"cheating" post and beam construction

[Night Raider]

jfl,
Thanks a lot for explaining that.  What did you mean by truss?  The slope runs perpendicular to this opening, but building a truss is appealing too, I wasn't looking forward to trying to handle a 20' log that big.

Thanks

[jfl]

Night raider:

Here is a link to a thread on the a milling shed:
http://www.norwoodindustries.com/townhall/viewtopic.php?t=2190&highlight=sawmill+shed+truss

What I mean by truss is exactly what is shown on the last photo, copied here for your convenience:

 



I'm not saying that this design is exactly what you need, or that 2x4 or 2x6 will be good, that's the idea.  What I intended to do personnally (I'm looking for a 10x24 shed) is to use 6x6 and build a 6 foot high by 24 foot long truss:




On the top member, there is the bending load and the compression load.  Those have to be checked and might require a larger piece (6x8 maybe? I haven't looked at it)  All the other member work in compression or in tension. I'd use don's column calculator for the compression one.  Just to illustrate, let's calculate that for my shed:

The total load shown on the model is 50+100+100+100+50 = 400 (I was playing with shaped) Your load is 3800, so lets say that the number in that model have to by multiplied by 10 to fit the reality. So the largest compression force is 212x10=2120 lbs in compression. Since it is in diagonal, the member length is 6 x 1.4142 =8.5 foot or 102 inches. I punch those numbers into don's calculator at:

http://www.forestryforum.com/members/donp/columncalc.htm

I use the cheapest wood I have on my property (aspen: Northern Species #2, Fc = 350 MOE = 1.1 million) and I get a column capacity of 23931 lbs, so way above what is needed.

For tension, as far as I know, there is no stability factor to take into account, so you just multiply the surface by the strength, so 6x6x275 psi= 9900 lbs.  Still many times more than needed.

The difficulty will be the connectors. The connectors also have to support the compression or tension strenth. That is as far as I got into my reasonning, but I'll be checking the metal connector mentionned above in that thread: it looks like what I need.

jf

[Brad_bb]

Why post and beam?  I mean, as my timberframe teacher once said, "It will take the same time or less to cut real timberframe joints than it will to fab the metal brackets and fit them, so why not do the real thing?"  No metal means no rust or rot from the interaction of metal and wood and water. 

[jfl]

Why post and beam?  I mean, as my timberframe teacher once said, "It will take the same time or less to cut real timberframe joints than it will to fab the metal brackets and fit them, so why not do the real thing?"  No metal means no rust or rot from the interaction of metal and wood and water. 

I'd be interested in «doing the real thing», mostly for cost (8x8R post cap to put a beam on top of a post from Simpson StrongTie is something like 140$!), but then I bought a few books, including "Timber Framer's Workshop" from Steve Chappell and researched in this forum and I found out that it joint have to be build tight, at least to 1/32th of a inch or 1/64th.  I have problem cutting wood up to 1/8th of a inch with a skill saw... (ok ok, maybe I can be as precise as 1/16 of a inch if I take my time and use a guide). But I don't see how I could be more precise than that with a wood chisel? Correct me if I'm wrong but if the joint isn't tight, it will not hold (be strong and reliable).

This brings me to how long it takes to make a joint: I've already read a thread on that subject a long time ago and I don't remember any conclusion: It depends on the joint. 

Which brings me to another question: Most of the time, traditionnal timber framing is done with wet timber, mostly because it would take forever to dry them and them (unless you use salvaged lumber).  Is it more difficult to chisel dried timber than freshly cut timber?

Don't get me wrong: I think Timber framing is an art and as such it's worth more than industrialy produced stuff.  But to hang on the wall, I'll take buy the cheap reproduction of the Mona Lisa (poster) instead of a an original painting from a living artist...

jf

[witterbound]

How long does it take to cut a joint?  It depends on many factors, principally, what kind of tools you have.  For example, I can cut a 2"x6" mortise with my mortise machine in about 5 minutes.  Then if I want the joint housed, it takes about 20 minutes for the housing, which I often rough out with a forstner bit.  I've found that I average about 45 minutes for most joints.   

