Thread: Secure wall sheathing to sill?

New construction home:
Are there any specific code requirements that say the wall sheathing must be run down to the base of the sill plate?

I can't find anything specifically saying that the sheathing has to be run down to the top of the foundation and be secured to the sill.

The home I inspected yesterday had at least most of the sill plate exposed as visible beneath the siding. (construction is : crawlspace, perimeter foundation with joist hangers hung down off the sill plate, 16" o.c stud walls, OSB wall sheathing, and about 1" OSB subfloor).

I also can't find a code requirement specifying the need to extend the housewrap/ WRB beyond the top of the foundation. The WRB stops at the base of the sheathing. I know I can just put in the report that all manufacturers of the housewrap specify the need to run the material beyond the foundation (violates manufacturers installation instructions), but I don't know who manufactured the material in this case.

Any help would be appreciated...

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I just got an answer to one of the questions. I contacted the state of OR structural program chief that said the sheathing should NOT be nailed to the sill plate because it would just rip the sheathing apart. I am pretty sure he just meant that the sheathing does not need to be secured to the sill plate.... therefore, it is not a requirement.

Originally Posted by Brandon Whitmore

I just got an answer to one of the questions. I contacted the state of OR structural program chief that said the sheathing should NOT be nailed to the sill plate because it would just rip the sheathing apart.

Absolutely the opposite of everywhere else I know of.

The only way for any loads to be transferred through the wall studs and sheathing (as a diaphragm) is to attach the sheathing to the sill plate, which is then anchored to the foundation.

Brandon, are you sure he was not meaning 'do not secure the sheathing to the foundation wall', instead of 'do not secure sheathing to the sill plate'?

Jerry,

I did ask him several questions and he did just shoot through them, and probably did not finish certain train's of thought. From what I got out of it.... sheathing does not have to be secured to the sill plate.

This same post started on TIJ--I figured I would try here as well.

As Brandon Chew (PE) stated on the other site, the sheathing must be secured to the top and bottom wall plates and studs. The sill plate is secured to the foundation, the subfloor to the sill plate, and the walls/ sheathing to the subfloor.

There are no specific code requirements that I can find that specify the need to nail the sheathing to the sill plate.

Originally Posted by Brandon Whitmore

There are no specific code requirements that I can find that specify the need to nail the sheathing to the sill plate.

Probably in the code under nailing requirements and nail spacing, however, it would also be in the APA requirements for attaching wood structural panels - which require attachment at the ends (which is the sill and top plate when installed on the vertical) and blocking (which is the sill and top plate when installed on the horizontal).

See:

TABLE R602.3(1)—continued
FASTENER SCHEDULE FOR STRUCTURAL MEMBERS

That requires "Wood structural panels, subfloor, roof and wall sheathing to framing, and particleboard wall sheathing to framing" - top and bottom plates are part of the framing.

Jerry,

I contacted the APA through their help line, and the guy I spoke with is not aware of any requirements specifying the need to secure the sheathing to the sill plate. The gentleman I spoke with checked in the IRC as well, and we are pretty much at the conclusion that there is no such requirement. He is going to speak with one of their engineers in the morning and call me with further details.

The way I read the nailing schedule in the table, the sheathing needs to be nailed to framing.... it is not saying it has to be to specific framing.

Originally Posted by Brandon Whitmore

The way I read the nailing schedule in the table, the sheathing needs to be nailed to framing.... it is not saying it has to be to specific framing.

"the sheathing needs to be nailed to framing"

Yeah, all the framing.

Go here: PDF Download | APA - The Engineered Wood Association

Page 16 of 80

D. Wall Sheathing

Nail 6" o.c. along supported panel edges and 12" o.c. at intermediate supports with 6d common nails for panels 1/2" and less, and 8d for greater thickness.

It is required.

By the APA in APA E 30.

Which is referenced in the I-Codes.

I may just be dense, but read the same info. differently. The APA does not specify exactly where those panel edges must be placed. IRC does not specify this either. I read that you must nail 6" o.c at edges (wherever they be located) and 12'' o.c in the field. So in this case, the sheathing may be properly nailed to framing as per the nailing schedule.

Say the sill plate is properly secured to the foundation, all hold downs/ straps are in place, etc. What would be the concern of not running the sheathing down to the base of the sill plate? (therefore, not nailing the sheathing to the sill).

Originally Posted by Brandon Whitmore

I may just be dense, but read the same info. differently. The APA does not specify exactly where those panel edges must be placed.

Apparently I'm a lost cause on this, or you are - don't know which.

"The APA does not specify exactly where those panel edges must be placed."

Allow me to ask you this, then ... Does it say to nail the panel edges?

If so, how in tarnation are you going to nail them if you do not place them against (here is that word again) "framing"?

