20x30 single story, floor joist hangers????

[rsbhunter]

I just recieved my plans, and i am planning on using 8" or 10" sonotube footings with simpson brackets..Can the joists be attached to the perimeter beams by way of hangers? And, it seems hard to find 2x12 -20footers for joists, if i don't go with I-joists, can 2x10s with a beam in the middle , and the joists attached in hangers on both sides? Brand new to this, and want to do it right...Thanks, rsbhunter

[John Raabe]

The joists can be hung inside the beams but you may need some plumbing to run down one of the long walls. You don't want to chop through a beam for the drain line.

2x12's especially select structural are hard to get in 20' lengths. Yes, 2x10 and an internal beam and pier support line will make a nice stiff floor.

[Don_P]

I can think of a couple of positives to that approach. The frame is about a foot lower. The girders would pick up lateral stability, they resist rolling better, by having the joists frame into their sides. I like wood on wood especially over a built up member vs attaching to the side of an outer ply, but I can see a couple of ways of looking at this.

[rsbhunter]

Thanks for the replies...Other than a water line from a tank, there will be no plumbing lines, one in, and one out.....This is to be built at 10,000 feet in the mountains.....compost toilet, water storage tank (either 1000 or 1500 gal.) and off grid power....retirement place....Theres no power for around 3 miles. I will run the piers every 6', and do a triple 2x12 beam, with 2-1/2" plywood plys) on 3 lines of piers.....i am thinking about using 10' high walls, with a 12/12 roof, will give me a semi loft...can loft floor joists be bolted to the wall joist at 7' (bottom of loft floor joist) with a stud  (2"x6")nailed to the wall joist ? Anyway, thanks for all the help...i'm excited and alittle nervous at the same time!!! But it will be done...rsbhunter

[MountainDon]

Nails, not bolts as a rule.

10,000 feet.   What is the snow load? The wind?  Those two things may make the use tall side walls with a dropped loft floor inadvisable. A structural ridge BEAM with a support column path down to the foundation or engineered trusses might be the best way to do that. The wind situation can also affect the foundation; a 20 wide with tall walls and a 12/12 pitch roof makes a pretty good sail. Is the ground level, more or less? How tall would the piers have to be? Surface rocks? Easy to dig deep holes for piers?

[rsbhunter]

I don't want the piers more than a foot AT most.... Should be able to go at least 2 feet deep, if not more...will know in about 3 weeks....it's 350 miles from my current location...If i can go deeper, i will....The cabin will be built on the north-east side of a north-south ridge...about 40' below the ridgeline....iv'e included a pic so that you can see the wind block from trees... Not having a "semi" loft is not a deal breaker, built as the plans are, just having the storage will be enough ......rsbhunter

[Redoverfarm]

Thanks for the replies...Other than a water line from a tank, there will be no plumbing lines, one in, and one out.....This is to be built at 10,000 feet in the mountains.....compost toilet, water storage tank (either 1000 or 1500 gal.) and off grid power....retirement place....Theres no power for around 3 miles. I will run the piers every 6', and do a triple 2x12 beam, with 2-1/2" plywood plys) on 3 lines of piers.....i am thinking about using 10' high walls, with a 12/12 roof, will give me a semi loft...can loft floor joists be bolted to the wall joist at 7' (bottom of loft floor joist) with a stud  (2"x6")nailed to the wall joist ? Anyway, thanks for all the help...i'm excited and alittle nervous at the same time!!! But it will be done...rsbhunter

I will have to agree with Don about nailing the floor joist in place at the wall studs.  The general practice is to let in a ledger to the wall studs and pocket the floor joist into the wall.  You could insert a cripple stud for the floor joist to sit on. Depending on the size of the floor joist you plan on using will probably dictate which method will work the best.  Just to get the terminology straight in that joist are horizontal members and studs are verticle members.

That looks like a long driveway/road.  Depending on the direction, your geographical location it may be a while for the sun to melt any snow given the tree line on both sides.  North west are the worst for the sun to get to and it tends to linger longer that direction. 

