Support for non-cast iron tub

el1973

Hi, trying my first DIY chat post here.

Remodeling and finishing an attic in a 1.5 story house built in the 1930's. During a previous project in the basement, we pounded out the concrete and Y'ed off the 4" main to bring a 4" drain up to the upstairs dormer along with water supply in prep for a bathroom.

The question is related to adding a bathtub upstairs and the support needed below it. We are thinking about extending the floor slightly by tying 2 of the first 2x8 joists together over the start of the stairway and adding a section of 3/4 t&g flooring. This will add about 16" of much needed floor space on the 2nd floor for a bathroom without getting below the 6' 8" stairway ceiling height requirement on the stairs.

This would mean that 1/2 the tub width (tub will be parallel to joists) would partially sit over this 36" wide stairwell opening on 2x8's probably thru bolted to the existing 2x8's. I could double them up if necessary.

I have no need to put a cast iron tub up there. I plan on finding a decent rated acrylic tub (anyone have suggestions on a model?) with a medium water height level.....say around 14" water depth. Most of these weigh like 50-75 lbs and hold around 35 gallons of water. So figure 575 pounds total with a 200 pound person in it and full of water over around 13' square area.

The tub area will basically sit over 3 doorways below and line up at the drain end with the center support of the house where the 2x8's come together ( So it's not sitting in the middle of a 15' span on an unsupported 2x8 for example). Below it are two 2x8 door headers, 2x4 walls with double top plates and at least 9 or 10 vertical 2x4's with all the jack studs and corners of walls below. These all transfer to 2x10's under the first floor.

Does anyone think this might not be enough support for a non-iron tub?

Any suggestions on how to bridge the stairway space with a few 2x8's? Is through bolting to existing 2x8's good enough as long as the bearing portion passes well over the double top wall plates on each side? I'm thinking 3 maybe 1/2" bolts staggered on each side?

el1973

I also should say the framing in this house must be some type of cedar. There aren't any markings on it, but it certainly smells like cedar when boring through it with a drill.

kaschmid3

R U gonna have til 9 for dro going to have to remove any framing in joists for plumbing

kaschmid3

R u going to have to remove any of the joists for plumbing big holes in them reduce their load capacity

oh'mike

You need to get us some sort of drawing and a photo----

We need to know the unsupported span length---and a good photo of the wood framing---cedar is weak and seldom used for structural framing---

where are you? is cedar a local wood?

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el1973

Hard to know what the framing material was....no markings. It just smells like cedar and looks pinkish in color when boring through it.

The "unsupported" length would only be around 38" on the 2x8's with all the vertical framing around the doors. There are also other perpendicular walls under this floor ....the far side of the stairway at 38" from the center line of the house and another 1st floor bathroom wall about 70" from the center line, so there are many 2x4's transferring load down to the 2x10's on the first floor under the 2x8's that will support the tub.