How to seal a sump pit with irregular, uneven liner

[nrgopks]

I am seeking some advice on how to seal up my sump pit. I currently get condensation on the walls and floor around the pit, and in the past there has been accumulation of mold on the walls, due to about 6" of standing water in the bottom of the pit. The air also smells bad and is somewhat humid in the area around the pit, which is surrounded by a cabinet and resides in a bedroom on the lower level of the house.

The sump pit that is almost 6' deep. The pit liner is a section of black corrugated plastic pipe that was probably cut to fit and installed by the original home builder when the house was built about 6 years ago. The top of the pipe is not flush with the concrete floor and is very near to the wall, and the floor area has some irregularities. As a result, a commercial sump pit lid does not fit onto the liner. The one in the photo is just sitting loosely on the hole. I have seen others install a piece of plexiglass over the hole but in my case this would be difficult if not impossible due to the uneven floor. I was wondering of anyone has a suggestion on how to seal up this pit.

Thank you

 

[Basher]

It looks as if the commercial lid you have is sitting on a reasonably flat annulus of the corrugated pipe. If this surface is flat enough to seal, perhaps with the addition of silicone, or pliable gasket strip, then you could fabricate a two-part replacement lid (or have it made).
If it were me I would template a new design of cover by cutting out two "D" shapes of cardboard until they accurately fitted (where the current lid is sitting), and fitted closely around the pipe/cable. Then use these outlines to cut plexiglass or thick sheet neoprene rubber to fit. Taping the resulting pieces in place should provide a better seal than you have at the moment.
If you don't have the tools or the inclination to do the fabrication, you should be able to find a contractor to do it for you!

Also I would make an effort to ventilate the area with a small extractor fan to stop condensation and mold, rather than shutting stagnant moist air in the cupboard. Installing a small pipe or duct to the outside with a small fan (which could be outside the room to reduce noise) would surely greatly help reduce the condensation.

 

[nrgopks]

It looks as if the commercial lid you have is sitting on a reasonably flat annulus of the corrugated pipe. If this surface is flat enough to seal, perhaps with the addition of silicone, or pliable gasket strip, then you could fabricate a two-part replacement lid (or have it made).
If it were me I would template a new design of cover by cutting out two "D" shapes of cardboard until they accurately fitted (where the current lid is sitting), and fitted closely around the pipe/cable. Then use these outlines to cut plexiglass or thick sheet neoprene rubber to fit. Taping the resulting pieces in place should provide a better seal than you have at the moment.
If you don't have the tools or the inclination to do the fabrication, you should be able to find a contractor to do it for you!

Also I would make an effort to ventilate the area with a small extractor fan to stop condensation and mold, rather than shutting stagnant moist air in the cupboard. Installing a small pipe or duct to the outside with a small fan (which could be outside the room to reduce noise) would surely greatly help reduce the condensation.

Thank you very much, those are very helpful suggestions!