If no, you and I are NOT reading the same thing.

IRC does not specify this either. I read that you must nail 6" o.c at edges (wherever they be located) and 12'' o.c in the field. So in this case, the sheathing may be properly nailed to framing as per the nailing schedule.

Huh?

Unless the sheathing is "nailed at the edges" (which, unless you know something I don't know, means that the edges must be on "framing") then it IS NOT "nailed to framing as per the nailing schedule".

Say the sill plate is properly secured to the foundation, all hold downs/ straps are in place, etc. What would be the concern of not running the sheathing down to the base of the sill plate? (therefore, not nailing the sheathing to the sill).

Well, for one thing, as I stated before, it will not properly transfer the loads to the foundation.

Also, the sheathing will buckle out all along the bottom and allow water, insects, etc. up into the wall cavity.

The sheathing is not as strong that way.

Are we using 9' plywood for this application?

Are we using 9' plywood for this application?

It is OSB and could be 8' or 9' panels. It is an inspection for a potential buyer and I can see what is visible beneath the base of the siding. (finished home)

Basically, you have a sill plate on the foundation wall, 1" OSB subfloor directly on top of the sill plate (not sole plate as this is a crawlspace), 16" o.c stud wall, with OSB wall sheathing. The bottom of the wall sheathing sits along the top edge of the sill plate around the perimeter (bottom edge is likely nailed into the subfloor in this application as well as into the sole plate)

Jerry, gotta run-- I will re- read all of the posts to see where/ if there has been some miscommunication

The only way for any loads to be transferred through the wall studs and sheathing (as a diaphragm) is to attach the sheathing to the sill plate, which is then anchored to the foundation.

I thought the studs/ framing transferred the load and the sheathing made things rigid.

Does it say to nail the panel edges?

Of course.

If so, how in tarnation are you going to nail them if you do not place them against (here is that word again) "framing

Say they left a one inch overhang beyond the bottom (sole) plate when they framed the wall. Once the wall is kicked into place, the section that hangs down is secured either to the very top of the sill plate and/ or to the subfloor--- framing.

Unless the sheathing is "nailed at the edges" (which, unless you know something I don't know, means that the edges must be on "framing") then it IS NOT "nailed to framing as per the nailing schedule".

See above.

Well, for one thing, as I stated before, it will not properly transfer the loads to the foundation.

I say the studs / bearing walls transfer the loads to the framing-- the sheathing makes things rigid.

Also, the sheathing will buckle out all along the bottom and allow water, insects, etc. up into the wall cavity.

The sheathing is not as strong that way.

If the sheathing makes things "rigid" (I am using that word due to the lack of a better word at this time), and the framing is the bearing section of the walls, I don't understand how the sheathing will buckle. If you are talking about racking, then that is why the sheathing is nailed per schedule on edges and in the field. I can't figure how the sheathing will buckle, since the framing will prevent buckling.

Probably in the code under nailing requirements and nail spacing, however, it would also be in the APA requirements for attaching wood structural panels - which require attachment at the ends (which is the sill and top plate when installed on the vertical) and blocking (which is the sill and top plate when installed on the horizontal).

Regarding attachment at ends which you say is the sill plate and top plate. Can't the ends/ edges be at the sole plate and top plates? I would think that should make the wall rigid, with proper attachment of the sill plate, subfloor, and bottom wall plate.

Brandon, not to steal Jerry P's thunder, but there are loads other than downward (gravity) that must be transfered to the foundation.
Wind, seismic, can literally push a house over or slide it off of the foundation.
If you bolt the sill in place, what holds the rest of the frame and walls down to the sill plate?
The studs and bottom plate nailed to the sill would typically be face nailed or toe nailed near vertical which is a weak connection in tension.
The much stronger connection is the horizontal nail through the sheathing into the sill plate that is bolted to the foundation. The nails would be in shear rather than tension, much stronger.

Originally Posted by Brandon Whitmore

I thought the studs/ framing transferred the load and the sheathing made things rigid.

Nope, the sheathing is what creates the framings ability to transfer loads.

"Does it say to nail the panel edges?"

Of course.

Then why are you asking if it has to be nailed at the edges????

Say they left a one inch overhang beyond the bottom (sole) plate when they framed the wall. Once the wall is kicked into place, the section that hangs down is secured either to the very top of the sill plate and/ or to the subfloor--- framing.

Depends on how the wall is framed up, but you want to nail the edges to the framing behind them.

I say the studs / bearing walls transfer the loads to the framing-- the sheathing makes things rigid.

The studs carry only the gravity load straight down, with sheathing, the load is transfered across the wall and down, making everything, as you say, "rigid". Without the sheathing (or other bracing), you could lean on the end of a framed wall and make it collapse like it was made of dominoes or cards.

