Author Topic: 28 X 40 California Redwoods  (Read 47339 times)

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Offline ChugiakTinkerer

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Re: 28 X 40 California Redwoods
« Reply #100 on: August 06, 2016, 10:44:36 AM »
Good eye, I went with Owen Corning Duration shingles in, estate gray. Didn't get the scotchguard moss killer, I'm hoping now that I've removed a lot of the trees I won't have issues with moss. I guess time will tell.

Forgot to mention, not sure if you can see it in the video, but we used a Genie Lift to get the shingles up to the roof, and as a working platform to shingle the front. My dad picked that up at auction two weeks ago for $75, that thing was a back saver. I carried 20 bundles of shingles up to the roof using a ladder a few weeks before we started, and man, it was so much easier using the Genie Lift.

Yay dad!  Sounds like he scored a great deal.  That's a good idea and something I need to keep an eye out for at auctions in my area.
My cabin build thread: Alaskan remote 16x28 1.5 story

Offline nailit69

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Re: 28 X 40 California Redwoods
« Reply #101 on: August 07, 2016, 02:24:31 AM »
Grace Ice and Water shield too... thats a tight roof.

I'm going to do the 4/12 portions of my roof in Grace in case I get any snow buildup at the transition from the 12/12.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #102 on: August 07, 2016, 06:28:05 AM »
Doing the whole roof in Grace was probably overkill, but a friend of my dads bought it for a job that he never ended up doing and was tripping over the stuff in his warehouse. When he heard we were going to be roofing, the stuff showed up in my dad's shop. If I hadn't gotten it all for free, I probably wouldn't have done the whole roof in it.

Offline nailit69

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Re: 28 X 40 California Redwoods
« Reply #103 on: August 07, 2016, 12:27:38 PM »
Not overkill... insurance.  You can't beat the price either... that stuff is expensive.

Offline kenhill

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Re: 28 X 40 California Redwoods
« Reply #104 on: August 08, 2016, 11:50:46 AM »
They sell a zinc metal strip that you nail near the ridge to prevent moss.  It slowly laches out the zinc to prevent moss build up.  It comes in rolls in the roof ing sections.

Offline nailit69

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Re: 28 X 40 California Redwoods
« Reply #105 on: August 08, 2016, 04:32:20 PM »
I've never been a fan of the strip... it works but not that well and not that long either.  I've found if you use that, it needs to be placed less than 8' apart and on shallower pitches it doesn't seem to kill uniformly... around here anyway but I live in moss country and that shit grows on everything.  I re-roofed my house 6 or 7 yrs ago and the moss is just starting to take hold again and I have no zinc or scotchguard.

Offline Don_P

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Re: 28 X 40 California Redwoods
« Reply #106 on: August 09, 2016, 03:55:47 AM »
It is very location dependent. I used the cheapest 3 tabs on the house, they are growing moss and lichen and are done, but actually made the stated life. The barn is in dimensional algae retardant shingles, also deep woods and are clean so far, about 15 years. They are also about done though, they are coming apart on the steep slope, I did 6 nail them but it is a 12/5 pitch on the sides. The barn got certified organic last week... I'm not sure they didn't just mean it will compost well when it's done  :D.

Zinc or copper strips, acid rain... galvanic reactions, a battery, hmmmm.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #107 on: August 18, 2016, 06:59:52 AM »
Headed up to the cabin in the morning with a buddy to deliver a new fridge, noticed the old one was crapping out on me while I was working on the roof. I might load up my trailer while we're there and do a dump run to clean up a bunch of crap that's been hanging around and driving me crazy, but we'll see. Just unloading the fridge, then grabbing some beers and heading down to the river sounds pretty appealing as well. It's just a quick trip, coming back home Saturday morning.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #108 on: March 10, 2017, 07:29:32 AM »
I've got a question for the builders...

I'm going to start on a little shade structure next to my horseshoe pits to keep us cool in the summer and dry in the winter but I'm having a hard time figuring out the beams.

