Why recement over an interior basement drain tile system ????

[Clarence Martin]

Been watching a few of those interior Basement drain tile installation videos, and the one thing that they do, which I don't understand the purpose of doing it, is that after they pour the gravel in the trench, they pour cement over the gravel , sealing the drain tile trench closed . WHY do that ???? Why not leave the gravel exposed , so that if any water were to leak through the walls, it would drain right into the trench ???

[Lon Crosby]

Radon, humidity, water control when the drain is overwhelmed, useable space and probably a bunch more reasons depending upon the area of the country you are in.

[Ruhi Arslan]

WHY do that ???? Why not leave the gravel exposed , so that if any water were to leak through the walls, it would drain right into the trench ???
Unless there is going to be a waterfall through the wall, it will drain into the "trench" through the drain tile at the perimeter.

[Larry Fox]

I have one of those systems in my house and while I didn't ask them I suspect it is for a number of reasons - several of which Lon mentions. The only one I can add is that the work they do jack-hammering the slab is not what I will call a precision cut and I don't think anyone (myself included) wants to have an 18"-wide exposed trench filled with gravel the entire perimeter of their basement.

[scott vroom]

Been watching a few of those interior Basement drain tile installation videos, and the one thing that they do, which I don't understand the purpose of doing it, is that after they pour the gravel in the trench, they pour cement over the gravel , sealing the drain tile trench closed . WHY do that ???? Why not leave the gravel exposed , so that if any water were to leak through the walls, it would drain right into the trench ???

Not my area of expertise but isn't the purpose of the drain tile to capture water that seeps in from from an beneath an exterior footing? I'm assuming foundation walls below grade have been treated with a moisture barrier to prevent water from entering the basement walls. Makes sense to me to cap the drain tile with concrete....why would you expect standing water to collect above your basement floor?

[Clarence Martin]

Water leaks in through the Bilco doors.

[scott vroom]

Seems to me you'd want to address the leak at the Bilco doors to prevent water from entering your basement, no?

[Matt Day]

You need to address the problem at the source - the doors. Either the installation, the doors themselves, or the materials used.

I don't know if anybody who would want an exposed gravel trench in their basement. I have one of those systems, and the concrete top allows me to actually use my basement and put stuff against the wall. Who knows what kind of critters would have access to your basement then too.

[Rich Engelhardt]

Why not leave the gravel exposed , so that if any water were to leak through the walls, it would drain right into the trench ???A lot of the systems will have perforated pipe buried under the gravel and have weep holes drilled through the base of the wall with a plastic shield installed up the wall that will divert any water that comes in and send it down to the perforated pipe.
The gravel/pipe/plastic is covered with a layer of cement to keep out pests and prevent water from overflowing the trench in the event the system get's overwhelmed.

The better and more reputable companies will also trench and cover the exterior.

@ least that's the theory.
During an extremely heavy rain, the system can be overwhelmed with too much water and any weak point in the "system" will become very evident.

We lost over $1,000.00 in damaged walls and flooring this past May 12th when an unusually heavy downpour overwhelmed the "system" at one of our rentals.
The company that installed it (Ohio State Waterproofing) is coming out on July 30th to replace the "weak area" that allowed the water in.
(Good company (Ohio State). Painfully expensive - real - real painful - like $10k painful, but, they stand 100% behind their work. )(No connection to them - I'm just a satisfied customer)

[Kevin Bourque]

Most waterproofing companies use a flexible material at the floor/ wall joint, that has holes in it for water to flow down through.

ALSO: Many municipalities require any basement or crawlspace floor to be covered with concrete. This is done in part to prevent termites and other critters from getting in.