[quote]If the sheathing makes things "rigid" (I am using that word due to the lack of a better word at this time), and the framing is the bearing section of the walls, I don't understand how the sheathing will buckle.[/quote

If the panels are *only* nailed to the studs, any moisture or anything else will cause the panels to buckle outward (because the edges are not nailed to anything).

Does that help?

http://www.shearwalls.com/errata/Fig_10.pdf
This is not as clear of a diagram as I have seen here in the past, but is helpful in this discussion.

Originally Posted by Brandon Whitmore

Jerry,

I did ask him several questions and he did just shoot through them, and probably did not finish certain train's of thought. From what I got out of it.... sheathing does not have to be secured to the sill plate.

This same post started on TIJ--I figured I would try here as well.

As Brandon Chew (PE) stated on the other site, the sheathing must be secured to the top and bottom wall plates and studs. The sill plate is secured to the foundation, the subfloor to the sill plate, and the walls/ sheathing to the subfloor.

There are no specific code requirements that I can find that specify the need to nail the sheathing to the sill plate.

Brandon W., that's close, but not quite what I said. Here is the quote from TIJ:

To resist racking, in the wall assembly the sheathing is required to be fastened to the top plate, sole plate, and studs.

To resist uplift, the code says the sill must be fastened to the foundation, the floor framing to the sill, and the sole plate to the floor framing (and the ankle bone is connected to the shin bone). Some seismic areas and high wind areas require foundation anchors that tie this whole assembly together from foundation to wall studs.

Elsewhere in the code it also says that sheathing needs to be fastened every 6" along its edge. Typical eight foot high stud walls (top of top plate to bottom of sole plate) and eight foot long sheathing panels means there is usually a horizontal joint in the exterior sheathing at the point where the sole plate and the floor framing meet. Then a smaller piece of sheathing is cut and fastened to to cover the subfloor, band joist, and sill. Some builders will use one piece of sheathing that runs from the sill to the wall. In this case they need to nail into the sill to meet edge nailing requirements and into the sole plate to meet bracing requirements.

After reading that again, in the second paragraph I would replace "require foundation anchors" with "need connectors" in order to provide a continuous load path. In the third paragraph, it might not have come through clearly but I'm saying that when they use the 8 foot sheet on the wall and then a smaller piece to cover the subfloor, band joist, and sill, it is the edge nailing requirements that cause that smaller piece to be nailed into the sill. Unsaid and probably needing to be said given the direction the thread here has taken is that in that two piece sheathing example, to meet the "continouous load path" requirements of the code, connectors that tie the wall framing to the floor framing may be needed depending upon the design uplift loads (nailing the sole plate to the floor framing might not have enough holding strength).

Now, to further the discussion here, there's nothing that I'm aware of in the code that requires a single sheet of sheathing that runs from the sill plate to the top plate on the wall. There are other ways available that can be used to meet the uplift and continuous load path requirements of the code. But if you put a piece of sheathing on the exterior framing and it covers the sill, the edge nailing requirements for the sheathing mean that you need to nail it into the sill.

Thanks for all the comments up to this point. I have spent pretty much the entire day studying shear walls, designs, etc.

I found some decent info. here: Anchorage

If you bolt the sill in place, what holds the rest of the frame and walls down to the sill plate?

Bolting the sill plate in place keeps the frame from sliding off of the foundation. Hold downs on the framing prevent overturning, etc.

Well,

I had another long response written up, but decided to delete it without posting.. my head hurts after a long day of study and it probably made no sense anyway's. I read what Brandon Chew had written and it makes sense.

Brandon--- Sorry to have misquoted you-- my bad. (I mentioned the other site so others could read your exact words).

I'm gonna sleep on it and see what I think in the morning. It feels like I just crammed for a final, and my brain is on information overload.

Not a problem, Brandon W.

Rest and resume in the am.

Originally Posted by Brandon Whitmore

I just got an answer to one of the questions. I contacted the state of OR structural program chief that said the sheathing should NOT be nailed to the sill plate because it would just rip the sheathing apart. I am pretty sure he just meant that the sheathing does not need to be secured to the sill plate.... therefore, it is not a requirement.

Well here's what I think he may be getting at. It's less of an issue when your floor framing is made from engineered lumber than it is when it is made from sawn lumber.

Remember when I said sometimes the builder will run a single sheet of sheathing from the sill to the top plate of the wall? When he does, he needs to horizontal nail it into the wall sole plate to meet bracing requirements and into the sill to meet edge nailing requirements.

The problem is that rim joists and floor joists made from sawn lumber shrink in width as the lumber dries out, and the sheathing does not. It varies by the moisture content of the wood at the time of construction and the depth of the joists used, but it's not uncommon for the wall sole plate to drop about 1/4" relative to the sill once the lumber dries out.

