Cam's Master Bath Remodel

[dcnichols]

Hello!

I've been lurking around the forum for about 10 months now. I'd seriously doubted that I'd ever need to post a question because it seems that most everything I would want to know has already been discussed, answered, and . This forum has been a gold mine for me as I've been researching and planning for my remodel. I like to have every planned out and drawn up before I start to minimize avoidable problems. Of course, I did do the demo without much planning, just gutted the room (the wife wanted "progress"). It's now been gutted and "progressing" for about 4 months. It's a good thing we have two bathrooms and it's just the two of us.

Well, I've finally gotten the room ready to start the fun part. I think I've finally done enough planning (read: procrastinating), and have decided on the layout, various fixtures, materials, yadda yadda.

1) I'm putting down a slate floor in versialles and I wanted some advice on my subfloor. I'm out here in the NW with my house built in '89, my floor consists of mostly 2x10 planks laid on 4x6 beams that are 4' apart. Seems like there are a couple 2x6's mixed in with the 2x10's. The planks have about an 1/2" gap between them and there are mostly flush with each other, though some are maybe 1/8" or so higher than their neighbors.

I'm planning on covering the floor with plywood, though I'm uncertain as to the grade/type/thickness. I was thinking 1/2" or 3/4". I'd like to keep it as thin as possible because I'm also doing electric radiant heating, and I don't want my tile to carpet transition too off.

2) As of now, I was planning my stack up to be 2x10 planks -> plywood -> 1/4" CBU -> radiant heating wire in thinset -> thinset & slate. Does this seem reasonable? I like taking my time, so I don't really want to goes the SLC route with the radiant heating. Any advice on this stack up or changes I should make to it?

I appreciate any help y'all can give. I've already got tons of help and ideas from reading though many hundreds of posts on here!

-Cam

[dcnichols]

So I've decided to use 3/4" plywood over my 2x10 planks. Over that I'll install the heating wires, then ditra, then my slate tiles.

I still have two questions about the plywood though:

1)Which way should I run the grain? I would think perpendicular to the plank flooring, but I'm second guessing myself. Some of the planks deflect about 1/4"-3/8" when I step on them with one foot in the middle of their span (4' OC, 210lbs). Any thoughts about which way is better for plank floors?

2) My lowes doesn't seem to have much selection, big surprise. In 3/4" marked flooring, they have CDX and CD, then 3/4 T&G without much markings but the tag says flooring. Should I look elsewhere? They have other 3/4" BC marked woodworking but would this have the wrong kind if glue holding it together? I'm thinking it should be exterior rated?

Thanks!

[scuttlebuttrp]

You need you one of them fancy injineers to confirm, but I'd remove those planks and beef up your joists to less on center.
Good plywood is:
3/4" T&G exterior grade BC sanded ply.
Stone would require 2 layers of ply but your planks may count as one. Not sure I only install on concrete which is why I mentioned the injineer.

[cx]

Welcome, Cam.

That's a fairly common floor structure out there onna Left Coast and our resident engineer, Injineer Bob, has done the calculations for us years ago. Unfortunately, I believe his calculations were based upon T&G planks rather than the square-edge boards you have. More unfortunately, Injineer Bob is currently on vacation.

Originally Posted by Cam

Some of the planks deflect about 1/4"-3/8" when I step on them with one foot in the middle of their span (4' OC, 210lbs).

That's actually about twice as much deflection as allowed by industry standards.

Now, there is still a requirement to add a minimum of half-inch exterior glue plywood over the T&G planks to bring the floor into compliance, and he may be depending upon that to help reduce the deflection, rather than just meeting the requirement to have the plywood surface. In your case, I think I'd be inclined to go with 3/4" plywood. And I can't guarantee that will be adequate over what you have. I'm not equipped to do the math on that.

All the above presumes, also, that your 4x6 beams are supported at intervals no greater than about 7 feet. You got that?

Now, having typed all that I see that you intend to use natural stone rather than ceramic tile. Disregard all the above.

Gonna be kinda tough to get to the required L/720 deflection requirement starting with what you have. Lot of those floors out there start with 4x8 beams rather than 4x6s and with the addition of another joist between them you can get where you need to go. But starting with 4x6 beams it's gonna be difficult unless your support posts are just surprisingly close together.

Maybe a nice slate look-alike in a nice porcelain tile?

My opinion; worth price charged.

[Edit]

When installing subflooring panels, the long grain (the strength axis) is always oriented perpendicular to the joists. Always.

[dcnichols]

Off topic: Well crap, I spent too much time typing a response and got logged out. After too much back clicking and forward, I lost my response! Easier on everyones eyes this way though, as I'll just summarize.

On topic: Re-measured (ok, actually measured) the movement of my planks, and the worst ones seems to only move about 1/16" to 1/8". This is over 4'. I'm going to laydown plywood and try it again. Then, if necessary, I'll add more support underneath.

Also, the supports are 5' apart, not 7'.

We bought all the slate a while ago so I'm gonna make it work.

Still wondering about the grain direction, though. I know it is supposed to be perp to the joists, no question there. But I don't consider what I have joists, but beams and planks. My understanding is you want the grain perp to what givea the most rigid support. Typically, this is 16" or 24". If I consider my beams the "joists" then that makes 48". Not helping the deflection much there. If I run the grain perp to the planks (though less rigid than the beam they are ~10" OC from each), then the load is better spread out and locked to the other planks. Instead of the load deflecting one 2x10, it is deflecting (though to a lesser degree) the boards next to it too.

