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#33005 - 06/05/15 07:50 AM Re: Barn comission conundrum [Re: timberframe]
TIMBEAL Online   content
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Registered: 12/10/07
Posts: 1871
Loc: Maine
If you're considering these splices, factor in the extra time to cut them. I am sure sourcing long timber would be a time and cost savings as well as a more sound structure. Any splice is not as strong as a splice. I could see splicing a couple or fixing for repair. To install all splices is going overboard. You can cut all the other joints on the post in the time it takes to make the two halfs of the splice, fit them and have them come out nicely. If you client has cost restraints you will we working for no return.

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#33006 - 06/05/15 08:37 AM Re: Barn comission conundrum [Re: timberframe]
timberframe Offline
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Registered: 08/23/11
Posts: 25
Loc: Canada

I agree completely Tim, was thinking along the same lines, thanks for the reinforcement though. Time to talk turkey.....

B

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#33007 - 06/05/15 09:23 AM Re: Barn comission conundrum [Re: timberframe]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 469
Loc: Vermont
I agree Tim, yet here are some thoughts/observations from over the decades...

I think in this case getting longer timbers is probably the much better plane, as they really aren't overly long...Not like a 40 tie beam or an 80 rafter plate, both of which are hard to work on and transport effectively or fiscally ($) easy to logistically manage either.

It does always "seems" faster in short view of this game to have full stock timber...yet perhaps the big picture would reveal more?

When we step back and really consider big stuff above 8x8 (these I think Brent said are 10x10) there is something there to think about. When we have truly examined all the logistics of log acquisition, transport, human ergonomics of lifting, moving, rolling, etc. the aspects of "splicing" starts to reveal perhaps a better path, as a smaller timber size...sometimes...may well rule out over using larger stock, or at minimum it works out pretty even.

As for strength, these joints evolved over millenia to try and incorporate as much "regained" strength" as possible...yet...I do agree they, on there own, no mater how well executed are going to be of lesser strength than a full natural timber. I would like to, however, suggest a few observations to the contrary or alternative of this.

I think when we state things like that...again we are loosing perspective of the larger picture. If we don't cut any joints in a cant (ie timber) it is strong, yet we wouldn't have a timber frame without those joints we cut. Placing joinery of all types...including splices...in the logistically correct spots they need to be is the..."art"...we practice. So adding a well planned, laid-out, cut splice to a column/post isn't really that much more deleterious...overall...than any other joints per se that we must cut...

I would also close with a very important aspect of this recommendation thus left out...glue. When this is added back into the equation for a splicing joint, we can usually not only regain complete strength back, but often (and these joints are heavily tested and even have competitions around them in japan) end up with a timber that would fail outside the area of the now "cut and glued" joint, just as rope breaks outside the knot rather than at it...

One added incentive...If after all the tally is in and it reveals a cost that is about 50/50 either way...I say lets pay ourselves for cutting neat joints and using joinery to solve our timber framing challenges...not just getting the biggest sticks we can... wink

Just some additional food for thought...ultimately do what feels right to you and the client with blessing from history's lessons of past timber frames...
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#33008 - 06/05/15 01:24 PM Re: Barn comission conundrum [Re: timberframe]
TIMBEAL Online   content
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Registered: 12/10/07
Posts: 1871
Loc: Maine
I hear what your saying, Jay and have no disagreement. I am expressing my view. I also have a mill at hand that is capable of cutting 70' My day hours are a mix of farm/lumber/framing mix and I get ancy sometimes when some aspect take from another. I try to be aware of how my time is dispersed.

Also, after 25+ years in the trade and I'm about to hit 50 I'm always looking for shortcuts but still retain the "art". More lodging of joist and long timber. Design buildings that work for us, and less we work for it.

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#33009 - 06/05/15 02:33 PM Re: Barn comission conundrum [Re: timberframe]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 469
Loc: Vermont
No worries Tim...this is a common academic discussion among all us Timberwrights.

It is more a "view on a spectrum" than a "due this or do that," kind'a thing...which I bet we both agree on 100%

Someone with your tooling and skill sets would be working against logic (and maybe common sense) to not take full advantage of the kind of tool and knowledge resources you possess. That is also why I hinted at the "chainsaw" milling aspect (or even hewing) as many project job sites have large trees "on site" that could be fashioned into very long timbers...and...that is part of our craft also.

I really do like keeping as much work "in house" as possible for each of us as Timberwrights. You like me also have experience being our own logger and sawyer...which I wish this was still a more common practice as it was with the House, Barn and Timber wrights of days gone by...