If it's all nailed together before the wood dries out, the movement could tear the nails out at either the sill or sole plate. To get around this, builders either use the two piece method and they leave the sheathing off the area of the band joist until they are ready to put the exterior cladding on the house, or when they use the one piece method they wait to nail the edge to the sill until just before the cladding goes on (and many times this gets forgotten).

Do- over:

The only way for any loads to be transferred through the wall studs and sheathing (as a diaphragm) is to attach the sheathing to the sill plate, which is then anchored to the foundation

That is one way and my comment yesterday was wrong on this, but hold downs are used in our area. Does nailing the sheathing to the sill plate satisfy shear requirements in some areas? I have not looked at the code book, just asking.

I just got an answer to one of the questions. I contacted the state of OR structural program chief that said the sheathing should NOT be nailed to the sill plate because it would just rip the sheathing apart. I am pretty sure he just meant that the sheathing does not need to be secured to the sill plate.... therefore, it is not a requirement.

Brandon-- that is possible and thanks for the explanation. Could he have meant that there is not adequate support in shear when the sheathing is nailed to the sill plate, and other methods are needed? (such as hold downs) If he meant that, I would take it to mean there is not adequate support, and the sheathing would just rip apart under load. Maybe some of both?


Jerry,

Thanks for going back and forth with me on this. Everything is much clearer to me this morning, and I learned a great deal as a result.

Originally Posted by Brandon Whitmore

That is one way and my comment yesterday was wrong on this, but hold downs are used in our area.

The hold downs do nothing for transferring the loads. Hold downs, well ... "hold down" the sill plate.

Think of it this way:

You have a rectangular wall: bottom plate, top plate, studs. The bottom plate holds the gravity load of the studs, the studs hold the gravity load of the top plate, the nails hold it all together.

The problem with the above is that the nails act as hinge points, pivot points would be a better description.

You could push on the top plate and that stud wall would tilt into a parallelogram.

Now, apply the sheathing, nailing only to the studs, now press against the top plate at one end the wall is stiffer, but it still moves. The sheathing is attached to the studs but not to the top plate or bottom plate, the sheathing is pivoting on the nails and bending the nails. If you could push hard enough, the wall would have the sheathing vertical, the nails bending, the studs at an angle, but the top plate and bottom plate still horizontal. The stud wall is a parallelogram with 'square' sheathing on it.

Now (after pushing the wall back up plumb and square) nail the sheathing to the top and bottom plates.

Now, if you had a strong enough piece of equipment to push the top plate, the wall would try to slide at the bottom plate / foundation joint, the wall itself being fairly much square, plumb and level. No more parallelogram.

[quote]Does nailing the sheathing to the sill plate satisfy shear requirements in some areas?[/quote

Nailing the sheathing to the top and bottom plates basically makes that into a shear wall, the load resistance of which is designed by the engineer based on nail spacing, sheathing thickness, etc.

The holds down hold the bottom plate down and hold the bottom plate from sliding.

Now, for uplift, take the same stud wall, no sheathing, just top plate, studs, bottom plate, all nailed together - using a crane, lift up on the top plate ... it will come apart at the nailed joints.

Now, nail the sheathing to the studs only and lift up on the top plate with a crane ... it will come apart at the nailed joints.

Now, nail the sheathing to the top plate and bottom plate, then lift up on the top plate with a crane ... either the top plate will break or you might be able to pull the entire wall loose from the foundation (which is what the hold downs is trying to resist). But the wall itself will tend to stay in one piece as long as possible. The difference is only that the top plate and bottom plate is now nailed to the sheathing, and the sheathing and its nails are now helping resist the uplift instead of just a few nails at each stud / top plate connection.

Does that help some more?

The hold downs do nothing for transferring the loads. Hold downs, well ... "hold down" the sill plate

I thought anchor bolts held down the sill plate to the foundation, and hold downs secured the framing to the foundation.
http://www.dietrichmetalframing.com/...pExp_58_59.pdf
http://www.icc-es.org/criteria/pdf_files/ac155.pdf

Now, nail the sheathing to the top plate and bottom plate, then lift up on the top plate with a crane ... either the top plate will break or you might be able to pull the entire wall loose from the foundation (which is what the hold downs is trying to resist). But the wall itself will tend to stay in one piece as long as possible. The difference is only that the top plate and bottom plate is now nailed to the sheathing, and the sheathing and its nails are now helping resist the uplift instead of just a few nails at each stud / top plate connection.

Correct, as long as the bottom plate is bolted to the foundation as in slab construction. If a sill plate is bolted to the foundation, a subfloor is attached, and then the wall sits on the subfloor as in my case, the wall would pick up off of the subfloor without hold downs in place, and/ or sheathing would have to run all the way to the sill plate and be nailed there.