Just thinking aloud, someone can set me straight though. Maybe I'll need to wait for a "real" injineer? My fancy piece of paper says I only get to play with magic smoke.

[cx]

Originally Posted by Cam

My understanding is you want the grain perp to what givea the most rigid support.

You want the strength axis of the subflooring panels perpendicular to the only support you have for your subflooring, Cam, and that's the 4x6 beams. Those are your joists, the planks are your subfloor. If you exchanged the planks for 1 1/2" thick plywood and wanted to add another layer of subflooring, which way would you orient the new panels? Right, you'd lay them the same direction as the ones already there - perpendicular to the joists.

If your beams are supported at five-foot intervals, you need only provide a way to install new joists centered between the beams and supported on the same posts. This shouldn't be overly difficult.

Having done that, you need only install another layer of half-inch plywood over your plank floor, install a tiling substrate, and then your stone.

My opinion; worth price charged.

[Edthedawg]

I'd be a big fan of adding a joist/beam between the 4-foot spaced beams, OR adding 4' joists spanning those bays, set 16" o.c.

Slate is not a wildly forgiving stone, but you can do this. The fact that you are seeing deflection now tho? tells ya you gotta do something more than just plop down a sheet of 1/2" ply and consider that "making it work".

Good luck to you!

[dcnichols]

I think I'll go with adding joists perp to 4' oc beams, then lay down 3/4" on top. I don't have much room to get under the house so I think 4' boards should be easiest to work with. What is a good way to secure these to the beams? Metal brackets?

Also, is there a significant advantage in going with T&G? I think the stuff at lowes was marked sturd-i-floor. Would this be better than 3/4" BC? A local lumber place has what they called "sanded shop". No marking, and after a quick search it seems these are either A or B faces with some manufacturing defects? The boards I saw looked good, no knot holes not even plugged ones, but had a strip of part of the top layer missing about 2" wide. Am I being cheap even considering these or is "sanded shop" mainly cosmetic defects?

[cx]

Cam, keep in mind that in using the short, perpendicular joists, you no longer have the option to take full advantage of the strength axis of both your subflooring layers. You'll now hafta install the plywood perpendicular to the existing subfloorig in order to take advantage of it's strength across the new joists. That does not provide the same support you would get if you added another joist parallel to the existing beams and installed your second layer of subflooring perpendicular to those joists, the same as your plank subflooring.

Will what you have in mind work? I dunno. Will it actually provide the L/720 deflection you're looking for? I dunno. Should be a pretty good subfloor, but I'm certainly no equipped to calculate just what you might end up with there.

You don't need T&G panels for either subfloor improvement method.

The Sturd-I-floor is a good product. If your other panels don't have some kind of grade stamp indicating an exterior glue, I wouldn't use it. My lumber supplier has nothing that is called "sanded shop" so I can't comment on what that might be.

My opinion; worth price charged.

[dcnichols]

Ah, I didn't think about that particular draw back for using short 4' joists. Maybe I can find some way to get longer boards under the house, maybe the crawlspace vents. My room is 11' long, seeming a bit long for a single joist board.
What if I use 3 4' joists perp to the beams, then attach the central joist (that is parallel to the 4' oc beams) to those? Or would having a solid joist the length of the room, supported from underneath be better?

What size joists should I be using? I'd think at least 2x8's, but my beams are only 6" tall. Will joist hangers work, or is there a better way?

[bbcamp]

I assume that you have posts set in a 4 ft by 5 ft grid. Set a 2x6 (or bigger) between the posts (parallel to the plank subfloor), then hang a 2x6 between the existing joists to reduce the subfloor span to 2 feet. Use joist hangers for both. Make sure the new joists are tight against the subfloor, use construction adhesive and screw from the top. You can then use 1/2" plywood and Ditra.

[dcnichols]

Thanks for the response, Bob.

Unfortunately, I already did the work this weekend.
Fortunately, I did exactly what you suggested for the joists.

My planks are now quite solid, with no noticeable movement, even when I jump on them. I'm going to put down my plywood tonight. I already bought 23/32" sturd-i-floor T&G, so I'm going to put that down. It was available and wasn't too expensive, and from what I've read around here, is a decent plywood for subfloors.

After that, it is on to building my tub surround/shower-bench and some plumbing. Thanks for the help so far! I'm sure I'll have some more questions as I progress!

[dcnichols]

Well, I'm back on my project and getting ready to build my mud shower pan. First though, I want to buy a kerdi drain and the membrane. There are a couple places around that will order it for retail list pricing plus 15%, but surely there is better pricing to be found somewhere in Oregon? Maybe a dealer who actually stocks product?

Anyone know of a good place to get Schulter products around Salem, Oregon or anywhere up to Portland?

Note: I've tried Schulter's dealer locator and even calling them, but they couldn't tell me who keeps stock. Their website tries to indicate who might with the orange trapezoid, but there was only one within 110 miles, and they didn't carry any, either.

[Houston Remodeler]

bump

[dcnichols]

Bump again...