Laying out the timber and joinery often takes as long as cutting it.  As with everything, you get better with practice (and more tools!).  I believe you will find that traditonal joinery has many rewards, but it takes time to do.  The metal connectors will save you a lot of time, if that's a constraint.  Just like most things, quality takes time.

Before you venture down the road of doing it the old way on a big project, start with something small.  You really need to attend a workshop or find a local timber framer to give you some learnin' before you tackle anything big.  You can't learn it all from a book.

Yes, it's more difficult to chisel dried timber than green.  Much more difficult in my experience. 

[Jim_Rogers]

and I found out that it joint have to be build tight, at least to 1/32th of a inch or 1/64th.  I have problem cutting wood up to 1/8th of a inch with a skill saw... (ok ok, maybe I can be as precise as 1/16 of a inch if I take my time and use a guide). But I don't see how I could be more precise than that with a wood chisel?

We have discussed, here on this forum, and on other forums about timber framing the level of accuracy or the amount of "tolerance" allowed with joinery. Once in my research of tolerance of joint connections, I walked around a conference trade show asking each timber framer I saw what did they consider the correct tolerance between two mating surfaces. And my questions was; "is a business card thickness between two parts of a joint to much space?" A standard business card is about 20 thousands of an inch as I remember it.
Some said yes it was too much, some said no. I felt like I was getting as many different answers as the number of people who I asked the question.
When I asked this question of the framers who take about old structures and they said they have seen as much as 1/8" gap between mating surfaces. Well of course they would, as these structures they are repairing may have stood for 100 years or more. And the timber should be completely dried out.
When I asked the engineers in the group, they said that load goes to stiffness. That means to me that if a joint is sloppy and loose then it doesn't have very much strength in holding up a load.

We often hear the phrase: "you learn from your mistakes." Well, this is true, but I like to learn from other people's mistakes and I've seen many, at times.

One that really stands out to me, and I learned a lot from this beginner, was about tolerance. He asked an engineer, a well known timber framing engineer, about tolerance between mating surfaces of joints. And the engineer told him it was ok to make sloppy joints, and what he explained was that the tenon could be 1/8" thinner then the mortise. So this beginner did that, and constructed his house addition with loose fitting joints.

I have been back to this addition since I helped him raise it. It has stood for several years now, and it doesn't look like it's going to fall down anytime soon. But, the wood has dried out a lot over the last few years and things have started to happen. Some of the joints have really opened up. Some timbers have really twisted. He used Douglas fir tie beams, for strength, but didn't put the correct tenon on the end and used a small spline instead. There was nothing to hold the timber true and it twisted out of the plane of the bent.

You have to understand and compensate for the drying of the timbers when using green wood. If you leave a gap there now, how big will the gap grow when it dries out? And what will the effect to the frame be if it does grow to be a bigger gap?

In my opinion, there shouldn't be a business card thickness between joint mating surfaces. If you cut a 2" mortise then the tenon should be 2", less just enough for it to slide together easily, without pounding it together with a commander. And not too loose.

To check joint tolerance, we use a framing square to go into mortises:



And to check the tenon we set a caliper to the outside of the framing square and use it on the tenon:



And then to check the tenon like this:



If the tenon is too thick then the caliper will leave a scratch mark on the tenon. Remove the scratch marks with either a chisel, slick or plane and the tenon should be the correct size.

Correct me if I'm wrong but if the joint isn't tight, it will not hold (be strong and reliable).

Correct it should be the right size, but not over tight.

Is it more difficult to chisel dried timber than freshly cut timber?

Yes, dry wood is harder than freshly cut timber.

