted purlin post plate system to redirect much of the thrust directly to the tie and away from the wall plate might look and be appropriate, both now and originally...

There are umpteen approaches that can be taken.

But this isn't really forum fodder and isn't something to be conjecturalized about without much more information.

this post needs pictures, measurements, relevant snow and wind loads (thanks for posting those), etc... etc...

all solutions posed without at least some serious background knowledge of the situation is conjecture, fantasy, and potentially dangerous and / or expensive advice.


and yes, all those methods could / might / should work, depending on circumstances.

as to the comment on steel cable... when done properly it works pretty well... inside or out.

relax.

Mike – I'm fully aware there are questions posed here on the forum which should not be answered...

I'm also aware there are answers sometimes offered that the questioners refuse to hear and will not listen to.

And, I never offer anything up without careful reflection.

You said, exactly what I said, only without the seed of potential. No one could interpret my statement as instruction, clearly it was meant only to provoke thought. If we have to dumb down to the level of losing all undercurrent of discussion and leaving much unsaid, I'm afraid we are lost.

Perhaps you can accept that, I cannot.

So I have to ask directly, why the diss ?

Hey Will T. -

That wasn't directed at you... I agree with your post completely! I actually lost a longer post (forum software gremlins!) where I quoted you and called out essentially the same spirit.

Sorry for the confusion.
No diss intended.

I was speaking generally to some posts above yours (and in other threads) that were talking about joinery without knowing anything about the spans, loads, date of original construction, etc. etc. etc.

I agree with you, as from what I've read you take a pragmatic approach to these things.

One does not need to know every detail about a building to offer up suggestions.

The person who posted this topic (and anyone else considering posting a question, seeking advice, etc.) should feel welcome to do so without possessing a degree in engineering.

Obviously our advice is merely suggestion and not a set of plans approved by local code enforcement. That's why there is a disclaimer at the Forum start page about following advice here.

This medium is for all skill levels (regardless of how many stars one has above their name!).

Not everyone is capable of providing a detailed set of CAD produced drawings with all load specifications in their posts, nor should they feel pressure to do so.

I'm not suggesting that Shawn need a PE degree or background nor need to provide detailed plans - but I just don't understand how we can discuss joinery without knowing basic loads, timber sizes, bent configuration, species (he did give us that), details on failure, understanding the foundation conditions, etc. etc. etc.

Basic information about the size and shape of the building, bent or wall configuration, piece sizes, etc. followed by a few photographs would greatly help these types of posts. Follow that up with the suggestions and further questions and the forum would be that much more professional and useful to novices and experienced timber framers alike. A doctor wouldn't (shouldn't) diagnose you over the web with just a paragraph of information. Timber framers and builders and engineers shouldn't either.

All I am asking for is more information - and to drop the armchair quarterbacking until there is real, tangible data that would lead to possible solutions.

And while I would agree that one does not need to know every detail of the building - in my experience many of these things in old structures are linked... sagging plates or dropping foundation on one side can contribute to a spreading roof just as much as poorly design connections or undersized members. Shear at the top of a post could be related to piece size, lack of a ridge or purlins, removal of too much material for a mortise, removal or interior posts by a previous owner, etc. etc. etc.

Yes, lets welcome any and all comers... and lets send them on their way with sound advice based on data - images, numbers, configurations... etc.

I think talking about old barns and their joinery is often more of an intuitive exercise than a rigid disipline. After in depth observations and studys of these old structures, which often prove highly diverse in typology and design, one begins to form a conceptual framework {pun :-)} about old joinery and the mechanics of buildings. Any framer, carpenter, scholar, restorer, hobbyist, etc. worth his/her salt can draw not only from this personal experience, but the written works of others, which often reside in the memory of one's own mind.

So when someone says an old "four-bent frame w/ dropped ties..." many of us can instinctively draw on our mental pictures and can begin to offer up suggestions. Of course we then ask for more specifics and information.

Applying rigid parameters to timber frame construction, such as the difference in the carrying capacity of ash vs. pine floor joists, is likely quite young thinking.

Designers like yourself have grown up in an environment where there is no room for error because of banks, insurance and modern building codes. All details must be proven and tested before you can even pick up a tool. You rely little on your intuition and the accumulated knowlege of the craft. I would argue that this is not a good development in the building profession.

