Progress on Floor Prep for Slate Tile
Hello, Here are some pictures of my DH getting the joist in place for my bathroom remodel. Background info can be had at the link at the end of this post, below. It was a post I started in the Remodeling Forum last fall. It answered most of my questions and helped me proceed.
One note that sticks in my head, from the Remodeling Forum link below, is where Renovator8 states:
"- The existing floor that you describe would have a maximum deflection of .135" (L/844). This is so high because the Moment of Inertial of the old joist lumber is 42% greater than that of the modern lumber. (I didn't bother to add the probable greater Modulus of Elasticity)"
The wood is old, and we used even older salvaged wood to put in the new joist. All in great condition. The "new" salvaged wood was taken from an old wooden grainery that my DH had taken down that was build around 1900. It was beautiful to see when we cut a length and saw the end grain.
DH getting the joist in place and getting ready for the next cut:
All but one up there. There is one more to go up on the very left of the picture. They are 10" on center. The existing subfloor is 1-1/2" thick which we will screw through to the new joist from above. The underlayment of plywood will be 3/8" of ac exterior grade:
And here's the happy worker :)
So using JB "Deflectolator" my original floor was:
"For joists that are SYP or Douglas Fir, in good condition, 7.25 inches tall, 1.5 inches wide, 20 inches on center, and 9.5 feet long between supports, the deflection calculated is 0.262 inches.
This translates to a deflection of L / 435.
Since the maximum deflection for tile is L / 360, and for natural stone is L / 720, your floor is rated for Ceramic tile, Congratulations!"
"or joists that are SYP or Douglas Fir, in good condition, 7.25 inches tall, 1.5 inches wide, 10 inches on center, and 9.5 feet long between supports, the deflection calculated is 0.131 inches.
This translates to a deflection of L / 871.
Since the maximum deflection for tile is L / 360, and for natural stone is L / 720, your floor is rated for Ceramic tile or Natural stone, Congratulations!"
Now if I consider what Renovator8 stated in his post on the other forum, I could have some outrageously high L/? value, taking into consideration that this is most certainly old growth timber we've used.
Hope that this info is of help to someone.
Here is a link that might be useful: Adding Joist to Existing & Intact Floor