Rainwater Management, or How to Prevent Wet Attics and Stained Ceilings

As I write this, it feels like it’s been raining for a month here in Southern Ontario.  While it can be a less than wonderful task, performing a home inspection during seemingly incessant rain can expose more issues that can’t be found on a nice sunny day.  Water is the most persistent and damaging element to houses.  As an old college instructor used to say to us, “Water goes where it wants and you usually can’t stop it.  It’s much more effective to direct it safely away from the house.”  And then he’d kick my backpack because he thought it was too far into the area he wanted to stroll while yelling at us.

I recently performed a home inspection in the pouring rain.  That house had a couple of perfect examples proving the benefit of rainy day inspections.  It seems obvious to say, but the first line of defence in preventing rainwater infiltration is your roof shingles or whatever material acts as the umbrella for your home.  This particular house had decent shingles.  There were no obvious issues from the outside.  To save the suspense, there was no evidence of leakage from inside the attic. 

The sloped roof was in good shape and was shedding the rainwater to the eaves.  This is where the second part of rainwater management comes in: Eavestroughs!  (Or ‘gutters’ for our American friends.) Without eavestroughs, the rainwater will just drop off the edge of the roof landing on the ground right beside the foundation.  We don’t want a lot of water against the foundation.  Older houses were built with little to no damp-proofing on the foundation wall.  They backfill was simply dirt that will hold the water against the foundation which will soak it’s way through the foundation wall which can lead to a variety of issues including mold, rot, spalling, etc.  Further, if the ground around the foundation is saturated, there is a lot of pressure (hydrostatic pressure, to be specific) pushing against the walls.  Even with newer houses with the most modern damp-proofing methods applied, we still want to move as much water away from the foundation as possible.

Another issue with the absence of eavestroughs is wall saturation.  As the water falls off the eaves, it can hit the wall surface and windows providing more opportunity for water infiltration and the damage it causes.

Okay, so are we now convinced that eavestroughs are necessary?  Back to the house in question.  They did have eavestroughs and of course, there were downspouts, but they were completely clogged with leaves and cones from trees. The result was that they were full of water eliminating the ability to manage the rainwater effectively. When there are tall trees around your house, it is important to frequently inspect your eavestroughs and downspouts and clean them out as necessary.  On a good rainy day, grab an umbrella and walk around your house.  Have a look at the performance of the eavestroughs.  See if water is spilling over anywhere, leaking out of the eavestrough at seams, etc.


Once these eavestroughs and downspouts are clean, they will be properly bringing rainwater down from the roof to… where?  Often we see downspouts that have a short elbow directing the water a few inches away from the foundation. Perhaps there is a small pad to move the water a foot further away.  Consider the amount of water that falls on the roof.  Now consider all of that is being collected and dumped into a single spot just a foot away from your foundation wall.  This saturation can be worse than having no eavestroughs at all.  The potential for water infiltration is high.  There is also going to be some erosion.  Your topsoil can get worn away creating a pit against the foundation wall which will then collect even more rainwater.  In extreme cases, the backfill can suffer erosion around the foundation wall and footings which can lead to further structural problems.

The solution is to direct water as far from the house as possible.  At minimum, this distance should be 6 feet.  Of course, some properties are difficult to achieve this due to small yards, walkways, driveways, etc.  There is usually a solution and sometimes contractor or landscaper can provide a creative solution.

I never take for granted that people are familiar with these issues.  I take as much time as necessary to explain to my clients why these issues are important to address and offer my suggestions on how they can be corrected.  And of course if you, dear reader, would like my two cents on anything going on at your home, please feel free to get in touch and I’m happy to have a chat.

I mentioned that the home in question had a couple of issues with water infiltration.  The rainwater management was only one issue.  The other was related to the chimney that penetrated the roof, but that one can be addressed in a later blog entry.  I have to go prepare for another rainy day inspection.

Click here to contact Jason at Cherry Home Inspections in Southern Ontario if you have any questions or if you would like to book an inspection appointment.

A rainy day inspection can provide more information than a sunny day inspection. These eavestroughs were obviously clogged and in need of some maintenance.