Old joiners and carpenters knew what worked because of hundreds and thousands of years of trade progression. Their fathers taught them. They did not know about exact snowload data, nor did they need to. Barns were built from 8x8s because that's just what you did. Timber spacing was "common knowlege." These buildings have lasted and lasted. Indeed, the TF revival seeks to emulate them.

Remember that in this post we are not discussing plans for a modern elementary school. Of course we must then have all data, both known and unknown.

So when you ask about needing to understand how we can discuss old barn joinery without knowing basic loads, timber sizes, bent configuration, species, etc... relax, many of us already know the model quite well. We can discuss with no trouble.

Don -

My formative years in the trade were surveying, dismantling, moving, repairing, and in most cases re-erecting a half dozen barns. Typology ranged from 1780's German (Pennsylvania) to fairly modern mid to late 1800's in Maryland. Mix in a trip to Ohio for one with massive 24" tall and 12" thick white oak swing beams (with 12x16" gunstocked posts) and another in New Jersey that had clapboards, evenly spaced windows, and slate on the main street side and board and batten and a few odd windows on the private side.

No need to assume that a young designer like myself wouldn't be able to intuit what the old carpenters did as common knowledge. While I currently design - I've cut my teeth moving from studying the old, working by hand, and proceeding on to the design side of things. No need designing things you don't understand... and most of my work is first intuition followed by applying the stats and data.

And 8x8 is not really a common barn size - in my experience it is far more common today in the 'revival' than it would be in traditional barns. Sizes that I've worked with ranged from 6x6, 6x8 to 7x8,9 to 8x10 to 12x16 depending on region and I suspect it had as much to do with what was available to hew as it had to do with 'common knowledge'.



If the model that was handed down from generation to generation works so well - why are we discussing how to repair or stabilize a failure? There must be a series of reasons for the failure...


I'm going to step away now and leave this to the experts, as there clearly must be a precedent for diagnosing repairs over the interwebs and calling out joinery and solutions without serious study of the problem - whether this means running an FEA on a proposed bent design or simply understanding what actually exists before submitting solutions that we might know from our past experience to work...

Thanks Mike:

"Stepping away" is probably best. I indicated that I would respect and leave my two cents out of the Automated Section and perhaps you'd agree to the same when it concerns traditional TF matters.

Mike - Thanks for clarifying, and I hope you find it understandable that I came to the conclusion I did.

I have not seen the thread you allude to or the willy nilly advice, but I have seen such before, and I will look for it.

If there is any serendipity to be found in this mess, it is perhaps that the idea of offering structural advice based a brief written description is simply not a good idea, and that thought has seldom been voiced here on the forum.

Will,

I'm not suggesting you were giving poor advice on another thread - but like you I have seen it before (on other website forums, in other categories on the TFG, even regarding unrelated subjects) and I think it is dangerous and unprofessional. Clearly the 'danger' part is relative to the subject and circumstances - but the 'unprofessional' part applies regardless.

And yes, I have the sentiment of your last sentence exactly. Giving advice to someone I do not know, on a structure I haven't seen, for a failure I haven't studied, with loads, circumstances, etc. I cannot verify - all based on 1 paragraph is foolish. Others may feel differently - fair enough. But simply claiming that there is a TFG disclaimer somewhere that absolves them of responsibility... well... I'll leave it at that.

The possibilities you list are all avenues I would suggest the author approach - and all possibilities I have seen in my travels and repairs of traditional barns on the central East coast. And I feel the way you posted was proper.

Again, apologies for the misunderstanding and I regret not re-typing the long post I lost to the forum gremlins.

Shawn's first and only two post so far have a lot of information. Some info left out is the height, width and length of the buildings? The post being 8x8, the tie 2' below the plate(is that an estimate?), many layers of roofing equating too much weight on the roof and more. Even photos here on the forum would not do justice, and you could send 10 different people to the site and still get a wide variance in opinion. I would like to see photos of the 2 buildings, if for nothing else to see the variations in building styles around the country.

I am curious if the post themselves have been stressed? They are hardwood, something I don't see in my softwood region. I am guessing, due to this, they should be holding up better than the spruce and pine 8x8's I see here. The buildings have been stabilized with cables ( the first stage) allowing some breathing room. I would strip the old roofing and install metal, lightening the load in the heavier times of the year.

