Yankee gutters and flat roofs

[Clarence Martinn]

Back part of the House has a flat roof and no gutter on that roof because the heating system for the upstairs( which was installed Decades ago) , has the duct work too close to the roof edges. Insulated with a ton of insulation in the attic and had the pipes wrapped and taped. Recently, had the outside dug up and exterior drainage installed. That is about a Foot or so down. There is also another underground drainage at footer level. So, 2 drain tile systems..

The contractor installed about a 10 ft section of L shaped Aluminum on the Flat roof over where the Bilco door is located, so that water would not pour on the Bilco Door.

That L shaped aluminum is working great!! Keeps the water from pouring onto the Bilco door like water going over Niagara Falls !!

Now, the problem.


Heavy rain tonight, and I went into the Basement to check things out. Noticed about 4 pin hole leaks on the Basement wall, Flat roof side. I can paint over them with Drylok, but then there is the 5th leak. More like you turning on the faucet and letting it blast out !! That is in a section of basement wall that has bowed out . The old paint they must have done years ago, got pushed out of the wall about 3 inches. It's about a 2 foot by 3 foot section that needs to be ripped out and repaired.

What I would like to know, is given the fact that traditional gutters have been installed before with disastrous results, ( Flat roof caved in through the attic and crashed through the upstairs ceiling during the Winter. The direct cause was due to 2 FT of ICE build up ) ; could that L shaped metal be extended all the way over to the side of the roof where the old Gutter downspout is located? Thereby letting the water drain through that ? The way it is now, not much ice builds up on the small L piece . But, it is big enough to carry water runoff from that section of the flat roof.

[Jim Becker]

Clarence, welcome to SMC!

Given how tricky flat roof situations can be, were it me, I'd at least have a consult with a roofing specialist about possible remediation of this water situation...which clearly needs to be done based on the amount of water that's piling up against your foundation and subsequently forcing its way into your basement. Extending the deflector may very well be the solution, but even if I had to pay a little for it, expert advice is what I would seek. While folks online can easily make suggestions, the characteristics of your specific flat roof situation really have to be examined up close and personal...

[Lee Schierer]

You have multiple problems.

Bowed cement block walls are generally caused by excess water pressure pushing in the wall. You may have wasted your money putting in the shallow drain without addressing the bowed wall and checking the footer drain to see if it was clogged with soil. There are proper ways to build wall drainage and unfortunately many contractors do not know how to do this properly. Painting the walls may stop the water coming in, but the blocks are still going to fill with water.

You need to get a competent contractor to come look at your situation and develop a complete solution, for the roof, wall and drains. It likely won't be cheap.

Flat roofs are notorious for leaks and problems. Flat roofs should really never be perfectly flat. They should be sloped so they drain. There should be a structural member (2 x 6) along the edge of your flat roof that is thick enough to install gutters using screws and brackets instead of nails and ferrels. You may need to use more than the usual number of brackets with shorter screws so they don't penetrate the edge board.