Flooring options [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-22-2001, 07:56 PM
My current project is the renovation of my own home. I have completed a good portion of the kitchen/family room including removal of old flooring, altered cabinets, ran gas-line for new cooktop, reposition heating vents, cut and set the slab granite countertops and installed some of the appliances.

My immediate concern is flooring options for this very busy area which include entrances from pool, main foyer, and garage. It is the center of activity with kitchen, TV and computer station in the 550 sq feet.This area previously contained a tile entry, Kaars hardwood floor, and linoleum. I want to tile it all. I have looked at granite tiles, travertine, porcelain, and ceramic tiles.

My confidence was shaken a bit when I read the posts by Ron et al. who debated the issue of particle board/tile and hardibacker. So I am seeking your advice.

It is 40 year old single story home with 3/4 subfloor over 16 oc 2 X 6 (8"?) floor joists, topped with 3/8 particle board. I just cut and set in place the 1/4 hardibacker board over the particle board. (It is not screwed down yet.)

The hardibacker is not being set with thin set per the instruction of the manufacture rep. who said, "We cannot tell you not to use hardibacker without thinset but we can tell you not to use thinset with particleboard." He suggested 1 5/8" screws to join these three surfaces together.

My concerns are these:

1. What about the particleboard? (It appears that the concerns expressed are for particleboard and water. If it is not recommended in the kitchen area, can it still be used in the living and entry areas where no water sources are located?)(If it is essential to remove some of it, can it be replaced with 3/8 ply so that heights of flooring materials match?)

2. What about the strength of the floor to avoid cracking--is a 3/4 subfloor, with 3/8 whatever, and 1/4 hardibacker sufficent? (The previous 16 yr old tile entry was still in very good shape just outdated.)

3. What is the best choice--granite, travertine, porcelain or ceramic tile? And what compound is recommended to set the tile?


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Rob Z
08-22-2001, 08:21 PM
Hi Diana

Thanks for visiting.

I'm not sure I'd listen to what that Hardi rep said about skipping the thinset over particle board. the thinset under a tile backer board is to fill in all the little voids that occur when the rough surface of a backer board joins the rough surface of the underlayment.

I really would like to see the 3/8" particle board go with 3/8" B or better grade plywood as its replacement. And yes, 1/4" Hardi on top of that would make a nice, sturdy floor.

The answer to your third question really depends on lots of factors-budget, uses, skill of the installer, brand and product availaility, and so forth.

A top quality porcelin will give great service, but that's no good if you can't find something you like.

Do you have access to a good tile supplier?


Rob Z
08-22-2001, 08:23 PM

One other thing-are those joists 2x8's? How much do they span?


08-22-2001, 08:26 PM
3/8" isn't very thick and I have some serious reservations about particle board that thin.I've seen 1/4" "wafer-board" that was nailed every 12" bow up between the nails.

I recommend 5/8" exterior grade plywood and 1/4" Hardibacker.This will mean an 1/8" difference in height but that is minor and properly trimmed will go unnoticed.The thickness will be sufficient with this application.

Porcelain would be the best "all-around" choice.It is extremely durable and considerably less expensive than Marble or Granite.It is the toughest in the Ceramic class.

Regardless of what surface you choose,steps need to be taken to insure that the subfloor is securely fastened to the joists and that the joists are in good condition.There should be no "bounce" when you walk on the floor.If you need to do some additional fastening use 2" or 2 1/2" deck screws.

Stay tuned...some of the guys will be here to lend their support and advice.

Rob Z
08-22-2001, 09:00 PM
Hi Diana

I think Keith may have missed the 3/4" subfloor under the particle board. While 3/4" plus 5/8" plywood, with 1/4" Hardi on top would make a very strong floor, it is quite a bit more than the bare minimum recommended by the MFR (usually only 5/8" plus 1/4" backer board over 16"oc joists).

If you choose to add 3/8" ply to the existing 3/4" subfloor, use lots of glue and screws to fasten it.


08-22-2001, 10:02 PM
Nah...I'm just addicted to overkill Rob.I did miss the part about thinset though.I'm helping Derek & Jacqui on a job and they tried to kill me today.My mind ain't working full throttle.

Rob is right Diana,even if you decided to keep the particle board you still should use thinset under the backer board.And use a good Latex-Modified Thinset to install the tiles.

Rob Z
08-23-2001, 07:16 AM
Hi Diana

I jumped in here before leaving for work because I don't want to get you confused by this. (We try to keep the debate among the regulars over at the Hangout so as to not distract our DIY'er friends).

