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Yesterdays home was a 7300 sf custom home. 1 Yr. warranty job.

When they started the home they poured a slab, then supposedly the city told them it was too low. (it may be in a flood plane) The builder then used pony walls with 2x6 double bottom plates and double top plates.

My question is, I know that if there are butt joints at the bottom top plate then a stud has to be added. Would a stud at the butt joints be required at the bottom top plate of these pony walls? (I donlt see why not, just wanna make sure before I put it down)

Also, some parts of this foundation had mil plastic stapled on the bottom side of the joist while most areas didn't. The batt insulation had the paper backing facing the floor.

I know paper is suppose to face the living side of the home in an attic, but how about in the crawlspace in a hot/humid climate?

I've seen it the other way on some pier & beam homes in the area. (paper facing the ground, no moisture barrier over the soil)


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I cannot imagine any good reason for a stud at a joint in a bottom plate no matter how many of them there are. The function of the stud at the joint in a top plate is to prevent a bearing condition (like a joist, rafter or truss) from occurring on a cantilevered plate. No bearing can occur at the splice point in a bottom plate, of course unless you put a stud there.

I've always believed that the moisture barrier faces the conditioned space everywhere.

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Let me clarify, a joint at the bottom board of a doubled top plate. If they occur in a structural wall, then there must be a stud there. I'm just wondering if they would be required at butt joints of the pony wall supporting the floor joist in the crawlspace.


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I was under the impression that an end joint in the top plate needed to be under a stud. However, when I looked through the IRC I could not find a specific requirement for a stud under a end joint in a stud wall. The specific requirements for a top plate on a stud wall in the 2000 IRC are:

§RR602.3.2 Top plate. Wood stud walls shall be capped with a double top plate installed to provide overlapping at corners and intersections

with bearing partitions. End joints in top plates shall be offset at least 24 inches (610 mm).

EXCEPTION: A single top plate may be installed in stud walls, provided the plate is adequately tied at joints,corners and intersecting walls by a minimum 3-inch-by-6-inch by a 0.036-inch-thick (76 mm by 152 mm by 0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d nails on each side,provided the rafters or joists are centered over the studs with a tolerance of no more than 1 inch (25.4 mm). The top plate may be omitted over lintels that are adequately tied to adjacent wall sections with steel plates or equivalent as previously described.

I believe the situation you have described would be addressed in IRC Section 602.9 -

§RR602.9 Cripple walls. Foundation cripple walls shall be framed of studs not less in size than the studding above. When exceeding 4 feet

(1219 mm) in height, such walls shall be framed of studs having the size required for an additional story.

Cripple walls with a stud height less than 14 inches (356 mm) shall be sheathed on at least one side with a wood structural panel that is fastened to both the top and bottom plates in accordance with Table RR602.3(1), or the cripple walls shall be constructed of solid blocking. Cripple walls shall be supported on continuous foundations.

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UBC requires a 4 foot offset in the plate joints. IRC 24". Not sure who accepts 16". IMO that is worse than not breaking over a stud due to the loss of lateral strength in the wall.

For the record, I always broke the butts over a stud and consider it good practice, while not being a code requirement.

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