2 basic Q’s – load paths and connectors
Hi
I have two very basic questions to begin with. I am in the planning stages for building a small home and have done a couple of renos before but have some questions about new construction.
1) Do load bearing studs have to line up with the floor joists below (or the squash blocks) so that the individual stud load paths are perfectly in-line? I have seen a lot of new homes going up locally and have serious doubts they are bothering with this level of detail. I am planning on a Gypcrete pour/radiant floor so the bottom plate would be doubled up to contain the pour. I am thinking this is similar to the double top plate and roof trusses on 24″ centres (ie many of them don’t line up). Although the loads are higher.
2) I have seen very long huricane type ties that extend from the rafter, over the two top plates and down along the stud. Is there any accounting for the shrinkage of the top plates or does the tie just bulge out somewhere? Are there other metal connector locations that have similar concerns?
Thanks for any advice
John
Replies
Welcome to Breaktime.
I've never seen anyone line up josts and studs before. There may be some out there who do it, but they're gonna be few and far between.
The tie down straps you mentioned shouldn't bulge if the top plates are KD lumber. I've never know that to be a problem.
i always layout studs, floor joists and roof rafters all in the same plane if i can. you can run the stud, floor joists and roof rafters locations straight up without having to remeasure the 16's. it also makes it easier to sheath and drywall.
i also go to the extent of lining all interior stud locations in a straight line with the exterior studs. once i find a stud anywhere in the house after it is sheetrocked i can find the stud in the rest of the house.
this also makes it easier to find plumbing and electrical connections that are lost.
also take many pictures of the open framing, rough plumbing and electric while the insulation is out and download to your computer. this will save many headaches in the long run when the sheetrockers cover over a wire or hit a pipe. which they always do!!
it may take more time to frame but it will save you over the life of owning a home
Sure but the thread starter is just building his first small house. The level of organization you throw into framing may be admirable, but is certainly unnecessary and you would have a hard time justifying it in any practical terms. I'd lay a bet your toolbox is similarly well laid out and it probably saves you some time too, but lots of good builders have messy tools and turn out perfectly good houses.
when building you're own house, that you are building, and new to the framing trade you should learn to frame by stacking.
imagine trying to hang cabinets and finding one 16, finding crown moulding 16's (ceiling joists and studs), even saving money on insulation and base moulding and flooring. that is especially useful for the new framer. who is trying to save money on the house he or she is building.
the only way to make a house plumb and square and perfect is in the frame.
if the frame is off than everything else is so much harder
make every stud and floor joist and roof rafter line up if you can. framers might yell at me but crown them all also
It is called stacking, and I agree with you. That is the way I was tought to frame man, many years ago.
Studs, floor joist,and ceing joist all stack to maintain an unbroken load path. Rafter when set 2' o.c. will stack on every other stud/joist line.
IIRCC the IRC specifcally says that they must line up or be within xx inches of lineing up. More than the allowed misalignment and the bearing plate has to be blocked with (2) 2x4s like a mini header between studs.
Stacking interior walls is also a good idea. It is required on load bearing walls for the same reasons as above. It may not be needed when a trussed roof is used, but is still a good habit to form.
I agree that this level of attention to detail is good to shoot for. It depends on the person though. Some people just like to throw things up and figure it out later.
We are talking framing.
I fall into the group of people that line everything up. One of the reasons I like to work alone.
"i also go to the extent of lining all interior stud locations in a straight line with the exterior studs. once i find a stud anywhere in the house after it is sheetrocked i can find the stud in the rest of the house."I'm changing my mind. While I still think it is unnecessary, especially for a first time builder, the more I think about your completely aligned framing the more the elegance of the system appeals to me. It certainly qualifies as fine homebuilding.
That is also the way I learned to frame. Back then most of the small houses I worked on had at least one interior bearing wall and sometimes two, or one that wasn't continouse on one side of a hallway, etc. We stacked every stud over a floor joist and it would end up with ceiling joist stacked over it. It was such a habit that most of the guys doing layout would continue such an alignment on none load bearing walls including end walls and all partition walls.
The old guy we worked for would check our work by walking around the house and sighting from one side to the other or one end to the other along the edge of any stud. He wanted to see all the way through without a misaligned stud obstructing his gun sight. After his walk around was complete we would start sheathing.
About 18 years ago I framed my FIL s house that way. I thought nothing of it untill the BI commented that he hadn't seen a framing job like that in a long time. The comment kinda threw me, so I ask what he ment by it. He said "oh, the stacking and stud/joist alignment you did. Framers don't do much of that now days. Takes to much time."
The gyp-crete becomes additional weight so I would look for an engineer. From your description, it sounds like the second floor will get the gypcrete as well. The gypcrete manufacturer or may be even the radiant heat manufacturer (or seller) may give you industry standard information on the engineering done for various situations. The engineered beam manufacturers typically give you engieering studies that building inspectors can accept.
