Starting off right... - Ceramic Tile Advice Forums

Texasgirl · 08-20-2001, 09:46 AM

Hi John!
I am just beginning my project and I want to start on the right foot. I have 300 square feet of kitchen that I am putting ceramic tile on. 100 feet of it is hardwood (layed around the year 1900). The other 200 square feet is bouncy, creaky plywood (layed in 1964).
Now I know I will be replacing the plywood section, but what do I do about the hardwood section? A tech at Wonderboard said I should replace the bad plywood with new, then put another layer of plywood over the whole floor. Or am I going to have to remove the hardwood (ugh!) in addition to the plywood and start from scratch? Under the whole thing is diagonally layed 1x6 cedar.
Also, there are gaps between the walls and the hardwood. Would I fill these? If so, with what?
I have been researching this project for about six months and at now I'm thinking of chickening out and calling a contractor.
I would appreciate any advice you have. Thanks for offering such a great website!

Bud Cline · 08-20-2001, 03:53 PM

The big question is what's below the 1x6 cedar. If the floor is bouncy tile won't last till the weekend. We need some information as to the structural aspects of your floor.

Specifically: What is the size of the floor joists? How far apart are they spaced? How far do they run (span) without support under them?

John Bridge · 08-20-2001, 04:55 PM

Welcome, Texas Girl (you're gonna have to give us a shorter name

)

First of all, don't chicken out for two reasons: 1) you can do it, and 2) you ain't gonna find anybody to to it anyway. Everybody in Texas that I know is burried.

This appears to be one of the projects that will go into several pages on the board, and that's great. So let's not get in a rush. About 19 guys will offer their views, and we'll have to hash everything out. Sorry, but that's how it seems to work around here.

So get back to us with the answers to Bud's questions, and we'll get going.

Oh, just one more thing. You can't come on this board calling yourself Texas Girl and not tell us what part of this great state you live in.

Texasgirl · 08-20-2001, 05:02 PM

Thank you so much for your quick reply!
The floor joists are 2x8 cedar on 16" centers. They span 12 feet.
I am anxious to hear what you think. Liz

John Bridge · 08-20-2001, 05:52 PM

Hi again, Liz,

2x8s are going to raise the eyebrows of all the pros around here, and the fact that you say they bounce isn't going to help matters. 2x8s running over a 12 foot span, for instance, will not support a tile installation of any sort. You would have to build a 2-in. mud bed above the subfloor at the least. And then, it would be iffy.

Maybe there are some beams under there running perpendicular to the joists, in between the end supports? I hope, I hope, I hope?

Texasgirl · 08-20-2001, 06:12 PM

Hi! Okay, a mud bed? Hmmm...
The house is 24 feet wide in that area. There is a beam running down the middle and that's where I got the 12 foot span from. I looked again and I do not see any other joists running perpendicular. As far as the joists bouncing, I am not sure, I know the cedar strips bounce that are under the plywood.
As you have probably guessed, this is a super old house. It has been in my husband's family for generations. I spent the weekend tearing up everything that was over the floor. Carpet over glue over linoleum over tar paper. Now I am down to the bare wood (with tar splotches on it). I really hope there is a way that tile will work.
Give me some hope, guys!
Liz

Ron · 08-20-2001, 06:43 PM

Texasgirl,
Not to worry.With the experience and confidence of the guys at this forum,tile is possible anywhere.To do it right though you may have to go the extra mile when it comes to the planning and the prep work.
Even a proud tile setter and mud guy(not yet a meister like John)like me learns from this forum all the time.So no worries,you'll be led in the right direction here.

Ron · 08-20-2001, 07:03 PM

TXgirl,
My advice on the bouncy floor would be to remove the hardwood(and other coverings,if any,like vinyl,carpet,etc.and even plywoods especially mahogany lauan,or other flimsy 1/4" plywoods)so that you are left with a floor that is uniform in height.Even if you have to go as far as the planks.
Then use some 2" flooring screws and a powerful drill and screw those planks into the joists.Now jump on the floor to check if it is more stable.A version of the Charleston will suffice too.Probably it will be less bouncy.
From here you can install concrete backer board with thin-set and screws or even 1/2" exterior grade plywood.I would then strongly recommend a product called Schluter Ditra which is a anti-fracture membrane and easy to install.
I would install a full mud bed,myself,but these are not really for the do-it-selfers.

John Bridge · 08-20-2001, 07:14 PM

Liz,

I'll offer all the encouragement I can, but I won't send you down the wrong trail (doesn't that sound like the Old West?)

