Regarding floor joist span?

[MikeVila]

Hello to all, just found this site. Lots of good info.
I am remodeling my bathroom in my 32x80 manufactured home. I wanted to install tile but the deflecto #'s (johnbridge.com) say it's a no go. The problem is mostly the unsupported span of the joists. No cross support. I know there are I beams under there but the joists do not rest on them, correct? So I would have an unsupported span of roughly 16'. I thought I saw a frame diagram that they are supported maybe towards the marriage line on the beams? If that beam was somewhere where it cut my joist span down to like 12' it might work. Basically I need to know if anyone here has good knowledge about the joist/beams underneath. Sorry for such a long post and I look forward to any info. Thx.

[flcruising]

Yes, the floor joists rest directly on top of the I-beams. The I-beams are about 3' in from the outside walls and the marriage wall for each half of your home. These walls are cantilevered over the I-beams, so the actual unsupported span is more like 8'. The critical thing to verify is the frequency of the floor joists. Are they 16" or 24" o.c., this will determine what additional blocking you may need, or whether to add another layer subfloor.

[MikeVila]

For real? SWEET! There 16" o.c. and in some places in bathroom there like 12" and 14" oc. Wow I should be good to go then. I am gonna take a peek then underneat to get a better idea. I really appreciate the info. Made my day.

[Greg]

Mike, If you are talking ceramic floor tile, We really don't recomend it unless you are on a full foundation. Mobiles can and will shift some, they are designed to flex slightly, ceramic tiles on the other hand simply won't. Greg

[TonyPa]

I found that they now make vinyl floor tile, that you use grout in between. They are now set far apart. You use spacers the size of a nickel. "width" of the nickel. The grout is like a paste type, that comes in a small plastic container already mixed I beleive.
Lowes just started carrying them about 5 months ago. I thought the display that was set up, was ceramic tile, until the guy told me that worked there. They looked like pieces of slate. I am wondering if this would work, since their vinyl, and the grouting is very thin in between?

[MikeVila]

I saw those vinyl tiles with the grout a while back at Lowes. They do look pretty real. The deflection was the main concern of mine. I will be using 1/4" Hardie on top of the 3/4" subfloor. I figure as long as i'm not tiling over the marriage line I should be fine.

[RandyD]

I will be using 1/4" Hardie on top of the 3/4" subfloor. I figure as long as i'm not tiling over the marriage line I should be fine.

Ceramic tile requires a STIFF floor, of about 1 1/4" min. + the floor joists aren't thick enough
Probably only 2"x6"
The tile will crack and come loose

[MikeVila]

I have to disagree Randy. Ceramic and porcelain tile requires a deflection rating of L360. For more info= www.johnridge.com. Subfloor only needs to be 3/4" with backerboard used per manufacturers specs. You need a subfloor of 1 1/4" for NATURAL stone only. Floor is plenty stiff enough with 3/4" subfloor on 2x8's spaced at 16"oc and some even closer than that (12" and 14"). My unsupported span was my only concern.

[NMBowtie]

When I tiled mine, I used the 1/2" concrete backer board screwed down every 6" over the 3/4" subfloor. The tile has been in for 2 years now, and I don't have any cracked grout lines or popped tiles. Mine is a 28 wide with 2x6 floor joists 24" oc but is set on a solid foundation. I think in your case, you should be fine as long as you have a good foundation. You might want to check out the thicker backer board, though.

[MikeVila]

Thx for sharing yours NMBowtie. Chevy guy also I assume lol. You got any pics of your tiling? Actually the 1/2" offers no more structural strength than the 1/4". I forgot the exact specifics. The 1/2" is usually used for the walls and people usually use the 1/2" on floors if they have some height to make up.
As far as foundation, I have the usual concrete footers with runners everys so many feet. My home is actually drywalled and haven't had no real problems with cracks except the ones that were there when delivered and I have been redoing them as I paint because they didn't do a very good job on them. Nothing new though so that is a good sign. What do you mean by "solid" foundation?

[Yanita]

Hi,

Solid/permanent foundation= below the frost line footers. If you live in a cold weather (below freezing) area your chances are good that your tile will crack. BUT, the choice is yours, you are the homeowner. We give advice that has been proven reliable for many years...

Yanita

[MikeVila]

Yeah my footers are definitely below the frost line. I thought he meant he was on a pad or something.