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Zukowski
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# Posted: 11 Aug 2015 12:23am
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Hello Everyone
Im currently designing a small family cabin for some later part in life but have a few questions before I continue to design it. Im thinking of a 10 by 16 with a loft built for northern Minnesota.
Here is a few questions.
1. I was thinking about using 2x6's for the whole thing, floors, walls, roof but I know nothing and the internet gives me mixed answers. Im going with a 10 foot and 12 foot wall on the 16' span for gentle slope. Will just 2x6's work or do i need 2x8s as well?(read 3 before you decide.)
2. I was thinking of doing a pier and post foundation because this guy will be tall, almost 15 feet if not more with foundation and i wanted to make sure it would hold against some of the stupid wind we get up here.
3. So i want to build a loft length wise, yeah thats right length wise. With the sloping roof i want to maximize my loft head room and the best way would be to run it along my 12ft wall which would give me 16*5*5. Can i do this without putting a beam in the middle of my floor? Will my 2x6s be strong enough for something like this?
Floor plans are one thing but making sure something is safe and done correctly for your family is another and I dont want to miss anything, like I said i have no experience but im learning as I go.
Thanks.
2.
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Don_P
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# Posted: 11 Aug 2015 07:09am - Edited by: Don_P
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For 3 to work you'll need a structural ridgebeam... need the design snow load for the area, usually the building dept can give you that.
2, nope, especially in wind. Post frame construction would be better, or a conventional foundation. Post and pier is illegal without engineering for a reason, this is it.
1, Floors will be heavier, main would be 2x8's, loft running 16' joists would be 2x12 or if there is a beam the 16'direction they could probably go 2x6 if the joist span is under 8'.. the 16' beam would need to be pretty healthy though.
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Zukowski
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# Posted: 11 Aug 2015 02:58pm
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Thank you for the information Don_P. This is a lot of stuff to consider and it seems like it would be smarter to go with a traditional pitched roof. My foundation would be done my professionals because I haven't a clue but I will read up on post frame construction.
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Don_P
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# Posted: 11 Aug 2015 10:24pm
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This is the main website for that type of construction, their "about" page;
http://www.nfba.org/About/default/whatispostframe.html
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Zukowski
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# Posted: 12 Aug 2015 11:28pm - Edited by: Zukowski
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Hello Don,
After looking through that stuff and then at my design i think something different will be better and easier to build, I drew up something here and was wondering if you would please take a look and let me know what you think?
This is just a 12x16 with a 8/12 pitch roof, I used 2x8s for the floor and roof and 2x6s for the walls and loft joists. For the loft itself I was thinking of using 6x6s to help span the 12ft and take pressure off the walls.
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Don_P
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# Posted: 13 Aug 2015 08:05am
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What you've drawn would go on a traditional foundation, a basement or crawlspace... is that the plan?
There are a couple of issues with the framing... let's start with finding out the snow load to see what kind of weight is coming down from above.
With those two pieces of info in hand we can kick around some ideas.
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Zukowski
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# Posted: 13 Aug 2015 01:04pm - Edited by: Zukowski
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This would be in upper minnesota and the snow load is 42 psf. I don't have foundation picked out so im open to suggestions but I don't need a crawlspace or basement.
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Don_P
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# Posted: 13 Aug 2015 11:35pm
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Actually the loft joists running the other way help tie the walls together, countering any potential roof thrust... a toggling action of the rafters, Make the loft joists 2x8's.
A ridgebeam is how I would build the roof, in this case the beam would be designed to support about 5,000 lbs at about a 15' clear span. A 4 ply 2x12 in #2 lumber would do it, or a 3 ply in #1 dougfir.
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Don_P
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# Posted: 14 Aug 2015 07:27am
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In the 4 corners and where you have drawn 6x6 posts in the center of the sides, the posts could extend unbroken from the top of the wall down to the footings (6 posts) There are simpson heavy duty hangers that can mount to the posts to support the floor girders. On the gable ends those girders need to be 3 ply 2x12's ~12' long and supporting the ridge beam. If a post is placed from ridgebeam straight down to footing the girders could be reduced to single ply (8 posts). On the eaves the girders would be 2 ply 2x12's spanning ~8'.
