The best approach when installing cement board or other tile backer around a tub is to keep the cement board out of the lip area.
Drywall around tub edge.
Above the lip of the tub.
A bathtub s flange or rim adjoins the surrounding bathroom surfaces.
It is 13 pounds lighter than other varieties for the same size and thickness.
Rough framing for tub is 60 tub is 60.
How to drywall around tub edge.
Apply it to the wall with the bottom edge about 1 4 in.
Leave a 1 8 inch gap between the bottom edge of the drywall sheet and the surface.
Water easily degrades drywall so you must seal the edges to prevent.
I generally will use a 3x6 white subway type tile but it can be whatever you want really.
Now remove the tear off strip for a clean finished edge.
2 if the wall flanges are flush or further back then that then you can install a tile border around the perimeter.
Hopefully that picture is clear enough.
How i finish the surrounding walls and bath tub drywall.
Then apply a generous amount of thin set to the bottom bathtub tile and position it 1 8 in.
If weight is still a concern consider ultra light half inch drywall.
Finishing drywall around a shower flange.
So after you add drywall your down to 59.
The thickest of all the types of drywall 5 8 inch drywall is often fire resistant drywall.
To prevent moisture intrusion caulk the gap between the shower bead and the shower bath unit.
Position the cut piece of water resistant drywall horizontally against the bathtub s rear wall and rest its bottom edge on the lip of the bathtub ledge.
Then mud and tape to the edge of the tub surround and finish just like drywall.
For additional protection lay a bead of caulk onto the shower tub flange and embed the support leg of the shower bead in it as shown.
Generally the surfaces around the bathtub are tiled which provides superior water resistance and are easy to clean.
But some bathtubs have drywall surrounds.
Make sure the bottom side edge of the drywall sheet extends down over the thin lip of the tub s mounting flange.
Make certain the sheet is held level then secure the piece to the wall framing using drywall screws typically spaced approximately 8 inches apart and 2 inches inside the drywall edges.