Tee off existing 4" drain pipe

[Rossn]

I have a surface drain system around my home for gutters, given I can't grade it properly. It is constructed of 4" SDR35 sewer pipe.

I need to tap into it for a new stand pipe, and given it is buried, the options I see are:

• use a 4"x4" rubber saddle fitting (Fernco)
• cut a section of pipe out, and replace with a section that contains a tee, using a rubber 4" coupling on each end.

Of course, being sewer/drain pipe, it has a smaller diameter, and I am concerned that will not seal well if I use the second option (will it?).

Which of these is the better option, or is there another approach I should consider, which may have better longevity?

 

[Tughillrzr]

I have a surface drain system around my home for gutters, given I can't grade it properly. It is constructed of 4" SDR35 sewer pipe.

I need to tap into it for a new stand pipe, and given it is buried, the options I see are:

• use a 4"x4" rubber saddle fitting (Fernco)
• cut a section of pipe out, and replace with a section that contains a tee, using a rubber 4" coupling on each end.

Of course, being sewer/drain pipe, it has a smaller diameter, and I am concerned that will not seal well if I use the second option (will it?).

Which of these is the better option, or is there another approach I should consider, which may have better longevity?

I have a surface drain system around my home for gutters, given I can't grade it properly. It is constructed of 4" SDR35 sewer pipe.

I need to tap into it for a new stand pipe, and given it is buried, the options I see are:

• use a 4"x4" rubber saddle fitting (Fernco)
• cut a section of pipe out, and replace with a section that contains a tee, using a rubber 4" coupling on each end.

Of course, being sewer/drain pipe, it has a smaller diameter, and I am concerned that will not seal well if I use the second option (will it?).

Which of these is the better option, or is there another approach I should consider, which may have better longevity?

either will be fine.
silicone if it’s really worries you.
I’m sure you could use a regular tee and center tee once pipe is cut. It’s for drainage purposes only?
Another option if you’d like
http://www.harcofittings.com/Products/PVC/Sewer/SDR35/sdr35_015.htm

 

[Sponsor]

 

[wwhitney]

I have a surface drain system around my home for gutters, given I can't grade it properly. It is constructed of 4" SDR35 sewer pipe.

I faced this exact question recently. What size connection do you need?

I wanted a 4" connection, and I couldn't find a saddle made for a 4" connection to 4" SDR35. If you read the details, most saddles for a 4" connection will say they are for a minimum 6" pipe size. I think I did find a saddle for a 3" connection on a 4" pipe, not sure which one that was.

So I ended up going with (2) Fernco couplings; assuming your pipe is buried, the closest fitting is 1056-44 (or the Mission equivalent). That's sized for Schedule 40 pipe (4.5" OD) rather than SDR35 (4.25" OD, I think), but cranking down on the bands should work fine. Out of an abundance of caution, I decided to use (4) glue bushings on the outside of the SDR35 pipe ends to increase the OD to 4.5". A hub cut off of a piece of hub end SDR35 pipe is the right OD. Or you can get a bushing purpose made for this, e.g.:

https://www.supplyhouse.com/Spears-P118-040-4-PVC-DWV-Adapter-Bushing

And of course if it's convenient for you to use Schedule 40 fittings/pipe for your new work, you'd only need (2) of those.

Cheers, Wayne

 

[Rossn]

Thanks, Tughillrzr - yeah forgot to mention that I'm adding a 4" to a 4"... that harco was what I was envisioning, but like Wayne mentions, it seems no one makes one that is 4x4 for SDR35. Now, Supplyhouse does have on for normal PVC, but I'm on the 4.25 sewer/drain pipe.

Wayne, perfect! I wasn't thinking about those adapters, and didn't think about using the bell end of the pipe... I have at least one of those. I guess I could also go with a normal sched 40 and extensions for the insert, but that doesn't save much in this case. I guess I have some digging ahead of me this weekend!

It's funny the variance I've seen reported in what a 4" should be able to flow at 1% grade. NDS says 135GPM. Another calculator says 73GPM. I'm not quite sure where reality lives. I'm also not sure exactly the slope they installed the pipe, but think it was around 1/8 per foot (1%). When I consider the 100 year flood intensity for my area and surface area (roof and french drain), I come up with 77 gpm. There is one point in the system, where water comes together from two different directions, shown below, at the point of full flow.

If it is going to be an issue, I could (down the road) cut it at this point, adding a parallel pipe, which would reduce the 100 flow around 14gpm and keep flow laminar, but it is not as if it would cut the flow in half. The risk of overflowing, is water entry to the home, since there is negative grade leading to the back of the home. However, with the french drain being added there is probably an extra 500-1000 gallons of reservoir. No ground absorption, since a layer of EDPM was added to flow water to the french drain.

Ross

 

[Tughillrzr]

That’s a good idea. Wayne is on top of it!!
Maybe this one as well but going back using his idea. Or riser stays pvc.
Sdr35 od 4.215
Using gasket kit ??
https://www.supplyhouse.com/Jones-Stephens-S26012-4-x-4-Saddle-Tee-Conversion-Kit-W-Gasket

 

[Rossn]

Thanks - yeah, I looked at those, and even called the company listed in the literature yesterday, and they couldn't confirm the size and if it would fit the smaller OD. Supply house didn't know either. I have to assume they are for standard 4" PVC.

Do you think the gasket would take up enough thickness to work on the sewer pipe? I see it mentions cast iron, and it loos like that is 4.4" OD (extra heavy duty has 4.5" OD).

Do you think I can structurally get away cutting a 3-1/2" hole in the drain pipe? The advantage there would be less digging (overall and underneath, where it will be harder to pack down).

 

[Tughillrzr]

Thanks - yeah, I looked at those, and even called the company listed in the literature yesterday, and they couldn't confirm the size and if it would fit the smaller OD. Supply house didn't know either. I have to assume they are for standard 4" PVC.

think you would be fine. Could order extra gasket and double up . Back fill carefully around vertical. don’t see how you’ll have any issues, .

Do you think the gasket would take up enough thickness to work on the sewer pipe? I see it mentions cast iron, and it loos like that is 4.4" OD (extra heavy duty has 4.5" OD).

Do you think I can structurally get away cutting a 3-1/2" hole in the drain pipe? The advantage there would be less digging (overall and underneath, where it will be harder to pack down).

 

[Rossn]

Finally got this gutter drain 'T-off' installed tonight.Since I didn't have the bushings readily available, I cut a coupling down the middle to increase the diameter to better fit the rubber coupling.

one more item checked off the long list!

Thanks for the support on this one!