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Author Topic: The Frame I'm Workin' on -- New Member Introduction  (Read 12754 times)

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Offline mudburn

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The Frame I'm Workin' on -- New Member Introduction
« on: February 26, 2007, 11:13:36 pm »
Greetings, All!

I've been lurking on the forum here for some time, and I just decided to sign up last week. I thought I might introduce myself and my project.

My name is Darryl. My wife, four children, and I live on 57 acres of God's beautiful country in South-Central Kentucky. We've been here four years (previously in Central Illinois). We've been planning on building a house here since before we moved. I've had an interest in straw bale building for several years and have always liked timber frames and log homes. We decided on a timber frame home with a straw bale wrap. Overall, the interior size of the house (size of the frame) is 26 by 36. The frame is a 4 bent, 3 bay design. The house will be a story and a half with 9 feet to the bottom of the tie beams on the first floor. The upper floor will be 8.5 feet to the collar tie. Here's a picture of the frame as envisioned:



The roof is 8:12 pitch. I lengthened the queen posts because I needed more head room upstairs after changing the floor plan. I had already completed several posts and the tie beams at that point. There will be 'trusses' (14" depth) set on top to allow for sufficient cellulose to be blown in. The 'trusses' will sit on a 2x4 framed wall (2' 8" height) on top of the outer girts. The tie beams are scarfed above the center posts.

Posts and beams are 8x8 oak. The girts and rafters are 6x8 oak. Floor joists and purlins (not shown) are 4x6 oak on two foot centers. The braces are also 4x6 oak.

At this point I've completed the posts, the beams, and all but three girts. I have the rafters, queen posts, braces, floor joists, and purlins to complete. Hopefully, we'll raise the frame by June.

I appreciate the knowledge and wisdom shared on this board and find encouragement in reading about and seeing what others are doing and have done.

Darryl
Blogging my house project at Cedar Ridge Farm.

Offline Kevin K

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #1 on: February 27, 2007, 12:34:57 am »
Nice project!

Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #2 on: February 27, 2007, 10:02:58 am »
Hello Darryl,

Sounds like you're going well! Is the design completely your own, and what are your main source materials for this?

How will the straw bales sit, external, in-line or internal?

Can't quite see from the pic; are the roof slopes unform or break as for a dutch barn?

Lee

Offline Raphael

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #3 on: February 27, 2007, 10:44:36 am »
Welcome to the FF mudburn, I'm looking forward to seeing your project come together.
I lurked here nearly 5 years before signing up... Now they can't get me to shut up.  :D
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Offline Thomas-in-Kentucky

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #4 on: February 27, 2007, 01:46:02 pm »
Welcome to the Forum!  Kentucky - that's cool!
Let me know if you want any help during the raisin'!

-Thomas

Offline Jayson

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #5 on: February 27, 2007, 05:26:14 pm »
Welcome Mudburn. Let me know about your raising too. I travel to Ohio occasionally. I'm just looking for an excuse to go see Thomas' mega frame. How about it Thomas? Would mind a visitor? Either of you?

Offline mudburn

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #6 on: February 27, 2007, 05:46:50 pm »
Thanks for the comments everyone!


Lee,

Quote
Sounds like you're going well! Is the design completely your own, and what are your main source materials for this?


The design is completely my own (with family input, of course). It's evolved over the last four years. When we thought we had the design figured out two years ago, I ordered timbers from a local Amish sawmill. I was going to use Cedars off the farm and mill them myself, but when I started figuring what I would need, I liked the strength of Oak and didn't want to use all my big cedars. The design has changed even since then, but within the confines of the beams I have (for example, it went from two stories with a basement, to one story with a basement, to one story with no basement, to 1.5 stories with no basement).

Quote
How will the straw bales sit, external, in-line or internal?

The straw bales will be external. I'll run 2x3s we've milled on the outside of the bales on which to hang the windows. The bales will be plastered with a straw-clay mix on the inside and outside. Additionally, on the outside I'm going to run stringers every 8" in order to put on a wood siding (shingle-type). I can get oak from a nearby pallet company that is perfect for shingle siding -- 1/4" thick, 4" or 6" wide by 36" to 42" long. This can be cut to 18" lengths for wood shingles. My dad's already sided his house this way.

Quote
Can't quite see from the pic; are the roof slopes unform or break as for a dutch barn?

The rafters on the frame break as for a dutch barn, but I don't want that look on my house. Originally, the frame wasn't designed that way, but after completing a fair portion of it, we decided we wanted the room upstairs to be more usable. So, I raised the roof, but it could only be done easily in the center of the frame. So, a dutch barn. But, to make a uniform roof, I'll make or purchase some 14 inch 'trusses' that are long enough to reach from the peak to the edge of the bales (about 18 feet). These will allow me to blow in cellulose insulation in the roof (need my R-value to equal or exceed my walls). I'll frame a short wall on the outside edges of the frame to support the trusses. I don't want the straw bales to support any load, although they could (our original idea was load-bearing strawbale walls).


