[jjustinia]

Another problem I could use advice on. My subfloor needs replacing. I have attached a pic of the old floor. It is the diagonal floor planks that are very bouncy. I think they are about a little over a half inch. I don't know how to cut it flush to the wall and don't think I can. If I use a circular saw I will get a 1 to 2 inch border around the room of the old floor. The new plywood I bought is 23/32 dimensional lumber, is CDX, supposed to be 3/4 inch but us short a 32 of an inch. I will be left with uneven floors and I don't know how to handle this. I will be putting 1/2 inch dura rock over the area to be tiled and that is the area that is the real concern. The area under the tub will get filled in with the structo lite I lay under the new tub. My concern is what do I do in the areas that will be seen? I would appreciate your thoughts and insight. Have you encountered this problem and what have you done. Thank you! Sorry if this is a little off topic. I have another venting question to make up for this I will pose tomorrow with a pict.

[jjustinia]

I wanted to go with the thick floor to provide a solid substrate for the future floor and support the new tub. I wanted to do it right.

[Milo Dolezal]

Your sub floor looks nice and strong. I don't see any missing or split planks. These boards are usually 3/4" stock. The diagonal installation adds to the structurality of your house. These planks arei under your plates and are nailed to the joists and blocking. Then, framing is nailed through these planks to the joists and blocking again.

If it needs to be cut flush with the wall you use sawzall with long blade.

But, I would not recommend to cut it out. It is quite an important part of your house. You can go with DuraRock board over the subfloor, attach it with Grabbers screws, through the subfloor to the joists. You can even apply thin set over the subfloor before you lay DuraRock board. The subfloor is a good base to build on to - so why to remove it.

You can use ply to go over if you wish - it but it will bring you too high.

[jjustinia]

I guess I took a picture of the better area of the floor, but the planks bounce a lot and move when I walk on them, and in some other parts there are thin planks that are bowed. I guess when dura rock is laid across al of them it may tie them together. But I thought if they are bouncing then they are not good underlayment for tile and would be prone to cracking. Obviously I woul drather not pull them up . But I do need to get under some of them to rip out some old galvanized draining pipes. Also if I used a sawzall would I cut through the joist to when I went across them?

[Milo Dolezal]

If your subfloor bows and is loose - renail it with ring-shank nails. Or screw it with 2" screws to the joists. If some of them are missing or broken - than, replace them with 1" x 6", #2 stock (Home Depot). You can place small square pieces of thin sheet metal over small holes so you don't lose too much Thin Set through them.

When you install DuraRock, make sure you screw it with Grabber screws or any other screw designed for this purpose ALL THE WAY through the subfloor to the joists.

I would definitely NOT cut the subfloor planks out. They are important structural component our your house.

[jjustinia]

OK. When you say Grabber screws what specifically are you referring to. Can I get them at home depot. Do you just mean long screws going through dura rock and sub floor? Or are they some brand that I should be looking for? Thanks for the advice.

[Milo Dolezal]

Ok, Grabber is a Brand Name. However, there are many other screws designed to by used with DuraRock or Hardi-Becker cement boards. I even think Dura Rock makes this type of screws, too. These screws are special coated screws and are very sharp. They easily penetrate 1/2" cement board.

Home Depot and Lowe's carry these screws. They are a bit on expensive side but you pay for quality. They usually hang on shelves in tile department.

[jjustinia]

Yes, I know what you are talking about. They are called rock-on at my home depot. I already have them for the job. They are 1 5/8 inches long. Will that be long enough? Do they make them longer?

[jjustinia]

Ps, do I need to put thinset down between the subfloor and dura rock? I never have. I just use the screws we are talking about. What's your thoughts?

[Milo Dolezal]

ps, do i need to put thinset down between the subfloor and dura rock? I never have. I just use the screws we are talking about. whats your thoughts?

You can do it both ways. I prefer to use thin set but 1/2 of our tile guys screw it directly on to subfloor with just about same result. I personally feel the diference when I walk on it. With thinset present, floor feels harder to your feet.

Yes, they do make these screws longer. Use 2" or longer screws ( 1/2" Dura Rock + 3/4" subfloor plank + at least 3/4" into joists).