This differs from pier and beam construction in that the posts are braced by the walls they are embedded in.
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Zukowski
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# Posted: 14 Aug 2015 11:09am
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Quoting: Don_P Actually the loft joists running the other way help tie the walls together, countering any potential roof thrust... a toggling action of the rafters, Make the loft joists 2x8's. A ridgebeam is how I would build the roof, in this case the beam would be designed to support about 5,000 lbs at about a 15' clear span. A 4 ply 2x12 in #2 lumber would do it, or a 3 ply in #1 dougfir.
Cool, I put them that way because i thought it would help keep the weight off the walls but I will switch them now and add a ridge beam to my drawings. None of which are to scale or perfect.
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Zukowski
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# Posted: 14 Aug 2015 11:19am
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Quoting: Don_P In the 4 corners and where you have drawn 6x6 posts in the center of the sides, the posts could extend unbroken from the top of the wall down to the footings (6 posts) There are simpson heavy duty hangers that can mount to the posts to support the floor girders. On the gable ends those girders need to be 3 ply 2x12's ~12' long and supporting the ridge beam. If a post is placed from ridgebeam straight down to footing the girders could be reduced to single ply (8 posts). On the eaves the girders would be 2 ply 2x12's spanning ~8'. This differs from pier and beam construction in that the posts are braced by the walls they are embedded in.
My main thought with those 6x6s was to notch them and attach them to my frame and bolt them or nail them(not sure what to do) and then snug a joist up to it to stop twisting(only cause i havent looked into connectors yet.)
What if i were to attach this cabin to a skid? Then i wouldnt be able to bring those 6 posts to footings would I? I only ask because I did a bit of searching for foundation and OwenChristenson says that a skid type foundation will work well for my size with the frost zone we have.
Thank you again for all your help and info, this has been a real eye opener for me.
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Don_P
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# Posted: 14 Aug 2015 06:54pm
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It would, skids don't get you out of the ground very far, I would use treated for the skids, floor and siding/sheathing down low. Mobile home twist in anchors at the corners wouldn't be a bad thing.
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Zukowski
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# Posted: 14 Aug 2015 07:12pm
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Will do with the twist anchors.
What way should i design my ridge beam?
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Don_P
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# Posted: 14 Aug 2015 09:03pm - Edited by: Don_P
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I prefer the one piece post. If the skids form a box and the post sits on that with full gravel support under all the 6x6's then that end girder can be just a single ply rim joist, the ridge post load (~2500 lbs) is supported on the 6x6 cross skid on the bed of gravel.. Timber screws and 2 rows of 6x6's laid up with the corners of the 6x's overlapping log cabin style would get you a foot above the gravel and it would help distribute the loads more evenly. There are no 6x's needed under the loft or vertically in the corners in that scenario. There is just a 2 row high crib of them underneath.
The gable end wall framing at the loft end would be best if platform framed under loft floor, then the loft floor, then the upper rake wall. The cathedral end would be balloon framed.
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DaveBell
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# Posted: 14 Aug 2015 11:00pm
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10 X 16 cabin, with loft, Northern Minnesota
2x10 floor joists on 16" centers
1x1" wood insulation board holders at bottom of 2x10s
install insulation boards in floor joists,
hold in place with spray foam and add 1-2 inches foam across
Air gap is desired
3/4 " plywood flooring, construction adhesive and screws
2 x 6 walls on 16" centers
Install factory or site made Attic Trusses
2 foot on center
made of 2x10 joists and 2x6 Top Chords
install 1/2 inch plywood sheathing on roof, exterior walls, and Truss floor.
Apply closed cell spray foam to entire shell, after electric and plumbing.
Install exterior finishes/doors/windows/roofing and you are weather tight.
The attic truss gives you more space just out of design engineering.
The closed cell spray foam on the entire shell provides highest R-value
you can cut in a staircase later, outside wall to middle of structure.
