Toilet installation during renovation

I'm renovating our bathroom and as part of it adding 5/8" of subfloor and tile, so the finished floor will be close to 1" higher than it was before. The toilet is being replaced. My question relates to the mounting flange - am I better to cut the waste pipe of below the floor, add an extension and then install a new flange once the floor is in and I have the finished height, or are the flange extensions sold by Home Depot an acceptable alternative?

Thanks for any advice - Steve

An inch is probably asking too much for extensions...I'd cut it out, add the subflooring and tile. Then install the new flange. If you notch the tile for the screws when installing, you don't have to risk cracking things doing it after the tile is installed. Depending on the drain pipe (3 or 4"), with the larger, you could tile up to the edge, and use an inside mount flange. With a 3" pipe, you need to leave room around it for the flange to fit outside.

You may want to check out www.johnbridge.com before you tile. Getting the correct subfloor is critical for it to survive long-term. Assuming the 5/8" is plywood, you need something else on top of it prior to installing the tile - either a membrane (like Ditra from www.schluter.com), or a cbu (like Hardieboard, or Durock). The Ditra is about 1/8" installed, while the cbu's are about 1/4". The minimum thickness second layer of ply that is useful on a floor is 3/8". Whatever you use, make sure it has the proper glue (exposure 1 or exterior), and both sides are at least grade 'C' (i.e., no unpatched voids).

Thanks for the advice, Jim. I am planning to use Ditra on top of the 5/8" plywood. - Steve