The structure will be 10' x 10', with a pyramid hip roof. When I was originally picturing it in my head I planned on using 6" x 6" for the beams, but now I'm realizing 6" x 6" aren't really meant to be structural beams so may run into issues. But at the same time I'm also feeling like I could be over thinking this. The roof will be plywood and comp shingles.

Here is my extremely rough sketch of my plan, still need to draw the creepers and the missing hips...

Any and all comments welcome.


Offline ChugiakTinkerer

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Re: 28 X 40 California Redwoods
« Reply #109 on: March 10, 2017, 09:14:51 AM »
You're probably overthinking it.  As drawn, each beam is supporting 1/4 of the total roof load.  That is 25 sf per beam.  If you have a big snow load you may need to be concerned, but assuming the live load is 30 lbs and the dead load is 10 lbs per sf, that totals to 1,000 lbs per beam.  Running a 6x6 through the beam calculator, it passes with a beam made of #2 Spruce-Pine-Fir.  A beam made of Douglas fir is much stronger than the SPF.

If snow is a concern then you probably should bump up to a 6x8.  The SPF#2 beam in the above calculation has a max load of 1,060 lbs, so it just barely passes.  For accumulated snow on a 6x8 beam (using 5.5" x 7.25" dimensions) it can hold up to 1,840 lbs.  That would amount to 63.6 lbs per sf of snow, which is probably greater than you ground snow load.

Edit: Whoops, forgot about the overhang.  That adds to the roof area and overall weight.  So that 6x6 of SPF at #2 grade won't be adequate to support 30 lbs of live load.  If your roof load is anything near that you definitely should look at 6x8 or perhaps even deeper.

The Timber Frame forum at ForestryForum.com has a lot of useful information when dealing with wood of these dimensions.  You might check out some of the older postings for some design ideas.

http://www.forestryforum.com/board/index.php/board,11.0.html
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Offline MountainDon

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Re: 28 X 40 California Redwoods
« Reply #110 on: March 10, 2017, 11:11:36 AM »
We built a 10 x 10 gazebo back before we built our cabin.  I used 2x6 like you have pictured, and added a 2x6 flat on top to provide resistance to upward horizontal rafter forces. It is a 6/12 pitch IIRC.  I also used a short section of 4x4 as a kingpost for the main hip rafters to be nailed to.  I believe Don_P commented once that he likes to use doubled hip rafters and bevel them so the sheathing has a nicer fit. Our 4x4 corner posts were set fairly deep in the ground.  We are going into our tenth summer; made it through all this time with no visible issues.

link
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Don_P

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Re: 28 X 40 California Redwoods
« Reply #111 on: March 10, 2017, 12:24:46 PM »
Without a post supporting the peak the hips are thrusting against the corners. Make sure they are well connected to form a tension ring. A metal strap wrapping outside around the corners in the birdsmouth area and very well connected would work at this size. I do like to double hips, these are beams and should be sized as such.

 Figuring out tributary area and beam moments on hip roofs is kind of tricky. Remember this is all done in plan view from above. Draw a triangle that represents one panel of the roof. The base of the triangle is 10'. The height is 5'. Half of each hip jack rafter is supported by the hip, half is supported by the perimeter carry beam. So, within the triangle that represents the roof panel, at midpoint draw a line that represents your king common and which has a horizontal span of 5'. Halfway up that span, at 2.5' make a mark and draw a triangle with the same 10' base and a 2.5' rise. This represents the inboard trib area to the beam. Notice it is a beam with load increasing uniformly to center of beam span. It has an area of 12.5 square feet. The overhang is treated as a typical uniform load, I'm assuming 1' wide x 10' long. Each of these produces a max bending moment that occurs at midspan but they are figured differently. Since both occur at the same point they can both be simply added together and checked against the max allowable moment for the size species and grade. That drawing also produced 2 more triangles that each represent the area tributary to their respective hips. Each of those represents half of the trib to their hip since the same thing is going on with their adjacent panels.  I need to reboot this beast and work on some drawings for a bit but this might be a fun exercise for you all. We'll need snow load info, species and grade, remember at 5" and thicker to use the heavy timber design values. I believe you'll find the appropriate equations in awc.org's DA-6.

