Install Outside Clean Out in Main Sewer

Hi!
I have experienced some roots in my main sewer line and was adviced by a plummer to install an outside clean out and snake the line from there.
Yesterday, I located the sewer line and it seems to be a 4-inch iron pipe, or possibly galvanized pipe. They are coupled together and I can see roots trying to get in there.
Does anyone have any advice of how to do this?
Could I cut the pipe with a metal saw and install a vertical piece with a cover to use for future clean outs.
I was thinking of renting a snake with a root cutter tip.
Thanks for any help!

It could be cast-iron. If it is you could cut a section out and rework it with PVC.

Back in my digging days we would set up 2 cleanouts served by opposite wye's with street 45's turned up with cleanout caps.

This way when the cable was dropped down either cleanout, there was no debating which way that cable was heading. They make a uni-directional cleanout tee that will work but most times when the drain is clogged, you can't see that.

You go entirely off how the cable glides in that pipe as your running the machine. The cable usually rubs against the opposite side you're trying to clear.

Thanks!
Would I insert a piece of PVC and connect it to the cast-iron using No-Hub Clamps? Would the PVC fit perfectly with this or any other type of connection? I assume the PVC would not fit inside the Cast Iron.

Thanks for any responses!
Fredrik

RUGGED said:

It could be cast-iron. If it is you could cut a section out and rework it with PVC.

Back in my digging days we would set up 2 cleanouts served by opposite wye's with street 45's turned up with cleanout caps.

This way when the cable was dropped down either cleanout, there was no debating which way that cable was heading. They make a uni-directional cleanout tee that will work but most times when the drain is clogged, you can't see that.

You go entirely off how the cable glides in that pipe as your running the machine. The cable usually rubs against the opposite side you're trying to clear.

Click to expand...

The inside diameter of the pipes is the same, only the outside are different. Now, that doesn't account for any accumulated crud that may be in the existing pipe, though.

Concrete Pipes To PVC

So after 3 more hours of digging last night, I found the root of the problem...yes, roots!!!
Also, I found that the beginning of the pipe that comes out from the foundation is 4 inch cast iron, it is then connected to a thicker concrete-like pipe.
The first piece makes a 90 degree turn and then each piece is about 3 feet long, the outside diameter is about 5.5 inches and each connection has some roots going into it.
My plan is to install the clean-out next to the cast iron, and then replace the next 3-4 sections of concrete with 4 inch PVC based on your advice using the no-hub clamps.
My problem now is, how do I connect between PVC and the concrete pipe?
I attached a couple of pictures of the CI to Concrete and the 90 degree bend and also the Concrete to Concrete part.