As to how long it takes to cut a joint, as mentioned, it depends.....
The more experience you get the faster you go, without sacrificing accuracy.

At workshops, I've seen a beginner timber framer, a middle aged man, take 4 eight hour days to cut all the joints on one post. In the same workshop, I saw a teenager, cut four timbers in four days. It all depends on the skills of the person.

Welcome to the forum and
Keep asking questions.....

Jim Rogers

[Brad_bb]

It seems to me that jfl has some misconceptions due to lack of learning.  Don't shut yourself off to learning about timber framing.  I also highly recommend a attending a workshop.  Even if you will not be building yourself, you learn a lot at a workshop, not only tons about timber framing and getting some hands on experience, but you learn principles and techniques that you can also apply to other types of building, wood working, and more.  I think most of us TF'ers are always open to learning, well most of us anyway. 

Heck, believe it or not I just attended my second workshop that was hand tools only, and I learned how to properly use a hand saw.  It's amazing to me how this simple skill has disappeared in both construction personnel and your average DIY craftsman.   With a properly sharp handsaw and knowing the proper technique, you can make very precise and very square cuts.  You can make much more precise cuts than with your circsaw. 

Today I actually taught my cousin how to use a handsaw.  He has used one many times in the past, but told me he never could get a straight or square cut.  Well today in just 5 minutes of instruction, he made his first precise, square cut with a hand saw.  Trust me, once you gain this knowledge, you'll be reaching for your good handsaw more often than your circ saw. 

But back to my point... like with the handsaw example, once someone shows you the technique, and educates you on the theory, you'll see that things are not as complicated or difficult as you now believe. 

Do a workshop, and I bet you will then want to TF it.  There are many things to consider for your case, metal and wood do not mix well in the long term. 

The time it takes to cut a joint?... It depends on you and your tools, and a little experience.  Just don't forget that while it takes a certain amount of time to cut a mortise or tenon, in post and beam you have to take time to fabricate the brackets, seal them somehow to try and get a little more protection, and you have to fit the brackets and hardware.  It makes me wonder if there is any time savings, or if there is, how significant is it?  Weigh that against the quality of what you are building too.. 

Don't be scared about precision in TF'ing, like it's some magical skill.  You can cut joints as precisely as anyone else.  You learn how to do this with the techniques you are taught, which are what all TF'ers are taught or learn.  I never would have thought it, but now that I've learned the proper way to use hand tools, I find myself reaching for them more and more.  I love a sharp hand saw, and a good brace and bit.  I hope we can lure you over to the good side of the force!

[jfl]

Brad,

I understand I'm on the wrong side of the force... but a little bit of background of where I am and where I'm going would explain better what I mean.

WARNING: GOING OFF TOPIC!

Ok, I bough a land 9 years ago, so my wife can have a barn (later in her life) I had a house built on that land in 2005 because my wife (finally) got pregnant (you could say that's my fault if we didn't succeed earlier, but now we are getting too far from the topic  ) Now I have 2 children, a forest to clean (I got a mill) and a few OLD machines (backhoe (1991), Bombardier J5 (from 1962) with claw trailer and 10-ish years old lightweight equivalent of a timberjack but using track instead of wheel and chain, and also a 1972 bobcat skidder).  I can tell you that A) I'd not very funny to remove snow from them before we can use them at winter B) they don't start very well in the winter C) Their seats are all cracked, so whenever it rains (every second day!) the seat get wet for a week, but mainly D) changing frozen oil at -15 degree in 2 feet of snow isn't fun.

So the plan is to build a roof over those machine the fastest and cheapest way. I have plenty of aspen on my land (large enough to build 8x8 beams, but not 12x7. (See Thread : http://www.forestryforum.com/board/index.php/topic,32299.0.html) So I see the construction using timber (to include both post-and-beam and timber framing) as a way to build cheaply because I'm using my timber.  As such the best information I've found relating to the engineering of post and beam was in the Timber framing book (A Timber Framer's Workshop from Steve Chappell) rather than post and beam books.

