I have a section of mud sill near a crawl space entry door that has suffered severe dry rot due to rain intrusion. I need to cut out and replace about 3 feet of mud sill. This will require removal of two closely spaced studs (5" apart and about 22" tall), resulting in a horizontal span of about 47" between the remaining studs (one stud bay is wider than normal due to the crawl space entry).

The wall above this cripple wall is single-story but peaked and covered in stucco (considered heavy construction by the seismic retrofit plan sets).

Can I get away with removing these two studs, temporarily, while replacing the mud sill, without adding jacks or other temporary supports? If not, what type and capacity of jacks would I need?

In the following photo, the two cripple studs to be temporarily removed are marked by green arrows. The portion of mudsill to be replaced is marked by blue arrows. The red arrows show the 47" temporary span that would occur once I remove the middle studs. After the rotten mudsill portion is replaced I would reinstall the two studs.

enter image description here

  • How much space do you have on either side of the cripple? Can you provide a picture? This does sound like it's bearing a serious load. – The Evil Greebo Aug 10 '18 at 20:20
  • I'll upload a picture in a few days. – MikeOnline Aug 24 '18 at 18:22
  • Note this cripple wall runs parallel to the 2 x 6 floor joists. The last of these joists sits directly on the 2 x 4 studs (no top plate). This is a weak stud-to-joist connection. I've sistered another 2 x 6 onto the end joist to provide a nailing surface for sheathing. – MikeOnline Aug 31 '18 at 6:27

It probably would not sag enough to do any damage, but "probably" isn't good enough.

Without a picture it's hard to figure exactly what you have from your description - I can't picture a cripple wall without a top plate. This is a typical cripple wall framing:

enter image description here

One way to build temporary support is to build a temporary stud wall a few inches in front of the wall you're working on, with the top plate supporting the joists. You can wedge some shims between the top plate and the joists for a snug fit. You can arrange the studs in the temporary wall so that it's easy to reach past the temporary wall to get to the sill and studs you need to work on.

Another way is to lag a 2x10 across the face of the studs, spanning two studs that won't be disturbed on either side. If you have 40" between the studs that won't be disturbed, and 16" to the studs on either side, an 8' 2x10 would work. This lets you cut the bottoms off the studs over the rotten sill, repair the sill, install a temporary stud between the studs you cut, remove the 2x10, remove the rest of the studs you cut, and finally replace the studs you removed.

A reciprocating saw will work, but an oscillating tool with a blade that can cut nails is very handy for cutting out the sill and studs.

  • I'll obtain a picture and post in a few days. – MikeOnline Aug 24 '18 at 18:22
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    I like the idea of building temporary stud wall. This would be easy if the cripple wall ran perpendicular to the floor joists, but in my case the cripple wall is parallel to the joists. So it would be too complicated to build a temporary wall and secure it to the joists above. I also like the 2 x 10 temporary ledger idea. I'll accept this as an answer if no one else responds; however, I am hoping for some guidance on using jacks as the temporary support. – MikeOnline Aug 31 '18 at 6:32

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