Septic Tank Riser Project

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BillT

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Since my last thread got a little confusing, I decided to start a new one along with my progress on it. To start with my Tank is deep in the ground and the ground above it is on a slope. The Low side depth is 32 Inches down, the High, 36 Inches down., therefore I want to put a Riser on it. I went to my local supplier and I am pretty satisfied on what they have for me. A 24 Inch Wide and 24 Inch High Riser along with everything I need to complete the job. This will mean that once installed, it will be 8 Inches down from the top of the ground on the low side and I am fine with that. The area of concern is the Tank's Concrete Lid. It is 22 X 22 and would be fine if it were Round, but it's Square. Which means it measures 28 Inches from point to point diagonally, and I'm going to have a 24 Inch diameter Riser. The bottom Adapter Ring is 33 X 33 therefore will seal fine on the opening but, of course, the Concrete Lid will no longer clear.

Would it be best to cut off the corners of the Concrete Lid so it would clear? Or just leave the Concrete Lid off altogether?

Also looking for opinions on the project in general. Let me know if you all would suggest anything different.

Thanks
 

JG plumbing

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What I said before.

You don't want to try to lift a concrete lid with almost no clearance from a hole that deep. Put a lid on the riser make a metal cover that will fit down into the riser for the tank. This metal cover is a redundancy for safety.

At least I think that's what I said before, lol.
 

BillT

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OK, thanks. I had thought that's what you were referring to, but not sure. Although in my case, I would have to have a Round Metal Lid a tad less than the exact measurement of the Riser's diameter. As the 4 corners of the opening will actually be partially under the bottom Adapter Ring.

Wish I knew how to draw it out on the boards here, but we need to think of it as a round opening over a square peg.

Also, this is if and only if, we need to completely cover it. If it's just for safety's sake, I guess some of it not cover would be no issue.
 

JG plumbing

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The lid on the riser should seal the gas well enough as long as it's a snug formed fit. You could cut a rubber gasket to fit the riser and set the concrete lid onto the gasket also to help.
 
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