questions on replacing a subfloor
Apologies in advance for the long-winded post...
I'm a novice DIY'er renovating the upstairs of my house. It was previously finished with 2 bedrooms and a bathroom, but for various reasons, I've demolished all the framing, plumbing, electrical, etc and will basically be starting fresh. So presently, I have one large open space from one gable end to the other.
The current subfloor is 1/2" plywood, and is sagging in several areas due to leaks in the bathroom and exterior siding (which I've since fixed). I've removed all of it - right up to the sole plate of the exterior walls - and have ordered 3/4" T&G OSB Sturdi-Floor as a replacement.
However, I'd like some feedback on my plan to install the new subfloor where it meets the exterior walls. Where the floor joists are parallel to the outside walls, I'm planning on installing full-height blocking every 12" between the rim joist and adjacent joist, and then screwing both the subfloor and exterior wall sole plate to the blocking. Where the outside wall is perpendicular, I didn't plan on installing any blocking. Is it necessary? If so, is it just supporting the subfloor panel edge, or do I need to screw the subfloor/sole plate into it too?
If it makes a difference, the joists are 2x8, 16" oc, and an unsupported span of 8.5' - 11' 10". I plan on installing a 1/2" BC plywood underlay on top, and then tile in the bathroom, and 5/8" hardwood in the bedrooms. The upstairs has a fully dormered back wall, connected by collar ties to the front rafters. Part of my concern is that the back wall is out of plumb by about 2.5" over a 7' height (!). My local inspector says this is due to the poor construction technique used when my house was build, and is just cosmetic (i.e. the house isn't going to fall down). However, I'm not sure if removing the subfloor somehow removed part of the support for the back wall...crazy thought?
Thanks for any advice/feedback
Last edited by Wm_Boston; 09-23-2007 at 10:11 PM.