need help in getting to goal for screened porch
in a recent addition, we planned a screen porch above a study at ground level. We were to do some of the finishing work ourselves, such as the tile floor planned.
Presently we have a 3/4 OSB floor over 2x 12 joists. We have been told that to support tile and to be able to apply waterproofing, we need to use 1/2 inch cement board over the OSB. If we do that, the tile is too high for the two doors, one french 6 ft and one single 36 " which provide house access.
Question 1 is 1/2 inch cement board critical or could we get by with 1/4"?
Question 2 I assume that to insure waterproofing, we would need to install flashing between OSB and cement board onto outside wall, correct?
We would also like to use cable railing to preserve views, but I understand that perforating the tile compromises the waterproofing. Can't attach outside because of screens. Any suggestions??
Many thanks in advance