Fibreglass tub surrounds are pre-made to fit standard size tub openings. On occasion, you can encounter an odd sized tub that requires a non-standard surround or the bathroom walls are less than the height of the surround panel and you will need to cut it to fit. When fitting the fibreglass tub surround around your bathtub, you will need to cut holes to accommodate plumbing pipes and bathtub fixtures.
Align one edge of a four-foot level with the outside corner of the bathtub. Adjust the level until the bubble is centred between the marked lines.
Run a pencil along the edge of the level to mark a reference line. Move to the other corner of the bathtub and repeat the process.
Measure the distance from one reference line to corner of the wall located at the rear corner of the bathtub with a tape measure. Compare the distance to the corresponding piece of the fibreglass tub surround. Do the same at the second reference line. Measure the height from the top of the bathtub to the ceiling at multiple points to determine the height of the wall. Measure the height of the fibreglass surround.
If the dimensions of the fibreglass surround are greater than the height of the wall or the length of the surround walls are larger than the width of your bathtub, you will need to cut the surround to fit the bathtub.
Mark the cut on the face of the fibreglass surround with a pencil at two locations. Stretch masking tape across the face of the surround, using the cut mark for the centre of the masking tape.
Align one edge of a four-foot level with the two cut marks. Draw a line along the aligned edge with a pencil.
Cut along the marked cut line using a circular saw with a carbide blade.
Remove the masking tape from the cut. Remove burrs from the cut with a fine-tooth file.
Measure the distance from the top of the bathtub to the centre of the plumbing pipe or fixture and the distance from the reference line to the centre of the plumbing pipe or fixture with a tape measure. Write the dimensions on the wall with a pencil.
Measure from the bottom of the surround with a tape measure and place a pencil mark at the centerline height of the pipe or fixture. Measure from the front edge of the surround and place a pencil mark at the distance from the reference line to the centre of the pipe or fixture.
Cover the intersecting point of the two marks with masking tape.
Drill a one-inch hole at the intersection of the two marks with a one-inch hole saw in a 3/8-inch drill.
Enlarge the hole (if required) by cutting out from the one-inch hole with a jigsaw. Keep pressure toward the tub surround to avoid the jigsaw bouncing and marring the finish of the tub surround.
Remove the masking tape from the cut area. Remove the burr left from the jigsaw with a fine-tooth file.
Wear safety glasses when cutting a fibreglass tub surround.