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WILL1E
Moderator
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# Posted: 11 May 2021 02:21pm
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Thought i'd start a fresh post to consolidate old threads and solicit help from everyone here on designing/constructing our 16x30 log cabin build. Our original intent was to build a similar size stick frame cabin, but given current conditions and new connection to a log supplier, we've changed direction.
Here are the known facts:
-16x30 cabin footprint
-5"x8" tongue and grooved white pine logs
-15 logs tall on eave walls
-Gable roof with metal roofing
-Cabin location is northern WI so specs are:
-Floor joist 40 live, 10 dead, L/360 deflection
-Rafters 40 live, 10 dead, L/240 deflection
-Ceiling joist (loft) 20 live, 10 dead, L/240 deflection
-At least 1 loft, ideally 2
-Windows already purchased, will post sizes when we get to that point
-Elevated foundation via post and beam construction
I would like to start this discussion from the foundation up....so let's get started!
I plan on using these 24" diameter by 6" thick precast concrete pads. I'll remove the top soil, put down some gravel and then set these pads on the gravel with my tractor.
On top of those i'll put at least 2 layers of 8x8x16" block. This will get me high enough so i don't need to use PT lumber on my joists. I'll likely fill the voids of the block with concrete just for some extra piece of mind and maybe toss in a stick or two of rebar. Hopefully i can take up any height variance from pier to pier with 2" and/or 4" thick 8x16" block or pressure treated board.
For the built up beams i'll need to do (3)2x8's with joints staggered over the piers.
Here's my first dilemma. We eventually want a covered wrap around porch on 2 sides of the cabin. But with lumber prices and tight budget, that will need to come later. But i think it would be wise to build on the deck portion of at least the 1 rake end of the cabin where the main entrance will be so that i can include that extra length into the beams and space the piers accordingly. I can add the roof for it and roof+deck for the other side if and when money allows. Would you all agree with this thought process?
For the floor joist system. The worse case scenario for the MoE is 1.2 for SPF. Since 2x10 would be cutting it close to make the full 16' span with insetting of the eave beams, i'm thinking of doing 3 built up beams and going down to a 2x8" joist system @ 16" centers. Or for nearly the same cost i could do 2x10" joist with 24" centers. Thoughts or pros/cons to either?
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jsahara24
Member
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# Posted: 12 May 2021 01:03pm
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Quoting: WILL1E Here's my first dilemma. We eventually want a covered wrap around porch on 2 sides of the cabin. But with lumber prices and tight budget, that will need to come later. But i think it would be wise to build on the deck portion of at least the 1 rake end of the cabin where the main entrance will be so that i can include that extra length into the beams and space the piers accordingly. I can add the roof for it and roof+deck for the other side if and when money allows. Would you all agree with this thought process?
Are you going to have PT beams? If you wait to cover it, or even when you get wind driven rain they will get wet....I am used to building the structure and then adding a separate deck....
Quoting: WILL1E For the floor joist system. The worse case scenario for the MoE is 1.2 for SPF. Since 2x10 would be cutting it close to make the full 16' span with insetting of the eave beams, i'm thinking of doing 3 built up beams and going down to a 2x8" joist system @ 16" centers. Or for nearly the same cost i could do 2x10" joist with 24" centers. Thoughts or pros/cons to either?
I would go with 16" on center joists....if you are going to use the 6" concrete cookies and not be below frost its not too much work to add an additional beam.....But I would recommend going below the frost line with your posts, and using two beams with properly sized joists to carry it...I have 2x10s at approximately 14' span and its pretty good...if you run around then you can feel a slight bounce but manageable for a cabin imo...
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Brettny
Member
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# Posted: 12 May 2021 01:58pm
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I wouldnt do 24in oc floor joists either. I would also not add the porch later. Theres very few good ways to attach its floor joists/girter to the current building.
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WILL1E
Moderator
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# Posted: 12 May 2021 02:37pm
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Quoting: jsahara24 Are you going to have PT beams?
I thought i'd be high enough off the ground i wouldn't need to..but i guess i'm not opposed to it as the cost difference is minimal.
Brettny So your saying you would extend the beams to include the porch on the rake end right away?
Since this will be a log cabin, there will be no sheathing/siding covering the rim joist. I was going to put some flashing down to protect the subfloor edges and rim joist, but is there any reason why i couldn't use PT lumber for the rim joist and regular lumber for the joist?
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Brettny
Member
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# Posted: 12 May 2021 02:56pm
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Quoting: WILL1E So your saying you would extend the beams to include the porch on the rake end right away?
Yes. I may even extend the main building roof out over the porch as well.
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Nobadays
Member
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# Posted: 12 May 2021 03:21pm
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Quoting: Brettny Yes. I may even extend the main building roof out over the porch as well.
Not only does this look great on a log home it is also very functional. If you tell your log supplier what you want to do on that end he could probably design/build you a round log truss and uprights.
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WILL1E
Moderator
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# Posted: 12 May 2021 03:46pm
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I don't want the main roof extended over the porch on the rake end...to high up. I'm thinking of something like this.
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NorthRick
Member
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# Posted: 12 May 2021 04:36pm
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I forgot where you are building this. If you get any snow that porch roof will be a problem for those steps. You can install snow fences to keep the snow from sliding off but water will still drip onto those steps as the snow melts. At night when it gets cold again you end up with ice on your steps.
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Brettny
Member
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# Posted: 13 May 2021 05:40am
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Quoting: WILL1E don't want the main roof extended over the porch on the rake end...to high up. I'm thinking of something like this.
Are your walls 10' like in the link? Typical roofing requires at least a 3/12 pitch so that may limit your porch depth. With a 8' porch and starting at 10' high and dropping to a 8' wall you will have a 3/13 pitch. You have to start at the top of a 10' wall though.
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silverwaterlady
Member
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# Posted: 13 May 2021 07:29am
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We did a extended roof in the front of our cabin with the intention of adding a three season room that could be independent of the main cabin to save on heating costs depending on our finances that year.
It took us 13 years to finish it.
You can click under on my member name and check my page under “Our Cabin†of the before and after.
As far as ice on the steps, do you plan on having a back door like most cabins. Just go out the back and treat the front steps.
We didn’t know the drainage was so poor around our cabin. This was after the fact. We had heaving of our foundation due to the thaw/freeze cycle. Had that and the foundation repaired.
So my advice is to be sure you have adequate drainage around your foundation.
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WILL1E
Moderator
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# Posted: 17 May 2021 08:28am
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Quoting: NorthRick that porch roof will be a problem for those steps.
The picture was strictly to illustrate the wrap around porch only being on 2 sides.
Quoting: Brettny Are your walls 10' like in the link?
Yes. The log supplier suggested doing a 10/12 pitch to get the most room in the loft. I haven't started the designs yet so i'm not sure what we are going to do yet.
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Brettny
Member
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# Posted: 18 May 2021 10:21am
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I wasn't specifically talking about the pitch on the main roof but the pitch on the porch roof. You still need 3/13 pitch at minimum and if you want head room on the low end of the porch roof you almost cant go wider than 8'
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gcrank1
Member
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# Posted: 19 May 2021 09:37am
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We had considered a low-pitch roofed porch off the scenic side of our 16x24. The cabin roof has a good 2' overhang so plenty of room to tuck the porch roof back underneath.
But when I factored in the pitch and how far out we wanted it wouldnt work. The high side at cabin isnt high enough to have the low porch side be enough for my 6' to walk under.
My wife isnt good at visualizing....so I did a mock-up with some 2x4s out there and a small shipping skid as the deck height.
The other consideration was the view from within, looking out the big window that proposed porch roof would cut off a huge amount of our good view. Neither of us liked the idea of exchanging the open view for 1/2 of it being the underside of a porch roof.
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Brettny
Member
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# Posted: 19 May 2021 09:57am
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This is alot of the reason why our living room will not look through a porch. I also dont want any windows on the porch as it can become a security issue. Also definitely no entry door side light windows and only a small window at the top of the door. And yes I'm aware that if they want in they will get in. I just want my cabin to be harder to get into than the neighbors.
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WILL1E
Moderator
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# Posted: 20 May 2021 01:26pm
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So do i need to calculate anything differently if i'm building a log cabin on the foundation system i described above vs. a stick frame? Gut tells me that the per square foot of log wall space would exceed that of completed stick frame (studs, sheeting, siding, drywall, insulation, wiring, etc.)
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WILL1E
Moderator
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# Posted: 26 May 2021 08:09am
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Another question for you log cabin builders....any of you have your wiring on the interior surface of your logs vs. drilled and chassed through the logs?
I've got a scenario running through my head where i don't insulate the floor and focus on just getting the floor and shell up as quickly as possible. Then come back and add wiring and insulation (in floor) later. This would mean the wiring would be run on the surface.
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