In the process of a bathroom redo, need to tile around the tub/shower and floor. Did a complete rip out and ready to start. I have my duro-rock then seal it with redguard and then thinset and tile. All good but I also have a window on the wall to tile around that is part of the shower wall, how can I assure this area is done correctly to keep moisture, or water out ?

Well, since you are using Rdgard, that's a good start. Place a bead of polyurethane caulk around the window framing and line the framing with your cement board, making sure the caulk purges out giving you a good seal between the cbu and the window. The stool needs to be pitched back to the shower, too. Next, allow it to cure and then coat with redgard, being sure to embed fiberglass tape into the outside corners. Find some 6" fiberglass tape to use. Since the tape will be embedded into the redgard, you needn't worry about it being alkali resistant as you would if you were embedding the tape into thinset. The redgard will completely isolate the tape from the thinset.

BLJACK, TY for your immediate response and I believe I understand how to accomplish this task.

Thank you, and one thing I did not stress though, was why the polyurethane caulk. Silicone would perform the same job of creating a water tight seal, but the redgard, nor anything else, will remain stuck to silicone, so don't use silicone. Good luck and post anymore questions on this project back to this thread please so that there will be no one needing to backtrack asking questions about prep steps leading up to your next questions. If you can find any of them, Laticrete 255, Custom's Megalite or Tec's 3n1 are all outstanding non sag mortars, they have all the portland based performance characteristics in wet areas as other modified thinsets, but offer the non slip properties of mastics which continue to make them the frequently used, bad choice for wet wall installations. For grout selection, Tec's accucolor xt grout cures so dense, it won't accept a sealer, and either that or Laticrete's Permacolor grout series offer outstanding color uniformity while curing. Tec's grout is available sanded or unsanded while Laticrete's is for joints as tight as 1/16" up to 1/2". Another positive about those 2 companies is that they make a very large assortment of there grout color pallet in 100% silicone caulks, which perform much better than siliconized acrylic or latex caulks which can be found to match all grouts. That will give your inside wall corners, tub/wall intersection and tile/window intersection outstanding long lasting seals.

Good luck.

By the way, I also just looked up to see if your other 4 posts had anything to do with this bath remodel. Well, while I don't know if they do or not, if you plan to tile this floor, and it has joists 18" oc, not 16" oc, you will need to lay at least 1/2" plywood over (I'm guessing) your plank subfloor prior to installing a cement board or membrane, or if the floor has beed replaced with plywood, add 1/2" to 5/8 or add 3/8" to the 3/4 plywood, all of which is not for the mythical "You need x" of plywood for tile," but because plnak subfloor need the seasonal movement of the dimensional lumber isolated from the backer or membrane and for joists beyond 16" oc, for a single layer to be acceptable, up to 19.2" oc, you really need all the solar constellations to align just right. Safer to ad the second layer of ply than to start relying upon pagan rituals for the longevity of the installation. :)

Thanks again, here what we have accomplished. I removed all the window molding and sill. Also removed the replacement window that was there. From there I power planned the frame flush with the studs and sistered the four sides of the window frame with 2x4's. Used your poly. Caulk on all faces prior to screwing in my duro-rock (used one piece so no joints) flush with the inside of the window frame overlapping it. Got some extra wide mesh and taped all outside corners then a liberal amount of redguard. Replaced the window with a better one and will start my tile work soon. Thanks again this forum helps reassure us homeowners that we can do get things done correctly.