Hand-in-Hand framing

Howdy,

Colonial Era. 1720's. No engineers, self described architects, or general contractors. Just Master Builders. Woolley and Tomlinson were there names (house-carpenters!)

40' x 40' rooms

Spanning 40' with a floor system is kinda tricky. 40' timbers might be hard to find and if you did, serious deflection anyhow. So they came up with putting queen post arrangements in the partition walls above the hand-in-hand (or grillage). Does this seem ingenous? Anybody know where they could have found precedence for this? Any other thoughts on hand-in-hand framing.

These are kinda of cool to examine.




Credit where it is due. Peterson, Charles E. and Nelson, Lee H.
Building Early America

Hi Mo,

Great find ! I can see elements of Serlio floor joist arrangements on the left and right hand side of the floor plan. This is reciprocal framing and if you check out my Christmas book list you will find a reference for a well illustrated new book concentrating on this timber framing technique.

Both the flooring and wall arrangments are typical Georgian town building techniques and this is still present today in significant quantities in major cities like London, Edinburgh & Boston however most of this timberwork is usually completely concealed by plasterwork and floor boards or in the case of high quality work the wall framework is covered by expensive stretched fabric (silk) finishes.

I am interested by your opening statement and would ask how you are able to make this statement with any degree of confidence ? Is there documentary evidence that substantiates this claim ? There are a number of good Georgian timber framed building pattern books (Newlands) and thus I would rather suspect that the design of this type of building is not actually first principals conceptual design work but more stylistic copying.

Can you also please explain your "hand in hand" framing term ?

Regards

Ken Hume

Hi Mo,

I have checked through my books and can now advise you better on this topic and have taken the liberty of extracting and quoting a small passage from The Repair of Historic Timber Structures by Dr. David Yeomans (ISBN 0-7277-3213-7) where he says:-

"re The New Carpentry

These developments are also dealt with in contemporary carpenters manuals, of which the most important are by Price, Nicholson, Tredgold and Newlands. Francis Price (1733) produced the first, well-illustrated book on carpentry. It was comprehnsive and above all the most accurate of the books appearing in the first half of the 18th century. Peter Nicholson, who first published in 1792, and Thomas Tredgold(1820) described the situation round the turn of the 19th century. A large number of titles were published in the name of Peter Nicholson, continuing till the mid 19th century, while Tredgold's work was revised and updated throughout the century. James Newlands also provides a good account of carpentry at that time."

It would therefore appear that Wooley and Thomlinson were already working in "The New Carpentry" style at least 13 years before the publicatation of Francis Price's book. Can you please reconfirm your date for this work and also provide a full reference re the Peterson, Charles E. and Nelson, Lee H. publication and hopefully also a weblink.

Your discovery is more than just a little exciting being very relevant to our understanding of the devlopment of The New Carpentry style and thus this topic really should have been posted on the TTRAG forum where we could solicit further expert advice.

David Yeomans was our structural lecturer on the Masters course at The Weald & Downland and so if you require I can raise this matter directly with him on your behalf.

Regards

Ken Hume

I am very interested in the pins (rivets?) that are attached to the flat straps which are then pinned through the queenpost. The drawing implies an oblong shaped slot presumably shaped so that the strap portion could be slid up through the beam, then the head of the rivet is large enough to overlap the sides of the slot for bearing so that they are not pulled through.

A very small chain mortiser might make easy work of the slot, I suspect they did something different, any thoughts on how this might have been accomplished?

Hi Mo,

I sent a note earlier today to Dr. David Yeomans and he has just come back to me with the following interesting information concerning Mo's post and which I am posting here on his behalf :-

" Thanks for bringing this to my attention. A more comprehensive account of the Serlian floor can be found in 'The Serlian Floor', Architectural Research Quarterly, 2 (1997), 74-83 an article by me and refers, inter alia, to the floor at Independence Hall shown by Mo. The origin of Mo's illustration is:- Nelson, Lee, 'Independence hall: its fabric reinforced' in Peterson, Charles E., Building Early America, Radnor, Pa: 1976. Lee Nelson worked for the National Park Service and was the architect in charge of this restoration. It was he who got me interested in restoration. I think Lee used the term hand-in-hand framing. The first published account of it is by Serlio - hence the term that I use, but Villard d'Honnecourt shows something similar used for scaffolding.