I also like Will's suggestion of the strap running along the tie and out through the mortice and down the post, this is where the engineer comes in and gives lengths number of fasteners etc., if one wishes to go in that direction. Is the mortice a through mortice? They have used straps with a small truss on the end of it bolted to the inside of the post, running along the top of the tie, more engineering.

I would venture to guess that even with a well engineered building, time will through in some chaotic aspects that were not allowed and result in failure, war comes to mind.

Bmike also points out the foundation and how this could change other aspects of the building worthy of noting. By the way, what is the expected life of modern concrete, 150-200 years? What happens when these concrete foundations fail? Is concrete like vinyl siding, vinyl is final.

Tim

Mother Nature really has nothing better to do. Gravity always pulls things down, wind likes to knock things over, and water tends to get everywhere we try to keep it out of...

Some interesting reading I just picked up: The World Without Us

And a cute little video based on the book:
YouTube Video Link

Gents,

I am 1/2 way across the state on another job right now. I'll endeavor to get your requested pics and additional measurements asap. I appreciate your input.

My original post did reference these two barns with their specific structural issues in mind but I am also trying to gather ideas in general about dealing with outward thrust when the joinery is already in place. Your posts thus far have given me some great ideas and have helped me expand the brainstorming that I do before getting down to the engineering.

Working alone, as I do in SW Michigan, it is wonderful to have this space to share ideas.

Thanks,

Shawn

Hey Shawn:

Glad to know we're providing some insights. And glad to hear we haven't scared you off!

I also like having this space to share ideas. It's interesting to explore what's happening w/ these old structures as the decades and centuries go by. Reports like yours help broaden everyone's knowledge base. In this way, the Forum can enlist a growing number of "scouts" that can be drawn upon for historic / regional TF discussions before more of these buildings are lost to disrepair and the real estate cycle.

In your case, I think Tim's roofing suggestions are good elements to consider. If only owning a barn (re-roofing) wasn't so expensive they'd all be fairing better...

Looking forward to seeing more of these barns.

And don't take any of our advice too seriously, OK?!

I like Will's idea of steel straps. Pull it all together and button it up. Might almost be worth investing in a truck mounted drill press and small forge to bend the puppy into a nice outside post/ plate to tie beam unit on site. If only to omit lags/ threw bolts and use wood pegs. Cancel that order. ha!

Shawn -

Are you familiar with the Michigan Barn Preservation Network?

Might not be timber frame specific information on there... but could be a good resource.

I posted to a similar list when I lived in Ohio - the Ohio State Ag extension (if I remember correctly) had a similar sounding group.

-Mike

Yep, I have read up on MBPN and have met Steve Stier who is a wonderful man, a talented TF preservationist, involved in the organization of MBPN, and the man who started the Michigan Barn Survey.

I plotted a map showing all the folks listed by MBPN as involved in restoration. It can be found at http://maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&ll=44.079693,-84.847412&spn=3.993443,8.481445&t=h&z=7&msid=116553168999666214092.00046c3c8e63586d6336b

OK, back to the barns I mentioned earlier. Today, I'll post photos from BARN 1. BARN 2 later.

Posts and ties are 8x8 mixed hardwood
Tie is dropped about 20-21 inches from the bottom of the plate
Barn is 24'x40' with bents spaced approximately 10' apart
Two layers of roofing (wood shingles covered with corrugated steel) - the farmer is firmly against removing the roof and replacing it.
Foundation is 20 years old at the most. The, presumably, rotten posts and sills were removed and replaced with hollow concrete block perimeter and a monolithic slab floor. The perimeter posts are now 24-30 inches shorter than the posts in the center of bents 2 and 3. I say presumably because the current owner does not have the history though she does know that the previous owner, who replaced the sills with concrete, housed hogs in the barn.
Clearly the last 7 feet or so of the tie shown in close up needs replaced. When I knocked on it it alternatively sounded wet or hollow. The rest of the timbers seem to be without this kind of significant rot.

[img]http://picasaweb.google.com/lh/photo/Jo4AJja7gD1Dbnu3zkG1ow?feat=directlink[/img]


[img]http://picasaweb.google.com/lh/photo/ibSdtEjD1rKOGYth7V0-hQ?feat=directlink[/img]


[img]http://picasaweb.google.com/lh/photo/mhvIz62o5vVahWpmqQ6tPw?feat=directlink[/img]

Hope these links/images work. I am using Google's Picasa. Anyone else have experience with Picasa and the TFG Forums?

