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First Timber frame - 8x10 shed

Started by pwk5017, May 19, 2020, 05:10:52 PM

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pwk5017

Hello, first post on the forum. I come to the craft with a decade of furniture making experience and very little carpentry experience. I did all of the trim in our first home, but really havent framed much. With that said, i want to do a covered front porch in the near future, but thought it prudent to start with a more manageable(and less visible) timber frame project to cut my teeth on. We need a shed, so i thought why not start there. I am in for permit, and have my pad mostly dug and leveled. I want to order my timbers, but first, i need to finalize the design. I thought i was there a week ago, but i read Sobon's book and another by Will Beemer the last few days, and wanted to see if i should change some things slightly to make the build easier/better. Overall, the thing is 8x10x14'+/-. Plan on doing a tongue and groove ceiling out of 6/4. I want to do this for the porch, so this will be my practice run. I have the shaper cutterheads already and a 5.5hp felder shaper with a powerfeed. I havent done much shaper work in my shop, but it should be easy stuff. Next, i plan on doing similar work for the flooring. Finally, i am not 100% certain on the siding, but initially thought 4/4-5/4 horizontal siding. I am inexperienced here, but saw Sobon liked vertical siding because it required few girts. I respect the sheer efficiency there, but it seemed like more work to then rebate the boards for a shiplap joint. Otherwise, ill have gaps between the boards which isnt ideal. Im buying hemlock pretty inexpensively at $0.50-.65 a board foot, so the ceiling, siding, and frame will be hemlock. I know it has its downsides, but i like the idea of using locally sourced timbers, and EWP, Spruce, and other options are considerably more expensive. Sill and floor joists will be PT. 

Frame questions mostly concern the locations of the tie beams and plates. In the first option, the tie beam(almost more of a collar tie, i suppose) is much higher and connects into the rafters. The posts also connect into the rafters at an angle. I saw this in a similar small timber frame, and it looked good. I like that the tie beam is higher in elevation, so as not to interfere with a door. However, after looking at Sobon's book, it became clear that this initial design involves a lot more angled joinery. My experience with furniture making has taught me that a 90° joint is 10x easier than any angled joint. This lead me to revisit the design in sketchup and make the second design. this one lowers the tie beam so it joins to the posts. Also, the plates sit on top of the posts in an M&T joint.  I assume option #2 is the better route to go? Although, this whole discussion begs the question of if there are general plans i can buy? Ive gone through a few iterations on this thing, and id rather be chopping wood than messing around with sketchup. I couldnt find any 8x10 frames with a king post and exposed rafter tails, which is how i ended up where i did. 

Look forward to the discussion and hopefully clarifying some of my confusion. 

Patrick



 


 

 


Don P

Hi Patrick
#1 is structurally not a particularly good idea. #2 will work if the tie is designed to support 1/4 of the roof weight as a point load at midspan. Those exposed tails are preventing you from really creating a roof truss, that is probably why you are having a tough time finding plans.

pwk5017

Glad I rethought the whole thing after referencing some texts!

For the calculator, I used #2 hemlock and 45psf of snow load, which said the 6" beam will deflect 0.25". I can't find info on snow load in Pittsburgh, but I have to be a lot lower than the 45-50 PSF of upstate New York. I assume that is acceptable? What are the "worrying" amounts of shear and deflection etc? Also, had to search the forum how to access those calculators and it turns out you are the author! Thank you, sir. 

Ah, one other question. Do the braces reduce the span of the beam at all, or do you take the span from post to post? I assumed the braces don't reduce the span and went with 84" span. 

Patrick


Don P

Uh, yeah, on the author part, I'm just a carpenter with a sawmill who needed to be able to size oddball stuff. This is all worth exactly what you're paying for it.

Yes, the span is from post to post, 84".
 
Looking at the snow load map, chapter3 of the IRC, I think you'd be fine at 30psf snow load + 15 psf dead load (self weight of the roof materials) for a total of 45psf. Your building dept can provide you with the snow load they require for design.
https://codes.iccsafe.org/content/VRC2015P2/chapter-3-building-planning

It looks like ~2' gable overhang + 1/2 the purlin span (5') = 7' x 1/2 the roof width (4')=28sf of area bearing on the ridge post
28sf x 45 lbs per sf =1260 lbs supported by the ridge post.

