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Quote:
Originally Posted by john70t View Post
Can you educate me on plywood?

The framing I assume is ballon-type.
The floor joists are true 2x6 and true 2x5, one foot on-center.

After about 140 years, the existing tongue-in groove floorboards are about the same weight as balsa.
They are held in place with a few #6 nails and are hacked up over the years.
There has been some repeat cracking in the ceiling above.

I want to sheet with 5/8" or 3/4" plywood, using liquid nails and deck screws to lock it all in place.

Weight is of great concern...

There is CDX and RTD(Resistance Temperature Detectors) type plywood but I'm not sure which to use and whether the 5/8" would conform to code.
No floor would conform to code, typically attics are not rated for storage. We are not allowed to put down a 'floor' in an attic space of a new house, without architect upgrading joists. The weight of the plaster may be overloading the 2x6 framing as it is. Hard to tell why it's cracking without more info. We usually find plaster is separating from scratch coat.

Practically, if you need the storage, I would throw a few sheets in areas where it is supported by wall below, and store stuff there.

If you want to strengthen the ceiling system, I suspect a strongback will do more. As in pic below, you would support ceiling joists mid span with a perpendicular beam.




Edit:

Are the existing joists sagging? How long is the span?
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Last edited by dad911; 09-11-2019 at 06:15 AM..
Old 09-11-2019, 06:01 AM
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