Water Management Part 1: Roof Drainage System

By Ben Golden

This week’s blog will be the first post in a 3-part series focusing on the importance of water management around your home or building. Basic water management systems prevent damage, such as foundation cracks, structural movement, leaks, interior water intrusion, and rotting building materials. You would be surprised how frequently these systems are not addressed until the damage has been done. With the aim of helping you take control of your home’s inevitable water situation, here is part one of the Water Management Series:

Roof Drainage Systems:

Shedding water off the roof and away from your home is absolutely essential for the preservation of your home’s building materials and foundation. This can be achieved by installing gutters with downspouts and extensions. These gutters need to be maintained and cleaned every year for proper function.

The two pictures below demonstrate a functioning gutter system. Water moves off the roof, into the gutter, through the downspout and extension, and away from the foundation.

Now, look at the pictures below. What do you notice immediately?

The red arrows on the first picture depict where water can escape the gutter and run down the side of the home to the foundation. The second photo shows a gutter extension that did not run out far enough to bring water away from the foundation. The key ideas here is “Water held by foundation”.

Standing water around the foundation is bad for several reasons:

1) Hydrostatic Pressure:

Hydrostatic pressure is the force per unit area exerted by a liquid on an object. A real-world example that we can all use to understand what exactly this means is swimming. Have you ever noticed that the deeper you swim under water, the more pressure you feel on your eardrums? This is because of an increase in hydrostatic pressure. Your home is greatly affected by this as well. When the soil around your home is oversaturated with water, hydrostatic pressure can actually start to force your walls inward, resulting in cracks or bows. The water can also breakdown the mortar between foundation parts and can cause mineral seepage which can be a slow demise of your foundation’s stamina.

2) Expanding Soils:

Certain soils are notorious for expanding when saturated with water. Minnesota in particular tends to have “clay-like” soils which hold water and expand. The expansion of soils, such as this, can put huge amounts of pressure on a home’s foundation leading to cracks, movement, and bowing. More info on this subject will come in parts 2 & 3 of this water management series.

3) Erosion:

Heavy rainfalls or underground springs can also cause issues for your foundation. This water can actually carry away existing soils leaving your foundation unsupported causing settlement. If you have noticed uneven floors, difficulties closing doors and windows, cracking in ceilings/walls, or sinking you may have a serious erosion issue.

Hopefully, you now understand why unmanaged water around your foundation is detrimental and why a proper roof drainage system is so important. It would be beneficial to look around your home and make sure you have gutters around every roof eave. Then check out the downspouts. Do they have extensions and are they bringing water away from the home? If yes, then step one in proper water management can be checked off your list. Keep an eye out for Part 2 coming soon.