Ok, so now with images and more structural details, any more suggestions about limiting the outward thrust at bents 2 and 3?

-Shawn

to use picassa and the forum, go to your picassa image and look for the 'link to this photo' option on the right. select the resolution and be sure to check the boxes to hide the album link or whatever. then select and copy the text in the box, come back to the forum, press the image button and paste in the text.

Slick, thanks for the tip Mike! I imagine there is a similar way to drop in that google custom map too.


One of you gentlemen suggested a wooden solution might be to support the ridge with an additional post. Given that the barn has posts through its centerline that seems a wise potential solution. This barn is not utilizing the "loft"space and so such a solution would not be obstructive.


This is actually a corner post without pegs that seems to be withdrawing as well. In fact none of the braces have pegs in this barn either (nor peg holes). New pegs in all the empty holes would also help. When I examined this barn I did not find any evidence of a wedged dovetail or wedge of any kind. I did, however, stick my fingers in all the empty peg holes to feel for tenon relish and found solid wood throughout.


This section will need a scarfed replacement. The water damage was from a leak in the original roof that has been since covered by the steel roof.


I have plenty of truck straps to take up some of the thrust while working on the structure and a few bottle jacks to lift the ridge (potentially). I think replacing the existing steel cable with a new one without rust could be worked into the budget. It seems to me that placing the cable up at the plate instead of the post would provide more thrust resistance where it is needed. Any suggestions on how to keep the wood from getting crushed/marred/strangled by the cable?

Shawn, you seem to have left out in previous descriptions the canted queens, I may have missed it though. Are the rafters one piece or two, breaking on the purlin? At only 24' I am guessing full length. They are reduced at the purlin. If there is a break/segmented rafter has the rafter pulled apart at the break, right over the purlin? Just something that may be noteworthy.

The queen system should be assisting with holding back the thrust of the rafters, there is the strut backing the queen post up, but if the ends of the ties are compromised, like the one in the bottom picture, the strut has no base and I can see it drifting. How many ties have rotted, just the one? Do the others show withdrawal of the tenon, other than the one with the missing pegs? It would be my suspicion that the repair of 20 years ago only sured up the building, leaving it distorted, did they correct the foundation in a way that brought the building true again? Check all the lower wall girts to see that they are all in the same plane, a bench mark, using a water level or laser transit.

Once back together that corner post with the missing pegs, begs for 3 new pegs.

Tim

do you have any details of the history?

it is interesting that there is a mix of sawn and hewn pieces... i've seen this before - but usually the smaller sticks would be sawn - braces, struts, maybe rafters, etc... but this looks like that corner post is sawn. has that been replaced previosly? are the center posts sawn or hewn?

I'm with Tim, From your previous description, I thought the roof system in question was one of simple rafters, which is why I floated a canted purlin post / plate system as a potential repair scheme...

This does much to drive home and emphasize why it is not just unwise, but not particularly useful to discuss these matters without photographs and dimensions.

Tim has the key there, are the rafters one piece ? And how do they join the purlin plate ? Is there an abutment of some sort ?

I'm guessing there is, and I'm almost certain the frames problem is not that of a thrust issue, at least not in the way you believe it to be. If it were, that massive drop and the resulting moment (were the thrust left unchecked) would have broken those spindly posts which are incredibly weakened by section removed in joining braces at the same locale (really really poor design) long before pegs sheared or relish popped.

Are any of the tying joints pegged ? Missing pegs may have ironically helped save the posts when the dynamic changed.

I'm thinking, the geometry was lost when that tie fell away and some thrust from the section of the roof above it (part of two bays) was redirected to the plates. And that who ever placed those cables did not have anything with enough uumph to pull it back together completely, ( neither do truck straps nor typical cable comealongs - Just because TF'ers use them does not mean they are appropriate rigging for tweaking buildings in restoration applications ) and called it done, short of being done. Something that is typical of stopgap repair. They did however, fix the leak and stabilize the situation, which ultimately did save the barn.