Regarding learning and going to a workshop, I would really like to.  But let's face it (unless I don't really understand what it is, which is possible... you know, I'm French and Canadian officially, so a lot of words may be mis-translated when I read them) So I understand that a workshop is an intensive course (with hand-on practice), spanning many (2 to 5 maybe) days. This must cost from few hundred to a thousand dollars. I've seen offers in various States (in the US). My only problems with workshop is A) time, to get there (away from young children) and B) associated cost (travel, course). This is not getting me closer to my goal to build something cheaper than with purchased 2x8.

There is also the taxation. Here the tax man is terrible. If I build something nice, they are going to evaluate it like it's worth a million dollar (with no relation to the actual cost of the building) and then tax it at 20k to30k per year. No that's not a joke. People who has small farms with a barn have seen their tax bill rise by a factor or 3, 4 or more in the last 5 to 10 years. People who lived in their house for 30 year can't live there anymore just because of the evaluation of the stable... But that's also off-topic.

On the OTHER side, I lended all my books to my father (who if few month from retirement) and he mentioned me that I should I showed him that 30 years ago (when I was 5? ) because he that's what he wants to do (he started practicing, did a dovetail!)

So I must wear both the dark side and light side hats.  When I put the dark side hat, I have to build a shed fast and cheap.  When I put the light side hat (when I want to have fun, and I can take my time) I want to build a timber frame.  But that first frame cannot be the 40x36 machinery shed I need ASAP...

Thanks for reading me.

jf

[ljmathias]

jfl: I can identify with your plight in several ways.  I have 5 grandsons and a brand-new grand-daughter that demand (at least that's how I see it) that I be around to play with them lots.  I also have older equipment all with cracked seats that absorb rain and give it back to the seat of your pants for days or weeks.  Looked at new tractors yesterday, and the one question I asked every dealer was why the manufacturers use such lousy material for their seats.  Only useful answer was: use lots of garbage bags to cover up the seats so they don't crack or don't absorb water when they do.  Why not just be a good seat?  Must be a huge market for them- I'd buy 7 or 8 right now if I knew they'd last for several years instead of the two max they last now.

Back to topic: I have built several barns and sheds to get equipment out of the rain and sun (it's the sun that causes the seats to crack) and every time I get one built, I end up using it for something else- storing Katrina wood in, storing lumber cut from trees so they can air-dry, storing firewood, storing an old jeep and my sons ocean boat, working on timber framing projects and woodworking...  Seems I can 't build enough barns and sheds fast enough.  I sympathize with your quick-and-dirty approach, done it myself on several of my buildings like the sawmill shed I finished yesterday so I could hurry-up and get the LT40 out of the weather, but in the end, I want the buildings to stand during my lifetime (whatever's left) and for my kids and grandkids to use during theirs.  Tough compromise and there's no easy answer.

Short answer: balance building fast with longevity of what you build, and keep at it.  Love the wife and kids while you're doing it, and as Jim says in his signature, whatever you do, have fun doing it.

Lj

[shinnlinger]

Sounds to me like a pole barn is the way to go....  Or maybe a purchased steel outbuilding (used???)..

[beenthere]

Off topic, but following through the open door..........

I like the comfort of the newer tractor seats, and wouldn't want to go back to the iron pans that stood up fine in the weather. If I have to leave mine out in the rain, I tilt them forward so the rain doesn't puddle in the seat and soak in.
But I can't leave equipment out in the sun and rain, so I keep putting up more shed. 

[jfl]

Sounds to me like a pole barn is the way to go....  Or maybe a purchased steel outbuilding (used???)..

