I’m in the middle of a remodel of a small bathroom and the homeowner wants me to look at another bathroom on the second floor. This is an old house (at least for L.A.) built around 1920.
They want to put in a big 3×6′ tub which will span across 5 joists which are 2x8s. Their span is approx 15′. I want to know if this is enough support for all the weight of the water plus the 200 lb. guy. The tub is cast iron which ain’t light either.
Can anyone point me to load tables for joists, or for the weight of water? I think water is 62 lbs. per cubic foot. Is this correct? Figuring 18″ of water I get a little over 1650 lbs. which will probably be less since the sides of the tub are sloped.
Any help would be greatly appreciated.
Replies
The specs for the tub oughta list the gallon capacity, and water weights 8.3 pounds per gallon. The specs also oughta list the weight of the tub itself. Add the weight of the owner and his/her sweetheart having a romantic moment and I'd say the joists sound a little light. You may be able to double some joists or maybe add steel c-channels to a few of them. Whenever I get a situation like this I run screaming to the engineer.
Thanks. Maybe I will request that he get an engineer in there to do some calculations.
Do you have experience as to how to broach that with the homeowner. Specifically, would you say something like, "I'm not sure the joists can support the weight of the tub, water and people. I'd like to have an engineer come out and give us his opinion."
That sound good?
Also, how do I go about charging for getting the engineer, etc.? Do you include an hourly fee on top for meetings, etc.? Or is this just part of getting the job?
Edited 2/17/2004 4:43:48 PM ET by workinhard
Hmmmm... I think you need to be authoritative. You're sure. "Those joists won't support the weight of the tub and we're going to need someone to specify a method of strengthening them." Personally I often give a speech about how 'there are plenty of contractors willing to double as structural engineers, and I'm not one of them.'
I have known contractors who bring in the engineer and charge the customer, and contractors who won't, stating that it's a conflict of interest. The latter makes some sense to me... the engineer answers only to the owner, therefore the contractor can't be accused of having an expensive solution designed or whatever. Actually, I'd be curious to know what others do. If you spend time on it, you should be getting paid.
You can say, "These joists are definitely not designed to handle that much weight according to normal lumber tables. We can do one of three things here"
1 - Forget this idea
2 - I double up the joists with sisters and you sign off on any problems that might show up.
3 - We hire an engineer to specify how to do it best. He might cerify a method that is even less expensive than doubling with sisters and save enough to cover his fee and give us both peace of mind.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Atta boy, Pif. Right answer for sure. And I hope for #3.
Mr. Micro, BSEngineering, Civil, emphasis structural, Case Western Reserve University, 1968
Note that I carefully word and present it so the HO would haver to be a fool not to go with #3 'cause it offers quality at a possibly cheaper price, while taking a firm stand on not overloading the existing - which areprobably overspanned already unless full 2x8 with the furr on and good grain.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I'm following. Obviously, for everyone concerned, #3 is the way to go. I get it.
They are full 2x8's, good lumber, but I wouldn't want to stress anything more than what they are. So, great tips from everyone. Let's see what the HO comes back with. If he wants to do #2, I'll probably back out of it. I don't want any part of a temp fix where the tub comes through the ceiling down the road, even if he signs off on it. He's pretty solid, though, so he may go down the engineering road. We'll see.
Thanks for the phrasing, people, much obliged. I need to work on my authoritativeness a bit.
The trick is to offer the information to get him to make the right decision. If you aren't interested in doing#2 then don't offer it and back out. phrase it to say, "Some guys would just sister some exrtra joists in here to add to the load bearing capacity, but I'm afraid to do that without an engineer's OK. It won't go crashing trhrough the floor, but you could end up with cracked ceiling finish below and a sagging floor up here in a few years. I don't want my reputatiopn tarnished by that sort of thing so why don't we call in an engineer."
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
#2 sounds iffy. A lawyer in an expensive suit will be able to make it sound like the contractor was offering an implicit endorsement of sistering the joists... "it'll probably work"... and will convince the judge that the contractor had no business asking the client to sign a waiver of liability. Get an engineer or get a client who wants their job done right.
If you really feel uncomfortable change the specs.
#2: I will sandwich the existing joists with an 1-3/4" x7-1/4" LVL on each side. LVL's will be through-bolted and glued with polyurethane adhesive.
The more "comfortable" you make the second option, the better #3 starts to look.
Jon Blakemore
Work -
I concurr - you need to get an engineer to look at this situation. But my advice is that the *owner* hire the engineer, not you. That puts the liability in his and his engineer's lap, not yours.
I'm not a contractor, but if I were, I would never offer to provide engineering expertise even from a hired consultant. If anything came back to haunt you, you could, of course go back to the engineer but why be in the middle?
Just my three cents.
...........
From Beautiful Skagit Co. Wa.
Dennis
I only recommended the engineer, but did not hire him. The HO called him, set up the appointment, etc. I met the engineer on site and talked with him and the plumber. I had the same feeling and certainly don't want to be in the middle between the HO and engineer. The engineer will specify the plan, the HO will approve it and I will build it. Works for me.
