Even if the insert is installed on top of hardiebacker concrete anchors will give you the support you need for hanging a frameless door of a reasonable size and thickness.
Installing shower door in fiberglass shower.
If you have separate pieces spread construction adhesive on the bottom of the pan and set it in place.
Place the door track in the middle of the bottom door frame of the shower.
Place the rollers on the top frame flange of both door panels and secure them with lock washers and machine screws.
Place the shower enclosure in place in your bathroom.
Without moving the track use a 4 foot level to adjust the jamb until it s plumb.
There are some who would suggest that you should never install a frameless door in a fiberglass shower insert but i have done this in the past with good results.
On the side of the shower opening that will support the door hold a jamb piece against the wall so that its lower end fits into the base track.
Make sure the taller.
Put on your safety glasses.
The installation process will vary depending on whether you re installing a swinging or sliding glass door but either way you ll need to start by assembling a frame for the door.
How to install a door on a fiberglass shower.
Measure the base of the shower doorway so that you can determine the length for the bottom shower door track.
Place the glass clamp sweep into place on the door s bottom edge and secure it at the door clamp.
Screw one side of the door frame into place on one side of the shower doorway image 1 and then dry fit the other side of the frame image 2 then the top of the frame into place.
Stick a pencil through the jamb s screw holes to mark the wall.
Acrylic shower walls that install by gluing panels to drywall are not an appropriate substrate on which to install any shower door.
Secure the sides of the door.
Drive screws through the pre drilled.
Put the finishing touch on your shower door installation.
Prepare the doors by installing roller and if applicable handle towel bar hardware.
Fiberglass gelcoat is short for gel coat fiberglass reinforced polyester more popularly known as fiberglass.
Attach the door handles and any towel bars.
Place end caps on the tops of the wall channels.
Attach the seal strip to the bottom of the door and cut it to the required length.
Screw in the other side of the door frame image 3.