Home & Garden

About the House: A Secondary Drain Can Save You a Great Deal of Pain

By Matt Cantor
Wednesday April 08, 2009 - 06:12:00 PM

I met a very nice fellow the other day. A composer. Funny how homeowners end up being something other than just…homeowners. Neat guy, writes music for films, TV, corporate films and the like. He also had the composure of a musician, smooth and philosophical. Good thing for all those involved in selling him this house, because let me tell you, it would be very easy to be acrimonious considering the experience he’s had.  

Seems the guy just bought a house way up in the hills. Must have cost a wee bit, too. Very stylish, lots of room, views to die for, and all those things that conspire to create the oh-so-modern manse. I nearly expected to see Hef lounging before the fireplace with a few bunnies. 

About a day after the musician moved into the house, there was a bit of rain, and he noticed paint sheets scrunching up on the wall downstairs from the entryway. Then water started dripping through the ceiling. Oh my! It’s not supposed to rain inside the house! He started by doing the right thing and removing some of the sheetrock from where the water was dribbling in. (This does two things: It makes it possible to examine the area where the leak is occurring and it helps to lower the atmospheric moisture level in the space, thus decreasing the growth of funguses that eat wood and all the pulpy stuff we build houses with these days.) 

He called me up and after a short while we found the leak. Funny, it was inside the door. He’d looked for several hours and run hoses all over the place and couldn’t get it to leak. Ah, but we inspectors have the magic of hindsight working for us. I’d seen my share of leaks that began their soppy work only after a windstorm blew water under the door. We both did the happy dance (his being more subtle and artistic than mine). 

Now as entertaining as all of this stuff is, it’s not what I want to talk about. It’s the porch itself. It wasn’t why he’d called me over, but when I walked down to the front door, my face turned white. The staircase—five or six steps—had solid walls all around, except for the front door, which I will refer to as “the drain.”  

Oh, there was an actual drain in this swimming pool of an entryway, but it was small and half- clogged with caulk and a bunch of other stuff I couldn’t identify. When the dog drops his gooey tennis ball, it rolls into the unscreened drain. (That’s where drains are, you know, at the bottom of the incline, just waiting to take in a gooey tennis ball.) Then the next rainfall can easily put four feet of water right against the doorway—glug glug). But not to worry. The door doesn’t hold water all that well, so it will just drain right into the house to meet you when you get back from Maui, all tanned and relaxed. 

It got worse. From the front entry, the house was virtually all downstairs—one of those hillside beauties where you park on top and walk down to the living room and down some more to the bedroom. Glug, glug, glug. Oh. My. God.  

Now don’t get me wrong. The entire calamity had not happened—but hey, misery lies in wait just around the corner, does it not? So here’s what I had to say to our friend the musician: Please, oh please, add a “secondary drain.” It’s not the only thing I recommended, but it was the absolute priority. The porch’s plywood was rotting away and this damage extended back toward the exterior porch quite some distance. Since the porch would have to be ripped up and replaced anyway, I strongly advised him to install a secondary drain when he put the porch back together.  

Now what is a secondary drain? Is it just another drain? No, it’s different in a couple of respects. To answer the question, let’s get up on your flat roof. If you have a flat roof with some short (or not so short) walls, called parapets, around the edge, you have… a swimming pool—just like our friend’s entryway.  

I see these all the time. They’re everywhere. The code books demand (and good builders provide) secondary drains on these roofs. Secondary drains are elevated somewhat above the main drain. This often means that they are up on the parapet wall a few inches above the drain in the roof surface or the “scupper” in the bottom of the parapet wall.  

This placement means two things. First it means that nothing is going to readily clog this drain because it’s above the roof surface—things can’t fall into a hole that’s up on a wall. It also means that it will be clear and unused until that fateful day when the main drain clogs and the swimming pool starts to fill up. 

When we put these life-saving secondary drains in, we should not use a downspout. This may sound odd, but there’s a very good reason for it. When the secondary drain starts to discharge, it means that something is very wrong, so we don’t want it going about its business in a quiet, friendly way. We want it to splash on the neighbor’s house, or knock a trash can lid onto the cat. It should announce itself. Although I’ve never seen it, every secondary drain should have a set of wind chimes dangling from the spout, just to heighten the effect. You want to take notice and get up there and clear Drain Number One as soon as you can, because a flat roof with parapet walls can amass hundreds or even thousands of gallons of water when the drain clogs up. 

So, that’s what I would like our musical fellow to have—a porch with a drain, and one more drain for good measure. That secondary drain could easily prevent $100,000 worth of damage if the next surfing junket goes on long enough. 

There’s another message embedded in this experience, one that is a little harder to see but just as vital: Looking at houses is a tricky business. If you have a list of things to check, it is easy to miss the forest for the trees. Sometimes you need to back up, cross the street and just stare at the thing until it hits you. I never know what “it” is going to be, but if I slow down a little it often becomes apparent. There are no books for these things, but my clever clients often pick them out without any building education whatsoever. So when you’re looking at your house, or a new house, or a friend’s house, take a minute to sit down and look. You might just find yourself turning white and saying, “Oh. My. God.”