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Discussion Starter · #1 ·
Here is some back round. 1930's home in excellent condition.
2nd floor bathroom remodel. Bathroom measures 86"x74" (measuring up to tub)

Joists are 2x8x10 16" on center running the 74" width (parallel). One end sits on load bearing beam, other end on studded wall with 16" on center 2x4 (basically 2x4 under each joist)

Subfloor is as seen in picture below in backround. Appears unknown width but 3/4" T&G, and on top of that is 1/4" ply with linoleum glued (done in 1980s) and then vinyl on top

My plan is take up vinyl, take up linoleum and 1/4" floor. Then add 5/8" or 3/4" plywood over the existing 3/4" T&G, level, use either DITRA or 1/4" Hardibacker then tile with 12x24 that are 4.5lb/sqft. For the joists, my plan is adding 2x8 perpendicular to joist span to stiffen and help with twisting.

All dead weight of new items (linen cabinet, double vanity) sit nearest load bearing wall.

Tub is alcove 60x32x20 soaker sitting parallel to beam directly underneath one, plan on strengthen with a box method. Finally, 1/2" Hardibacker around tub with same tile for floor on the tub surround.

A conservative delfecto says I am good to go (L/367 for unknown wood as no stamps). Joists are in very good condition, with only minimal notches for plumbing.

Any other recommendations for tiling the floor?
 

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Tileguy
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Hi,

I'll bet your 85-ish year old home's 2x8 joists actually measure 2x8" and not 1.5"x7.25" as you entered in that Deflecto tool. Plus your 2nd paragraph above has me confused. I can't tell what the span is. In any case, your framing sounds better to me than L367.

You can tell us more about the subfloor once it's exposed. Try to remove the ¼" underlayment with the two vinyl floors still attached to avoid having to deal with scraping either of the floors because they might contain asbestos.

Jaz
 

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Discussion Starter · #3 ·
Hi,

I'll bet your 85-ish year old home's 2x8 joists actually measure 2x8" and not 1.5"x7.25" as you entered in that Deflecto tool. Plus your 2nd paragraph above has me confused. I can't tell what the span is. In any case, your framing sounds better to me than L367.

You can tell us more about the subfloor once it's exposed. Try to remove the ¼" underlayment with the two vinyl floors still attached to avoid having to deal with scraping either of the floors because they might contain asbestos.

Jaz
The joists measure 1.75" x 7.5".
The second paragraph just means that one end of the joists sits on load bearing beam, and the other ended sits on a studded interior wall. Span is 10'. Also, the bathroom sits parallel on the joists meaning the 84" length of the bathroom runs perpendicular to the joists running length.

Also, I did plan on taking up the 1/4" board that the linoleum to glued to.

Thanks for your response. I will post pictures of progress when I get started.
 

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Discussion Starter · #4 ·
Bump to top.

Joists measure 2x8 (1 5/8 x 7 1/2), 10 foot span, 16 inches on center, unknown grade.

Tub is 60x32x20 acrlyic alcove soaker, on top on 1 joist running parallel. Existing tub is 60x30.

Subfloor is 3/4 T&G wood. Plan on adding 1/2" ply then DITRA

Question about the tub. Can 1 joist handle the weight of the extra water or should I sister or even possibly add 2x4 on bottom of joist making it into a I beam to stiffen.
 

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Tileguy
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I know it's easy for you to understand what you've written, but we're getting more confused. In #1 you said the room is 86x74, later you referred to the 84" wall. Adding the words "parallel" & "beam" only made thing worse.

No one is going to be able to bless your joists since we don't know their species and grade, not to mention their condition or if they were installed correctly in the first place. The info the Deflecto gave you is obviously not correct, although I think you're close.

I would say most of the commonly used species would meet min. specs at about 10'6" span. I think you'll have to defer to your seat of the pants judgement and not any facts. I think the extra size of the joists because of their age will help save you.

Although there's only one joist under the length of the tub, there's actually 3 supporting. You forgot about the subfloor. However if the floor is open and you can sister the joists, why not do it.

