Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Welcome to John Bridge / Tile Your World, the friendliest DIY Forum on the Internet

Advertiser Directory
JohnBridge.com Home
Buy John Bridge's Books

Go Back   Ceramic Tile Advice Forums - John Bridge Ceramic Tile > Tile & Stone Forums > Tile Forum/Advice Board


Thread Tools Search this Thread
Unread 02-12-2021, 02:21 PM   #1
Registered User
Join Date: Feb 2021
Posts: 2
Beefing up floor for slate tile.


I plan on putting 12 in. W x 24 in. L x 3/8 in. thick slate tile in my kitchen/dining room. The tile weighs about 60 lbs per 10 sq. ft.

We have an unfinished basement with exposed joists which are in good condition, 9.25 inches tall, 1.5 inches wide, 16 inches on center, and 11.5 feet long between supports. This includes one supporting beam between two walls. The beam itself has a pillar for support 5 feet in from the wall, and another pillar every 7 feet after that.

I have never sistered joists before so I don't know how much wiring/plumbing is too much to make it a big job, but I have attached some pictures for reference.

Would sistering be the only option in my case or is there anything else that I could do to get my deflection to L / 720?

Attached Images
barryshannon is offline   Reply With Quote
Sponsored Links
Unread 02-12-2021, 03:02 PM   #2
Carbidetooth's Avatar
Join Date: Mar 2010
Location: Boise, ID
Posts: 1,602
The sistering you're proposing would be significant work. Remove and replace most all electrical and plumbing in the affected area.

If you were to install beams and lally columns, like what's pictured, mid span on the joists, I suspect you could get there without sisters. Bear in mind that the lally columns need to bear on footings that would require excavation and pouring concrete at each location.

So in theory, it could be done. Do you intend to finish basement beyond what we see?

Silicone (not silicon) Sealant Ranger
Carbidetooth is offline   Reply With Quote
Unread 02-12-2021, 03:30 PM   #3
Registered User
Join Date: Feb 2021
Posts: 2
I don't have any plans to finish the basement so adding extra beams wouldn't be an issue if that's the best approach. I'm guessing since 16" on center is pretty common that reducing the joist length would be the approach that would have the greatest impact anyway.
barryshannon is offline   Reply With Quote
Unread 02-12-2021, 04:24 PM   #4
Moderator emeritus
cx's Avatar
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,801
Welcome, Barry.

You needn't put that support beam in the center of your joist span if it'd be more convenient somewhere else. You need only reduce that unsupported span a couple feet (less if the joist are of good grade and species) to get the deflection down where it needs to be for natural stone tile. Plans, or lack of plans, for future use of that space can change, eh?

You must also add a second layer of subflooring to accommodate the stone tile.

My opinion; worth price charged.

cx is offline   Reply With Quote

Stonetooling.com   Tile-Assn.com   National Gypsum Permabase

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Suggestions for beefing up floor? mystryda Tile Forum/Advice Board 4 08-09-2008 11:44 AM
Beefing up an L/625 floor summilux Tile Forum/Advice Board 7 04-01-2008 01:46 PM
Beefing Up A Floor With Extra Plywood - Step by Step Information Please Tileworks Professionals' Hangout 4 03-09-2006 08:01 AM
Beefing up floor joists with steel plate gwh1bass Tile Forum/Advice Board 3 06-15-2005 05:54 AM
Beefing up the floor from underneath? maggiethelab Tile Forum/Advice Board 11 05-19-2004 07:26 PM

All times are GMT -6. The time now is 03:34 AM.


Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC