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Small Cabin Forum / Cabin Construction / Roof questions
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Nickscabin11
Member
# Posted: 5 Aug 2019 17:15
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Finally got around to making an account haha. My next step for my 16x16 cabin is the roof. What pitch should I use? Best rafter for a loft? (Don’t need much headroom but enough to sit up..it will be just for sleeping) spacing would be good to know as well. Walls are 2X4, rough cut lumber. Roof will be 2x6 rough cut.
2E5B0E74587440639.jpeg
2E5B0E74587440639.jpeg


Steve_S
Member
# Posted: 5 Aug 2019 17:40
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Usually you line up the rafters with the studs so the load transfers down through the line. It would help if you mentioned which type of roof you want, sorry but....

There is an excellent set of tools / calculators to work out many things including roof material, cuts etc...
https://www.blocklayer.com/

DaveBell
Member
# Posted: 5 Aug 2019 19:46
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What's the plan here?
127685_4.jpg
127685_4.jpg


DaveBell
Member
# Posted: 5 Aug 2019 19:58
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Loft - What grade and species of lumber are you planning on using for ceiling joists across a span of 16 ft?

Nickscabin11
Member
# Posted: 5 Aug 2019 20:56
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The original plan wasn’t to place that 6x6 across however I was looking for a large window and long story short the guy said it was about a 6’ window... turns out he meant 6’ tall and forgot to mention 10’ long lol but for 200$ I got 4 windows and my door.. but I placed it across leaving enough room for a 2x6 to line up with the rest of the walls.. currently waiting on the rest of the lumber for top plate and roof.. roof will be gable however open to any suggestions. And for the loft I’m not 100% yet what lumber I’m going to use.. hoping I could receive some information and recommendations here. I’m a 20 year old plumber not a 50 year old carpenter haha I have lots to learn.. thankful for any help I can get

Nickscabin11
Member
# Posted: 5 Aug 2019 21:00
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Below the loft there will be a wall in the centre for a washroom so I’m assuming that will be able to hold some of the load from the loft

DaveBell
Member
# Posted: 6 Aug 2019 02:49 - Edited by: DaveBell
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Probably the best thing to do is to keep weight away from that window. Loft dead load + loft live load + roof dead load + roof live load.

Fill in on top of the 6x6 then buy a 2x6x16 for a top plate to tie the left and right walls together.

Lets put the bottom of the rafters over the window so the main load (ridge board bearing) is on the left and right walls.

2x10x12 rafters on a 2x12x16 ridge board.
Ridge board top at 6' above top plate.
Provides 8/12 pitch with little over 5' interior rise.
(10' board at 6/12 pitch only gave 3'11" of rise with only 2" overhang)
Overhang will be 2' which can be used or cut back.
The 2x10 rafters should also provide good roof insulation depth for the great white north.

The ridge board end support will be a 5' 2x6, with 5'11" boards nailed left and right. This makes a U to cradle the ridge board.

Cut the top of the rafter angle to meet the ridge board and cut a birds mouth so the rafter rests on the wall. Use Simpson Strong Ties on the top and the bottom of the rafters. NO toe nailing.

After the rafters are in, install 2x10x16 ceiling joists (on top of the top plate and nailed to the rafters) on the back side coming forward for 8' to make a loft.

DaveBell
Member
# Posted: 6 Aug 2019 03:27
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Assume Spruce-Pine-Fur #2, 2x10x16 16" OC for ceiling joists. 2x10 also 16" OC for rafters.

DaveBell
Member
# Posted: 6 Aug 2019 03:43 - Edited by: DaveBell
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Put the wood stove on the left, chimney exit at top of wall (no roof exits = no roof leaks) double walled pipe outside, single wall pipe inside, run up outside to 2' or more over the peak of roof. Secure outside pipe to to outside wall with 2 or 3 chimney brackets.

Check wood stove fire code clearance requirements to wall, to rafters, and to loft edge. Install wood stove on top of Concrete backer board.

DaveBell
Member
# Posted: 6 Aug 2019 03:59
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You may want to keep the 2' overhang. Metal roof panels come in 12', plus that might help keep deep snow away from walls.

Brettny
Member
# Posted: 6 Aug 2019 07:15
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You need a deeper header over that 10' wide window. It dosnt matter if its a 6x6 it should be at least 2 2x10s with 1/2in plywood screwed and glued in the middle of them. A 6x6 is not stong or ment to be used in the way your useing it there. Its prob not even as strong as 2 2x6 with 1/2in ply in between.

Go streight up through the eoof near the peak with the chimney. Putting turn in the chimney makes the smoke cool and creasote forms. Having turs also makes it a real pain to clean.

As for the rafters. Use the blocklayer.com calculator. When useing this calculator and figuring out head room dont forget you need to add in the depth of tour floor joists. 2ft overhang is good if your useing metal roofing as you may never beable to keep gutters on that roof.


