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03-06-2006, 11:58 PM
hi everyone i am Namrata - Nams for short - from central florida.i have to say wow what a goldmine of info this site is and i am so glad i found this forum.

my husband and i are building a house in central florida in clermont. its a 2 storey house with both the baths on level 2. i wud like to install travertine - honed and filled, as flooring and shower/tub surrounds. the builder wont do travertine only tile, so we decided to let them install the standard vinyl as flooring and vikrell as shower surround.

now one tiling company said since the 2nd level's floor is wood and not concrete travertine is too heavy and over time our floors cud bow or cup under the weight of the stone :uhh: any truth to that? is it not recommended to put natural stone on level 2 of a two storey home?

for the surround they said if i try to pull out the vikrell i shall find no drywall behind it :scratch: what will be there i didnt get from that conversation.
so shud i or shud i not install travertine 6 x 6 as shower surround considering that i will have to rip out the vikrell and find whatever it is that there is underneath it and make the stoone adhere to it.

what shud i do? my husband and i work in imports, our respective emloyers' deal in natural stone so we cud source travertine for almost the price of ceramic. i really love the timeless quality of natural stone, but am scared of making a costly mistake.

so please help!

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03-07-2006, 12:02 AM
the vikrell is a solid surface shower tub surround which is screwed right to the studs. what are the joist, size, span, 3/4 ply on top of that what i am getting at is we need alot of info to answer some of those questions. can u find out all the above info from contractor?

03-07-2006, 08:52 AM
Welcome, Nams. :)

On new construction it is very simple to design the floor structure to accommodate the natural stone. Your builder knows that (or certainly should) and apparently didn't want to do it or you asked for it too late in the construction for an easy upgrade, would be my guess. There is no other reason not to use that kind of flooring on a second floor. Whether your floor structure "as built" will now accommodate the stone, we don't know. You'd need to get that information from the designer or compute it from the type, size, spacing, and unsupported span of the floor joists, and determine the type, thickness, and number of layers of the subflooring.

For the shower, I'm not familiar with the material you have there, but apparently Kevin knows it. Whatever it is would need to be removed and an appropriate tiling substrate installed in its place. All that would have been a thousand times easier and less expensive before the current shower was installed, of course.

Were you and the builder just not getting along at all? :D

My opinion; worth price charged.

03-07-2006, 10:19 PM
well i am buying the home from a builder. u know the drill - pick a community, a lot and a floorplan. we loved the town, the community and the lot. so bought the house from the builder,cudnt really afford to go custom home route.

the builder offers as an upgrade - ceramic tile in wet areas, but whats the point paying $$$ to upgrade to ceramic tile only to gut it out and replace with natural stone which we love so more. hence the decision to ask the builder to put the standard vinyl for now and then change to natural stone later.

but i have a lot of concerns and qs. one being deflection - to calculate which i need the number and size of joists, which i cant go see, only bcoz there are no basements in central fl. and how many builders do u guys know how provide that detailed info? as far as i know builders build to comply with basic code if that. not many exceed code. so as per central fl code if the std deflection reqd is L/360 then thats what they will put there. for natural stone we need less than L/720, what to do? can i strengthen the floors to support the natural stone? or is it completely ruled out?


03-07-2006, 10:33 PM
Well, the builder should know right off the top of his head what the design of the second floor is, especially if it's a plan he's built before. Prolly knows if he can give you an L/720 there at this stage of the game, too. You axe him?

Once construction is complete, it's highly unlikely you'll be in a position to stiffen the floor to that spec easily, though. Depends upon the layout of the first floor and the joist structure and all. He could do it during framing, but after that I think you'll wanna live with what you got.

And I don't understand the no basements in Florida part. I thought all the stone flooring was to go in upstairs baths. That not the case? If you want it on the first floor, you're almost certainly talking about a concrete slab as I remember my Florida days.

My opinion; worth price charged.

06-02-2006, 10:01 PM
i asked my builder the joists are i - joists 24" on center.

what shud i do ?



07-02-2006, 07:27 PM
as i had posted earlier i need to know if i can install marble in the bathroom of the house we're building. the bathroom's size is 9' x 10'

i cant calculate deflection using the calculator here bcoz we have engineered wood i-joists that are 24" OC and the longest unsupported span is 19' - from what i measured from the garage underneath the bathroom. :scratch:

what is the verdict on my joists? engineer bob please weigh in.

the subfloor is 3/4" OSB(manufactured by advantech), so for any natural stone i wud need to add another layer. what shud that be? plywood or durock or wonderboard? how thick? what about the additional height - how will i squeeze that in? how will things change if i use ditra? so many words, so many possibilities :crazy:

help! i really need the expert's opinion here



07-02-2006, 08:37 PM
Hey Nams, sorry about the delay. I'm looking through some specs on eng. I beams right now...The single layer 3/4" I believe will fly with Ditra just fine so long as you meet the deflection criteria...l/360 tile or L/720 for stone,

How new is the house? Do you have any info /p[lans ect that would give you some original data on the calcs ?

