FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Do I have to use Wonderboard for a ti…

| Posted in General Discussion on April 23, 2001 06:57am

*
Hi,

First time I’ve posted to the board.

I’ve got to lay some ceramic tile over an existing 3/4 inch plywood subfloor in a kitchen. The kitchen is roughly 175 square feet. I’ve seen an heard alot of people use cement board or woderboard to beef up the subfloor. Do I have to use it? It’s kind of expensive up here in Nova Scotia. I think a small sheet approximately 3′ x 5′ is about $35! What I’d like to do is use a 5/8 plywood to beef up the floor as its about 1/2 the price. Am I better off in the long run with the wonderboard? Also, there are a few hollows in the floor and I know you put down some thin set when applying the wonderboard which would really help fill in the hollows. Can I do that with plywood too?

Any help would be apprecited. I’ve got to try annd get it done before the end of the week.

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. Allyson_Stiles | Apr 16, 2001 01:26am | #1

    *

    B,

    Backer board is not used to beef up the subfloor. It is used to to
    be moisture resisant
    something tile and thin-set(mastic, ect. can adhere good too.
    It would be my recommendation to use backer board.
    Where is it being used? That's another consideration. In wet areas, I'd definitely say wonderboard.
    Plywood will work , but I would not use it.

    Billy

    1. Carl_Shaw | Apr 16, 2001 02:06am | #2

      *Ditto on the backer board. But $35.00? Even if that's Canadian dollars it's a heck of a mark up.

      1. Joe_Hennessey | Apr 16, 2001 07:03am | #3

        *B, Your post leaves a vacuum information wise. Do you mean the floor is flexing now? And you hope to cure the deflection by screwing wonderboard to it? It won't work long term, the grout will crack and maybe the tile too if it's flexing enough.You are thinking 5/8" ply would be better, with tile and thinset you are adding at least an inch and maybe more like an inch and a half to the floor height. Is this gonna work? If there's a dishwasher in there, you are about to seal it in for life & lower the countertops at the same time. Hope your clients are on the short side.Need more info, sounds like the beginning of a steep learning curve there in the North. $35 a sheet!! Yipe!! Might be time to go into the trucking business. JoeH

        1. Scooter_ | Apr 16, 2001 08:18am | #4

          *Most tile installations use a mortar based product, simply for the purpose of bonding and adhesion. Tile bonds better to mortar then anything else. Most folks use Wonderboard (or a similar product) but Hardibacker and Denshield ar making huge inroads. I would recommend one of these three for your project. You will not be happy with tile thinset onto plywood, as plywood will expand and contract at a different rate than the tile, so you will see cracks fairly quickly. The product you use will have specific installation instructions as to attaching it and the thinset to use. Follow those instructions.If you must use plywood, then I would an expoxy thinset.

          1. B_Horne | Apr 16, 2001 02:57pm | #5

            *Hi, To answer some of your questions, the tile is going in a new kitchen and no appliances or cbainets have been installed yet. As for the floor flexing, the floor isn't flexing but the thin set that I've used before recommends that you have a 1 1/2" subfloor. After the tile has been installed there probably will be a 1/2 transition between the kitchen and dining room. I'd like to use the wonderboard as it seems to be the best way to go but it's SO expensive up here.

          2. FXDP_ | Apr 16, 2001 04:31pm | #6

            *Why not do it the old fashioned way? Once you're sure the subfloor is up to spec, nail down some building felt, lath, and float 3/4" - 1" of mud (cement and sand)? It's solid, and the best way to go, and you won't be paying $35 / sheet of board. Then use thinset cement to secure the tiles.

          3. Qtrmeg_ | Apr 16, 2001 11:35pm | #7

            *Plywood works fine for a kitchen. Unless; your frame is spanned to the max or has other issues, your sub-floor is weak, you use cheap plywood, you don't use a quality thinset with a latex additive, you mix the thinset wrong or use it too long, you somehow break the bond of the tile before it has set, etc, etc.Don't tell me you saw a bad floor tiled over plywood and blame the plywood, that is just a piece of the puzzle. I think we are splitting the hairs of quality here, Wonderboard isn't a magic fix for stupid.

          4. Tom_Crosby | Apr 18, 2001 06:33am | #8

            *B HorneIf nothing is down yet take up the plywood subfloor and install 1x4 ledgers and install strips of 3/4 plywood between joists. Lay down builders paper and diamond lath and float mud. If you install plywood low enough you can float mud to level below adjoining floors and set tile to level. This is a lot of work but its a quality job.Tom C

          5. Tom_Moller | Apr 23, 2001 06:57am | #9

            *The going rate for 1/2" Wonderboard 3'x5' in Denver is $10. 1/4" Hardibacker 3'x5' also $10. The price you mentioned sounds more like a 4'x8' sheet. Maybe your supplier is reading the wrong price sheet? Have you checked with other suppliers?I do a lot of ceramic tile, and I absolutely refuse to put tile on plywood or greenboard. I've seen too many that cracked or rotted or just turned to mush.Troweling in a layer of mortar is a good alternative to backer board if you are ok with the time / cost trade off. Best to trowel it with wood so the surface remains gritty for a better bond to the tile mastic.Get it as flat as you possibly can so the tiles don't rock on ridges.

  2. B_Horne | Apr 23, 2001 06:57am | #10

    *
    Hi,

    First time I've posted to the board.

    I've got to lay some ceramic tile over an existing 3/4 inch plywood subfloor in a kitchen. The kitchen is roughly 175 square feet. I've seen an heard alot of people use cement board or woderboard to beef up the subfloor. Do I have to use it? It's kind of expensive up here in Nova Scotia. I think a small sheet approximately 3' x 5' is about $35! What I'd like to do is use a 5/8 plywood to beef up the floor as its about 1/2 the price. Am I better off in the long run with the wonderboard? Also, there are a few hollows in the floor and I know you put down some thin set when applying the wonderboard which would really help fill in the hollows. Can I do that with plywood too?

    Any help would be apprecited. I've got to try annd get it done before the end of the week.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

FHB Summit 2025 — Design, Build, Business

Join some of the most experienced and recognized building professionals for two days of presentations, panel discussions, networking, and more.

Featured Video

A Modern California Home Wrapped in Rockwool Insulation for Energy Efficiency and Fire Resistance

The designer and builder of the 2018 Fine Homebuilding House detail why they chose mineral-wool batts and high-density boards for all of their insulation needs.

Related Stories

  • Guest Suite With a Garden House
  • Podcast Episode 688: Obstructed Ridge Vent, Buying Fixer-Uppers, and Flashing Ledgers
  • FHB Podcast Segment: Finding the Right Fixer-Upper
  • Keeping It Cottage-Sized

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data