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Zukowski
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# Posted: 16 Aug 2015 11:56pm
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Quoting: DaveBell 10 X 16 cabin, with loft, Northern Minnesota 2x10 floor joists on 16" centers 1x1" wood insulation board holders at bottom of 2x10s install insulation boards in floor joists, hold in place with spray foam and add 1-2 inches foam across Air gap is desired 3/4 " plywood flooring, construction adhesive and screws 2 x 6 walls on 16" centers Install factory or site made Attic Trusses 2 foot on center made of 2x10 joists and 2x6 Top Chords install 1/2 inch plywood sheathing on roof, exterior walls, and Truss floor. Apply closed cell spray foam to entire shell, after electric and plumbing. Install exterior finishes/doors/windows/roofing and you are weather tight. The attic truss gives you more space just out of design engineering. The closed cell spray foam on the entire shell provides highest R-value you can cut in a staircase later, outside wall to middle of structure.
Sweet thanks for the info Dave, I honestly dont know what half that stuff actually means but I will look it up! Thank you.
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Zukowski
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# Posted: 17 Aug 2015 12:08am
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Wow Don_P you are a busy man, after doing some research ive seen your name helping in different places, you're awesome.
I cant get this loft idea out of my head and I can only tell so much by reading so I figure I would just ask. If I put in loft and used a beam in the middle end to help support do i still need 2x8's or can i drop down to 2x6s? If I do use a beam in the middle to support the loft can I bold the loft joist right to the wall frame and add a ledger below on all three sides, or do I have to attach the ledger to the wall frame and then use joist hangers between the ledgers?
I have tons of questions but I dont want to flood you, thank you for your time.
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Zukowski
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# Posted: 17 Aug 2015 12:40am
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This was kinda what I was thinking.
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Don_P
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# Posted: 17 Aug 2015 07:13am
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What you've drawn works fine, as a house gets wider there is often a load bearing wall down the center doing the same thing. The post needs to be well supported, generally straight down to a footing... or over a cross skid that bears on the gravel, etc. You've also picked up a post and a beam in the layout, just something to think about as you lay out rooms. With that post there you can continue it up to support the ridgebeam. By dividing its' span in half the needed beam size would drop radically. The ledgers need to be "let in" to notches in the wall studs so that the ledger is actually bearing on the stud rather than simply hanging on nails on the sides of the studs. Then by crossing the joists over the ledger and nailing them to the sides of the studs it helps tie the building together. But, in the process you have created an open flue between floors, block the stud bays between joists to prevent fire from having that channel around the floor. We still need to talk about the gable frame before you finalize. An engineer friend laughed when he found he was reading one of my posts while researching something.
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Wilbour
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# Posted: 17 Aug 2015 09:34am
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Quoting: Don_P The ledgers need to be "let in" to notches in the wall studs so that the ledger is actually bearing on the stud rather than simply hanging on nails on the sides of the studs. Then by crossing the joists over the ledger and nailing them to the sides of the studs it helps tie the building together
For those of us who are limited to 2x4 walls, I used Jack studs to hold up each end of the loft joists. Letting in on such small stud was not feasible for me.
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Zukowski
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# Posted: 17 Aug 2015 07:01pm
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Quoting: Don_P What you've drawn works fine, as a house gets wider there is often a load bearing wall down the center doing the same thing. The post needs to be well supported, generally straight down to a footing... or over a cross skid that bears on the gravel, etc. You've also picked up a post and a beam in the layout, just something to think about as you lay out rooms. With that post there you can continue it up to support the ridgebeam. By dividing its' span in half the needed beam size would drop radically. The ledgers need to be "let in" to notches in the wall studs so that the ledger is actually bearing on the stud rather than simply hanging on nails on the sides of the studs. Then by crossing the joists over the ledger and nailing them to the sides of the studs it helps tie the building together. But, in the process you have created an open flue between floors, block the stud bays between joists to prevent fire from having that channel around the floor. We still need to talk about the gable frame before you finalize. An engineer friend laughed when he found he was reading one of my posts while researching something
I havent shown it yet but i plan to add fire blocking between studs.