[jjustinia]

Like I said before the planks are only 1/2 inch. That was one of the reasons I wanted to replace with ply 3/4.

[Milo Dolezal]

As I said: it is not a good idea to do.

[Milo Dolezal]

Hi, Jjustinia...
Thank you for your negative feedback. Appreciate it. But I still stand behind my advice to you...

What went wrong ? It is a general practice to apply DuraRock board as I explained to you. Our licensed tile men do it this way all the time and their installations pass City inspections with flying colors. To be honest with you, I have never heard a complaint as you described it in your negative feedback left in my profile. That floor has to be solid so you don't get any movement transferred to the surface resulting in cracks in grout or stress cracks in floor tile...

I think the kibitz who came after the floor was installed gave you incorrect advice. I still think I advised you about the installation process as I should have.

Here is what eHow | How To Do Just About Everything! says about installation of DuraRock over subfloor. Or go to : How to Install Durock Flooring | eHow.com to read the original...


How to Install Durock Flooring
Ds_caseyl12380 Contributor
By Casey Holley
EHow Contributing Writer
Article Rating: (1 Ratings)

Durock flooring is a type of cement board that enables you to lay tile, wood planks or other flooring options to almost any type of subfloor. This is a cost-effective and time-efficient alternative to having to replace a subfloor. This do-it-yourself job can be done alone or with help, depending on how fast you need to get the project completed.

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Difficulty: Moderate
Instructions
Things You'll Need:

* Underlayment Mortar or adhesive Trowel Tape measure Miter saw Durock flooring 1 ¼ inch Durock wood screws Drill Joint tape

1.
Step 1

Lay down underlayment on top of the subfloor. You will have to apply a thin layer of adhesive or mortar to the subfloor. The type you choose depends upon your location. Generally, humid locations require mortar, and dry locations require adhesive. Simply run a thin layer on the subfloor with a trowel and place the underlayment on top of it.
2.
Step 2

Cut your Durock flooring. To do this, measure your floor with a tape measure. Write the measurements down. Once you have done this, plan how you will place the Durock flooring. Finally, use a miter saw to cut the flooring.
3.
Step 3

Apply a layer of mortar to the top of the underlayment with a trowel that is equal to the space where you will lay one piece of the flooring. Place the flooring onto the mortar. Step gently onto it to set it into the mortar. Be careful not to make it slide when you are doing this.
4.
Step 4

Continue applying mortar and placing flooring onto the mortar until the entire space is covered. Leave a 1/8 inch space between each of the flooring boards.
5.
Step 5

Use 1 ¼ inch Durock wood screws to anchor the boards to the subfloor. These must be placed approximately 8 inches apart and no more than ½ inch from the edge of a board.
6.
Step 6

Create a seamless area by applying joint tape over the spaces between the boards. Apply a layer of thin-set mortar or grout to the top of the entire floor. Apply floor tiles to the floor according the manufacturer's directions.

[jjustinia]

https://www.askmehelpdesk.com/interi...el-377846.html

Please see this thread. Both massplumber2008 and bljack both disagree with you. All whom advice that planked dimensional lumber MUST have a layer of ply or some other uncoupling system in between to avoid the expansion and contraction due to weather changes. Having screws through the durock into the joist compounds the problem, as the shift due to environmental shifts are directly transferred to the tile. A phone call to the makers of durock also this thinking. If this is inaccurate I would be happy to remove my feedback but it seems that my feedback was honest and accurate.
I hope they are wrong and you are right, but it does not seem to be the case. I know you did not intentionally give this misadvice, but others should know what the issues are or fall prey to the same mistake.

[jjustinia]

I sure hope you didn't spend the money and pour the self leveler yet.

All your durock needs to come up and the thinset scraped away

Durock (or any other cement board) CANNOT be installed over dimensional lumber subfloors. You must install a layer of 1/2" bc graded exterior (exposure 1) plywood over the plank subfloor, fastened with coated deck screws to the plank subfloor every 8" within the field and every 6" around the perimeter. Do not screw the underlayment plywood into the joists. Do not use any adhesive between the plank and plywood. Long edge of the plywood crosses the joists, even if it's more convenient to run it the other way. Maintain a 1/8" gap between sheets and a 1/4" perimeter gap.

