Septic Tank - raising manhole/inspection cover

gramlab

Tank backed up recently. Had to dig up garden to access the inspection hatch (concrete). Don't want to dig again so I now need to raise this. Have been told to build up a few courses of blocks and put the hatch on top. Is there anywhere to get large (110x60) steel/plastic manhole covers rather than try to rest existing one on top of blocks(wont be very water tight).

Also, because opening is recessed I assume it's OK to hang the base row of blocks over the edge of the opening to allow the manhole to rest on top.

Anyone else do this before??

reilig

gramlab wrote: »

Tank backed up recently. Had to dig up garden to access the inspection hatch (concrete). Don't want to dig again so I now need to raise this. Have been told to build up a few courses of blocks and put the hatch on top. Is there anywhere to get large (110x60) steel/plastic manhole covers rather than try to rest existing one on top of blocks(wont be very water tight).

Also, because opening is recessed I assume it's OK to hang the base row of blocks over the edge of the opening to allow the manhole to rest on top.

Anyone else do this before??

That's exactly how its done, except you should use concrete bricks rather than blocks and it will save you a lot of time rather than cutting blocks. In order to make it water tight, you need to mix some concrete, put it all around the manhole and slope it up to the rim of the lid (just make sure it covers the bricks).

The existing cover should be ok if you break it out with a kango or a chisel. Otherwise, you will be able to get a new cover in any good hardware.

gramlab

Cheers

Will have to use blocks for base though as these need to overlap opening by about 1.5 inches to allow hatch to rest on bricks.

Thought there might be some sort of inspection box out there that I could use instead but no joy in finding anything.