Offline MountainDon

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Re: 28 X 40 California Redwoods
« Reply #112 on: March 10, 2017, 12:32:01 PM »
Good to mention the corner straps; I forgot.  I did not do that in the beginning but after sitting there many nights under the roof and doing more thinking, I added galvanized straps wrapped and nailed around each corner, just to be sure there was more holding the top together. I had entertained using steel rods crisscrossing inside tying diagonally opposites together.
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #113 on: March 10, 2017, 07:59:19 PM »
Thanks for all of the info everyone, forgot to mention we do not have to worry about snow. And the common rafters will have ties, mainly so I have something to hang a few lights from.

Commons and creepers are 2 x 8
Hips are 2 x 10

edit: Was also planning on doubling up my hips, just seems to make sense to do so. And will be pouring substantial footings for each post.

Offline Don_P

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Re: 28 X 40 California Redwoods
« Reply #114 on: March 11, 2017, 04:03:46 AM »
I haven't tried to do any math but my gut says that is way more than enough. Check that your rafter and jack plumb cuts are fully supported on the hips. If the roof is "tied" there is no thrust to worry about. With a hip you need to tie in both directions. This can be ceiling joists running one direction with lumber or steel strapping running above that in the other 90 degree direction. I think at this size if the king commons are well tied that would be sufficient. Without snow minimum loading is 20 psf live, 10 psf dead.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #115 on: March 13, 2017, 08:19:31 AM »
Another question I had is the recommended joint for the beams at the corner, I was planning on doing a simple lap joint. But I'm not sure if there is something better I could be doing.

Offline Don_P

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Re: 28 X 40 California Redwoods
« Reply #116 on: March 13, 2017, 02:53:12 PM »
The problem with a simple half lap is one side has a 50% notch unsupported and loaded. I inset the notching to get at least 1" of support for each member. Ignore the square tenon these were 8x8's but look at the way the notches work. You still need to tie it down sufficient to resist the roof uplift.





Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #117 on: March 13, 2017, 05:04:12 PM »
Found this one online...


Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #118 on: April 12, 2017, 02:49:08 PM »
Well I think I might take the easy way out on this one and fabricate brackets to support the beams and weld them to steel posts. I'll add some j-bolts to the footings to secure the posts, now I just need to find a way to securely tie the hips to the beams. I'll have to think about that more...

Offline Don_P

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Re: 28 X 40 California Redwoods
« Reply #119 on: April 12, 2017, 06:22:52 PM »
An L on top of the beam flatways with upright tabs welded at 45 degrees to the L to bolt through the hips would work. Make the L out of ~1/4x4"x~4' and lag down into the beam well. That should take care of the thrust as well.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #120 on: April 14, 2017, 06:09:48 AM »
I think I smell what you're stepping in Don, I like that idea and it should be pretty easy to do. I think my dad has a bunch of flat that were drops from a job he was on. I like this plan, I've got all of my brackets drawn up, now I just need to figure out what I'm going to use as posts (probably old oil field pipe as it's cheap) and send the drawings off to the water jet.

Offline pmichelsen

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Re: 28 X 40 California Redwoods
« Reply #121 on: May 16, 2017, 08:27:45 AM »
Headed up to the cabin next weekend with the goal of getting my Bobcat back in working order and doing some general clean up. I blew a hydraulic line in the Bobcat last Memorial Day weekend and I still haven't fixed it. I'm actually pretty embarrassed that it has been a whole year. I did attempt to fix it over Easter; however I found that I got an incorrect part. The original issue was one of the soft lines for the right side lift cylinder, but I figured while I was in there I would change both lines... well I made an assumption that both lines would be the same, and well, you know what they say about assumptions. I now have the correct lines to replace both soft lines for the lift cylinder. The left side appears to have been changed out already, so I'm hoping those are okay (they were a little tougher to get to). While there over Easter I also removed the cylinders from the grapple bucket, they haven't worked in years, the seals were all shot. I rebuilt them and it will be nice to be able to use the grapple bucket again. For the past five or so years we've had ratchet straps holding them open  :-[

Assuming the Bobcat is back in action I'll clear a lot of brush and trees that fell earlier this year and restock all of the wood sheds.