Jaz
 

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Now, I'll say right away that I'd defer to Jaz's FAR greater experience in this area, but just to expand on what I think he's getting at, as well as what I'd want to have done if it were my project (and these days I'm thankfully able to do less of the endless labor than a while back but still get my hands dirty often!) IF the asbestos issue isn't a concern (and I know that's a big "if" there, but there's a lot of great info on the net about id'ing asbestos tiles AND the tiles as well as the exterior siding are often not as "just stay away from dangerous" as far as the asbestos fibers being released into the air, as compared to the pipe wrap for one, which whenever I run into I simply call my preferred local licensed asbestos guy, who's of course on my phone contacts! A little reading on the subject and the "friable vs non-friable" discussion as well as IF these are asbestos tiles at all in the first place could go a long way here)

What I think Jaz is getting at and definitely what my viewpoint would be is:

When you add up ALL the various steps that will certainly be involved in this project, whether you are able to cut a few steps here or there or not, no matter what still adds up to certainly a fairly big undertaking, not a day or two of easy work, but also one which IF really done totally right on, should leave you with a GREAT result to last for decades, so why not try to make the comparatively small extra step to just get down to those floor joists and have em exposed, so you can most likely sister, maybe cross block or whatever else to your heart's content (and once you get there, that part isn't usually actually that hard, especially for sistering if you can get a 2nd set of hands for half day)

Its just making the cuts with miter saw, skil saw, even a jigsaw if you like to watch that blade painfully SLOWLY cut through each board and its not rocket science, but needs a little forethought.

Then, you'll almost certainly end up with a hell of a lot stronger base structure to attach (as per guidelines) your plywood subfloor to, backer board, etc and once that grout is cleaned up and you look at your awesome new floor, you'll fell GOOD inside too, knowing you've got solid underpinnings!

I just always think of ALL the various steps, going to look for the tile, beating myself up over which almost identical grout color, then picking it all up, lugging it inside and prob upstairs too, ALL that work and much more and then even if less invasive subfloor redo works perfectly for decades, you may have that nagging worry for decades too, "damn I should've reinforced the joists and laid new subfloor" vs comparatively small extra labor and confidence in your structure, I like sleeping soundly at night!!
 

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Discussion Starter · #7 ·
I hear you....

My plan is sister joist under new soaker tub, and block the rest of the joist together to make a sound structure.

I have time in my front foyer already and that is on #2 SYP 2x8x11 so I know the original 2x8x10 will be fine.
I also understand this is not a weekend project and I plan on this taking me at least a month moving at my pace since I am doing the work.
Will post progress as it goes along. Gutting next weekend.
 

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Discussion Starter · #8 ·
Just and update....
Looked at numerous Deflecto tools for my 2x8x10 and within specs. Tile it is...

Gutting begins next weekend. Plan is as follows:

-Gut down to studs and 3/4" T&G plank subfloor
-Sister 2x8 joist running under tub
-Block 2x8 joists at 1/3 span and 2/3 span to prevent twisting and tie into 1 sound structure
-Square and level tub framing
-Add 1/2" ply to plank subfloor, screwed or nailed every 4" on the edges, ever 6" in the field
-Plumbing, electrical next
-Install 60x32x20 acrylic Kohler Bancroft soaker tub, alcove style
-HardiBacker tub surround with 6mil vapor barrier behind Hardi
-Drywall, tape, spackle and sand
-DITRA the floor using Mapei poly-modified to set the DITRA, then per DITRA, Mapei Uncopuling un-modified to set the tile 12x24 on the membrane
-Using Mapei Ultraflex LFT, tile tub surround 12x24 tiles
-Niche in tub surround, likely will use Kerdi pre-made one
-Glass moasic accent strip 3/4 way up wall
-Grout with Tec Sanded grout
-Install vanity, linen cabinet, medicine cabients, toilet, fixtures, molding, finishes

I am hoping all goes to plan
 

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Discussion Starter · #9 ·
Keith's Bathroom Reno

Well we began our bathroom renovation yesterday.

Day 1 consisted of bathroom walls, demo soffit above tub area, pull all drywall nails, sister 2x8x10 joist under tub, block the rest of the joists, lay down 1/2 plywood over existing subfloor, re-frame one wall of tub area for new mixing valve, and adding stud in for extended tile area.

Tub area is as square as possibly can be and studs are all nice and level with each other.

No surprises were found. Original plank subfloor was in excellent condition. New ply subfloor has no waves to it and only slopes 1/4' over 9 feet. All in all productive day.

Next up is electrical and plumbing.
 

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