- This topic has 10 replies, 5 voices, and was last updated 20 years, 7 months ago by bungie.
12 Sep 2000 at 5:52 pm #278671MasterPlumbersKeymaster
We have a large tree in our back yard that has infilltrated our main sewer drainpipe. The roots in the pipe are quite large and we get sewage backup into our basement all the time. I need help deciding what to do about it.
Here are my 3 options given to me by different plumbers:
1. Completely dig up and remove existing sewer pipe and replace with PVC.
2. Dig up each end of existing pipe, clean out with california rod, add a 6inch outdoor cleanout, and put 4inch PVC pipe inside existing sewer pipe, which is 6inch pipe.
3. Dig down to existing pipe, add a 6inch cleanout, california rod the existing sewer pipe, and maintain once a year by snaking.
Three different options at 3 different prices.
I have no clue which one is the best way to go. Help!!
13 Sep 2000 at 12:46 am #299018Art_xyz
Best repair is #1. Next best #2. #3 is not cost effective unless you plan to sell SOON.
13 Sep 2000 at 3:40 pm #299019SylvanLMP
Personally I would never use plastic under ground UNLESS soil conditions dictate its use due to acidic conditions.
I also don’t understand how ANY “plumber” could arbitrarily say reduce a sewer line by 2 commercial sizes (6″-4″)
Sewer lines are sized by fixture units connected not just a size picked out of the air.
By increasing and decreasing any drain line your looking to create lots of flow problems with bottle necks and various scouring action reductions over sizing a drain pipe could be worse then under sizing it.
This would be my best advice to you.
Get another Licensed Master plumber to actually Size your fixture demand and NOT guess sizes.
To properly size the sewer/drain the plumber must count every fixture in your home, figure the pitch he/she will be using (normally 1/4″ per ft) and read the code book that says MINIMUM size shall be and work from there.
The key to installing a new sewer line is also the proper bed this pipe is laid on and the back fill.
Rather then guessing how much damage you have I also would contact MicroEngineering in California and see about a video inspection so you know EXACTLY how much piping has to be repaired.
I have several hundred accounts with root infiltration where I have them in the computer for a yearly cleaning with a cable and cutting heads.
Preventive maintenance works.
Plastic pipe if not properly installed is known for cracking and having dips and worse of all the drainage fitting are ALL SHORT RADIUS which causes stoppages.
I only use long lasting Cast Iron soil pipe with LONG radius fittings plus I install a clean out EVERY 50 FEET.
This way I never have a problem for lack of access.
14 Sep 2000 at 11:02 pm #299020Art_xyz
Sylvan is absolutely right about the sewer pipe sizing. You need a well qualified MASTER plumber like sylvan to come to your house and add up the fixture units of your house to determine if the sewer line can be reduced to 4″. It is very difficult and you MUST be extremely accurate in adding up the DFU’s because if it is not figured absolutely accurately you may have an EARTHQUAKE. That’s right, now you know why California has so many earthquakes, It’s not the ground faults, it’s “plumbers” reducing sewer lines from 6″ to 4″ without reguard to the EXACT DFU’s.
P.S. If you have (like the vast majority of people in California):
25 bathrooms (including toilet, lav, tub)
1 kitchen sink (with disposal and d/w)
2 laundry tubs
2 clothes washers (you need at least two for all the bath towels)
4 bar sinks
you better call sylvan and let him count the fixtures for you (hey with 25 bathrooms you can afford to pay his travel time).
BUT if you are in the minority and only have between two and six bathrooms (I’m really going out on a limb here) a 4″ sewer line is just fine.
Also, any sewer line improperly installed (including C/I) is subject to cracking and settling. As for long sweeps in plastic pipe, “plumbers” have been using them for at least twenty years now. Where have you been sylvan?
LOL at you sylvan.
15 Sep 2000 at 12:56 am #299021Art_xyz
Your welcome. When ever you get confused again I’ll be glad to enlighten.
15 Sep 2000 at 4:35 am #299022SylvanLMP
Thank you again Art.
Does this guessing sight unseen down sizing also work for roof drainage?
Up to now I had to use interpolation to convert square foot of roof area and roof pitch with an average yearly rain fall based on a ten year period to find my fixtures unit capacity on a combination system.
Can your guesstimate also work for this kind of piping sizing?
I am in the process of figuring installation of roof/storm drains on a building 150,000 TOTAL Sq. ft of storm drainage with a sanitary fixture unit factor of 4,035 on an 8″ soil stack.
What size would you reduce this to safely?
By the way this job will be inspected and the existing sewer I will be connecting to is 12″ bell and spigot
How many 4″ roof drains would be required for the larger roof 1000 1125 ft on the adjoining building? And what would be the total fixture unit demand figuring the roof is pitched @ 1/8 per ft thank you.
just give me to total gallons of this combined and ILL do the rest OK Art
Thanks LMP Art
You DA Pro
15 Sep 2000 at 10:47 am #299023Art_xyz
Actually the answer is amazingly simple. Combination sewers are ILLEGAL IN MOST PARTS OF THE COUNTRY so it is a non-issue.
P.S. I’ve heard that on an average day NYC dumps appx. 40% of its sewerage directly into the Hudson totally untreated and another 45% only partially treated. Is this true? If so, perhaps NYC should join the rest of the country and outlaw combination sewers. What do you think?
15 Sep 2000 at 1:52 pm #299024Guest
Hi, it’s me. I asked the original question. I live in Michigan, not California, and my line is 6inch because my house was built in 1953. All new construction in our area uses a 4inch diameter sewer line, and all new construction uses PVC for the sewer line, so I don’t think reducing the size of my line or using PVC is going to cause a problem in my home. I have 1 bathroom, washing machine and dishwasher. That’s it. Any comments taking into consideration this information would be appreciated.
15 Sep 2000 at 9:26 pm #299025SylvanLMP
With little fixture units connected 4″ would be adequate and sleeving should not be a problem
They also have a process of pipe relining that also proves quite well for damaged drainage systems
17 Sep 2000 at 2:12 pm #299026bungie
Just use a camera to find the cracks dig up and replace the damaged section with PVC.
Any pipe not correctly bedded will bend, crack, and break, even cast iron
Unless “150,000 TOTAL Sq. ft of storm drainage” comes in at less than 3000 fixture units an 8″ stack will not handle it.
19 Sep 2000 at 10:54 am #299027bungie
Dont reduce the sewer size.
You can just about bet somewhere up stream is a full size inlet to the sewer line, vent or inspection opening. All you need is a kid to drop a ball down the line and hit the reducer and you are screwed
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