elevated drain line under tub

[Brenda OH reregister]

Ok, so much for thinking it was getting easier to do this plumbing stuff! lol

the question: is it hard to cut and lower a drain line that is running under the tub for 4 feet, and is elevated about 4 inches above the current flooring? the flooring is shot and is being repaired/replaced. the drain line looks like it is black abs type material, maybe a 3 or 4 inch diamater? previous tub had the foam removed to make it fit, and cracked there. could there be some structure under the floor that made that the only way to put the line in? the floor damage runs out under the wall under the existing wall.

history: I am working to repair a ruined bathroom floor. Removed toilet, cut access panel to tub plumbing, found the likely leak sources (cracked tub faucet body, and an old icemaker line branching off the tub cold water faucet supply line just cut and folded over and left in laying under the tub)

found ways to deal with the odd sized quest? gray lines (I'll post that topic some other time separately grin)

when I removed the tub, found out this home still had some surprises up its sleeve.... .this is a 1986 fairmount.

the drain is in the usual place, and a stack comes off the drain. But a 3 to 4 foot section of the drain line (black color, 3 or 4 inch abs like material) runs under the tub, ABOVE THE FLOOR!

to allow the tub to fit, at some point the plastic tub bottom insulation was cut out for to make a space for it. so the bottom styroform was missing for about 4 inches wide and 3 feet long section. the tub was supported on a flimsy frame work under its front edge of 1 x2s, and a piece of wood was next to the drain line, trying to make support for the tub in the general area.

well, the "engineering" solution did not see to work out long term, the tub had cracked in that area, and had been patched with bondo. I thought the patch was why the floor had failed, but with all of the damage to the sub floor, it was really hard to tell if the leak had been focussed in that spot.

I do not want to cut the new tub foam, but I have never worked on drain lines, need to know what made someone (who may even have been the manufacturer) choose to run the drain line where it is. could there be a joist or something in the way under the line?

do I need to remove all of the flooring there to see what the heck is going on? I am not sure how to do that in a way that will not crack that drain line.

life gets weird when you are fixing mobile homes....

Brenda (OH)

[flcruising]

So the drain runs under the tub then elbows down through the floor?

I think it's time to crawl underneath and cut away that section of belly. That way you can see for yourself what's going on under there. OR, since you are replacing the subfloor, just rip it up and work from above.

[Brenda OH reregister]

well, further research found the following:

the black plastic pipe was "abs" and luckily one lowes in my area stocks it. otherwise would have had to get it at local RV store which charges $35 for a pipe that costs $7 at Lowes.

managed to get the floor out, without cracking the pipe.

may be able to nudge pipe over enough to fit new tub without cutting.

pipe was across/above the joists, I cannot tell if that was a repair decision or as designed at the factory.

also had water coming into the tub area from the wall, found one leak at the outdoor electrical outlet box, still have to see if any water coming down from the top of wall.....

now, just have to decide if I will use JDs handy dandy floor around flange replacement method, found in the archives, or let the cotractor do it his way on next Wednesday. sort of itching to do it myself and then I will know it is plenty of support especially since I plan on using the facilities during the rest of the mh rehab lol

Brenda