I'm not sure how I would add this information myself as I'm not a member of the Timber Framers Guild."

Regards

K Hume p.p. Dr. David Yeomans, Manchester, England.

Take a look at the floor plan - now imagine those darker lines as arms, with hands at the ends where they meet at a right angle to the connecting beam... 'hand in hand'. Similar to configuration I've seen at 'square', 'contra', or 'called' dancing, with 4 persons circling, each with an arm (hand) in towards another - but all 4 locking together.

Hi Bmike,

This is an absolutely fascinating explanation. I wonder if you or others can provide illustrations for each of those terms. I just checked the TFG Glossary and these terms are not included so we really should get them added for the benefit of all. I shall let Dr. Olga Popovic know about this discovery.

Regards

Ken Hume

Fascinating indeed.

You all should have access to edit the Glossary as a Wiki.

Please confirm that you can, or I'll need to write a small tutorial.

http://tfwiki.org/mediawiki/index.php?title=Main_Page

Hi everyone,

Ken, no I can't back up the opening statement with any degree of proof. I thinking more along the lines of what we think of those professions today. I was reading a little bit of a book about the lives of the carpenters during this era in Philadelphia. I probably am a little bias, in that I want to believe they encompassed all of those roles.
The book is:

Moss, Jr., Roger William. Master Builders: A History of the Colonial Philadelphia Building Trades. University of Deleware, Ph.D. 1972

This book (a dissertation) describes the lives of these carpenters and their roles in society instead of the works they built. Pretty interesting.

According to Nelson, "To the best of our knowledge it was one of the largest buildings in the colonies at the time of construction, which commenced about 1732 and continued in the 1740's"

I found the book Reciprocal Framing that you mention when doing research. Neat book.

Looking through the Microfilm at the library Tregold was found. Most of the names you have mentioned are familiar with a little research that a team of us was doing.

Paul, That is different and an odd shape for those straps. None of the literature in the chapter addresses the tooling process of that diagram. Looks like one bore, then I don't know...

Here is a picture of what bmike was talking about.


Anyone got any ideas on how they raised this? From the research there are no chase mortises present.

Hi Mo,

I have experienced on several occasions when I have established conceptual and / or working designs that once these are delivered into the hands of others that a perceived change in ownership can take place especially where money has changed hands. The builder has a high public visibility and is often credited with the work whereas in fact he really might do nothing more than construct the ideas of others. There are also opposities to this experience, for example, it is generally accepted that Hugh Herland devised, designed and built the new hammer beam roof for Westminster Hall (1390's) but it is unlikely that he built this himself. It is more likely that someone like the Bishop of Winchester who maintained a large workforce and operated in a similar fashion as a general contractor does today actually built this edifice. Who should get the credit ?

Thanks for the illustration and the term "Hand-in-Hand" now makes perfect sense.

I can send you a PM of the full refs for the books referenced by Dr. David Yeomans if that will help you with your researches.

The author of the Reciprocal Frames book - Dr. Olga Popovic will attend the UK Carpenters Fellowship Frame 2009 event in September and this will provide those interested in this technique with an opportunity to learn a bit more about her researches on this and other timber framing topics.

This is a good post Mo and has promoted interesting discussion. More please.

Regards

Ken Hume

I have been following this threas and each morning I read it and go over it and go back and look at the first drawing. This morning there it is, thanks for the hand in hand picture, bmike and Mo, perfectly clear now.

If someone can create an idea in his head but has to have someone build it, it should be a shared credit, wouldn't you say? The idea/thought is just that, without the builder, whoever he is, the idea stays in that dimention. The builder brings the idea into a phyiscal dimention.

The workers under the bishop should get the credit, in my book. Why do we not hear about them? Too low on the spectrum, perhaps. Where did the bishop get his ideas from?

Tim

Are you talking about the hand in hand floor beams?