When you go to reinstall your cement board, secure it only to the floor, do not screw it into the joists either. Maintain the same gapping as you did with the plywood. Any leveling gets done over the cement board and I read that you are aware of the primer.

I decide to go back and check out your other posts, see if any were related to this project and see if maybe you got the durock info off this site. Sorry, I'm not a plumber so I don't look over there in that subforum often, just a quick glance for key word like "shower" or "tub surround." Had you posted in the interior home improvement section, you would have received the correct advice from the beginning of the project. I can say with certainty, though, that Milo by no means intentionally steered you wrong, and he can only go by what he sees other tile installer do on jobs where he is working. Unfortunately, he's worked around a lot of really bad installers.

This is what bljack had to say about your advice.

[jjustinia]

Hi Jjustinia:

Bljack is absolutely correct and really knows his stuff. The fact is that durock (any cement board) should not be installed over tongue and groove flooring as this type of flooring can buckle over time and start to crack/pop the tile/grout floor.

That being said, I have seen many contractors get away with installing it just like you did with no issues that I saw as many as 10 years later. I have also seen where the tiles and grout cracked and the job had to be redone less than a year later.

I never liked doing it, but always removed any tongue and groove wood and replaced with plywood....yucky, hard work but being a contractor that doesn't want to have to go back after a job we simply had to do it according to manufacturer recommendation...can never go wrong with that.

In my opinion, if you lift and fix now you can be absolutely sure that you won't have issues down the road. If not, well, when the tiles crack/pop you certainly can't blame Bljack...;)

Hope that helped a little!

MARK

And here is massplumber2008 in agreement.

Please Milo tell me who is wrong and why? Again, I am on your side, as I want you to be correct for my sake.

[Milo Dolezal]

Jjustinia: Excuse my untimely response to your last post. I am presently away and do not have access to the internet as would wish...

Please, accept my sincere apology if you think I misadvised you. It was not my intention to give you incorrect advice. My intention was to give you an advice that would help you with a successful completion of your project.

Mark and BlJack gave you excellent advice as well because they are Experts in the field. I am glad you stopped and listened to them. I listen to them too. There is never enough to learn no matter how long you've been in business. That's because it is always a good idea to get opinions from several other licensed contractors before you proceed with your project. I would just wish they would jump in and offer their advice while we were conversing, not afterward. It is an open Forum and communication is strongly encouraged.

I have to tell you: you did a great job. There is nothing wrong with what you have done. My advice was just fine for your size of the project and Manufacturer of DuRock confirmed it. The question other Experts raised over the installation were dismissed by the Manufacturer itself. So calling my advice "...really terrible.." and award me with negative feedback is at least in my opinion not right. This is not the "Big Dig" project in Boston - but a 22 square feet area of flooring for heaven's sake ! And if you decide to put in a regular size cabinet in the same bathroom - that project will shrink even more - to 16 square feet ! It is not even 2 sheets of DuRock you will be installing. So do not worry about it and proceed with finishing your floor.

If it was a large area to cover, like entire living room or kitchen with unstable joists and deteriorated sub-floor than my advice would be synonymous with the advice offered to you by Bljack and Mark.

Do not loose any sleep over it. Do as manufacturer told you: leave it as it is and don't worry about it. You did great. All 22 square feet of it. Do not let anybody tell you otherwise. There is always somebody who will come afterward to tell you in red letters what you did wrong.

Make sure you tape the joint between two DuRock sheets you will have with mesh tape. Install tile so they overlap the only seam on DuRock. It would be great if you could set them in diagonal pattern. Use Fortified Thin Set and add Acrylic Additive to your Grout to finish the project. Mix grout by hand, do not use any mechanical mixing tool. Let it stand for 15 minutes before you use it. Seal with grout sealer in few days after grout cures. You will be very happy with what you 've done.

Suggestion: use Porcelain tile for your floor if you can. Porcelain tiles are durable, install well and maintain their color for as long as you'll own them. These days they come in all sizes and colors to blend with your design. Home Depot carries great selection of floor tiles for great price. Don't go small on the floor. Go at least 12"x 12".

Congratulations on doing such an excellent job ! Please, don't forget to share with us photos from finished bathroom !

Best Regards

Milo