A great floor would be 2 layers of 3/4" tongue and groove plywood, or as keith suggested, a layer of 5/8" T&G ply over your existing subfloor. Adding a layer of tile backer board is a great thing too because it gives a good bonding surface for the tile mortar.

The bare minimum is, according to the MFR's, 5/8" T&G plywood with 1/4" backer board. All of us here at the forum would like to exceed MFR's minimums, and recommend that you do too.

I think we would all feel better if you will tear out the particle board and add some plywood in its place. 5/8" is the thinest plywood that comes T&G, but I can tell you that makes for a VERY STRONG FLOOR!! I have to deal with the elevation issues all the time, especially with thick bed mortar on floors. I just make oak thresholds to deal with these transitions.

Okay, enough preaching and off to work.

Let us know if you're going to pull up that particle board, and we'll give you some tips for making it easier.


08-23-2001, 07:46 AM
Thanks for responding.

Looking forward to the "tips from the pros": What is the best way to pull up particle board?

I will not be able to remove it under the wall cabinets, the L shaped cooktop and sink pieces or the island. How can I cut around the bases of those to get the particle board out? (A dremel is tedious and the 4" blade on my hand held Makita won't fit under the cabinet overhang.)

You are suggesting a 5/8" T & G plywood over the top of my 3/4 T & G subfloor that already is in place? Or are you saying that I can get away with what exists and just add the 1/4" hardibacker (with thinset of course)?

Let's assume that you are suggesting Maximum flooring 3/4 + 5/8 + 1/4. That will effect some "tight" areas--trash compactor cabinet space and the dishwasher perhaps. Have you run into these problems before?

The transitions from this tile area into the other rooms is from tile to carpet. Will a thicker pad make the transition easier? What else might you recommend?

I am not certain of the availability of great tile outlets.
I am in the East Bay of the San Francisco area and know of the standard ones--Home Depot, Sacramento Tile, and House to Home. I did not see anything I liked in Dal or Western Tile outlets. Do you know of others I might try for good porcelain?

You guys are great! Thanks for the tips.


Rob Z
08-23-2001, 07:27 PM
Hi Diana

I will categorically bad mouth Home Depot and other big box stores when it comes to tile. I know they buy lots of seconds and odd lots, and I don't think they are worth the trouble.

To get the particle board out...Rent a toekick saw from a rental store to cut under the toe kick. It will make it a breeze. DO NOT try home made tools like a saw blade in a drill...true story, one of my customers did this, even after I spent 15 minutes telling him how dangerous this would be. the result: he ran the saw blade up his forearm and had to have surgery.

Cut the field of the particle board itself into pieces no bigger than 2' x 4' with a circular saw with the blade set to the thickness of the particle board.

Get a crowbar that has a fulcrum built into the end of the tip. Once you get a few pieces up, you'll be able to pry up pieces fairly easily. I bought a crowbar from Tool Crib that has such a tip, as well as two hooks at the other end that are bent in two different directions. This type of crowbar can make your demo go a lot easier.

The height restrictions of the dishwasher and other appliances is a common problem. Figure out how much adjustment you have taking those things up, and plan your subfloor accordingly. We would prefer that you add more underlayment rather than go with the MFR's minimum requirements. And we really don't want to see the particle board stay.

Once you figure out the subfloor and backer board and tile thicknesses, we can decide what type of transitions. to use. I don't think that thicker pad will solve any problems.

I'll be back later.


Bud Cline
08-23-2001, 07:54 PM

The procedure Rob describes above isn't really that difficult. The "toekick saw" is a wonder tool. Corners and areas that are hard to get to with the saw can be cut in a way that will allow you to break out what the saw won't reach. It is sometimes difficult to make clean cuts within dishwasher cavities and the like. Do the best you can with the saw and pry and break the rest.

Afte rmaking your 2' X 4' cuts throughout the area then break out the first "slab" in the middle and work in all directions from there one slab at a time. You can start your first slab with something small like a screwdriver or wood chisel placed in the sawcut.

08-24-2001, 10:51 AM
Bud and Ron

Sounds like the tool I have been searching for. I shall rent it. I don't think I will have too much of a problem getting it up the way you have suggested. I appreciate all your advice regarding the particle board vs plywood.

