How to fix a dipping flat roof that collects standing water
Flat roofs with slight dips can collect standing water and debris, leading homeowners to wonder if an expensive full tear-off is required. People are looking for cheaper overlay options or sloping methods that can redirect water away from walls without a complete replacement.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1putting something over it that angles down away from the walls
- 2digging open pits
- 3lining pits with fabric
- 4using small excavators to dig out collection areas
- 5Cleaning and clearing the debris and guards out multiple times a year
- 6Switching to large scuppers that are easier to maintain
- 7Snaking clogged downspouts
- 8installing a channel drain along the edge where it meets the grass
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“We have a large pond of water that collects in our front lawn every time we get a large rainstorm (1” rain).”source ↗
“It’s about 120 cubit feet of water in most routine storms and results in a puddle often 20 foot in diameter and as sometimes as deep as 6 inches deep.”source ↗
“Unfortunately I noticed last year during the winter time (when it was raining), water was pooling up on the roof near these gutter guards in the winter time.”source ↗
“It seems like leaves and dirt and debris were building up around and underneath these guards, preventing the water from going down the downspouts and allowing water to build up”source ↗
“I’m hoping that I can design some form of dry well to allow water to collect under the soil as it drains in the days following the storm, rather than remain surface water for a week at a time.”source ↗
“As shown in the the attached infrared image, I have some standing water in the lighter areas of my concrete driveway.”source ↗
“In the winter it pools leaving a dangerous ice patch.”source ↗
“What is the best way to speed up the drainage without modification to the driveway itself, and minimal modification to the lawn?”source ↗
“EPDM, clearly has slight dipping towards the end there that’s also collecting water and leaves. If a full tear off and install of new EPDM is required, what would you charge (MN)?”source ↗
“What would be the cheaper/easier options? Would sloping it away from the walls be the right solution, or would that still require a full tear off replacement?”source ↗
“It’s roughly 3ft by 8ft and I feel like it could be involved to tear out and could be costly. Is it possible to put something over it that angles down away from the walls?”source ↗
Where this came up
People with this problem also raised
- 5Water pooling around sprinkler head
- 9How to stop water pooling against the house from sinking concrete
- 2Why does water pool in flat bottomed sinks?
- 6How to temporarily waterproof a damaged roof until replacement
- 4Standing water in basement foundation plumbing cutout
- 3How to stop roof runoff from missing the gutter and hitting the deck