Hello all, first time poster here.
I have a septic tank where I'm trying to bring the outlet riser cover to grade level, currently it's about 6" below grade. On the inlet side of the tank, I already attached a riser extension to the existing Polylok riser to bring it to grade level. However, on the outlet side there's currently a metal riser (sorry if this isn't the right technical term, not sure what else to call it) and a manhole cover. I talked to Polylok, and they suggested getting their 24" riser adapter and the extension to bring it to grade level, but now I'm trying to figure out what the best way is to secure the Polylok riser adapter to the existing metal riser. The metal riser is about 7/8"-1" thick where the adapter would meet it, and I'll need to go through the plastic adapter and a couple layers of butyl tape, which together is about 1/2" thick. In the infinite wisdom of the previous owner, they installed the tank under the driveway, so it should be a secure enough connection to handle residential/light commercial traffic. I'm thinking perhaps some type 1 hardened thread cutting screws, but I've never had to drill into such thick metal before, and I'm not even sure where to buy these.
Thanks all.
-Eric
I have a septic tank where I'm trying to bring the outlet riser cover to grade level, currently it's about 6" below grade. On the inlet side of the tank, I already attached a riser extension to the existing Polylok riser to bring it to grade level. However, on the outlet side there's currently a metal riser (sorry if this isn't the right technical term, not sure what else to call it) and a manhole cover. I talked to Polylok, and they suggested getting their 24" riser adapter and the extension to bring it to grade level, but now I'm trying to figure out what the best way is to secure the Polylok riser adapter to the existing metal riser. The metal riser is about 7/8"-1" thick where the adapter would meet it, and I'll need to go through the plastic adapter and a couple layers of butyl tape, which together is about 1/2" thick. In the infinite wisdom of the previous owner, they installed the tank under the driveway, so it should be a secure enough connection to handle residential/light commercial traffic. I'm thinking perhaps some type 1 hardened thread cutting screws, but I've never had to drill into such thick metal before, and I'm not even sure where to buy these.
Thanks all.
-Eric
