As a general rule, replacing a bathtub is NOT considered a do-it-yourself project -- especially if your changing the type and size of the tub. Changing anything means refiguring the drainlines, vents and waterlines and that can get a bit tricky and frustrating. But if your old tub is cracked or damaged and you simply wish to replace it with the same kind, then the project becomes more manageable.

Most bathtubs in mobile homes are plastic. When plastic cracks or breaks, it cannot be permanently repaired like fiberglass can. If the crack isn't too bad, the best you can do is temporarily repair it by using one of two methods.

First method is to purchase an epoxy repair kit. The biggest advantage of the epoxy kit is that the repair isn't as noticeable because the color somewhat matches the tub. The disadvantage is that it works best only on small cracks because any movement on big cracks can cause the crack to reappear.

Second method to repair a cracked plastic bathtub is to apply a piece of quick fix tub repair tape to seal the crack. The advantage of the tape is that it will move with the tub so the crack will not reappear (unless the crack runs). The disadvantage is that it looks somewhat gaudy but by gosh it does work!

If you've decided to replace your bathtub, besides the size and color you will also want to understand how and why the bottom of your tub is supported. Most plastic tubs are supported in two ways -- plastic legs or styrofoam.

Pictured to the right is a tub supported by plastic legs. If you have a sewer pipe running directly under the tub, then you will need this type of tub to make room for the pipes. The disadvantage of using a tub with legs is that the tub can creak if the subfloor under the tub isn't flat causing the legs to sit uneven. The legs have to installed into the bottom of the tub. When doing so, push them in straight or you'll risk breaking a tab that holds the legs in.

This photo on the right shows a tub that uses styrofoam for support rather than plastic legs. The styrofoam sits directly onto the floor. Overall, the styrofoam offers better support with way less creaks. Obviously the disadvantage is that you can't run pipes directly under the tub.

First shut off water to the bathtub. From underneath the tub, unscrew pipes from drain. This can be accomplished by either taking apart the p-trap (pictured right) or unscrewing the pipe directly from the tub drain itself. If your tub has an overflow, there will be another pipe going up the back of the tub to the overflow. In this case simply take apart the p-trap and the rest will come out with the tub.

Again, be sure the water is shut off to the tub. Next unscrew the waterline connections from the back of the faucet. Remove the nuts from the hot and cold nipples and slide the faucet out. Older faucets can be much more complicated to remove as the faucets themselves may have to be disassembled along with the spout and shower head.

Once the faucet is removed, next step is to get rid of the old tub surround. If the old tub surround is held in place with plastic rivets (below), cut off the head with a knife or drill them out. Then with an utility knife, cut around the edge of the tub surround to loosen the caulk. Finally, grab a corner of the surround and carefully pull it off the wall.

With the tub surround removed, the lip of the tub will be exposed. Remove all the screws from this lip.

The old bathtub should now be loose and able to be lifted out and removed from the bathroom.

Prepare the opening for the tub. First be sure that the rim support boards are set at the proper height for the new tub. Use boards longer than what's shown in the illustration to the right. Set level and secure into the studs of the wall.

Most likely your old tub had a skirt track fastened to the floor. This helps stiffen-up the skirt on the tub. If the old skirt track is in good shape, leave it. Otherwise replace it with the one that probably came with the new tub.

Nothing is more frustrating than having a water leak after the new tub is installed. The best way to head-off a leak is to install a new drain, faucet and waterline ends. Get rid of the old parts -- once removed they may never seal right again so start with new. More info on obtaining and installing the correct drain assembly can be found here.

Before setting the new bathtub in place, secure drain to tub. Again, more instructions can be found here.

With drain installed, set new tub into place. Be sure that the skirt slips into the skirt track.

Secure tub to wall by driving screw through lip into wall stud after predrilling hole. Carefully use a countersink bit to round-out hole (below) so head of screw sets about flush with the lip. Snug but DO NOT overtighten as overtightening may crack the lip of the tub.

One rule of thumb when chosing a tub surround is to buy one with the least amount of seams. The more seams you have, the more chance it will leak even if sealed with caulk that will turn gaudy in a year or so. One-piece tub surrounds like the one illustrated here are preferred over the several-piece kits. Whatever you buy, pre-fit it now. Some kits requiring cutting and that should also be done now.

Tub-surround glue available in tubes is illustrated here. Other methods of gluing include spray glue and glue troweled on from a can. Here we outlined the surround on the wall and applied beads of glue inside the outline. Next the tub surround is set into place and pushed into the beads of glue. Then the glue is 'aired' by pulling back the tub surround, waiting for 2 minutes and then reapplying. Every few minutes, give the surround a full rub-down to ensure it stays adhered to the wall.

Along with the glue, you may also wish to install plastic rivets to help secure the tub surround to the wall. First picture shows what a plastic rivet looks like. Next predrill the hole. The hole does not need to be drilled into a stud. Then put a dab of caulk in the predrilled hole and insert the rivet all the way into the hole. Finally, tap the pin flush into the head of the rivet. That's it!

With the tub secured in place and the walls up, next is the faucet. If you wish to change or upgrade your faucet, now is the time before you make new holes in your tub surround. If your faucet comes with a template, use it to mark where to drill your holes. With the faucet in this example, a 1" spade bit was used to make the holes. Two big tips -- plug your drain to keep debri from falling into it. And, measure twice, drill once!

Apply plumbers putty to the back of the faucet and insert it into the holes. Secure from the back with the enclosed nuts.

Replace faucet ends, add shut-offs and screw waterlines to faucet. If you haven't already, be sure the drain is connected.

Caulk around tub surround using bathroom silicone and let cure for 24 hours.

Hang curtain and pour yourself a hot bath!

Mark Bower owns Aberdeen Mobile Home Repair and is the author of "The Manual for Manufactured/Mobile Home Repair and Upgrade" available on this website.

The Manual for
Manufactured Home Repair & Upgrade

"Every winter my roof leaked around the swamp cooler. We even had a couple mobile home repairmen out to seal it. Nothing worked and this went on for 5 years," said Maureen of Elko, Nevada. "Then last summer I ordered The Manual and it suggested I use neoprene to seal the leak. Since then I've had no leaks at all!"