Double or single plate options come from fairly recent practice of better insulation and wood conservation. Single plate with studs and rafters lining up would make for better practice but I think double plate is insurance and it probably has some valid uses bourn out of practice, it may prove to be necessary nailer in some cases, for example, and makes life simpler especially if you are designing the house yourself.
For single family houses built with 16" o.c. stud spacing and double plates, you don't have to worry where the loads end-up as long as the load is carried directly (e.g. squash blocks) to the foundation. Header openings such as single doors and windows don't need direct transfer of loads, I think these loads can go to double plates without the blocks under them. I renovated my house this way and inspector did not say anything about that. You have to engineer the load carrying beam in the basement other than the foundations.
I don't know much about the hurricane ties, but houses are typically built with wet wood, tie or no tie. I suppose drying out and settling decreases some of the ties' engineered strength but you can account for only so much. If you are worried about bulging ties that somehow would damage the sheetrock, you should look into ties that do not contact interior surfaces, though this is only guesses from my part. Hope this helps.
Code does not require stacking as long as you use double top plates. the load from above will transfer down thru a double top plate if you are 16" on center or less on a 2 story structure.
With that said, it is easier to cut your hvac ductwork and utilities thru when you do layout and stack your walls. All you need to do is keep laying out from the same corner of the house (most guys lay out from the back left or right corner from what I learned) and keep your joists and studs on same centers and you should stack.
re. gypcrete, I had my lumber company run the numbers on my house for the gypcrete and there was only one part of the home we shrunk from 19.2 centers to 16 centers for the I joists. Most other areas were still within allowable design parameters.
Good luck.
You will love the radiant floors!!
I was taught to stack also. Structurally it is stronger but under normal loading not necessary. The real advantage is running the utilities in the house. It gives a clear path for the HVAC and Plumbing Guys.
Was taught to always stack. Very easy to do, if you are a good layout person.
The insults about framers, I will meet you out behind the tavern!
We almost always stack our framing--it's slightly stronger and makes things easier for everyone else down the line. Not required by code though.
Those straps shouldn't buckle because your framing shouldn't be shrinking that much.
For any good framer this is just standard OP.
Youve heard the soog qualities about stacking but there are viable reasons in cases for not stacking too. When I started out we pretty much did the whole house not just the framing. Other considerations like drywall waste, paneling waste, tub and sink fixtures that need to be mounted at just the right place. I got tired of having to go back and replace my studs and hearing the plumber gripe, so I dont always stack mine. It depends on the ap.
Remember too that when nailing your double top plate, dont put any nails between the studs were the electrician will be drilling any holes. Them bits when they hit a stray nail can be a wrist breaker. And they'll still have one good wrist to hit you with lol.
Where there's a will, there are 500 relatives
Like everyone else, I try to stack where I can but don't loose sleep over it when I can't.What I am suprised hasn't been mentioned yet is point loads.The wall framing spreads things fairly well, but suppose that you have a openning arch between the dining room and the living room about 8' wide. That header transfers a lot of weight from second floor frameing and possibly the roof down through the jacks on either side. If those happen to land on the plywood subfloor between floor joists, there must be blocking under there to handle the load and direct it to the foundation. I was called to one house to correct frame deficiencies that included amoung other things, a situation like that where the subfloor there had a 3/4" sag in that 14" space.
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Where will this home be built?
John
Thank you for all the great replies. I am in Vancouver Canada - leaky condo capital of the world. Because of this there has been a lot of design attention focused on the causes, one of which is differential settlement/shrinkage of the framing. For example in four storey units the balconies may be supported by columns but the side supported by a ledger on the building drops 1" when the plates and rim joists shrink causing the decks to drain INTO the building. Other exterior joints open up too.
I am trying to avoid the gypcrete floor from breaking over some beam that doesn't shrink the same as the rest of the deck. For that reason I am using an engineered i-joist system for the deck that will support the gypcrete pour. (I am curious about having the i-joist resting on double mud sills but the beams resting directly on the concrete wall (and not settling).
Anyway I am looking to build my own to avoid those pitfalls. I have a good grasp of the issues and have done a complete gut and reno, as well as other reno jobs.
The concensus seems to be that lining up the joist and studs is just "best practice". It may not be necessary in 2 storey framing but is still the best.
Thanks again, will likely have additional basic questions in the months ahead.
John
Do you have seismic engineering in Vancouver?John
Strangely enough considering the risk of quakes, Part 9 of our code, which covers wood frame residential doesn't include any of the shear or tie down requirements I often see referred to here.
I'm still curious about the hurricane straps buckling when the lumber shrinks..............
Yes we have seismic engineering here. Our soils vary considerably (from peat to saturated silt to dense gravel to bedrock) so it really depends on where exactly you are building (major structures anyway).
I believe the extensive use of ties etc is for hurricane resistance. We don't have extreme winds like that so mud sill anchor bolts are about it for us. (I was in a house under construction in Florida and they use steel cables extending from the anchor bolts to the roof!)
Lining up the studs with the joists makes a lot of sense when you consider utilities. (I may have overlooked that due to the radiant floor heating system (ie no large ducts)). Points loads obviously must be dealt with.
John