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Joining Sill Plates

mark2457

Well-known member
Joined
Feb 10, 2014
Messages
179
Location
Chicago, IL
Hi All

Just ordered my lumber for 22x24 garage build. My sill plates are PT 2x4, but longest I could get locally was 20', so i have to join them on two walls. I know current IRC requires the end of each piece to be bolted withing 3.5 to 12 inches of the end and a min of 2 bolts per section.

AFAIK people frequently join then under a stud, but wondering if that is really necessary with the bolting requirements. If I did join under a stud I'd definitely use a double stud.

My top plates will be 10' 2x4's so I will have quite a few joins in those that will have to be over a stud and 4' overlaps, so I'd like to like to try and avoid a join in top plate and bottom plate over same stud

Anyone know what the requirement is for joints in the sill plate?

thanks

Mark
 
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matt_i

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Mar 14, 2008
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10,725
Location
SE Michigan
Maybe I'm confused. The sill plate you are describing is the bottom plate set flat side against a concrete wall or floor?

I think a double stud would be standard practice at the joint. In other words, you build the walls in sections, you'd want a stud at the end of each section. Then, as they are butted together, the double stud happens at the top and bottom plate joints. The double top plate bridges across and makes it so you don't have to have perfect alignment with the trusses @ 24" OC and the walls at 16" OC.
 

T_R

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Jul 2, 2015
Messages
902
Location
Maine
My 24x24 I just used 3 8' PT for the sills. There is a single stud over each joint. Once it's bolted it's not going anywhere. No real need for a single piece of lumber for the sills.

I can't imagine that a 20' PT 2x4 is anywhere close to straight. That may be more of a problem for you than joints.
 

theoldwizard1

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Joined
Feb 22, 2011
Messages
43,109
Location
SE MI
If you are paranoid, you can double the sill plate making sure no seams land on top of each other. Using 8'ers would save a couple of bucks. Second sill plate does not need to be PT.
 

Kevin54

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Joined
Jan 12, 2005
Messages
29,341
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Urbana, Ohio
When I had to join the bottom plates we just double studded the area. I suppose you could use a Simpson Strong tie ******** both sides of the plate, but double studding will give you more support.
 
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matt_i

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Mar 14, 2008
Messages
10,725
Location
SE Michigan
The bolting requirement is to the ends of the bottom plate to the concrete...not the individual pieces to each other. Thus, there will be a couple of anchor bolts closely spaced to each other.

Another thought, if you build the wall flat on the concrete, raising up a 20' section of wall from flat to vertical is going to be a task for 12 men.

Also aside, its a good idea to try to preplan the anchor bolts so they can be cast into the concrete. That's a cheap way as they are a couple bucks apiece. The expensive way is to put in epoxied anchors, which is several dollars more for the quickcrete epoxy tubes that only come half full. One can use wedge anchors which are cheaper, but a liability on the edge of a slab, they do not have the holding power of the precast or epoxy anchors.
 
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Kevin54

MEMBER EMERITUS
Joined
Jan 12, 2005
Messages
29,341
Location
Urbana, Ohio
Hi All

Just ordered my lumber for 22x24 garage build. My sill plates are PT 2x4, but longest I could get locally was 20', so i have to join them on two walls. I know current IRC requires the end of each piece to be bolted withing 3.5 to 12 inches of the end and a min of 2 bolts per section.
AFAIK people frequently join then under a stud, but wondering if that is really necessary with the bolting requirements. If I did join under a stud I'd definitely use a double stud.

My top plates will be 10' 2x4's so I will have quite a few joins in those that will have to be over a stud and 4' overlaps, so I'd like to like to try and avoid a join in top plate and bottom plate over same stud

Anyone know what the requirement is for joints in the sill plate?

thanks

Mark

That is for your anchor bolts in your stem wall whether in block or solid concrete.

As far as lifting a 20' long wall, that will be tough. We built my walls in 12' sections, sheeted them with OSB, then 4 of us put them in place. It was a little bit of a struggle seeing that they were 2x6 walls, but doable. Any longer and we would have had more people.
 

jack stand

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Joined
Feb 29, 2012
Messages
3,314
Location
Lakes Region Maine
Around here, that would not be a problem, we just try to leave as little legnth of sill plate un- bolted. That is split your joints between 2 bolts. Usually the bottom wall plate covers any "evidence" any way. You might give your building inspecor a call and express your concern. This will show him your "good intent" and build a little trust, at the worst you drill in a few wedge lock type anchor bolts to keep him happy.
 
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mark2457

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Joined
Feb 10, 2014
Messages
179
Location
Chicago, IL
The bolting requirement is to the ends of the bottom plate to the concrete...not the individual pieces to each other. Thus, there will be a couple of anchor bolts closely spaced to each other.

Another thought, if you build the wall flat on the concrete, raising up a 20' section of wall from flat to vertical is going to be a task for 12 men.

Also aside, its a good idea to try to preplan the anchor bolts so they can be cast into the concrete. That's a cheap way as they are a couple bucks apiece. The expensive way is to put in epoxied anchors, which is several dollars more for the quickcrete epoxy tubes that only come half full. One can use wedge anchors which are cheaper, but a liability on the edge of a slab, they do not have the holding power of the precast or epoxy anchors.

IRC says this:

There shall be a minimum of two bolts per plate section with one bolt located not more than 12 inches (305 mm) or less than seven bolt diameters from each end of the plate section.

that reads to me absolutely as each section of a joined plate; otherwise; it would say per wall or something, no?
 
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mark2457

Well-known member
Joined
Feb 10, 2014
Messages
179
Location
Chicago, IL
Around here, that would not be a problem, we just try to leave as little legnth of sill plate un- bolted. That is split your joints between 2 bolts. Usually the bottom wall plate covers any "evidence" any way. You might give your building inspecor a call and express your concern. This will show him your "good intent" and build a little trust, at the worst you drill in a few wedge lock type anchor bolts to keep him happy.

I have at least 3 per section, so I should be good.

I think I'll take a chance, as long as I can be assured it can be fixed after the wall is up if there's an issue - e.g. strong tie or drill through plate and into concrete to insert a missing bolt
 
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