# Can my house support a bathroom addition?

When I bought the house, it was a 4 bedroom, 1 bath rancher with basement laundry. We have since "converted" the smallest of the 4 bedrooms to an upstairs laundry, and took the closet out to accomodate a larger master bath on the other side of the wall.

In the very near future, we would like to split the current laundry room into a second bathroom, with tub, and a small laundry space. I am confident in doing all of the work DIY, but am unsure about the structural side of things. My floor joists are 2x8 beams 16 inches on center. What do I need to consider from a structural standpoint before proceeding with this plan?

• Is the added weight your main concern? Do you have other worries? Can you add additional support in the basement? Jan 17 '20 at 20:41
• Added weight is my main concern. A tub full of water, with one or two kids in it has to be several hundred pounds at least lol. The basement ceiling is entirely opened up from a current re-wire project, so I can do whatever needs done there fairly easily. Jan 17 '20 at 20:47
• 2x8 is a small joist by modern standards but should still support a standard tub. What's the span? Jan 17 '20 at 20:55
• I think you're OK with your 2x8's, especially if the tub is going to sit across 4 joists (assuming the tub is 5 ft long). But like isherwood said, need to know the span of the joists to make a better guess, Jan 17 '20 at 22:16
• It changes the load on the joists. Instead of the 300 lb - 500 lb+ weight of a filled tub being carried by 4 or 5 joists, it will be carried by at most 3. Understand the issues trying to put a full-size bath + laundry into a 12x12 area. You should be able to calculate the total load on your joists carrying the tub. Then go to a span table using 2x8 for your joist size and 15' for the span and see where your are. I think the design standard is 40 lbs/sq ft. Jan 18 '20 at 21:59