That post is centered on the tie and delivering that load to one point at midspan. Just for background a concentrated load at midspan produces twice the bending moment in a beam as compared to the same load if it were uniformly spread out along the beam. In other words a concentrated midspan load stresses the beam twice as much as a uniformly distributed load so that takes us to this calc;
https://forestryforum.com/members/donp/beamclc_ctrpointload.htm

My inputs were 1260 lbs, 84" span, 6x6 timber, Fb 750psi, E.9, Fv 155psi.

Bending is close, no room for a mortise at 6x6. If any of my assumptions above as to sizes or spans were incorrect double check this with your actuals. Deflection is about 3/16, for a typical roof ~3/8" deflection is allowable so fine there. Shear is at about 26psi, allowable is 155 psi, no problem there.

No need to apologize for using hemlock, if its good material, shake free, I'd take it over white pine any day. It doesn't throw a whorl of knots every 2' up the tree. Carpenter bees don't enjoy it nearly as much and compare the strength values. All pluses in my book.

pwk5017

Frame is coming along pretty well. I severely underestimated the weight of a soaking wet hemlock timber, but all in all pretty good. I have a few questions concerning raising techniques. Assembling the bents on the ground and tilting them into place went very well. My brother and i had a side and my wife lined up the post stub tenons into the sill. Both bents were vertical without a hiccup in probably 15 minutes . However, putting up the two plates was a chore. Once again, wife holding in braces while my brother and i had an end. I clamped some 2x4s to the posts to act as resting platforms as we worked our way up the post on ladders, but the process sucked. Thank god my joinery fit very well on the first go and i didnt have to take them down for fine tuning. Now that i am at the point of putting up the king post gables and the ridge beam, i wanted to see if there is a method used for doing this easier than my struggle with the plates? I have a sturdy frame now that i can build a loft/platform on top of. My plan was to temporarily use the 3x6 rafters to make a floor spanning the plates. I can then carry the gables up in individual pieces, assemble them on the platform, and tilt into place similar to the bents. Is this how it is typically done? Any tips for lifting a 14' 6x6 ridge beam about 14-15' in the air?

Patrick 


 

 

Don P

Sweet! 8)

One thing I think I would modify if doing something like that again. There is very little relish in the kingpost between the top rafter chord and the ridge tenon on the post. I think I would joggle that joint to help keep it from wanting to shear.

I thought Jeff's lifting rig worked great, pg 2 of the "FF pavilion thread". Watch the ouch video for the warning, don't use your head to stop the winch handle.

Brute force and ignorance has gotten me where I am now. I sound like a sailor when I get up :D.

Jim_Rogers

test fit the king posts into the ridge beam on the ground to make sure that they fit correctly, first.
Put heavy strong planks on tie beam or on plates to stand on.
Learn how to par buckle timbers up the side of the frame to get the ridge beam up on the planks or slide it up over one gable end tie beam.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

pwk5017

I havent been on the site since completing my timber frame shed, and as i was reading threads, i came across my own build thread only to realize i never added the completed photos. I will pick up where i last left off.  Looking back on things, the design looks 10/10 with the exposed rafters and overhang, but it was about 25 times harder than it had to be when it came to raising. Instead of assembling a complete bent on the ground and tilting it into place, i had to do the bottom half of the bent, then put the tie beam/top plate in place, and finally the king post gable on top of that. It dramatically overcomplicated things for one guy to get the gables in place 10' off the ground. Certainly covid and not having any help made matters worse. However, i made a temporary platform with my uninstalled rafter timbers and OSB. With that in place i was able to tilt and push my timbers one by one onto the platform from underneath. Assemble and peg them on the platform and then tilt it up into place and into the mortise for the king post. Whether it was by luck or skill, i thankfully never had an issue with joints not fitting. I was especially blown away with the stub tenons of the posts going into the sills. Those were not sloppily cut, but a perfect piston furniture fit and they seated perfectly as i tilted the lower bents. One note, two of my principal rafters' birdmouths were messed up somehow. I dont know what caused it, but one side seated perfectly down onto the top plate, and the other side was 1.25" up in the air. The king post seated fine into the mortise, and to this day i am unsure why those cuts didnt line up where they were supposed to. I dont know if you can see if in the photos, but i had to take offcuts, resaw it to 1.25" at the bandsaw, and then glue and screw it to the top plate to make up the gap. Ticked me off a bit that it wasnt perfect and i didnt have an answer, but thankfully it isnt visible so it doesnt really matter. 


