Got asked to provide a quote to builder I work with, a new house they recently sold the new owners found out the sewer line isn't draining properly. Bad enough as it is, worse that there is a brand new garage and deck over the lines. They scoped it and found there is a hump, but not sure of exact point. About 70' of run from house to alley, 10' of driveway, 20' garage, 30' open, 10' of a deck so fairly good chance it's not in the open part. They originally wanted a quote to replace entire line, but upon seeing the garage in the way, I don't see how without tearing down the garage, removing garage pad and driveway, possibly breaking up part of basement floor if there isn't enough slope in the line. To make it worse, it's a duplex so it's really 2 garages. It's already going to be a nightmare digging with a 2 ton machine trying to get through the 3-4' of frost we have here. Unless i'm missing something, I cannot see any possible way to replace the sewer line under the garage without removing it, or at least cutting out a trench in the floor. The driveway is only about 10' long and then there's the alley. There is only 4' wide access past the garage to get into the yard so not much room to get any equipment in. Part of me wants to say i'm not interested, but I want to continue doing all of their new digs. So far I told them if they can re-scope it and pinpoint the hump, and if it's lucky and it's in the open I can quote an exact price for fixing that hump, contingent that it is the only problem.
before you do anything have the line video taped with a camera and you can see exactly whats going on and where, then you have a better idea what your dealing with..
Send in a camera so you can see the problem and have the entire run located, and get the video.
If it's a straight run with fall under the garage. And the backfill is outside the garage you could just dig the section with backfill and regrade and relay the section. If the run under the garage is in bad shape but with fall you can pipe burst it requiring both ends of the run dug up.( i would find a contracting who knows how for this ) Or just dig the whole thing up through the floor. Either way it's going to suck.
If your in Canada I'm assuming not draining properly = Frozen from the house to the low point that's holding water. What kind of depth, are there cleanouts , is the garage a floating slab, etc? Sounds like a nightmare, we have a local utility that has a compact boring machine that can do a lot of things pretty economically. It comes in handy for residential water lines and its pretty competitive compared to reclaiming landscaping, etc. Never tried to get them to do a sewer line, but I'd make some calls and pick some brains. I should clarify, is it backing up and freezing? I'd assume the main is in the alley or street and it ties into that, was this a new install or something that was existing and re-used? Look on youtube for trenchless sewer line replacement, if its under the garage, boring 20' in some manor or other shouldn't be impossible, don't get me wrong there will be a lot of screwing around, digging on both sides of the building, figuring out your elevations, etc, etc, but its possible and should be more cost effective than the alternative. If your elevations are tight replace the entire line in schedule 40 insulted pipe for some extra insurance. (Not advocating improper practices, but sometimes you gotta do what you gotta do and insulated pipe is some pretty amazing stuff) Totally understand that there are a lot of factors known and unkown in this situation and these are just some ideas without seeing it first hand
Iv sean a hydra vac under exavate 10 feet. Would really suck to do it below freezing.
Directional bore and 2 smaller holes at your connection points. Propane IR ground heaters will do a foot a day. Cover and tent at night. Figure out where the water runs!
I would definitely run a camera on it if you can go trenchless that would be the way to go since you only have to dig up to sections and that's to do the tie ins I would be curious to know how bad the hump is what size line is it 3"-4" if that is the case and if the line is freezing and if your at a 1/4" per foot and its 4" depending on what code is up there in Canada you can go 1/8" per foot that would allow you to go a little deeper and still make your connection in the alley without being to low and give you just a little more cover from freezing possibly that is if you have to dig the whole main up and fix it
Either reroute the sewer around all obstruction if possible and use an open cut method or call in a very reputable hdd company to shoot a new line on grade. I've subbed out a few sewers I couldn't dig to a friend of mine that dose directional drilling. I'd thought it never possible to install a new 8" sewer at .05% grade but I've personally seen it done. My friend did charge a very good penny to do it but told me it would work or I wouldn't pay a dime.
Can you make a force main out of it
.04% is very common on 8" sanitary lines. that's 4 tenths per hundred. not hard at all to do.
What was the outcome?