You need to hire in a consultant that knows what they are looking at, and can recommend the right equipment to pull things back into contention and help you choose a proper tension scarf for the tie.

As an aside - Restoration is as much about rigging as it is about carpentry, which is to say it is as much or more about knowing how to read a frame and realign the geometry a frame was built to, than it is about cutting the repairs, and knowhow is as important as skill. It is a demanding business on multiple levels, and often entered into by those who are under-equipped and think they can just wing it.

It is typical of hungry carpenters to turn to barn repair during downturns in the economy, often as much bad as good is the result.

Tim,
I did not look for a break in the rafters but I would suspect they are continuous as well. Only the one tie has rotted. Ties are missing pegs/withdrawing at the corner post and at both sides of bents 2 and 3. In total 5 of 8 ties are withdrawing from posts. I did not check the foundation with an instrument, just visually, your suggestion is well noted. I could see now that what appears to just be outward thrust could have a couple of contributing factors. I'll check with my water level next time I am back at that barn. I agree with the new pegs in any open hole. Even if the forces in this barn are beyond the shear strength of pegs they have to provide some additional strength to the structure.

Mike,
This is the fifth barn I have run into in SW Michigan that has a collection of sawn and hewn beams. I have not run a study yet to see if there was a size limit for local saw mills above which beams need hewn but it does seem to be the larger beams that are hewn. As an alternative to a "size restrictions at a mill" theory I should say that Jack Sobon mentioned he had run some numbers on his apprentices hewing work vs sawn timbers and found that timbers 3x5 and smaller were more economical to have sawn and anything larger his apprentices could manufacture for less than a mill. It looks like just the plates, ties, and purlins are the only hewn members in this barn. I would suggest it was a length issue not size. The center and corner posts are sawn. I can not offer any information about the pictured corner post being potentially replaced.

As far as history in SW Michigan. This area was settled in the 1830's and was known for it's hardwood forests. Forestry gave way to agriculture as the trees disappeared. TF building slowed by the 1900's and was extinct by 1930, having been replaced by pole barn and stud construction.

Hi,

Just stepping in and out with a question. These last few posts in here are great. Will's post attempt to answer the "Why" of the situation. I find this part the most interesting.

Will, when you say the "tie fell away". What do you hypothesize caused this. If I am understanding correctly, the canted posts are supposed to negate the thrust, which would in turn negate the tension in the "tie". Is this thinking right? If it is right why would the tie fall away? That midspan post I expect contributes to this equation in some way.

In the second picture, you can see the tie is away from the housing and it appears that the tie has dropped from the force of the strut and canted post. I can see this making the post bend above the tie (extremely it looks)from the rafters falling with. So does that mean the ridge is dropping in the middle bays? Does the ridge have a concave sweep to it when looking at the barn from outside? Would looking at the plumb cuts of the rafter at ridge, give an indication of how much this ridge has fallen?

Sorry to butt into this great topic. Im a firm believer in answering Why before What to do now.

Really appreciate everyone's knowledge around here.

Mo

I find it interesting that the braces weren't pegged. As they work in compression, and in pairs, I guess you can get away without pegging, but it is certainly not common in the barns around here. The tie beam pegs being missing is a real mystery. Not much to hold the frame together without those. Good job on the pics, my interior barn shots always come out very dark.

My horse barn is a mix of hewn and vertically milled timbers. All of the scantlings and at least one of the posts was sawn on an up and down mill.

I agree that a hewer can match some timbers in cost, depending on the labor rate of the hewer. Over length and larger cross section timbers demand a higher bd/ft rate at the mill, especially the long stuff, requiring specialized equipment. Three years ago Jack mentioned the turning point was an 8x9 timber over a certain length, probably over 24'. Most mills get about $1.50 a foot for pine/hemlock in that dimension. That's a $216 timber.

Hi Shawn:

Nice to see more details.

The vertical ridge supports I suggested would be convenient w/ posts already there at midspan of the building. Of course the existing posts need to be sound enough / large enough and on footings capable of handling the added compression.

Will's advice on getting some professional opinion is wise. Though there's nothing wrong w/ offering up suggestions here--many forum members have a lot of experience--there of course could be more issues at play.

And I also see a lot of mixed hewn and sawn stock here in Maine. I agree that it's a length issue. Most mills could only handle about 24' of length, which is why the longer members were typically still hewn.