y gable
 


pwk5017

Forgot to add the debacle that was getting the ridgebeam into place. Thankfully, it was 2-3 months after the hemlocks were felled and sawn, but the sucker still weighed a ton. I bet it lost 75lbs+ of water in those months. Once again, no help from anyone because of covid and my wife being down and out for medical reasons. I moved it into place behind the shed where the grade is 4' higher and seesawed it up onto the temporary platform. From there, i clamped 2x4s to the king posts and laddered one side up at a time. Surprising how one guy can position some of these pieces vertically into place by working slowly. However, it really would have been better to have a genie lift or some other machine assistance. In a way, i wish i was building a home where i would have spent $500 in a heart beat for a telehandler or similar; however, its hard to justify several hundred dollars to lift 1-4 pieces into place on a shed. After the ridge beam was in place, i was off to the races with the rafters. They sit in a 1/2" dado and have a timberlok 6" screw down into the principle rafter. It sat for a bit after i completed the actual timber frame, because i was dumb enough to think making my own ship lap flooring and ceiling was a good idea. I had 6/4 rough sawn hemlock from the same sawyer that i S4S in my wood shop and sent through my Felder shaper with a rebate cutterhead. Thank God i have a power feeder, but this was so much work to save like $400 in material costs. I made so much sawdust and wood chips from this process. After the roof was on, i laid down the appropriate 30lb felt roof underlayment and got to work fastening the metal roof panels in place. Im not one for heights, so this was my least favorite part of the project. Frankly, another area where i should have paid someone, or rented a machine. Be that as it may, i made a temporary ladder/scaffold to lay on the rafters and screw into them. This gave me a little ledge to lift the metal panels onto from the ground and hold them there while i climbed the ladder. After installing the ridge cap and foam filler strips, it was back down to the ground, thankfully. I made skinny 2x4 frames to infill between the timbers. This allowed me to screw the beveled cedar siding in place, fit windows i salvaged from a dumpster, and apply painted 1/2" OSB to the interior. The total thickness was 2.75-3", which fit perfectly between the outside of the 6" post and the inside of the 3" braces. I wanted the interior to show the braces etc. instead of burying a lot of it behind OSB. It was roofed in with siding etc by the middle of September. At this point, i was a little burnt out from working on it, so it sat for months without doors until i made two custom doors and hung them in January/February of this year. They are now painted blue to match the blue roof.

A few closing thoughts. One, chain mortisers are totally worth it. I purchased a used protool 220v mortiser for $2200 with a 2" bar, and it was amazing. I later sold it to a pro framer, and it didnt cost me anything, so very worthwhile. Two, this was incredibly rewarding for me, but extremely frustrating in the moment. It was a brutal summer and wet hemlock is so so very heavy with no mechanical assistance. Im not a roofer either, and so theres a lot i would not do again given the choice--Excavating the foundation by hand, making the shiplap, and putting the roof on. However, on such a small project, you are almost forced to do the whole thing yourself, because it doesnt make a whole lot of sense to spend $10,000 on a small shed. And lastly, i now have the bug. I dipped my toe in on this small project seeing if i was capable and if it would be 'worth it'. Not a day has gone by since that i havent thought of our next house and cutting the frame for it. Its actually what brought me back to the site after a 6 month hiatus. 

Ah, almost forgot, that is a small loft made of leftover timber to hold a whole pallet of lump charcoal : )


 

 

 

 

 

 

 

PeterJackson

Wow! That is beautiful.  The addition of a nice door and windows are a huge transformation from your initial fully clad picture.

Do you have a picture of the studwork before you added the cladding?

Edit: just noticed how many hinges you added on the doors.  No danger of the doors falling off :-)

HemlockKing

That came out a lot nicer than I expected. I was thinking with it being so tall and such a small shed it would look awkward but it all tied in great. Good work sir 

The stacking of the stones is a nice finishing touch too
A1

pwk5017

Quote from: PeterJackson on June 19, 2021, 04:08:12 AM
Wow! That is beautiful.  The addition of a nice door and windows are a huge transformation from your initial fully clad picture.

