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Bathroom Reno - Closing up and installing the tub

posted Feb 3, 2012, 8:10 AM by Michael Dekker   [ updated Mar 16, 2012, 6:13 AM ]
Floating on air
So at this stage of my renovation, I am floating on air... well, suspended on a couple of 40 year old pieces of lumber. It wouldn't have been so bad had it not been for the fact that it was 3/8" plywood, partially rotted through, on 24" joists! The 2x4s you see on the left are for cutting up for some additional horizontal supports between the floor joists, to further reduce the bending of the plywood as we step on it. Any bowing of the flooring will result in cracked tiling, so I want to reduce it as much as I can. Since I have the floor taken apart, I may as well go the extra mile! "Ya might as well!"

Nothing to stand on
So this is what it looked like when I had most of the supports installed. The problem I ran into was the copper drains were not sloped properly... By that, I mean they did not slope down! That was the reason the tub drained so slowly! So I re-soldered some joints (that had rusted apart anyway), and added additional supports, and soon everything was ready to be closed up again.

Ceiling in need of repairs
Of course, there was one small complication... Was a little overzealous with the pry bar when we were removing the old shower-enclosing wall where all the plumbin g went. The pry bar was braced on bare drywall, where there was no 2x4, and... oops! It's OK, since I fixed it later anyway.

Subfloor installed
The real sign of progress was when the sub-floor went in. It is a 5/8" sheet of OSB followed by a 6mil poly sheet followed by a 3/4" sheet of OSB. Plenty of screws sprinkled around mean there should be absolutely no squeaking, even if it ever manages to shift. At least now I don't have to worry about taking a wrong step and landing in the room downstairs!

Insulation and vapor barrier on bathroom wall
Of course, since I had the wall taken apart anyway, I decided to beef up the insulation. Even though this is an interior wall, the insulation keeps the heat in the shower area, the poly keeps the moisture in the room with the fan, and the insulation also adds some noise reduction, to keep the sound of a shower from disturbing the people sleeping in the bedroom next door.

Floor cutout for drain cavity below tub
Toilet area floor drain cutout
Of course, now I have to cut holes in my nice new sub-floor... First one for the tub access/plumbing, and another for the toilet flange and HVAC vent. Challenging to line up the water supply pipe holes with the pipes, however you can make bigger holes. Probably should have... but <shrug>. 

And of course, next came the actual installation of the tub, and dry-fitting of the plumbing connections. According to the supplied schematics, I made the access hole the correct size for this particular model of tub, however I found it VERY cramped. Make yours larger if you can!

New tub installed and drains connected
The rebuilding of the shower wall was next, and in hindsight I would have been more careful with the positioning of the vertical beams. With 16" centres, the studs would interfere with the pipes. But with the current configuration that I made, I ran into trouble getting a drill in between the studs to cut the holes for the copper tubing! Oh well. Live and learn. One thing I did remember though is to test the tub before committing myself. Fill the tub to the overflow drain, and check for leaks. Run a hose from the outside through the window if you have to (like I did), but don't skip this step! Had a friend who bought a house, and first shower they took they turned on the water, and could hear the water running, but no water was coming through the showerhead or tub... Turns out the plumbers installed the copper, but did not solder! Nice cleanup job afterwards ;)

Shower wet-wall roughed in
Anyway, you will note the insulation tucked around the tub in the image to the upper right. I did this to reduce the heat loss through the tub walls. Who wants to lounge in their tub for 1/2 hour, only to find the water getting cold?? :)

Once you are happy with the location of the tub, mark where the feet hit the sub-floor, put a blob of mortar between some 6mil poly sheeting at those locations,then lower your tub back into place. Use a level to make sure the tub's lip is absolutely level, and make sure the tub's base drains properly. Do not step into the tub for 12 hours. This will make sure the tub will sit flat on the floor, will not rock, and will be properly levelled.

Bathtub/shower fiberboard/backerboard being installed
Bathtub/shower backerboard/fiberboard shown from inside the tub
So of course, the next step is to install the concrete backer board around the tub. Remember to separate the sheets by 1/8". This is easy to accomplish by using a couple scrap pieces of cardboard. It is remarkable how close to 1/8" it is, even after being compressed! Use the appropriate screws to install this stuff, since concrete is a pain to screw through. After you have a few screws in to hold the board up, try drilling the rest of the holes before installing the screws. It makes installing the screws far less dangerous for your fingers... I found screwing in the screws without drilling a bit hazardous, since the screws tend to twist out of line before catching, even though they are self drilling.

The next instalment will probably cover the plumbing (dreams of Mario Brothers piping nightmares), final testing of the plumbing before sealing up the wall, and tiling. The final instalment will cover the installation of the actual woodwork: the birch bathroom cabinets that I made! Oh, and some more plumbing for the sink and toilet, but those are rather straightforward, compared to what had to be done for the tub.

So until next time! Let me know what you think of the bathroom so far. I know this is a woodworking blog, but in a roundabout way, this is woodworking, isn't it?
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