Yeah, I'm considering that. I'm on their mailing list and I get the end-of-year special. But the building that seems nice to me is 30-ish k$. The 10k$ ones are not high enough for the backhoe.  now to hold the roof I'll have to build a full foundation (ho, I feel here I'm doing bad translation... What do you call the concrete wall you put the the building wall on?)  I wanted to do concrete pier, but then how where does wall sit on? If I would build a cabin or house, I could just jack it up and build a wood floor.  But I don't think I can build a floor strong enough for machinery.  And with the frost I can't have the wall resting on a bed of gravel (Can I?) so I'm a little stuck with concrete foundations...

jf

[Brad_bb]

jfl, I just didn't want you to unfairly rule out TF, because of lack of experience/understanding, or misconception.  It sounded like you were when you mentioned your ability for precision etc.  It also seemed like were thinking brackets were faster than joints without considering time and cost to fab the brackets and fit them.

I understand that all things must be considered for such a choice.  For the last two days, my cousin and I have been rennovating the open add on of my shop which formerly housed cows.  It's a polebarn and I'm enclosing and sealing it to be heated storage space (to clear space in my shop to timberframe).  I only plan to be in this shop for max 5 years, so I am rennovating with stick framing.  If it were my permanent shop, it would be TF.  I'm doing this so that I can build my new workshop timber frame.  My cousin kids me saying, "This is not a show builiding Brad".  He's saying I'm too detailed and thorough, as if I do everything like the show cars I've restored.
But I digress, sometimes it must be quick and dirty, and sometimes doing it the best way should be considered, and sometimes in between.
Bon chance, mon ami Canadien! 

[shinnlinger]

JFL,

If you pour a one piece concrete "monoslab", it will rise and fall with the frost and would save you some digging.

BRad,

How would you inexpensively insulate a timber frame and still have the timbers showing?

[jfl]

JFL,

If you pour a one piece concrete "monoslab", it will rise and fall with the frost and would save you some digging.

Yes, that's exactly what I though initially. But initially, the shed was more like 24x32.  I've been discussing with peoples (architects, builder's) and I'm starting to think that the monoslab would have to be so thick that it would cost more than full fundations.  And digging is (almost) free (because of the backhoe I'm trying to put in the shed).

Do you have any experience on up to what size a monoslab make sense?

Thanks,
jf

[shinnlinger]

I am no concrete guy.  I would talk with one or two in your area and discuss the pros and cons of stemwall w/slab vs monoslab.  I would think the concrete amount would be similar either way if you were planning a slab for the stemwall.  Either way, pay close attention to insulating the slab/foundation.  I would have that conversation with the concrete guys also.

I have done a few stemwall slabs but that was in Oregon where I only had to go down 18 inches. Here in NH if I would have to go  down 6 feet so I would want to make a full basement while I was down there, but that doesn't make sense for you.

[moonhill]

I don't believe a floating slab is suggesting it will float on the frost.  It floats on the ground and if frost get under it you could have an issue.  A floating slab allows you to not dig a trench for the frost wall.  But is advisable to insulate around the perimeter of the slab at least, and under it if you are going to heat the slab and you have the extra cash.  Frost would have to penetrate through the top of the slab to get under it.  With a structure over the slab you greatly reduce the night time radiation heat loss.  Now your driveway exposed to the night sky will have far greater chance to have frost build up under it.  Well drained soil is a plus. 

I also think it would take more time and energy to fab steel plates than cut joinery, my bias opinion. 

Tim

[slowzuki]

I was in your position with equipment to cover on new property.  I built a socket systems building which went up very easy.  I'd guess that my beginner skill on steel sockets was as fast as a pro timberframer.  But I sure like the look of proper timber frame.

If I did it again I would have built two buildings, a house and a shop.  I would have built a pole barn or fabric building for the shop.  Pole barns go up fast and cheap as long as you don't need to mess with insulation.

In NB, fabric buildings aren't taxed as permanent as long as you don't have a slab.  Saves lots of money.

One of the better companies is:
www.HiqualProducts.com  but they are pretty expensive compared to the cheap ones.