Installing a bathroom from scratch

[Brad G]

Hello all,

I am a genuine beginner and new to this message board. I am looking at installing a guest bathroom including shower in my basement; I would like to do as much of the work as possible. The room is about 6' x 10', the floor is concrete, and the ceiling joists and wall studs are currently exposed. I have 2 lines of questions for now (I am certain there will be many more to come).

First, I want to install a subfloor to match that of the adjoining room (which is based on 2'x3's) with ceramic tiles forming the final surface. Are 2'x3's sufficient? How far apart should I space them? How far apart should I screw them into the concreter (I was thinking of using tapcon screws)? What thickness of plywood should I then use?

Second, I am installing a fan to exhaust the humid air. Due to the location of the basement I need to run the duct (4" flexible) to the side of the house. My ceiling is composed of engineered I-beams (10" from top to bottom), which run perpendicular to where the duct will pass. Can I cut a 4.25" hole in the web of the I-beams without effecting their structural integrity?

Any advice would be appreciated.

Brad

[Doug Aleshire]

Brad G

1. First, I want to install a subfloor to match that of the adjoining room (which is based on 2'x3's) with ceramic tiles forming the final surface. Are 2'x3's sufficient? How far apart should I space them? How far apart should I screw them into the concreter (I was thinking of using tapcon screws)? What thickness of plywood should I then use?

2x3's are ok - spaced 16" O.C. with 3/4" plywood. Use W/T 2x3's or at least place 6 mil Vapor Barrier down over concrete then 2x3's. Tapcon's are ok.

2. http://www.lpcorp.com/productfiles/97LPIJoists263036560.061501.pdf (see page 16)

Hope this helps!

[Brad G]

Thanks for the help Doug.

[Joe.Carrick]

Hello all,

I am a genuine beginner and new to this message board. I am looking at installing a guest bathroom including shower in my basement; I would like to do as much of the work as possible. The room is about 6' x 10', the floor is concrete, and the ceiling joists and wall studs are currently exposed. I have 2 lines of questions for now (I am certain there will be many more to come).

First, I want to install a subfloor to match that of the adjoining room (which is based on 2'x3's) with ceramic tiles forming the final surface. Are 2'x3's sufficient? How far apart should I space them? How far apart should I screw them into the concreter (I was thinking of using tapcon screws)? What thickness of plywood should I then use?

Brad

A couple of things to consider:

1. You will need to first cut a trench in the concrete for the tub/shower and toilet drain lines. This plumbing must be in place before you do anything else and it must be tied into the existing sewer lines with provisions for vent pipes and drain connections to the new lav.

2. Any wood in contact with concrete must be Pressure Treated so you will probably have to use 2x4's but you could buy 2x6's and rip them to size.

Second, I am installing a fan to exhaust the humid air. Due to the location of the basement I need to run the duct (4" flexible) to the side of the house. My ceiling is composed of engineered I-beams (10" from top to bottom), which run perpendicular to where the duct will pass. Can I cut a 4.25" hole in the web of the I-beams without effecting their structural integrity?

Brad

An exhaust fan can not be legally installed with flexible duct. You need to use rigid ductwork for this purpose. If possible, put in a lower ceiling so you can run the ductwork without cutting thru the joists. You should check with the building department as to the minimum ceiling height. If you do it just over the shower you can probably go as low as 7' but for the entire room it would in most cases be a 7-1/2 ft minimum. How high is the bottom of the I-joists? You may be able to cut a 4-1/2 " hole in the webs, but it would depend on the location in the joist span. This type of hole is not advisable in the 25% of the span closest to the ends. If allowed at all, it would have to be in the center 50% of the span. Again, the building department or the I-Joist manufacturer would be the place to check. If you have to go thru the joist webs then you will want to insert the rigid duct from the outside after drilling all of the holes. Make sure you get it positioned correctly because you won't get a second chance.

A bathroom must have its own electrical circuit protected by a GFCI. You can't just tap existing circuits.