I will be out of the state for about a week and so will not attempt this project until I get back. I will keep you posted with progress and problems as they happen. My intent now is to remove the particle board and then use the 5/8 tongue and groove ply on top of the subfloor. You suggested additional screws to attach and strengthen this combination to the floor joists. (2-2 1/2" as I recall) Is there a recommended spacing for those? What kind of adhesive do you recommend to glue the layers together?

I would appreciate any suggestions for a source for good porcelain tiles. Who do you use? I am thinking about 16 X 16 or larger for the floor. Are there special cautions about this size as opposed to the 12 x 12 ones?

Thanks so much for taking the time to answer all the question.


John Bridge
08-24-2001, 02:32 PM

I might have missed it, but I don't think you told us what part of the country you are in. Maybe someone could recommend a supplier.

Also guys, Diana has plywood under the partical board. Would she really need to install 5/8 ply? I'm not arguing. I'm just asking.

Bud Cline
08-24-2001, 03:30 PM
In "these here parts" a 3/4" subfloor is typical and generally all there is to work with. Adding 1/2" CBU to the existing 3/4" takes you a little past the recommended minimum of 1-1/8" ahead of the tile. I would go with that if it was me. This assumes the structural requirements are met.

Diana states the joists are 16"oc and are 2" X 6"(8"). Now we need to know which it is 6" or 8"? Six inch is unacceptable and needs to be corrected somehow, even 8" may be marginal. Without going back and rereading the thread I guess Rob feels the additional 5/8" would help to make up for the abreviated joists. I just don't know. This is a "judgement call" based on an "eyes on" inspection which we can't do.

08-24-2001, 06:29 PM
The 5/8" ply was my idea.I suggested it in place of the 3/8" because I have seen buckling in material that thin more times than I care to remember.Perhaps with a bed of high quality adhesive designed for ply to ply applications in addition to screws every 10" or so,the 3/8" would be o.k.

I'm a devoted believer in overkill.I can't stand to do something or use a product that is "acceptable".For example,if I were building my own floor for tile, I'd put floor joists 12" on center with two layers of 5/8" e.g.ply mod.thinset(TEC),1/2" wonderboard,mod. thinset(TEC),and Porcelain Tile...OR joists 12" o.c.,3/4" plywood,tarpaper,metal lath,2" - 2 1/2" mudbed with latex additive,waterproofing membrane,mod.thinset(TEC),Porcelain Tile.

I could sleep with NO worries about the floor.

Rob Z
08-24-2001, 06:55 PM

I use heavy duty subfloor adhesive-whatever brand is available at the lumber yard. Don't buy the Liquid Nails brand adhesive for projects. It is not as strong.

Screws in the field should be 8" o.c. While your renting the tockick saw, check out whether or not they have a Qwikdrive brand autoloading screwgun. For the amount of floor that you have, it will be worth it. I bought one last year, and love it.

Large tile like 16" x 16" require and extremely flat floor. We need to get you to go over your floor with straightedges first to determine how flat it is.

Check in before you put down the second layer of T&G plywood (if that is what you decide to go with) for a few handy hints.

Keep us posted.


08-24-2001, 08:16 PM
If there is 3/4 EG plywood beneath the particle board, that is sufficient to meet hardibackers requirements to install 1/4" perpendicular to the existing plywood subfloor. (1/2" if it helps with transition height differences with adjacent floors) If you have reasonably easy access to the support system beneath the plywood (joist etc) I think you might be better off "beefing up" the structural support of the floor rather than adding additional height on top.

Just make sure the plywood beneath the particle board is in good shape and secured to the joist well. (Secure as necessary before attaching the hardibacker)
All of my hardibacker floor installations go over a "leveling bed" of thinset and I would recommend you use thinset between the hardibacker and plywood.

Removing the particle board will be the worst part of this job, and one of the best things you can do for the long-term "health" of your installation. And even that won't be that bad if you follow the advice given earlier. Best of Luck.

Rob Z
08-25-2001, 04:11 AM
Hi Diana

As you can see, you're getting varied opinions here. That usually is the case.

What Latney suggested about going with the Hardibacker over the single layer of plywood is the minimum MFR recommended approach. Getting under the floor to strengthen the joists is always helpful, but it is frequently not practical because of the wires, pipes, and ductwork that run through out.

All of this discussion doesn't solve your problem though. Only you can decide how bouncy your subfloor is (that's one thing none of us can do by computer).

If your floor vibrates when you walk across it, or dishes in the china cabinet rattle, or a floor lamp moves back and forth, then your floor may have too much bounce. In the tile business, this is called "deflection".

