I'm trying to build walls for my basement, and not surprisingly, many walls are longer than 8/10/12/16ft. For many walls, I was thinking of putting up two 8' or 10' walls with the stud straddling both walls. I was planning on doing a single top plate and was looking at the code [see below], but have some questions:

1) If I have a single top plate, does it matter where the seam is? Is there any restrictions or preferences?

2) My joists are 24" oc, but I was planning on doing 16" oc walls. Is that ok? Exception #2 makes this a little fuzzy

3) For the long stretches I've seen the rectangular splice plates referenced in the table. What do the plates look like for the corners and T-intersections?

R602.3.2 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 not less than 24 inches (610 mm). Joints in plates need not occur over studs. Plates shall be not less than 2-inches (51 mm) nominal thickness and have a width not less than the width of the studs.

Exception: A single top plate used as an alternative to a double top plate shall comply with the following:

1. The single top plate shall be tied at corners, intersecting walls, and at in-line splices in straight wall lines in accordance with Table R602.3.2.

2. The rafters or joists shall be centered over the studs with a tolerance of not more than 1 inch (25 mm).

3. Omission of the top plate is permitted over headers where the headers are adequately tied to adjacent wall sections in accordance with Table R602.3.2.


CONDITION TOP-PLATE SPLICE LOCATION Corners and intersecting walls Butt joints in straight walls Splice plate size Minimum nails
each side of joint
Splice plate size Minimum nails
each side of joint
Structures in SDC A-C; and in SDC
D0, D1 and D2 with braced wall line
spacing less than 25 feet 3″ × 6″ × 0.036″
galvanized steel plate
or equivalent (6) 8d box
(21/2″ × 0.113″ ) nails 3′ × 12″ ×0.036″
galvanized steel plate
or equivalent (12) 8d box
(21/2″ × 0.113″ ) nails Structures in SDC D0, D1 and D2, with
braced wall line spacing greater than
or equal to 25 feet 3″ × 8″ by 0.036″
galvanized steel plate
or equivalent (9) 8d box
(21/2″ × 0.113″ ) nails 3′ × 16″ × 0.036″
galvanized steel plate
or equivalent (18) 8d box
(21/2″ × 0.113″ ) nails

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

2 Answers 2


Basement framing is 100% cosmetic. I am not sure if it is code yet because I would never worry about the code but all places that I have done basements require 16" or less. And when I say I don't worry about it is because all basements we do are either 16 or 12 so I have never gone back to see if 24 or 18 is code. If memory serves me 16 is needed for drywall but 24 for paneling.

Some inspectors make sure that there are two points engagement on both the bottom and top plates every span or 8 feet. I have had maybe 2 inspectors out of 50 ever care.

In essence almost everything you are worrying about is for framing that is load bearing - for you this does not matter.

Some things you do need to worry about:

  • if you are doing a long wall most basement walls bulge. Start at the bulge or give yourself adequate space. You do not want any of the framing touching the wall.

  • bottom plates are PT

  • put some styrofoam under bottom plates

  • Lay down a chalk line on the floor for long walls.

  • When we are framing basements we build upright. Mainly because the heights differ and I want my install snug. We measure floor to joist on each side - one joist over. Then minus three inches, make our two cut and slide those in snuggly. Once we have the wall level and our boards are OC at 16 we now have a moveable wall piece that we can make slight adjustments to. We then do the rest of the verticals OC and nail them in. We have not attached the bottom or top plates. We do this for the rest of the wall. If we need to add some crossers to attach a header do our sections don't bow up then we do. Once the wall is done then we double check the levelness and alignment. We then nail the bottom plates in - 3 per section. We check levelness and alignment again and then attach top plates.

Where to split long walls in basement? Where ever you want.


Go with 16"oc, it's just stronger for the drywall regardless of the drywall's thickness. While I can't disagree with a double top plate, those are just for both load bearing walls & wind shear resisting exterior walls, so they're not a concern for a non-structural basement finishing.

Concerning walls longer than your lumber it's best to build complete sections & butt their ends together with no top or bottom joint offsetting. This allows for the abutting end studs to be securely screwed or nailed together for a very solid wall.

However, one point of importance in doing the stud wall sections is to land or meet your top joints centered on a joist. This, allows both top plates to be secured at a shared point & that joist now has a double stud support if the house ever needs it.

Meaning, you can purposely bolster for loads or conditions above. Like, a Hot Tub, Refrigerator, Bath Tub, Piano, Entertainment Center, China Cabinet, Sculpture, Fountain, Taking The Bounce Out Of An Open Floor Plan, Bottom Of Stairs or Load Bearing Walls.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.