07-02-2006, 09:14 PM
Hi, Nams. I merged your post with your previous thread on the subject. Please don't start new threads with each question, but keep all the questions for the project on one thread so everyone who wants to help or learn can keep up with the history. If you don't get a response in a day or so, just make another post and bump the thread to the top of the queue. That'll work, no matter how old it gets. :)

I see you and your builder are still not providing the necessary information here. That because he won't give it to you, or you just don't want us to know? :D

We must know the particulars on the joists you have in order to give you any meaningful information on their suitability for the stone installation. I'm gonna guess, since your builder was only willing to install ceramic tile initially, that the floor structure was designed no more rigid than that. And the fact that you have 24" spacing is gonna make me guess that your floor is not designed for the requisite L/720 deflection criterion that is the industry standard for the natural stone. It's possible, but it's very unlikely.

I think it much more likely that your joist system was designed at no more than L/480, and may be under that. Nearly any good builder these days will go higher than the minimum L/360 with engineered floors with that kind of span. But you never know until you check - which you must do.

Even if your joist structure is suitable, or if you elect to lay the stone without regard to that requirement, your subfloor must have an additional layer of plywood, correctly installed, and then some sort of tiling substrate. No substrate manufacturer I'm aware of is gonna specify his product for natural stone over a single-layer of subflooring. Gotta have more plywood, preferably at least a half-inch.

My opinion; worth price charged.

07-03-2006, 07:56 AM
thanks for the reply CX and Trask.

in my previous post i told u all i knew about the floor and those joists. they are 24" OC, longest unsupported span is 19'

if there's any other info u need tell me what it is and i will try to find out from my builder.

i think i agree with the requirement for more plywood. how do i install it - with its grain perpendicular to the direction of joists.

and how do we address the issue of added height?

thanks again


07-03-2006, 08:16 AM
You gotta have the manufacturer's name, model number, and size to make any determination on the joists, Nams.

The additional layer of plywood must be oriented perpendicular to the direction of the joists. Best done using the method described here. (

Transitions for differences in finished floor height depends somewhat upon where the transition is being made (door, doorway, open area, etc.) and the type of floor you're adjoining. It's always a manageable issue in one way or another.

My opinion; worth price charged.

07-03-2006, 08:26 AM
TRUS JOIST is the manufacturer's name, model no. is Silent Floor TJI 360, joist depth is 11 7/8" deep, installed 24" OC, longest unsupported span as per what i measured from the garage is 20'.

when i read thru the manufacturer's site i saw that these joists had been manufactured for deflection levels of L/480.

i need 720 - how do i get there?

07-03-2006, 08:36 AM
From my post #5:Well, the builder should know right off the top of his head what the design of the second floor is, especially if it's a plan he's built before. Prolly knows if he can give you an L/720 there at this stage of the game, too. You axe him?

Once construction is complete, it's highly unlikely you'll be in a position to stiffen the floor to that spec easily, though. Depends upon the layout of the first floor and the joist structure and all. He could do it during framing, but after that I think you'll wanna live with what you got.About the only thing you can do at this point is add a support beam under, and perpendicular to, the existing joist structure. You'd need to call TrussJoist, give them the existing floor plan above the joists and ask them where the support could be placed if you're not willing to put it in the center of the span.

How high is the garage ceiling below?

My opinion; worth price charged.

07-03-2006, 08:43 AM
i have 9'4" ceilings on the first floor so i am guessing my garage is that height too!

i will speak with the builder today.

can u not open a branch in central florida cx, that wud be gr8

07-25-2006, 08:23 AM
i have a copy of the engineering package from my builder.

in the section about the floor joists, there is a lot of information which i think can help us determine the stiffness ofour floors. problem is its all greek and latin to me!

are we looking for a table called design controls?

what is the info i shud be looking for?

please help!

07-26-2006, 07:23 AM
Nams, from the data you've already provided and the Trus-Joist data sheet in the Liberry, I can tell that your floor won't meet the L/720 requirement for stone floors. The current plan meets L/360, which is standard residential construction. To meet the L/720 criteria, you need to install these I-joists every 12" apart.