There are ways to precisely measure deflection, but let's start off with a simple bounce test. Jumping up and down on the floor to feel the give in it or to see if the dishes rattle is where we should start. And this should be done after the particle board is removed.

Let us know when you get to that point after your trip.


John Bridge
08-25-2001, 07:44 AM
Just one more note, Diana. 2x10 floor joists will only measure about 9-1/4 inches high. 2x8s are only 7-1/4 inches high. Very old ones will be just a hair beefier.

08-25-2001, 08:48 AM
Thanks guys,

Tile suppliers.... I live in the San Francisco California area...actually east of SF about 35 miles. Would love recommendations.

As soon as I return home I will remeasure the joist height. BUT I do know that running perpendicular to the joists (ie lengthwise of the house) are 4 x 6's. These 4 x6 's are spaced equal distances apart under the entire house and rest on post set in poured cement bases. ( I will measure the dimensions of all of it exactly next time I am under.)

I have not noticed any "deflection" when in the house but will be certain to try a few dishes on the counter and get the boys and friends to come over and jump around.

Thanks for the suggestions on the toe kick saw and the drill with self loading screws. Sounds like the trick.

You are all great!


08-25-2001, 06:42 PM
Wow!! That is a heavy-duty foundation Diana.How many of those 4"x6" timbers are there? We may have discovered why the builder felt that 2"x6"(8") joists would be sufficient.
My guess would be that the particle board was installed as an inexpensive substrate for the linoleum.We use to do this in rentals to help "smooth" the floor for linoleum.

08-26-2001, 08:15 PM

I agree that the particle board was probably for the original lino.

I am rather excited to get back home and measure the joists and supports. Will get back to you (all of you) on the 2nd of September.



09-13-2001, 10:24 AM
Hi guys...I'm back from vacation and have "looked" under the house to see the size of timbers. ( I came home to the aftermath of a broken waterline that dumped thousands of gallons of water into the yard and under the house. The soil under the house was so soft a rod went in to a depth of 16".)

Anyway back to the flooring dilemna. I have 4 X 6 inch beams running lenghtwise of the house. There are 3 supports The first support is 5 feet (approximately) from the rear wall, the middle support is 8 feet from that--ie at 13 feet or the center of the house and the last is 8'from center and 5' from the front. The floor joists running front to back are 2 X 6 16"oc. The subfloor is 3/4 " t & g plywood.

Questions: Will I need 3/8 or 5/8 more ply on top of the 3/4 and before the hardibacker?

Are there any concerns about the dampness of the earth under the house affecting the tiling process (ie, thin setting the hardibacker or tiles?)

Some one mentioned that with the use of 16" or larger tiles I need to take extra precautions to make certain the surface is level. I have a 6' level...will that work and what is the procedure to follow?

Thanks for all you help.

John Bridge
09-13-2001, 04:09 PM
Hi Dianna,

Hey, a six-foot level. That's great. You're more concerned about "flat" than you are level. Use the level as a straightedge to check the surface of the floor for high spots, low spots, etc. Don't worry too much about whether it's absolutely level.

I think you've got enough support if you add the half-inch ply and quarter-inch backer board. I'm not the best qualified on that, though. Somebody help me out here.

Wetness under the house won't affect the tile installation. It might cause mold and odor though. Make sure the crawl space is well ventilated so it will dry out quickly.

09-24-2001, 06:47 PM
Hi Guys,

...Last minute question.
I have taken up all the particle board and am ready to begin rebuilding the floor with a new layer of plywood. What was the final recommendation? In reviewing the messages I got mixed suggestions (3/8 or 1/2 or 5/8 ply)

Just a quick review. I am putting the layer over 3/4 T&G which rests on 2 X 6's. 2 X 6's are supported by 4 X 6 beams running perpendicular to the joists. I will be adding 1/4" hardibacker with thin set to the top of the new layer.
Porcelain will go on top of the hardi.

[Good story about the porcelain. I have been looking for weeks. Wasn't satisfied with anything I had seen--color, style, or cost. Well surprise, UPS dropped a large box on my porch last week, containing just one tile--porcelain with a hardness of 5, perfect color match with cabinets and granite countertops and with the non-smooth surface--just I had been looking for. Have no idea who sent it --consider it a miracle.

The manufacture gave me a couple of local distributors though. I am eager to get started.

Could use your "final" recommendations before I order the ply tomorrow.

You have been great to help out....


John Bridge
09-25-2001, 05:09 PM
My vote. Half or five-eighths. Three-eighths doesn't do much.