Do you have a picture of the studwork before you added the cladding?

Edit: just noticed how many hinges you added on the doors.  No danger of the doors falling off :-)
haha my neighbor said the same thing about the hinges! The doors are 2.75" thick to accommodate the dumpster salvaged windows, so they are quite heavy. Also, Home Depot or Lowes sells their glide bearing cheap hinges in packs of 6(i assume to do a pair of doors), and i didnt feel comfortable with only 3 hinges per door and the doors not sagging. Anyhow, that is how i ended up with the homemade piano hinges : )   I will say, they swing beautifully. The doors themselves are homemade stave core from KD pine, and then skinned with homemade poplar shop veneer. 
I dont have great photos, but here are the two i could find on my phone. I turned studs the opposite direction of a traditionally framed wall. You can see how it jusssttt squeaks inbetween the outside of the post and the inside of the brace. The OSB had to be hammered into position with a deadblow in some cases, because its a friction fit behind the braces. For the dumpster windows, i made homemade sashes/frames and they sit in dadoes within that frame. Never built a door or window before, but it seems to work thus far. 
And yes, i very much agree with your comment and Hemlock King's. The windows were always planned if i could find them cheap enough. Thankfully, i found them for free. That happened very early on, so the windows were locked into the plan early, however, the cladding was a last minute change. After the frame went up, i was quite surprised at how tall this is. Part of it is the driveway sits a foot or two below the FFE of the shed, but its like 18'+ above the asphalt. To your point, it is disproportionately tall. Instead of adding cladding on the outside of the frame, as you normally would do, i was bummed it would cover up the structure that i just labored on for months. This isnt a home with insulation values to worry about, so i framed inbetween the king post gables like i did on the bottom level and added the cedar siding between the timbers. Im glad i went through the extra work, because i think it looks excellent, but more importantly, that level of height and uninterrupted cedar siding would look dumb af. Its a bummer i couldnt enlarge the footprint, but zoning is what it is, and the topography is what it is too. 

 

 

PeterJackson

Thanks for showing the studwork.  It's always interesting to see how the finished product is put together.  The end result is so good.

I guess "zoning" means the local planning laws.  Interestingly, in the UK, you can build up to 18 sq m internal floor area without planning consent, but only 2.5m or 4m tall depending on how close you are to the boundary.

pwk5017

Technically, I believe it's planning and not zoning that is to be blamed. They are intertwined in America. In this case, they limit how close I can build to my neighbor's property line, and a setback off the street. Both values proved to be very limiting in the location of this shed. It is why it is not 12x12 footprint. 

The review process was pretty simple for a permit. I submitted the Sketchup drawing with dimensions along with a survey of my property and where the shed would be located. I think it's more a means of taxing you $50-100 than actually reviewing the build details. 

Don P

QuoteIn this case, they limit how close I can build to my neighbor's property line, and a setback off the street.
Setbacks are zoning.

Quote12x12 footprint.
That part is planning.
Interestingly enough the model code language does not include timberframe in the accessory structure exemption, it is describing light frame construction. Most departments aren't too fussy but here is typical building code language. (my state is fairly lenient on size at 256sf, check your jurisdiction, that varies alot)


Quote

  • 1.One-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, not exceeding 256 square feet (23.7824 m2) of building area, provided all of the following conditions are met:

    • 1.1.The building eave height is 10 feet (3048 mm) or less.
    • 1.2.The maximum height from the finished floor level to grade does not exceed 18 inches (457 mm).
    • 1.3.The supporting structural elements in direct contact with the ground shall be placed level on firm soil, and when such elements are wood they shall be approved pressure-preservative treated suitable for ground contact use.
    • 1.4.The structure is anchored to withstand wind loads as required by this code.
    • 1.5.The structure shall be of light-frame construction whose vertical and horizontal structural elements are primarily formed by a system of repetitive wood or light gauge steel framing members, with walls and roof of lightweight material, not slate, tile, brick or masonry.
All depending on where they measure the area, typically the footprint, larger overhangs can bring the eave down and provide more covered storage as well as help balance the look of the building. (Zoning is probably measuring setback from the furthest projecting part of the structure!)



 


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