Why am I using a ridge beam and not a ridge board? Is that because i have a snow load? I thought i could do a 2x8 ridge board then collar tie the rafters that not part of the loft, that should stop the roof from spreading. The more I look at my roof the more i might want to contract it out but im already going to do that with my foundation so that would be spendy to get people out there twice.
If i use a ridge beam then i need to balloon frame the gable end right?
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Don_P
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# Posted: 17 Aug 2015 09:12pm
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Either way you need to balloon frame the gable. Studs run unbroken from points of lateral support. Lateral support in that case is from floor to floor or from floor to roof... never frame a top plate in air, it should always be tied to floor or roof framing.
When there is a kneewall or untied rafters the roof should be framed with a ridgebeam rather than a ridgeboard. Snow load is part of the driving force behind the rafters spreading, as is the dead load, and wind. I know, people often think otherwise on the kneewall, in that case the spreading force is being resisted by a chain of connections, studs to plates, plates to each other, rafter to plate, joist to stud... that's asking an awful lot of multiple connections. Then, is the notched stud up to the thrust, maybe, engineers say no. If it's hanging from a ridgebeam all that nonsense goes away and she can change your mind and omit the ties.
If there is a post to ridge at midspan the ridgebeam load is 2500 lbs per span. Call the span 96", my calc is being balky for me, here's the link
http://www.timbertoolbox.com/Calcs/ddsimplebeam.html
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Zukowski
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# Posted: 17 Aug 2015 10:11pm
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Sweet, I'll work on another drawing in between looking up terms. I've seen a few posts of yours on the same subject on different forms so I'm digesting that info too.
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Zukowski
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# Posted: 18 Aug 2015 12:20am
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While I've been looking into this I keep seeing these subfloors are built different with ballooning and im wondering if in can build a platform style subfloor with my balloon walls or I'd that creates a weak point.
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Zukowski
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# Posted: 18 Aug 2015 02:50am
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Here are my balloon framed ends along with my platform walls, as you can see with the red circle i have no idea how to connect the balloon to the platform or if im doing that right. Also i have no idea how my gable top plate should be so that it lines up with the rafters.
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Don_P
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# Posted: 18 Aug 2015 07:19am - Edited by: Don_P
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The wall sheathing ties those walls together, if you are concerned with that connection run a metal strap around the corner, to get to code nailing it'll take a block in the rake wall and 6 nails each side of the wall IIRC.
Draw the rafter in first and then the rake wall. Ideally the rake wall would be either a 2x4 or a 2x6 below the top of the rafter to allow the overhang's lookouts to plane in with the roof and bear on the rake wall. block between lokouts. Builders often "loft" the rake walls on the floor, snap it all out on the floor deck, rafters and all, then measure down the typical 2x4 drop and snap that on the floor, then tack the members to the floor deck and measure for the studs.
I don't follow your subfloor question.
With a post at center of ridgebeam a single 2x12 is sufficient as the beam, or a double 2x8, although the single 2x12 is stronger and stiffer.
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Zukowski
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# Posted: 18 Aug 2015 06:24pm
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Ive been looking up balloon framing and the sill plate is bolted to the concrete. Do I just build a subfloor and put osb on then attach my sill plate to that?
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DaveBell
Moderator
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# Posted: 18 Aug 2015 08:33pm
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Don_P, 10x16, family size, why not go with an attic truss for double space? Wouldn't that be stronger than toe nailing a rafter with Minn snow load?
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Rdkng07
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# Posted: 18 Aug 2015 08:45pm
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Just order plans from these folks. I built a 12x16, very easy to do and strong.
The trusses are built attic style, and you simply cut out the ceiling joists where you would like an opening to get up to the loft.
I removed three in the center of the building and have two lofts.
If nothing else the $30 bucks for the plans will show you how to build a small barn.
URL
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DaveBell
Moderator
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# Posted: 18 Aug 2015 09:28pm - Edited by: DaveBell
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Attic Truss Vs Loft, You have to put on a roof, why not engineer for better space.
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