The plumber has already rerouted a couple of lines so they won't notch the existing joists. Also, the plumber was on site to tell the engineer which joists he will need to notch and where the lines are running, etc. Even with 3x material, there will be plenty of room to maneuver. Looks like I'll just have to reroute one electrical line thats running right through the middle of every joist. I haven't traced it, but it's probably running an overhead fixture somewhere on the first floor. It's romex, so it ain't as old as the house.
Sounds a bit light to me, too. My bible (Contractor's Field Guide) says 2x8's @ 16" centers are only good for 11'9" at a 60 pound live load, so I'm guessing that both the live load is higher, and since the span is greater, you've got a problem. Sistering up the joists provides some help, and good bridging (if you can get at the joists) could help a little, but basically, you may still be just spreading the load back to other framing members that are also light. What about a nice shower? Seriously, the other fellow is right, it's time to get a practical structural engineer into the act.
Andy,
What does the bible say about 2" x 6" set on 16.5" centers (yes, it is that unbelievable) joists, made of 1914 dried white pine, span is 6.5". Bathtub is a clawfoot model...weight distributed on the feet, not evenly across the floor. Bathtub is 5' feet long, cast iron. Depth is 18", width is 27", length is 5' or less for water filled portion.
Average user? 135 lbs On the rare occassion? Other user is 200 lbs
We are drawing it up as perpendicular to the joists. Anything there when you gaze into your crystal ball? :) I mean, magic constructon bible?
We are definitely sistering the joists. Is it enough?
hi jmo,
Well, the bible says you're well within the 'magic ring of safety'..such a short span, and perhaps its because I'm getting as old as the lumber, but I tend to be a lot more comfortable with older, more dense framing like what you've got there. The only problem we've run into in similar situations is when the layout of the room causes the clawfeet to rest between the joists instead of on them. We had one in a second story of an older home where the subfloor was 1x6 T&G laid diagonally, then 3/4" yellow pine flooring. Since both the flooring and the subfloor could give, we built up an area under the tub with 3/4 ply. The tile guy wasn't happy about having to work that into his job, but it spread out the load over several joists.
Apparently, rulers used to read differently than they do today. I've run into plenty of 17", 18" spacing, or just about whatever else...so much for the "old world craftsmanship". I think in some cases the carpenter just looked at the total area to be framed and divided the joists evenly accross the space.
Thanks Andy! We're going to be replacing that subfloor to spread out that weight...we'll try to get those feet on joists as well.
I don't fancy ending up in the guest bathroom riding in an old bathtub.
> Apparently, rulers used to read differently than they do today. I've run into plenty of 17", 18" spacing, or just about whatever else...
Some of that may be due to cloth tapes that would stretch, but the main reason is that before there was plywood and sheetrock, accurate spacing of joists and studs just wasn't that important. They'd sheath with solid sawn one by on a diagonal, and cut off the end that didn't quite reach the next joist.
-- J.S.
I think you've nailed it. Not only subfloor, but plaster lath and roof decking were all cut and fitted piecewise.
Good news. I've got the HO to hire an engineer. He called Boris, who was mentioned in this post and he's coming out tomorrow. I'll let you all know what he comes up with. The HO said he would switch to an acrylic tub, but after all the calculations, it still looks like he should have joists rated for 80 psf and he's only got ones rated at 60 psf. So, engineering is the answer. Hopefully he has some elegant solution.
Thanks for everyone's input and especially the wording. Made me look like a pro. I do quality work, but just don't speak with confidence sometimes.
Excellent. Best jobs are the ones where you've got the owner following your every instruction. My prediction is structural steel under the tub--got your welding shop close by, ready to cut and drill some channels?
Another happy customer!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Engineer came out today. Looks like he wants to sister the joists. He's coming back with what he wants to sister with and what the nailing pattern will be. Maybe 3x8? We'll see. Since it's under the floor and there's plenty of room in between joists, I'm guessing we don't have to go with LVLs. Is there some reason I should push for them instead of regular lumber?
Anyway, at least he'll sign off and get the permit. Then I can just tear up the floor and build it.
He'll probably specify 3x sistering that completely interferes with your plumbing!
Ny engineer always gives me two or three options and lets me weigh the installation cost. I'm betting that LVLs will be more expensive but will be the stronger choice.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Been there, done that. And in L.A., too. I can guarantee that you won't get a permit for that without an engineer's wet stamp. A good engineer will look not only at the joists, but at everything from the tub down to a couple feet below the surface of the planet. Mine had me replace part of the pier and post with a new footing in the middle of the house. The pictures of that may still be in the photo gallery on this site.
If you want a good engineer who will also pull the permit for you, I can recommend Boris Gulkarov, (323) 655-8122. He's in West Hollywood. If you can measure and draw this well enough, he might be able to do the job without the expense of a site visit.
-- J.S.
Just a question...
I agree with LVL s, and an engineer is really a great idea. What about a steel "I" beam?
Quality repairs for your home.
Aaron the Handyman
Vancouver, Canada
I agree with Pippin and many of the guys , the only thing I would add is dont give the homeowner a choice , forget about losing the job . I would just tell him my concerns and that he needs to get an enginer here before I can go any further and at his cost. same on a job like a bathroom remodel where theres a leaky roof , get the roof fixed first then ill start the job.
I hate authority figures , thats why I try to be one every once in awhile.
Dogboy
Also check out how the joists were placed and the condition they are in. they could be splitting thus reducing the load that they can carry.