I would guess the beam pockets in the masonry were deeper than needed and the beams were slid in too far and then back out to engage the mortise. They would also have needed to scaffold the beams until the connections were made.

Hi Tim,

Strangely enough we do know the names of the craftsmen involved in the making and building of the Westminster Hall hammer beam roof and also even the names of the cart drivers who carted hundreds of loads of finished timbers from Farnham to The Thames for onward transport by barge down to Westminster. This job was incredibly well documented I suppose because such good financial accounts were kept by the Bishop's bailiffs. I think that I have a *.pdf of this information somewhere if it is of interest to you.

Some artists design works of art in timber and then get craftsmen to make the works of art to their design but the accreditation lies with the artist and not the craftsmen. I don't like to give the impression that I am promoting a downer on craftsmen however many more people can make or copy things but few can conceive original ideas. I concurr with your idea for all round recognition but that is not how it seems to work - life's not fair at times !

Regards

Ken Hume

Mo, this post is really interesting.

A great example of documenting the history of TF through the internet. In less than a week there's been books quoted, and enthusiasts from two countries talking to each other. Imagine seeking this info 10-15 years ago.

"Hand-in-Hand" looks a bit like spokes in a wheel, but w/ a square hub. It would be a neat way to frame a floor for an opening...maybe a stairwell. And the exposed beams would make for a unique display as the ceiling below.

Thanks for posting!

Surprised no one has taken a stab at this one. It's a great question.

My guess is a drill started it, then maybe a long narrow "keyhole"-type handsaw? Or maybe a file/rasp of some sort??

I was surfing around during this weekend's snow while feeding the woodstove and critiqueing Christmas cookies. I read a thread on another forum about a reciprocal roof which lead to a link that mentioned Dr Popovic. The concept of the roof was intriguing and I was having a hard time wrapping my mind around it. It seems to be a modification of what is being discussed here.
It worked with any number of members greater than 3.

The connections were just 1/8" holes drilled with #12 copper wire loosely hooked through to prevent the members from sliding. I was fully expecting a collapse but it was quite strong.

Just call me easily entertained.

nice!

That's interesting... a good example of "many hands make light work."

for the purposes of quick math, if you weigh 200 lbs, each of the 7 "spokes" only need support 28.5 pounds.

No thrust on the walls, either?

Is this like building something twisted to its furthest extent, there for it can't go any more? Take common rafters for example, but they exert thrust on the walls. If you release them from their accepted form by twisting them into this new approach, there you have it? Could torque be involved? Where does the energy go?

Don, was it a complete wrap of the wire and twisted off? Did it relax under your load, stretch to tighten up, just a bit?

I may have to give this a try.

Tim

Nice Don P

Some good information here on the geometry.

This post was slightly modified in order to respect the copy rights of the Author of the book in question. It appears to have been uploaded to SCRIBD without her knowledge or permission.

I just did a little figuring, this could be cool, If I'm doing my math right, apparently by dumb luck I'm at the hairy edge of breaking this thing.


So if we carry that thought further... At my weight I point load each rafter with 27 lbs.
Each rafter in this case is simply supported beam. With a point load at a distance-"a" from one end.


I measured the sticks, they are 19" from the foot to the upper hole, 15" from the foot to the lower hole, so the holes are 4" apart. The sticks are 15/16" square (.9375")

Maximum bending moment is under the joint in the 2 rafters
Mmax=Pab/L
Mmax=(28lbs*4"*15")/19"
Mmax=(1620)/19
Maximum bending moment=85 Ft/lbs

Section modulus required= (Mmax * 12)/Fb This was clear (Select Structural) white pine so NDS allowable Fb is 1250psi.
Sr=(85 Ft/lbs*12"/ft)/1250psi
Sr= (1020 in/lbs)/1250psi
Section modulus required=.816"^3

The formula to determine section modulus of a rectangle is (breadth *(depth*depth))/6
I drilled a 1/8" hole vertically through the rafter at the point of maximum bending moment.
Sm= ((.9375-.125)*(.9375*.9375))/6
Sm= .714/6
Section modulus of my rafters=.119"^3