Thomas, I've admired your frame since I first saw it on the tfguild forum. I marvel at your ability and the complexity of what you've tackled. This is my first frame of any type. I figured that it's like a great big piece of furniture. I've taken my time and will also have a full fit up before raising. I'll be recruiting as much help as possible when the time comes, so you, Thomas, and you too, Jayson, are welcome as are others. I'll let ya'll know when it'll be (I'm aiming for Memorial Day weekend right now). I thought it was going to be last summer, but others things caused me to change that idea (good thing too because the design changed).

I'll see about posting some pics of my dad's siding on his house -- he used the culls from the pallet company -- $2 per pallet load. He probably has less than $40 in his siding, including the staples he's used to put them on. Also, I'll see if I can post a pic of my floor plan if anyone's interested.

All help and input is welcome!

Darryl
Blogging my house project at Cedar Ridge Farm.

Offline Thomas-in-Kentucky

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #7 on: February 27, 2007, 06:08:01 pm »
Jayson,

You are welcome to stop by if your travels bring you through here.  I would appreciate meeting anyone with timber framing experience or interest, as I am still looking for opportunities to learn, and if they drive up to my front door looking to help for a day, then all the better.  :)

Darryl,

Thanks for the compliment.  W.r.t. your raising, I know how plans change.  I was going to be living in my house by now, watching TV at this point.  (I don't have a TV - because if I did, the house would be another year behind!)  My project is large because I very much underestimated the magnitude of my project.  I guess that's what inexperience/naivity got me.  Well, if you want to visit here or need any help down there, give me a holler.  I would welcome a day away from my own project.  (Today I chased 3 cattle back from the highway, and worked on fence for half the day)

I love your (and your Dad's) siding idea.  After fooling with this slate roof, I know your oak siding will work.  (I guess your dad has the proof!)  And whether it lasts 10 years or 100 years, you can't complain too much about the price!  I am still looking for siding ideas myself.

-Thomas

Offline bigshow

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #8 on: February 27, 2007, 07:31:46 pm »
Muddy,

do you have any renders of your house showing how it will look when finished???

would love to see them, and a floorplan, and, and....

frame looks sweet though.....
I never try anything, I just do it.

Offline Jim_Rogers

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #9 on: February 27, 2007, 10:06:40 pm »
Welcome to the forum....

Jim Rogers
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Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #10 on: February 28, 2007, 03:18:59 am »
Thats interesting. I had considered straw bale, but the wall-depth seems to create foundation problems. You are avoiding that they load-bear, but then you must create a load bearing wall outside of them to support rafter/truss.  This implies support for the posts, and a support ring outside; that seems to be a lot more foundation, or have you found another way around this?

Lee

Offline mudburn

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #11 on: March 02, 2007, 11:05:03 am »
Thats interesting. I had considered straw bale, but the wall-depth seems to create foundation problems. You are avoiding that they load-bear, but then you must create a load bearing wall outside of them to support rafter/truss.  This implies support for the posts, and a support ring outside; that seems to be a lot more foundation, or have you found another way around this?

Lee

Actually, the wall outside of the bales is not load bearing. It will consist of 2x3 on 3 or 4 foot centers (I haven't decided) running vertically. These will be strapped between the bales to the timber frame. This will provide rigidity to the bales and the 2x3 framework. The 2x3 will serve to hold the stringers for my wood siding and to attach the windows to. The 'trusses' will tie into this framework, too, but the trusses will spread the load out over the timber frame and to the foundation through it.

So, that leaves me with the need to support the weight of the strawbales. I'll do that with piers probably on 6 foot centers at the outer edge of the bales. I will frame a 'floor' for the bales to sit on that attaches to the first floor level of the timber frame, transfering some of the load to the frame's foundation. On three sides, I will extend this 'floor' out about 10 feet to make a porch (still with the piers for the strawbales, though). Originally, I was going to have a concrete block wall around the perimeter of the bales, and when the time comes, I may still decide to do that.

Darryl
Blogging my house project at Cedar Ridge Farm.

Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #12 on: March 02, 2007, 04:51:13 pm »
Thanks Darryl, that does sound relatively complex and I would need to see a plan to understand it further, but I know that straw bales make sense for a number of reasons.

I'm way back in the construction process, just prepping braces now; would you care to give me a few  big t-f tips, the sort that maybe others miss stating (or has it all been said before) ?

