septic riser - drilling into tank for baseplate/adaptor ring?

[WIHD]

Looking to install a septic riser. Issue is one has to 'drill' into the top of the tank to install the concrete anchor bolts which hold the adaptor ring (see pic)

Our septic is prob 40 years old, we are concerned about drilling into the top of of the tank to install these bolts.

Don't want to drill then have the tank crack or something God awful.....any insight here? Is this something I should be concerned about?

Thanks for any input. Calling the company and asking about this was of no help.
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[OccupantRJ]

I would be hesitant also. I saw a service guy poke a locator rod clean through a concrete distribution box that had all but dissolved. Could the top of the tank be pressure washed, allowed to dry, then the ring bonded in place with plenty of suitable construction adhesive?

 

[manwithtools]

Yep, just bond it to the tank with adhesive. The surrounding soil once backfilled will keep it from moving laterally. Proper adhesive or mastic should keep it from floating.

 

[dcg9381]

Looking to install a septic riser. Issue is one has to 'drill' into the top of the tank to install the concrete anchor bolts which hold the adaptor ring

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What's the existing access port? Even the old *** systems I see usually have a > 24" access port.. I'd build a riser there (maybe pour my own concrete) - or build it out of steel. I'd hesitate to drill the existing tank too, let along cut a 24" hole.

 

[no704]

5200?

 

[PCustoms]

If you're worried about drilling the top then shouldn't you be looking at fixing the tank?

I'd drill it all day

 

[jack stand]

I agree with the backfill keeping it in place just fine in the yard or most situations.
Heck I built my riser out of PT lumber (12" +/-) and none of my mowers have ever caused it to move around.
At our previous house I used a cast manhole and riser and it never was attached in any manner. Just the backfill.
This timeline is 30 years between the 2 and is all the proof I need.

 

[mike93lx]

I'd use glue as well, but the tank should be strong enough for a couple tapcons.

I had a tank fail a couple years ago. The inspector easily pushed a probing rod right through the top. No issues with screwing a riser to the new $10k poly tank

 

[PCustoms]

No issues with screwing a riser to the new $10k poly tank

Damn, you could have bought the tank, a mini ex and plenty of beverages to diy at that price!

https://www.homedepot.com/p/VPC-1500-Gal-Yellow-Polyethylene-Two-Compartment-Septic-Tank-87-41760/328984559

 

[mike93lx]

Damn, you could have bought the tank, a mini ex and plenty of beverages to diy at that price!

https://www.homedepot.com/p/VPC-1500-Gal-Yellow-Polyethylene-Two-Compartment-Septic-Tank-87-41760/328984559

I seriously considered it. If I had a shop to store a mini in, I probably would have

 

[Cheep]

Set it in place, dump a bag of readycrete and back fill.

 

[WIHD]

What's the existing access port? Even the old *** systems I see usually have a > 24" access port.. I'd build a riser there (maybe pour my own concrete) - or build it out of steel. I'd hesitate to drill the existing tank too, let along cut a 24" hole.

huge concrete lid you have to dig up every few years on the circular access port. riser system would replace that per post 1.

 

[WIHD]

If you're worried about drilling the top then shouldn't you be looking at fixing the tank?

I'd drill it all day

? nothing wrong w/ the tank, being proactive when drilling 40ish year old concrete (?), why not prevent a bigger issue by putting thought in before hand - the point of the thread

 

[WIHD]

Set it in place, dump a bag of readycrete and back fill.

this is about where I've landed. set it in place, seal to surface, readymix around perimeter then backfill. still researching a bit....

 

[JohnX14]

I was going to say similar, concrete riser and mortar it to the tank

 

[PCustoms]

? nothing wrong w/ the tank, being proactive when drilling 40ish year old concrete (?), why not prevent a bigger issue by putting thought in before hand - the point of the thread

My point was it's fine to drill.

If it's crumbly or shouldn't be drilled for some other reason then you need to be focused on replacing the tank

 

[Hooked]

Consider waiting until the next time you need to dig it up then replace the lid(s) with access port already installed. I had to do that last fall when both lids collapsed while having some concrete work done.

As for attaching the access riser. On my old ones I used a section of 12" pvc pipe and attached it using mortar mix.

 

[dcg9381]

huge concrete lid you have to dig up every few years on the circular access port. riser system would replace that per post 1.

Got it. I didn't understand that the riser goes around the lid. If the purpose is just inspecting/pumping, can't you "rebuild' the huge concrete lid, add a (smaller) riser to that and not have to drill the tank?

 

[firebirdparts]

The lid might be a separate piece, and thus if it cracks it really wouldn't hurt anything.

 

[WIHD]

My point was it's fine to drill.

If it's crumbly or shouldn't be drilled for some other reason then you need to be focused on replacing the tank

thanks. Like working on an old vehicle and trying to loosen a bolt then it 'snaps' etc. I guess in age and time I try to think through a bit more (go slower) as to not create a bigger problem.

Anyway, 100 degree temps this week so may wait a minute to get this in motion.

 

[WIHD]

To clarify...I've already dug the lid up multiple times since owning the home to have the septic pumped. Its a huge circular concrete lid. Sure, I can do that every few years when it needs to be pumped, but last time the lid looked like it was getting a crack....and, this seemed like a meaningful solution as lid is 8-12" underground. I just don't want to create a bigger headache in any way which is why I asked etc.

Thanks for all the replies.

 

[a_thiel24]

Just added plastic risers to mine a few months ago. The septic tank/pumping company recommended a butyl rope to seal the new riser to the old tank. Put the butyl down, set the riser on, and give it some nice, even pressure and then you're good to backfill.

 

[WIHD]

Just added plastic risers to mine a few months ago. The septic tank/pumping company recommended a butyl rope to seal the new riser to the old tank. Put the butyl down, set the riser on, and give it some nice, even pressure and then you're good to backfill.

thanks yes most kits come with it in some form though I plan to beef it up etc.