If adding studs horizontally, have each horizontal stud 'rest' on short vertical studs screwed to the existing vertical studs on either side. Then screw the horizontal stud to these extra 'shelf' studs. This will also give you some extra mass.
Just adding horizontal studs isn't ideal. You want some additional support.
Hope this helps.
Just adding horizontal studs isn't ideal. You want some additional support.
Hope this helps.