Offline mudburn

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #13 on: March 03, 2007, 03:47:54 pm »
I'm way back in the construction process, just prepping braces now; would you care to give me a few  big t-f tips, the sort that maybe others miss stating (or has it all been said before) ?

Lee,

I consider myself a novice. This is my first frame. I've just approached it as being something that is doable and that doesn't require rocket science. It really is like a big piece of furniture. I've tried to consider, anticipate, and calculate the different aspects of loads and rigidity and such (same thing for furniture), but I've missed things. In fact, I've adjusted my frame again -- mainly the upper story -- because of suggestions/concerns from another timber framer. He caused me to go back and redo some of the calculations I'd done before. And you know what? I got different results this time because I used a different calculator (Don P.'s in the toolbox). So, I adjusted what needed adjusting (I think smiley_anxious). I'll have to post a new image of the frame incorporating the changes I've made (these changes were needed because I changed my original design once already, and I didn't do it quite right).

So, with the above caveat, my big t-f tips (and they may have already been stated):

  • Know that you can do it; believe in your ability. Overall the project is large and can be intimidating, but one mortise or one tenon isn't that difficult. The overall project is made up of little things that you can do.
  • Seek and accept input from those more knowledgeable than you. Wisdom comes through experience, and those willing to share their wisdom can help you a lot.
  • Measure twice, cut once. If you forget, it's not the end of the world. You probably can correct your error with a little creativity.
  • Use tools that you like and are comfortable with. I have a Sorby 2" chisel that I bought off of Ebay. It's my favorite one to use because of its size and weight. It doubles as a slick, too. In fact, I'll reach for it before a slick.
  • You don't have to have expensive tools to do the job. My frame is being completed with a 7.25" circular saw, a 2" chisel, a 1.5" chisel, a 2" slick, a 1" corner chisel, a high torque drill, a 2" self feed bit, a 1.5" self feed bit, an old cross cut saw (the one in my pic to the left), a tape measure, a builder's square, a combination square, and a hand plane. Sure, a chain mortiser would be nice, but I can't justify the expense for this project. I made a beam mover. I make mallets (and wear them out).

I don't know if these are the types of things you have in mind, but that's what I offer now. Maybe after I get this frame finished and raised, I'll have more things to add to the list.

Darryl
Blogging my house project at Cedar Ridge Farm.

Offline LOGDOG

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #14 on: March 03, 2007, 07:40:25 pm »
Welcome aboard Mudburn. Looking forward to lots of pictures and input from your project.

LOGDOG

Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #15 on: March 04, 2007, 02:43:47 pm »
That is purrr-fect; I'm glad to hear that the mortiser is not assumed obligatory!

In respect of design changes, something occurred to me; safety factors. Have they been standardised by the NDS? What s-f's do you incorporate into your technical characteristics Don (those tabulated - accessible with your calculators); are they correct for dry or green wood?

I have assumed Tedd Benson's s-f's as detailed in 'Building the Timber Frame House' - OK. I note that Tedd's design values derive from (in case of Douglas)  the least strong green selection possible (as listed in Forestry Service manual). Don's figures are higher, ie. present Douglas as stronger  ???

This seems to be one subjective loose thread in my design process.

Offline Don P

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #16 on: March 04, 2007, 10:06:53 pm »
Welcome to the forum Mudburn  :)
Remember what you paid for those calcs, they're worth every penny. I hope they didn't make you downsize anything.

The application of the design values is not subjective in the codebook, NDS numbers.

First thing to keep in mind is that trees don't read the tables, keep your eyes open, misread the wood and it doesn't mean a thing.

The wet service factor. The design values I attached to the calcs are for heavy timber, 5x5 or larger, used at an in service moisture content of 19% or dryer. It can be installed green and dry in service. That covers most of our situations. There are connector adjustment factors for nails, screws, bolts, etc that go in green wood that then dries vs going into dry wood that stays dry. A big one there is if you nail to green wood use a ring or spiral shank nail.

  For heavy timber used in wet service where the moisture content remains above 19%, Fb (bending), Ft(tension), Fv(shear), E(stiffness) and Emin(column stiffness) remain the same as published. Fc lowers, that is maximum allowable fiberstress in compression.To arrive at an adjusted design value multiply the base design value of Fc perp, a side loaded timber (beam) by .67. For Fc parallell (a post) multiply the base design value by .91. If you think about it the difference there makes sense, you can crush the side grain of a green beam pretty easily, it doesnt matter so much if its green or not to the end grain of a post .

Unlike 2x lumber which has several design value adjustment factors, heavy timber only has 3 possible adjustments. The wet use described above. A factor to be applied if timbers are deeper than 12" and a factor to be applied if the load is applied to the wide face, the flat use factor. So generally you just use the design values for heavy timber straight from the NDS table.