[rsbhunter]

On the loft joists, i was trying to explain using a cripple stud, if that is a stud that is under the joist, that runs to the sill plate, or floor , being nailed to the stud. The property actually faces North towards the left and east on the right hand side.......Might end up selling and buying something else, as i already have a bunch of $$$$ in new solar modules and a power center, i'll have to do a solar site evaluation........rsbhunter

[Redoverfarm]

On the loft joists, i was trying to explain using a cripple stud, if that is a stud that is under the joist, that runs to the sill plate, or floor , being nailed to the stud. The property actually faces North towards the left and east on the right hand side.......Might end up selling and buying something else, as i already have a bunch of $$$$ in new solar modules and a power center, i'll have to do a solar site evaluation........rsbhunter

Now that the correct terminology is in place you may proceed.   It really doesn't make any difference where the property faces as long as you can set your solar to the correct position.  Be that at the back, side, front to get the most sunlight as possible.  If you have enough property you may even be able to clear some additional trees to get what you need.  I am not up to speed on solar as some others here at CP but it may be possible to just do what you described as a "site evaluation" to determine where you would place your panels.  Keep us posted and we may be able to throw you a hint every once in a while.

[John Raabe]

My Sunkit is a simple solar site evaluation tool that will tell you what part of your property will get the most usable sunlight and where you could benefit from some tree cutting. I recently had to do serious logging at my place to get back some of the solar access that has be in steady decline from 30 years of tree growth.

[rsbhunter]

Yes, i have the sun kit, and plan to take it with me when i go up there...i have 5 acres, and i am willing to clear any or almost all , as solar is my only option....Have even planned on making a telephone pole tower (4 poles in a square configuration with bracing) to get the panels up 20 or 30 feet more!!! I have seen pictures of one that has been done successfully...... So, if a cripple stud is used under each loft floor joist, can the joists be secured to the wall studs (10') with simpson joist brackets @ 7'? These will have to be the I-joists, because of the span i understand...The loft will be used as a spare brdrm...Thanks again for all the help, i ask alot of questions, because i HATE not knowing something, and guessing, then being wrong!!!! Thanks, rsbhunter

[John Raabe]

For the loading of the loft you can use 2x12's and they can be nailed directly into the 10' studs and you can nail the cripple underneath. You don't need hangers.

I would use 2x4 for the cripples as that is plenty of bearing and it leaves room for better insulation.

[John Raabe]

Look carefully at the detail on sheet 5 of your plans. Note the connection - the joist sits ON TOP of the let-in ledger. Some folks on this board think the let-in ledger is weakening that connection. That is only true if you hang the joists off the ledger with hangers (I don't recommend that - it is both weaker and more expensive). When the joist sits on top of the ledger and is nailed into the studs, it strengthens and stiffens the short wall above and connects the two sidewalls. You can replace the ledger with cripples if you like but nail the 20' joist (lumber or I-joist) to the tall studs.

Note that you want the stud spacing to be the same on both bearing walls. They need to be directly across from each other.

[Don_P]

Even though there is a pin connection of the joist above the ledger this is tension side notch... which does weaken the stud considerably. The raised kneewall is something every engineer that has looked at this has said is a bad idea. This is a poor detail that needs work. The taller the kneewall, the worse it gets... until you can lower the rafter ties above to a level where they provide adequate tieing action.

The joist connection to the stud is a tie, the joist is not simply sitting atop a ledger or cripple, it is also tieing the opposing walls together against the horizontal thrust of the sloping roof planes. This connection should be specified according to roof load. If you do attach joists to the face of the let in ledger the connection will fail by withdrawing the ledger from the wall notches as the walls lean outward... the joists connected directly to the studs tie the walls together in shear preventing this. Using a connection through the web of an I joist to create a tension tie is something that should be thought through.

[John Raabe]

OK, I'll check this out.

This is not an issue if a truss is used for the roof structure and there is no outward thrust on the wall. But I know that some folks are using a common rafter system that would put some thrust on this wall.

[Don_P]

I know that some folks are using a common rafter system that would put some thrust on this wall.

In a 12/12 pitch the vertical load is also the horizontal reaction at the rafters feet... a half ton of vertical load on the roof translates to a half ton of horizontal thrust trying to tip over the kneewalls or push the walls apart, the forces being resisted can be quite significant. Lower the pitch, at 4/12 the thust in this example would be 3000 lbs.

I slapped this together to illustrate this a little.

The proportions are grossly exaggerated to show the forces at work. This is a common rafter pair tied by a floor joist dropped below the rafter feet.



Notice the horizontal spreading force, thrust, on the kneewalls when a load is applied to the rafters. I tied the joists by using a roofing nail in withdrawal, it is pulling those nails. If you nail the joists to the sides of the studs the nails are in shear rather than in withdrawal. Look below the tieing joist, immediately below the joist is where a ledger would be notched in. If I make a slice on the interior face of that stud, is it clear that it is weakening it significantly?