I'm actually more prone to "go big" than just joint...but...I have the skills to hew/mill my way to get what I want...just like you do. Which is better than jointing...I agree... grin
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#33010 - 06/06/15 05:49 AM Re: Barn comission conundrum [Re: timberframe]
Jim Rogers Online   confused

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Registered: 03/14/02
Posts: 1598
Loc: Georgetown, MA, USA
I was originally thinking that the scarf in a post to make it taller would be best at the base of the post. I just thought that the top above any other joints may be where there is some stress that might not be the best location.
What would be wrong in putting a "post extension" on the bottom of the post and keeping the top in tact from top tenon down to post extension scarf?

Jim Rogers
PS. post scarf location maybe a question for an engineer to answer.
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#33011 - 06/06/15 07:37 AM Re: Barn comission conundrum [Re: timberframe]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 469
Loc: Vermont
Usually when we see then at the bottom (the most common location as Jim has pointed out) it is either to replace an already standing frame post bottom where the it has been comprised in some fashion or it is planned from the beginning with a stone scarfed plinth as illustrated in the link I shared.

I think, in Brent case, the goal is not having to mill or handle a really large long post. This may not be perhaps such a challenge for some, while for others, both wight/size and transport/cost logistics are inhibitive. In this case, after considering also Tim's insight and from past experience, I would centralize the splice and probably make in a meter or perhaps longer, it must be reinforce with adhesive there by rendering the timber virtually whole and solid once again. I would most likely incorporate the through tenon of the "anchor beam to also lock and tighten the scarf. In that scenario, I believe we get the best of all worlds. Two shorter almost equal sized timbers, and good location that works in concert with the other timber joinery. It may perhaps even become somewhat invisible if cut using a version of the recommend kai-no-kuchitsugi (clam shaped splice.)

That, at least, would be my solution if I had to split the timber into smaller size for any reason. I have had this discussion with Ben years ago at Fire Tower PE and noted several more "approved" forms as just described while studying the Asian original forms. I do agree with Jim, that checking in with a PE is advisable if uncertain of ones skill sets in such advanced joinery placement, or at minimum discuss all pro/con with client as it affects cost.

Regards,

j


Edited by Jay White Cloud (06/06/15 07:44 AM)
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#33012 - 06/06/15 08:32 AM Re: Barn comission conundrum [Re: timberframe]
Dave Shepard Online   content
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Registered: 02/19/06
Posts: 705
Loc: Alford, MA
The problem I see with scarfing posts is that you don't want all of your posts to be scarfed. On my last Dutch barn restoration I scarfed five posts, and replaced the other five. This was the architects decision. Having available material length dictate your design is really tough. You may have to broaden your search for a different mill.
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#33013 - 06/06/15 09:07 AM Re: Barn comission conundrum [Re: timberframe]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 469
Loc: Vermont
I think David, that much of this is perhaps a perspective on a very subjective continuum. Scanning back through every point made by each of us has its validity either in a give situation or from a given perspective.

When discussing "new work" it is vastly different in my mind and ethos from that of heritage conservation, restoration, or reconstruction. Here I tend to be a very "hard liner" following a strict ethic as set down by the likes of the Burra Convention, where "like for like" in means, methods, and materials" is a cardinal mandate of any heritage work, with regard to architecture/artifact restoration/reconstruction. Conservation efforts are different in the since that elements of modernity are often employ, even though all efforts are suppose to be made that these be reversible.

I think the concept of placing scarfs in multiple location in "vintage material" may have some merit as the necrotic elements of a vintage frame are all that typically requires the repare, so by that nature could/would be in multiple local. Brent's dictates are different than what would be reflected in a heritage Dutch Barn. Thus far the material logistic that Brent faces may be more of a challenge and constrictive.

Material do often dictate design and for this reason we see the fast range of different timber framing modalities between regions and cultures whether it is a Japanese Minka, Indian Kath Kuni, or some Pacific North West Tribal timber structure. Material and method dictum's are the norm in my view of this craft. Kind'a like the old adage the Amish I learn this craft from would say...

"...we plow with the horse we have...not the one we wish we had..."


Edited by Jay White Cloud (06/06/15 09:10 AM)
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#33014 - 06/06/15 12:25 PM Re: Barn comission conundrum [Re: timberframe]
Dave Shepard Online   content
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Registered: 02/19/06
Posts: 705
Loc: Alford, MA
My point about scarfing all the posts had nothing to with restoration. I only mentioned it as a basis for my experience as opposed to just someone with an internet connection and an opinion. We would have scarfed all of the posts to save the historic fabric, but that was deemed to be inadequate by the architect, Jack Sobon, and we decided to put five new purlin posts in to give the frame more strength.

I am aware that materials dictate design, but in this case the preferred design is in the North American range of English or Dutch construction, and they use a lot of longer timbers. I don't think I've seen a thread yet were you haven't tried to mash some other, usually Asian, framing "modality" into the mix.
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