I would need a section modulus of .816 to be code, I had .119, so I was just a tad overstressed, by code it would need to be about a 1-3/4"x1-3/4" rafter in the model to be safe. But it didn't break... I wondered why. I pulled out the "Wood Handbook" and looked up the Forest Produts Labs test data. Average modulus of rupture for clear, dry, white pine is 8,600 psi
Going back to Sr= Mmax/Fb I plugged in average modulus of rupture for Fb
Sr=1020/8600
Sr=.1186"^3 I was a cookie away and living dangerous

There have been more posts since I started ciphering and we got rained out today;
Timbeal, I bent the copper wires straight on the underside this morning, they were just an L shape to keep them from dropping out. Stepped up on it and no difference, held just fine. There is some thrust caused by the deflection of the rafters but not the thrust of an untied pair of rafters. IMO if the rafters were sized correctly for deflection then there would be no thrust. Seems like it would be simple enough to put a tension ring around the outer perimeter though.


Since it hadn't failed yet I had my wife start handing me books.

It supported 230 lbs and failed at 235 lbs, the failure was at the hole, the point of maximum bending. Backtracking through the math;
235/7=33.57lbs/rafter
Max moment was 106 ft/lbs
That works out to a MOR of 10,690 psi.
My guess here is that my test apparatus is not frictionless so some of the load was "absorbed" as axial column type loading between the rafter foot and the floor, the deflection thrust. But, off the top of my head that is also within the coefficient of variation in the material, maybe my white pine is better stuff than I thought. I'm not positive of any of this, still just trying to wrap my head around it.

Thanks for the links bmike, more to read.

SOunds like an article for Timber Framing. Are you game?

nice breakdown donp!

i started to step into a model of it... but i'd be lost down that path for days - so i stepped away from the temptation and went back to looking at pictures of bicycles on the internet... (while trying to get some work done...)

wondering about the tension ring. i don't think the point load transfers out the length of the rafter - rather it would want to roll the rafter and try to slide down its mate, before pushing straight out - twisting the entire structure perhaps?

obvious in your example that it is not needed in a straight down load, and add some shear planes to it (sheathing, boards, something) and it starts to become a very stout structure.

check out that first link - there are some geometry calcs in there for getting to optimal member sizing vs. number of spokes.

Don
In your mock up, you are not distributing your weight evenly over all of the beams. Chances are the beam that broke had far more weight on it than the others did. Not quite fair for the poor little stick that broke.

Thane

small piece of ply on top would solve that... except then you would be loading the tips of the rafters first. tricky to get it loaded 'evenly'.

A tall live load which is swaying to and fro transferring more load to one foot or heel. Dead weight evenly distributed using a Styrofoam my work better.
Even still, the little roof stood up well. If that was full size it could hold the "Green Giant".

I hear a little gorilla glue will fix that right straight again, and still hold up.

All very interesting.

Tim

Joel, that makes me feel good but I'm certainly out of my league. Surely we can find a more knowledgeable writer on the merits of Christmas cookies

Thane, that picture must have been taken during the unbalanced loading portion of our testing. But yes, this is far from scientific or exhaustive. I did try to distribute my load on it better this morning.

I've been doing some reading in the links Mike posted, try this on for size. In a flat reciprocal frame, what Mo introduced this thread with, a grillage floor system, the members have no axial load, they experience only bending. The math I used above should be a fair fit for that situation. This is a model of grillage floor beams atop walls, they could be joined together in one flat plane.

As soon as the members begin to incline they begin to act partially as a column and partially as a horizontal beam. Take the cosine of the rafter angle and multiply it by the load. I think it would yield the bending load. The rest is travelling down the rafter as an axial load.

As an example if the rafters in my model were 20 degrees from horizontal;
Cos(20)= .94, so 6% of the load is axial and 94% of the load is bending the rafter

Now stand them up more
Cos(45)=.71, 29% of the load is carried by the beam as a column and 71% of the load is causing bending.

Getting closer to reality?

Hi Don,

Your reciprocal rafter failure looks like its the result of extreme fibre bending stress followed in turn by a horizontal shear failure.

