Replacing All Above Joists In Bathroom Reno... - Flooring - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Flooring


Thread Tools Display Modes
Old 12-02-2008, 09:51 PM   #1
Join Date: Dec 2008
Posts: 1
Rewards Points: 10

replacing all above joists in bathroom reno...

Howdy: I have demolished everything in my upstairs bathroom, all the way down to the studs and joists. My plan is to replace all floor materials and finish with ceramic tile or stone. What materials do I need to put down (including thicknesses) prior to laying the tile or stone. The joists are 2X8 on 16" centers and in very good condition. The floor dimensions are approx 8 1/2' by 10'. The floor will support a corner shower base/glass enclosure, a whirlpool tub + sink & toilet. Thanks in advance for the help.


Bob the blunder is offline   Reply With Quote
Old 12-02-2008, 11:00 PM   #2
JazMan's Avatar
Join Date: Feb 2007
Location: Troy, Michigan
Posts: 5,860
Rewards Points: 422

Hi Bob,

OK, you have 2x8 joists @ 16" o.c., what is the unsupported span? I recommend that you start by sistering those joists since the floor is open. But you should anyway because of the added weight the tub and in case you decide to install natural stone tiles. You also need to add additional joists or blocking to support ends of plywood that were cut, and so do not have t&g.

Your base subfloor should be 3/4" subfloor grade exposure 1. If you go with stone tiles and the joists are stiff enough, you will add a second sheet of plywood, I recommend at least 3/8", prefer 1/2" or thicker. You then install either a tile backer board or a membrane like Ditra. Then the easy part, the tiles. You may not need the second sheet of plywood if you stick with ceramic or porcelain tiles, but it would give you a better floor. The more plywood the better.

Measure and post back with the unsupported span and see if you can read the species and grade stamped on some of the joists.



TILE GUY - retired- TROY, MI - Method & Product suitability consulting.

JazMan is offline   Reply With Quote
Old 12-03-2008, 08:40 AM   #3
I have gas!
Clutchcargo's Avatar
Join Date: Mar 2007
Location: Massachusetts
Posts: 1,975
Rewards Points: 1,374

I'll be doing the same thing to my bath. You may be able to get away with a single 2x8 depending on the span. From what I've researched, you need to get an L/480 for tile or a L/720 for stone.
Use the span calculator here:
I use Spruce-Pine-Fir #2 for the calcs.
I tear things down and build them up.
Clutchcargo is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Replacing a bathroom fan switch cmacjr22 Electrical 4 11-04-2008 06:14 PM
Replacing pipes in bathroom, need advice Steelmesh Plumbing 7 11-04-2008 11:30 AM
Replacing a bathroom fan RickT General DIY Discussions 2 10-28-2008 09:49 AM
Help!? Possible failed joists under bathroom Ski-Age Flooring 2 10-26-2008 05:27 PM
Replacing bathroom ceramic floor PeteRich Flooring 9 10-06-2008 02:53 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1