Go another step in the thinking process, many folks have asked if they can have an open greatroom using this method but without any ties. Think about what happens with absolutely no tie.

[rsbhunter]

Ok, i'm a simpleton as far as this, does this mean that i should stay away from using 10' walls, with the floor joists of the loft tied (nailed) to the wall studs (2x6s) with a cripple stud nailed to the wall stud under the joist? Or , if it's questionable as to being sound building practices, what kind of space would i have if i went with engineered trusses (16" oc over studs) in the "attic/loft area? Thanks again for the help...i just spent 4 months learning about solar, and with the help of great people, alot like you all, i now have a decent knowledge of the basics, and i will buy a framing book....And for the suggestions   i will make the studs parallel, can you explain what the "let in ledger" is?If needed, and for safety, i am not above running a beam from the end wall , so that i can support the loft floor joists in the middle of there span, supported by a built up beam, running vertically up to the beam( best i can describe it is like a "lolly column....rsbhunter

[Don_P]

Trusses are engineered for your building to support the loads and prevent horizontal spreading.
If you build a properly tied roof according to the prescriptions in the codebook, it will support your loads and will not thrust on the walls. When you step outside of the codebook provisions or the truss company's engineered design it is not only law, it is good design to have an engineer review your design.

Look again at my model above. If a horizontal tie was attached across the rafter feet and then Michelle pushed down on the roof, would the rafters be able to thrust outward on the wall? That would form a triangle, triangles are fixed, they do not change shape. There is the codebook provision.

[John Raabe]

As I understand the topic here, rsbhunter is building a 20' wide single story house. That is the plan he has and that design has a standard 8' tall wall with either a truss (flat, attic or other shape) or standard 2x8 rafters and a 2x8 attic joist tied together at the top of the walls. There are no balloon framed walls or unknown outward forces to deal with.

We have all moved off topic and got to talking about the 1-1/2 story in this thread. That is probably not helpful to rsbhunter.

And since these are standard trusses that would be the simplest way to frame the roof and have it engineered for local snow and wind loads.

[Redoverfarm]

Thanks for the replies...Other than a water line from a tank, there will be no plumbing lines, one in, and one out.....This is to be built at 10,000 feet in the mountains.....compost toilet, water storage tank (either 1000 or 1500 gal.) and off grid power....retirement place....Theres no power for around 3 miles. I will run the piers every 6', and do a triple 2x12 beam, with 2-1/2" plywood plys) on 3 lines of piers.....i am thinking about using 10' high walls, with a 12/12 roof, will give me a semi loft...can loft floor joists be bolted to the wall joist at 7' (bottom of loft floor joist) with a stud  (2"x6")nailed to the wall joist ? Anyway, thanks for all the help...i'm excited and alittle nervous at the same time!!! But it will be done...rsbhunter

I think this is were it started John.

[John Raabe]

Ah, that's where it went. A pretty big mod from a one-story plan. But we can help him out.

I am looking at simpler ways to frame the 1-1/2 story plan and will meet with my engineer on Tues.

[rsbhunter]

The confusion is my fault.....I didn't really want the expense of a 1-1/2 story, but all the advantages of it!!!!! I just honestly didn't know if going to a 10' wall height, securing a 12" joist at 8' of the wall height would increase the space of the loft/attic area enough to be feasible . I'll probably just stick to the plans i bought....It will be plenty big enough for my needs. Does anyone know what kind of headroom/ space is left if using floor joists on the "loft floor, instead of the "open" ceiling? Is it enough for storage of small items? Thanks for all the help, and sorry for any confusion.....rsbhunter

[John Raabe]

If you did the roof pitch of 10:12 that is shown in the elevations, and you did an attic truss, it looks like you would have headroom of 6' or more at the center. You can check with a local truss company and they can likely come up with one that will give you plenty of storage. The lower the pitch of the roof the less height there will be, of course. You can do just about any shape you want (including a gambrel) but if you make it too attractive then you have to find space for a stair! Probably best to keep it simple.

[rsbhunter]

I had planned on a 12/12 pitch, because of the amount of snow.....Is it not better to have a steeper pitch for a high snow area? I am planning on having a steel roof.....rsbhunter

[John Raabe]

That will work fine and give you even more height at the peak. A metal roof will keep most snow off the roof.