I am installing a toilet in a new location in an existing home and have found that there is a floor joist right where the flange under the floor is to be located. | am going to cut the floor joist and install a header to re support the floor and want to know how much distance I should leave for the flange bell to make sure there is no interference. I know that the center line of the flange is 12 inches from the wall (finished or rough framing?) and I would estimate that I should leave 4 more inches to make sure I am clear. Does anyone know for sure?

Thanks!

The rough-in is 12 inches from the finished wall but you can cheat a 1/2 inch and get by with it, some people will tell you that you can cheat a little more but I have found out that it depends on what brand of commode you buy.
I would leave at least six inches between the two headers that you are going to put in, also if I were doing it in my house I would double the headers, and also use joist hangers on the two ends of the headers and also on the floor joist that you cut.

The rough-in is 12 inches from the finished wall but you can cheat a 1/2 inch and get by with it, some people will tell you that you can cheat a little more but I have found out that it depends on what brand of commode you buy.
I would leave at least six inches between the two headers that you are going to put in, also if I were doing it in my house I would double the headers, and also use joist hangers on the two ends of the headers and also on the floor joist that you cut.

Thanks for your reply. I was going to use a double support for the header already but for those who don't know it is very good advice. I assume that when you mentioned using two headers that you were meaning that you would frame in front of and behind the flange for the toilet. I wasn't going to do that - I was just going to put one in front of the toilet. Now that you mention it though it seems like a good idea as it is a very good location to have extra strong framing.

Thanks again!