I think you ought to reconsider. Maybe a different floor covering. Maybe laminate? Maybe wood?

Otherwise, I'm going to recommend going under the house and doing some serious carpentry -- adding a whole bunch more lumber. I don't think the floor will be stiff enough as is, even with the modern things we have available to us nowadays.

I am deeply sorry, ma'am.

John

Ron · 08-20-2001, 07:27 PM

Yeah,John,I forgot to stress the importance of reinforcing the joists first to accept the added weight of a tile installation.Seems that in her case this may be very necessary.But i don't think that all is lost.She can still have a beautiful tile floor when all is said and done.

kalford · 08-20-2001, 08:48 PM

Liz,
Your situation is exactly like mine and I'm installing tile in my home.I already tiled the bathroom and am making plans for the kitchen.Put your mind at ease,I've been in the construction/remodeling fields for over 20 years and I'm positive we can make it work.

I assume this is a single story with access to get under the house.It will be necessary to get under there to do some work(which needs to be done,tile or not)

First;Everything should be removed down to the 1 x strips.These were layed diagonally to add strength.The down side is that over time they twist and thus push whatever is above upward gradually working it loose.The UP side is,it's an easy fix.Ron is absolutely right about the 2" screws.Use deck screws and put two in the boards into the joists.This will greatly strengthen the subfloor and stop the twisting.Put screws ina board at least in everyother joist...every joist is better.

Second;Get under the house and measure the height from the ground to the bottom of the joists.This measurement will be needed to calculate how many cement blocks(called Spreader Blocks) you will need to do the needed additional bracing.You'll need a pillar every eight feet under everyother joist.This is needed to give added support because of the small joists.For each pillar there needs to be a "footer" block a "cap" block a 2"x8"x16" pressure treated wood cap and two wood wedges.

footer:16"x16"x4" cement block used to support a cement pillar

cap block: 8"x16"x4" solid cement block placed on top of spreader blocks for added strength.

The footer is put in place under the joist(centered
Place a "spreader" (or two) on top of the footer a cap block on top of that,the wood cap on top of that.
With the pillar in place there should be approximately 1" or less,space between the top of the wood cap and the bottom of the joist.
Place the two wedges on top of the wood cap with the sharp ends facing eachother.One should go on top of the other.Tighten them by striking them with a hammer first one then the other till they are tight.It will be necessary to check inside to be sure there are no "humps" or "dips" in the floor.Dips can be fixed by simply driving the wedges in a little further,humps by loosening them.

Have someone heavy walk on the floor while you're underneath and watch for any flexing.Note where it is and brace it up.

You will also need to add cross-bracing to run between the joists from one to the other about every eight feet.

Once this is done you can decide if you want a mudbed or plywood and cementious backer.Personally,if I went to the trouble of doing what I just described(and I am)I'd go with a mudbed.

Texasgirl · 08-21-2001, 09:22 AM

My mind is reeling. My husband's jaw is still on the floor. However, I am not ready to abort mission yet.
I will go to the lumber department and add some things up. Then I will be asking ya'll several more questions. But first I am looking for the smelling salts for the husband...

Bud Cline · 08-21-2001, 10:56 AM

Am I understanding this corretctly?

The 2X8 floor joists run the length of the twenty-four foot span but are divided down the center by a beam. This beam runs perpendicular to the joists, and this is how you arrive at the twelve foot span you report. Is this correct?

So there are two twelve foot spans involved. If this is the case, maybe only one support post will be required under the beam to stiffen the entire floor area.

If this is correct, then this isn't a major problem. The 2X8's are somewhat abreviated by todays standards but if the beam provides center support for the joists then I assume the beam is also a little soft and flexing.

Another problem is the cedar in that cedar is very soft and in its 1X form will easily flex even over 16" joist centers. The 16" joist spacing is the only saving grace in this situation. Before we go too much further how big is the beam and am I correct in my summation of the structure?

kalford · 08-21-2001, 02:33 PM

If you are right Bud,then it might be possible to add more beams(6"x6") to run under the joists and three or four pillars under the beams.Probably in that scenario,only two to four beams 12' long would be needed.It may be necessary to place one or two additional pillars under the existing beam.I'm sure it has sagged some.This will reduce the number of pillars needed tremendously.

Bud Cline · 08-21-2001, 04:18 PM

I'm thinking the entire area is moving like a boxing ring. If this is so, then even one little ole "jackpost" with a solid footing in the center (two would be better) of the beam would help greatly. If the 1X planking is in fact cedar then it isn't helping the situation.