Regards

Ken Hume

I love empirical testing! Hope you didn't roll an ankle in your quest for the truth. CB.

that design would make an excellent free standing bouldering cave, for rock climbing. in fact it may. just add plywood and tnuts. thanks for the inspiration

Serlio floors, how much fun is this?

Cheers, Chuck

Here's another one. It started out as a model of DaVinci's temporary bridge, another hand-in-hand frame. Laying some purlins and common rafters on it and a roof wasn't too difficult.

Anyone have a good ideas about running 4" hosing for central air? The reciprocating timbers are 15" deep.

This is definitely one of the challenges of a reciprocating system; no continuous joist bays within which to run utilities. Short of cutting in large holes and then supporting the weakened timber with corbels or knee braces, anyone have some suggestions?

Cheers, Chuck

drop the timbers a bit, or raise the plate and add a 2x6 lightly framed floor atop the timbers. timber>1x T&G>2x6>sheathing>finish floor - it also gives you some room for plumbing, electric, can lights, etc. etc.

pack it full of cellulose and it also deadens sound transmission between floors.

Hi Mike, thanks for the suggestions.

We are really trying to have the reciprocating timbers visible, both from above and below. It would be a shame to go to all the trouble of making this floor and then covering it up with decking.

While we will be sound deadening and covering the ceiling in parts of the house, in other parts, we want the floor decking visible, to give an enhanced feeling of space.

I really don't want to cut a bunch of holes in the timbers though, so, maybe, it is just a small boxed out chase running around the perimeter of the house. I have the headroom for it, and we can make it look a little sexier than just a box.

I wish they had Cadet chiller units as well as heaters; that would be handy.

Cheers, Chuck

I'm to assume then that you are using bone dry material - or have an interesting detail where the timber meets the finish floor...

IME with shrinkage I'd stay far away from trying to get that interface to work out. To me finished floor + top of timber + even minimal shrinkage doesn't sound like a winning combination.

Good luck. Curious as to how it works out.

Hey Chuck,

Is there a basement under the shown floor? You have the openings in the center of the floors, do you have plans for what goes there?

I wonder what Serlio would have done with modern conveniences? Possibly a full study of solar exposure and stone placement to radiate and cool..

Don P, that is really neat. enjoying your models. did you assemble the model as it would be raised at full scale? whole nuther can of worms, huh?

Hey Mo, que pasa?

This floor is the ceiling for a lower floor. I am voting for clear plexiglas in the reciprocating openings around the posts; there will be knee braces underneath the floor and it would be sweet to be able to see through the floor.

Mike, let's, for the moment, assume that we are going to use green oak for the floor beams and the decking. I am expecting a significant amount of shrinkage, no doubt about it. The decking will sit in rabbets cut into the reciprocating timbers. We will be giving the entire floor surface a grind and a rough sanding before finishing. What part of this would give you concern?

Thanks for the good luck wish; I appreciate it!

Cheers, Chuck

the 'green' part gives me concerns when integrating it with a finished floor - specifically tying the floor surface together with the top surface of the beam. the green oak part makes me want to run far far away.

your clients are looking for 'rustic', right?





green oak will shrink, then shrink some more. and then some more. and it will twist. and check. i've built several porches with white oak, and a frame or two with red, and plenty of structures with RF dried red oak. i wouldn't use green oak for the design you are trying to achieve. i might be convinced to try it with RF dried fir.



you are looking going from green to 'interior of house dry' in the neighborhood of 5% radially and 7% tangentially. so depending on how those timbers are cut - 3/4" to 1" is possible.

Here's a great PDF from the UK. See page 23-24.

Red Oak

White Oak


So your flooring notch will have to account for minimal shrinkage along the length of the floor boards, but plenty of shrinkage across the top of that oak beam, and you will end up with gaps @ the floor / timber interface - more on the long edge to long edge interface, and less on the long edge to butt edge interface. and that flooring will most likely cup... so you'll want a grind well along into the process, most likely after you get a season or two of heating into the space.

DonP on the forums could probably elaborate much more...