Hello everyone,
I recently, demo-ed the floor in my bathroom. This was quite a task. The home was built in the 1920’s and the tile and mortar bed were well built.
The tile and mortar bed covered 50% of the floor. So, the joist were cut to lower the floor for the mortar bed. Was this a common building practice?
Also, I plan to go with tile in the remodel. So, I will need to lower the floor ( the other 50% ) to be flush with the hallway, which is wood. Is this a common practice in a remodel?
Any insights will be appreciated.
Thanks
Drake
Replies
Yeah, lowering the floor was common in the day. I wouldn't lower the rest of it, though. I'd build it all up to the same level, top it off with CDX, and tile atop that. Assuming the floor's structure meets the Tile Council of America's L/360 deflection standard, that is. That means that under the design load, probably 50 lbs. per sq. ft., the floor can't deflect more than 1/360th of the length of the joists.
I don't think backer board adds anything to the equation on floors, and the TCA does allow tile directly on 1/2 in. CDX for residential purposes. There will be much screaming and gnashing of teeth about this opinion, however.
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
I don't think backer board adds anything to the equation on floors, and the TCA does allow tile directly on 1/2 in. CDX for residential purposes. There will be much screaming and gnashing of teeth about this opinion, however.
I thought their latest recommendation was a floor thickness of not less than 1-1/8" including the combined subfloor and backer board thicknesses. ?
Beer was created so carpenters wouldn't rule the world.
It is 1 1/8 in., and my assumption was at least an existing floor of 3/4 in.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
It is 1 1/8 in., and my assumption was at least an existing floor of 3/4 in.
I'm with you now. When I originally read your post I thought I was hearing 1/2" cdx with no other subfloor. :-)
Beer was created so carpenters wouldn't rule the world.
No, no. That's only legal in Pennsyvania, from what I've seen.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
*chuckle*
What's so funny?
No, no. That's only legal in Pennsyvania, from what I've seen.
Andy
What Andy said.
Beer was created so carpenters wouldn't rule the world.
Funny, I think thats what the HO did in my place. Damn PA building codes!
Google Jeff Remas, or Remas Inspections. The guy has a blog showing some things he's found as a home inspector in PA.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
And the manual I have, btw, doesn't require backer board for residential. CDX is fine. And unless you're adding a waterproof membrane, I can't see backer board as making any difference in the durability of the floor. If it gets wet, the underlying strate gets wet too.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
Drake,
Welcome to the forum. I'd second Andy's advice to build the existing joists up to level instead of lowering them to meet the cutout for your original mortar bed area. If you lower the rest of the joists you'll compromise their ability to carry the load for the tile you plan to install. This deflection calculator from John Bridge might be useful to you as well: http://johnbridge.com/vbulletin/deflecto.pl
Hello Forum
This is a small bathroom, 5 by 7. In reexamining the floor joist, 80% have been lowered to accomodate the mortar bed. A bathtub sat on the other 20% of the floor. It looks like an inch was removed from the joist.
My goal is lto level the bathroom floor with the hallway floor. I don't want the finished bathroom floor to sit an .5 inch above the hallway floor.
Would heads roll, if I lower the the remaining 20% of joist and sister new joist to the old.
Thanks
Drake
Lovely! I think that no matter how you do it, some leveling is needed. I'd sister some wood next to those old joists, and sheath the whole thing with 3/4 ply topped with a perpendicular layer of 1/2 in. Whether you lower the existing joists would depend on their overall span.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
In your pic, do the joists run to a bearing point that is beyond the plumbing wall in the pic? In order for sister joists to have any efectiveness they must bear at both ends, otherwise you are just adding to the load and not adding any strength. Solid blocking(bridging) down the mid-span would also help stiffen the floor. What's the height difference between the top of the existing cut-down joist and the finish floor in the hallway?
Geoff
Hello Geoff & Forum
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Wow! An important point.
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At one end, I have an accessible bearing point. Yet at the other end I do not. So, sister/ing joist would not be effective. It would only add to the load. Unless I built another bearing point.
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The height difference between the cut joist and the floor looks to be about 2 inches.
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Thanks
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Drake
It looks like access to the crawlspace there is pretty difficult. One thing you might consider while it's open is to spread out a vapor barrier on the dirt.
While sistering joists that don't reach both supports won't add strength, it's likely an easy way to level up that framing. The sisters don't need to be the full depth of the originals - 2 x4s would probably work. And the weight they'd add to the system is really inconsequential compared to the weight of the mud floor you've removed.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
Hello Andy
Thanks. The original mortar bed and tile was substantial in weight. The mortar bed was close to 3 inches thick and a bear to remove.
I'm definitely going to open up that crawl space up. Due to a total plumbing failure, I had to do some work down there before the floor was opened. It was brutal.
Thanks for the 2 by 4 suggestion, that would help level the joist, and give me a nailing surface for the subfloor.
I'm just wondering if I should add a second bearing point to support the floor.
Drake
You'll never have a better opportunity to add more bearing. I'd consider it if I were the least concerned about the floor being spongy.
BTW, it's hard to overemphasize the importance of the plastic on the dirt crawlspace. Search on that topic here and you'll get tons of discussion. In short, dirt crawlspaces are a chief source of moisture that enables mold, rots wood (including roofs - but that's mor complicated than I want to get into right now), and peels paint. Check out http://www.buildingscience.com for more info.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Book of Merlin
Drake,Let me preface this with the advice that I am not a professional builder, nor engineer, and that the remarks of those who post here are much more likely to be more correct than what I have to offer.All that aside, it is my understanding that when sistering joists you do not need to span to one or both bearing points. What's needed is to span (roughly) the middle 2/3rds of the joist, or any areas that have excessive notching. If you can run it to either bearing point, so much the better. In your case you are going to want to run a sister the full length of the room in order to have a level surface to support the floor, but I don't believe that you need to run it all the way to a hidden or unaccessible bearing point. However, I'd make sure that someone here confirms this as I don't want to give you erroneous advice.Hope that helps.