All that said, real world, green wood is far weaker than dry. If there is a beam pushing the load limits or heavily point loaded, prop it for as long as possible to let it season and gain strength in an undeflected shape.

The design values published by the NDS or any of the major grading agencies are by species or species group, and by grade. Benson is deriving his design values from the Wood Handbook, so is the NDS. The NDS numbers are recognized by the code, deriving from the Handbook is not, doesn't make it wrong if you do it right. You'll be on the same page as your engineer if you stick to the NDS numbers.

Safety Factors;
My understanding of the math is this, 95% of wood within a grade should fail at 2.1 times the published values or more. 5% may fail between the design value and the 2.1x design value. All should be at least design strength. By careful selection it is possible to pull a board out of the stack that will break at up to 8x the design value. Keeping your eyes open you can improve the structure greatly by using stronger wood where its most needed. I used some glulams not long ago that had "proof loaded" joints in the laminations. They had been stressed to 2.1x the designed load for that beam.

The textbook answer; All design values are based on the 5% exclusion limit, except E and Fc perp, which are average values.
5% exclusion limit = avg strength-(1.645 * std deviation)
To get Fb, = (5% exclusion limit)/ (1.6 load duration * 1.3 safety factor).
Design values for wood products are derived this way because the variability changes from grade to grade and product to product. This is more complex than just a safety factor but is supposedly better with a material of widely variable nature like wood. I think Benson is using a safety factor that amounts to more than the sum of all that above.

An example from a text will help.
A test of a large number of SYP 2x4's gave an average bending strength, Fb, of 9,138 psi, standard deviation was 3,205 psi.
Applying the 5% exclusion limit- 9.138 -(1.645 * 3205) = 3866 psi
Fb=5%/2.1 or 3866/2.1= 1841 psi allowable design value.

Then to loosely quote the building code " to be designed according to accepted engineering practices and/or AFPA's NDS".

Standard engineering texts help to calculate the loads. Chapter 6 of Benson's book is excellent, I appreciate the boost to sit here and thumb through it again.
 The NDS tells how to apply those loads maintaining allowable stresses on the wood.

I asked the engineer who runs the test equipment at one grading agency how to non destructively check my grading of timbers. He said they proof load timbers at the third points to 2.1x the designed load. That eliminates the vaguaries of grading, it proves it with a safety margin.

Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #17 on: March 05, 2007, 07:04:26 am »
Thanks Don, I am much reassured, and appreciate the effort you have gone to, to make these formulas accessible to all. The greatest area of subjectivity then, is outside of figures and calculations:

Quote
First thing to keep in mind is that trees don't read the tables, keep your eyes open, misread the wood and it doesn't mean a thing.

This is apt for my decision-making; graded wood is not available from the local saw-mills here, which means its just up to me  :o I have already refused some wood with large knots, so hopefully, the proprietor will respect standards for the future.

Lee

Offline mudburn

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #18 on: March 05, 2007, 09:42:53 am »
I've designed my frame with 14' 8x8 beams and 12' 8x8s in each bent. I used Benson's numbers to run all my calcs previously, and passed. I then changed my roof from plain rafters and queen posts (8:12 pitch) to the 'dutch barn' type in my image above. This was to gain headroom and useable space upstairs. However, that really focused too much load on the 14' side of the tie beam. Thankfully, someone directed my attention to this. So, I played around with the design a while, and redesigned the roof lines in order to avoid over-stressing the tie beams. Here's what I came up with:



One of my other objectives in this redesign was to not have to redo what I've already done, including the posts and tie beams. In an ideal situation, the posts on the left side of this bent would be continuous to the rafters. I tried to come up with an acceptable compromise.

Don P., your calculator failed me in places that my calculations using Benson's numbers passed. I've not changed the size of the beams that failed. I changed the load on them -- I left the center bay open to the rafters. The primary area of concern was the 14' side of the tie beams when it had to support a floor on two sides (and area of ~156 sq ft), especially with a queen post focusing extra load in one point. Your calculator was worth every penny I paid for it  smiley_clapping

Darryl
Blogging my house project at Cedar Ridge Farm.

Offline Griffon

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Re: The Frame I'm Workin' on -- New Member Introduction
« Reply #19 on: March 05, 2007, 03:04:52 pm »
Darryl, I hope someone else will tell you that the braces at ground level aren't necessary ...
Its not clear to me what the ground level beams are, not sill plates? If the posts are anchored independent of these beams (straps) then the upper braces should be enough.

The upper floor-level braces also look like they'll attract some cussing in time. Have you thought of keeping your original design, but putting girts down the building centre line? This would allow the joists to span in a sense parallel to your tie-beams (in two 'floors') and the tie beams would take ONLY the weight of the QPs.