As for floor joists spaning 16ft you will need to use a prety deep board. If you could add a post and beam or wall in the center it makes things alot easier.

Aklogcabin
Member
# Posted: 7 Aug 2019 12:15
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At 16’ wide. On our cabin I used 2”x12”x16’ for roof joists. At a 12/12 pitch. Provides much better headroom. With a 12” roof joist I was able to use r-38 insulation and have a good inch of air flow above my baffles. For baffles I was able to get some old 4x8 corrugated plastic signs. Metal roofing comes in any length you want. I used 16’ stuff. At 16’ lengths I have an overhang of about 3’. Drip line for water and snow is further away. Snow is important for me because we can get snow really deep. And keeping it from stacking up against the cabin is important for me because bears could use it to reach the windows. I believe all dimensional lumber is hem fir or pine. So don’t know why folks keep asking that. I placed the woodstove in the middle so that the snow wouldn’t shear it off. Straight up from the stove. The rain collars used are easy to make waterproof. My stack was close enough to the ridge that the collar flange went over the top of the ridge.
The extra cost of the longer, wider lumber is minimal in the big picture. The extra insulation will be the best money you spend. I would not be concerned about large headers in a non load bearing wall. I used tung n groove 2”x6” pine 16’ wide . Makes a nice ceiling downstairs n solid floor upstairs and ties everything together.
I did use 3 floor 4”x12” beams and 11” TJIs so I don’t have floor deflection. And used 10’ walls so I would have more headroom upstairs. We did a full upstairs for bedrooms.
Will try n post some pictures for you.
Front
Front
Upstairs
Upstairs
Vapor barrier
Vapor barrier
Side
Side


ICC
Member
# Posted: 7 Aug 2019 15:16
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Quoting: Aklogcabin
I believe all dimensional lumber is hem fir or pine. So don’t know why folks keep asking that.


What is sold varies with location. Lots of Doug Fir sold where I am but little Southern Pine. A friend in VA sees lots of SP but less DF.

Yes, metal roofing can be had almost any length. Even Loee's near me will order in whatever you want for lengths, though the store that sells metal building panels ]roofs, walls, etc] offers a heavier gauge.

I too would suggest rafters in the 2x12 size only because of the extra depth available for insulation. Well worth it .

I do not like chimney bends or angles, especially 90 degree things in order to pass the pipe out a wall. A straight run is best especially with modern EPA approved stoves that have less flow than pre-EPA. There are excellent silicone boots available for flashing an insulated chimney through a metal roof. They use a "dead-soft" aluminum ring molded into the base of the boot. Fasten to the roof with screws. I've used a lot of them for chimneys as well as all the numbing vent perforations.

IF that big window is in a gable end wall a header is not required, as the roof load is carried by the side walls. However that end wall is poor design. There is virtually nothing to stiffen that wall yo prevent strong winds on one of the side walls pushing the end out of square. Good building practised requires at least a full 4x8 vertical sheathing panel to make the wall rigid. There are also narrower shear wall designs but that end wall is all door and glass. Not good.

Do not count on an interior wall to provide support for the loft floor unless the main floor and foundation has been designed to transfer loft load down to the earth.

If you are in snow country you can buy snow stops that keep the snow from sliding off metal roofs. That way you can use rain gutters and not have to replace them every spring. You must size the rafters and use the correct number of fasteners to handle the snow build up. I did that as I wanted to collect all the snow melt and all the rain instead of a well.

At 16' wide you really need 4x10 ceiling joists unless you gave a proper center load bearing wall, beam, foundation. 2x8's would be slightly spongy, anything smaller will be bouncy.

Nickscabin11
Member
# Posted: 11 Aug 2019 19:10
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Thanks everyone for all the responses. This has helped a lot! However I figured since the wall with the big window would be fine since it’s not load barring.. is there anyway I can add some strength? Since I do understand what you mean by winds knocking it out of square (there isn’t much wind in there anyways but still concerning..) I won’t have room to put 2x10 headed since the window is so big... will I just have to bite the bullet and find a different window?

Atlincabin
Member
# Posted: 11 Aug 2019 19:51
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You might fix the "big window" problem by lowering the sill by several inches and adding the appropriate larger header. That could allow you to keep the window you have.

DaveBell
Member
# Posted: 11 Aug 2019 20:22
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The 6x6 timber frame approach will span 6' because there is no second story load. I do not understand why you guys want him to tear out the wall just to stick build it like a house.

Aklogcabin
Member
# Posted: 12 Aug 2019 11:54
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As Atlincabin suggests. Having the window low enough allows you to see out better. When you are sitting on the couch. I have thought about putting a 12” window below my front window so I could see out better.
Whatever you do, you are doing a great job. If this is your dream cabin in the woods. Build what you want.

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