And no dovetailed/wedged tenons on those tie beams? That really is a poor design. Not much stopping any withdrawal.

Good luck; keep us "posted."

Mo – You have it there, the thrust was redirected away from the wall plates and the tying joints, and perhaps completely negated, until the Tie fell away, (rot took it, a spot leak high in the roof, guessing water ran down the strut and sat in its mortise, the adjacent purlin post and its connection to the Tie and the Purlin Plate likely warrant close inspection, a resistance drill might be in order) when the Strut and Tie were lost, everything changed about the way the loads traveled through the frame. This dynamic changed again when the cables were placed.

And there are potentially, and more than likely, other things at play in there, which is why a trained eye should be brought in.

Ok, so I have met Tom Nehil, of Nehil-Sivak Engineering in Kalamazoo, through a timber framing course at Tillers International. I imagine he would be an acceptable trained eye for such a project and familiar with the local timber building styles and structural requirements. What services should I be requesting from an engineer for a project like this? Any guesstimates as to the cost of such a request? I imagine the benefits would certainly be worthwhile and valuable though there is a limit to the repair budget for this simple barn.

-Shawn

i buy the whole 'length' argument on the hewn vs. sawn - but there are other posts in the frame that are hewn. is that post the only sawn post? or are there others? if it is the only one, it may be a clue to the history of the structure... or maybe the hewer bought stock in a local mill by the time he got around to that post.



as to questions to an engineer - be careful here. find someone first that does barn repair work - then perhaps they can recommend an engineer sympathetic to your needs. otherwise you may end up with more steel cable, flying buttresses, or a sky hook.

kidding aside - a tension scarf may be tricky to pull off in situ, so you'll have to get creative with how it gets pulled together. will t. is right - correcting / repairing a barn like this is as much about rigging as it is about woodworking.

based on what i've seen (and i'm no engineer, just dangerous enough with how it all works for people to think i might be) i agree that the geometry changed and developed outward thrust at the plate. if i have time i might model it as an FEA just for fun to see what comes out.

Shawn – I can appreciate budgetary concerns, but there is much there, and it is probably an easier chore to bring it back to its intended working configuration than you might imagine. I also have met Tom, he and his partner were guest speakers at the PDW a few summers back. While I'm sure they could be of great help, it may be less expensive and answer more questions if you brought in a timber restoration specialist, as they might provide more insight as to rigging scenarios, they may also have a better eye or methods for finding signs of rot ( a timber that has been wet over a sustained period, will often look relatively sound on its exterior but be compost inside – look for water stains, mold and listen for hollow thuds – And that resistance drill was not a stretch, perhaps IML can point you towards someone in the area that has one ) in the rest of that Tie or adjacent members,.

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Though...

Running calcs on that tension scarf will be in order, the dueling struts will see be having it doing its duty.

Speaking of the struts, they usually fall over braces, I can't tell for certain from the photos, but have some of the Tie to post braces been removed ?

You should expect to pay their going day rate plus mileage, plus a fee to prepare a report if one is desired.

Best with it -

Will,
Regarding struts and braces. In the first photo you can see in the bottom right a brace but in the third photo (which happens to be the opposite side of the same tie in photo 1) no brace. It is literally hanging on by a wire. The owner was installing some romex and happened to attach to that brace with a staple. Soon after the brace fell out, remember no pegs, but has not been lost due to its connection to the electrical wire.

I'll try to catch up to Steve Stier this week since I'll be back in Lansing for another job. He should qualify as one who has barn restoration experience.

I think it is starting to come together, this thread and the barn, at least one of them.

The bracing effect of the barn is lost, it must have a lean in one direction, probably in the direction of the rotted tie? Is the wall plumb? I think back to assembling bents on the ground and things are moving right along and realize a brace has not been installed, we have to back things away to get the brace in, it has to come apart a fair distance, distorting the frame. This barn has done that.

Tim

Tim,
The 4 corners are relatively plumb but the long sides definitely bow outwards at the top plate mid barn on both sides.

That makes sense, the corner post that has withdrawn still has me wondering, missing pegs? I am wondering if when it was stabilized they took the pegs out to allow it to come back and never finished trying to bring it back, the pegs were not reinstalled??????

Tim

Anyone got links on any available books on barn restoration?