That was the tile fairy who dropped that tile on your porch. Good things happen to good people. ;)

09-26-2001, 09:57 AM

I will go for the 1/2 inch ply. It is readily available at the places nearest my home. Thanks you so much for sharing your knowledge and taking the time to answer the questions.


Rob Z
09-26-2001, 09:37 PM
Hi Diana

Glad you are on your way. Make sure that plywood is "B" grade or better-no CDX plywood for underlayment!

Rob Z

09-27-2001, 09:58 AM
Go to http://www.ctdahome.org this is the site for the Ceramic Tile Distributors Association.

They should be able to provide you with a list of distributors in Northern California.


Dale Watnee
09-27-2001, 08:42 PM
Look for Bedrosian Building Supply in the yellow pages. I worked all around your area before moving back east, I believe there is a store over by Airport Blvd. They have a flagship store in San Jose, which should not be a big drive over, there is also a smaller natural stone store of their's over in Hayward.

09-29-2001, 09:53 PM
Ok, Thanks for the tile distributor suggestions. I will probably track down the supplies of the porcelain tile that arrived at my door.

About Plywood. You suggested 1/2 inch but said "No CDX"....tell me the reason for that. They stock "Shop, CDX and ACX" at our local store close by, but no T & G. The guys at the lumber department tell me that the T & G doesn't have a ACX or CDX label. Why are some labeled or other are not? Can you teach me more about the grades of lumber?

I understand that one grade is guaranteed "no voids", is there a distinction in the way it is produced, the glue used or the quality of the lumber?


Rob Z
09-29-2001, 10:30 PM
Hi Diana

If you realy want to know a lot about how plywood is graded, visit the Amaerican Plywood Association website. There is more to this topic than can be covered here. For your specific questions, T&G plywood comes in underlayment grade, which means the knots and voids have been removed, plugged, and sanded. The thinnest T&G (I think) that is available is 5/8". While the face of T&G is not pretty enough for furniture making, it is a solid, strong piece of wood with no voids.

The grades with letters are evaluated based on the finish of the two surfaces of the plywood. A is better than B is better than C is beter than D. An A-A piece of plywood is very nice on both sides. An A-D piece is nice on one side, full of knots on the other side.

The X indicates exterior grade glue is used between the plies. ACX is no different than CDX, except for the quality of the faces. CDX has a lot of knots and voids, and is not strong enough for underlayment, especially for tile.

There are many other types of engineered lumber out there, but this will get you started. Go for the BC or AC plywood, or the T&G underlayment if you don't have a problem with the thickness. If you have a choice between pine and fir, fir is better because it is more stable (and more expensive).

No one on this forum recommmends OSB as an underlayment for tile.

I hope I answered your questions.

Rob Z

John Bridge
09-30-2001, 07:14 AM
"Shop grade" will work and is more economical than AC. Shop is equal to CC-Plugged. AC is very expensive, and as Rob said, CDX is not good enough. It's usually used for exterior sheething on roofs, etc.

09-30-2001, 07:21 PM
I would suggest that the CDX is just fine where it is. Any surface defects can be filled with thinset while laying the backer board and life will be good.

An advantage of the CDX is that you at least know that there will be no voids in the inside larger than 2" and most will be smaller. Unless a large change has been made in the last few years, exterior grades must use AT LEAST D grade veneer for all interior layers, which means a maximum of 2" diameter holes. I don't think there is any such limitation for interior grades. C grade veneer can have holes no larger than 1" diameter, so one side should be at least that good.

Rob is certainly correct in picking through the piles of plywood, though. All CD sheets are equal, but some are much more equal than others.

I'll go with Bud's disclaimer, but:

My opinion; worth price charged.

10-01-2001, 11:11 AM
WOW--love these discussions and varied opinions.

OK, the plan (from all the suggestions) is:

Leave the CDX that is down. I will check out what I have and then compare it to what is available at the store.
I am going to see if I can get a comparison sheet from them that shows the differences in the grades that they carry. That will help me decide.

I will fill any existing visible knots before I thinset the hardibacker down. The floor is being checked as I go to make certain there are no high or low spots so I believe that the tile will set easily.

The tile is an 18" porcelain with a hardness of 5. I will mortar those down on the hardibacker.

Thanks for your help on this floor. I am glad I found your site when I did. Your knowledge is invaluable.

Who knows, next week I might be asking about the easiest way to lay out the diamond pattern floor or how to put in a door where a window used to be....