How to investigate perimeter drainage

[stanigator]

What happened: water leaked through the basement walls after 27+ inches of snow followed by 6 inches of rain.

I have already hired a drainage contractor to run a camera through the storm drainage system with limited success of finding the issue. I'm thinking of running 3 garden hoses at the affected corner simultaneously to attempt reproduce the issue before hiring contractors to excavate the corner before getting a drainage contractor to reinvestigate before beefing up the perimeter drainage. That being said, there is also the possibility of further wrecking the perimeter drain in an attempt to ensure that it is the problem before excavation.

What do you think of my strategy of doublechecking the issue before the excavation?

 

[tomtheelder2020]

I have already hired a drainage contractor to run a camera through the storm drainage system with limited success of finding the issue.

What do you man by "limited success"? What did they find? Were there portions of the drain system they couldn't access?

I'm thinking of running 3 garden hoses at the affected corner simultaneously to attempt reproduce the issue before hiring contractors to excavate the corner before getting a drainage contractor to reinvestigate before beefing up the perimeter drainage. That being said, there is also the possibility of further wrecking the perimeter drain in an attempt to ensure that it is the problem before excavation.

What do you think of my strategy of doublechecking the issue before the excavation?

It seems to me that if running 3 hoses doesn't flood the area, you won't know if that is because the problem is somehow resolved or just that 3 hoses wasn't enough. If it does flood, what will you learn except that the drainage isn't adequate?

I think you need a detailed plan of the drain system showing layout, sizes and depths. That might require potholing. If the system wasn't fully accessible to the cameras, cutting into the drains at potholes for camera access might be warranted if you think there could be a blockage.

More questions. Was this snow/rain event extraordinary or had your drainage handled similar conditions in the past? Do you know for sure the basement wall have not leaked before? Has anything about the ground surface that could affect drainage changed?

Note: I don't know issues related to snow (I think we have had it here once or twice in the past 30 years) or basements (but, dang, I wish I had one) so hopefully someone more knowledgeable will chime in.

 

[stanigator]

What do you man by "limited success"? What did they find? Were there portions of the drain system they couldn't access?


It seems to me that if running 3 hoses doesn't flood the area, you won't know if that is because the problem is somehow resolved or just that 3 hoses wasn't enough. If it does flood, what will you learn except that the drainage isn't adequate?

I think you need a detailed plan of the drain system showing layout, sizes and depths. That might require potholing. If the system wasn't fully accessible to the cameras, cutting into the drains at potholes for camera access might be warranted if you think there could be a blockage.

More questions. Was this snow/rain event extraordinary or had your drainage handled similar conditions in the past? Do you know for sure the basement wall have not leaked before? Has anything about the ground surface that could affect drainage changed?

Note: I don't know issues related to snow (I think we have had it here once or twice in the past 30 years) or basements (but, dang, I wish I had one) so hopefully someone more knowledgeable will chime in.

The drainage technician wasn't able to find the cause of the leak from the camera investigation. He did recommend excavation (I'm not sure if you meant the same thing by "potholing"). But I want to double-check if this is the cause before I go through the work of excavation and beefing up the perimeter drainage. Hence asking here for second opinions.

The snow/rain event was extraordinary. However, given they will likely happen more often in the future, I want to do as much as I can to avoid having this happen again. The basement leaked before from a pump failure (it didn't fail during the weather event).

 

[Steve123]

We don't know enough about your situation to make any meaningful comment about how well your double-check will give you any meaningful insight.

3 garden hoses will likely be pretty close to the same amount of water as one garden hose unless two of them are coming from both of your neighbors.

Age of house ?
Poured concrete or CMU block basement walls ?
Any insight on exactly where the water was getting in ? (i.e through cracks in floor, through wall, between slab and wall etc ?)
You have a sump pump ? Any idea how often it runs and for how long?
Where is the sump pump relative to where you saw the water intrusion ?

 

[stanigator]

We don't know enough about your situation to make any meaningful comment about how well your double-check will give you any meaningful insight.

3 garden hoses will likely be pretty close to the same amount of water as one garden hose unless two of them are coming from both of your neighbors.

Age of house ?
Poured concrete or CMU block basement walls ?
Any insight on exactly where the water was getting in ? (i.e through cracks in floor, through wall, between slab and wall etc ?)
You have a sump pump ? Any idea how often it runs and for how long?
Where is the sump pump relative to where you saw the water intrusion ?

The house is 30 years old. I suspect the walls are poured concrete. Appears to be through the cracks in the floor. The sump pump is installed in a well just over 1 m away from the house. It runs every couple minutes for 5 minutes.

 

[Steve123]

At least with a house 30 years old, you won't have the old clay perimeter drain tiles. The plastic pipe won't break like clay, but could still get clogged with roots.
1m = one meter ? Not one mile, I hope. So sump pit is outside the house? I have never seen that in an area that freezes. Running for 5 minutes out of 7 seems like a heck of a lot. Did the drainage guy have anything to say about what you have.

But if water is coming up through cracks in the floor, I think that means your foundation is sitting in a lake when it rains, and your perimeter drain and sump pump are not doing its job.

I don't see what you would show with the 3 garden hoses.

 

[stanigator]

At least with a house 30 years old, you won't have the old clay perimeter drain tiles. The plastic pipe won't break like clay, but could still get clogged with roots.
1m = one meter ? Not one mile, I hope. So sump pit is outside the house? I have never seen that in an area that freezes. Running for 5 minutes out of 7 seems like a heck of a lot. Did the drainage guy have anything to say about what you have.

But if water is coming up through cracks in the floor, I think that means your foundation is sitting in a lake when it rains, and your perimeter drain and sump pump are not doing its job.

I don't see what you would show with the 3 garden hoses.

Yes, 1 meter. The sump pit is outside the house. The area rarely freezes though. The drainage guy couldn't find anything wrong with the storm sewage system, but without the perimeter drainage area excavated, he can't investigate further. The house is sitting on top of a local bog though if that helps with context.

 

[William01]

Hey, I am no expert, but double-checking the problem before going for excavation sounds good. Here are a few tips that I think might help you in your situation:
-Check for clogged or blocked drains: Sometimes debris or dirt can accumulate in the perimeter drains, causing water to back up. Ensure that the drains are clear and flowing properly.
-Consider using a dye test: Adding a colored dye to the garden hoses you mentioned earlier can help you trace the path of the water and identify any potential leaks or blockages along the perimeter drainage system.
-Inspect downspouts and gutters: Make sure your downspouts and gutters are clean and free from debris. Clogged gutters can contribute to water overflow, potentially affecting the basement's drainage.

 

[Jeff Handy]

I agree with checking the gutters.
They can overflow and dump water right next to the Foundation.
You can also get larger size gutters.
And downspouts need to be long enough, and properly located.
The soil may have settled, you might need to bring in some top soil to raise the grade so water is ramped away.
You can also have the leaking spots filled with epoxy or polyurethane by a waterproofing service.
If you have window wells, they might be flooding and leaking into the basement.

 

[zepper]

I suppose we can bypass the "have you considered an indoor pool" jokes, BTW