Our image shows the vulnerable parts of a roof, which are most likely to be where the sections join. These, as far as this particular roof goes, are the ridges, hips, and valleys.

Other ‘danger points’ include joints in the roof coverings, whether they are sheets or tiles. However, many home owners forget to include the area behind the eavestrough gutters, which is our subject for today.

Roof Splash and Guarding Against It

The force of water flowing down is a combination of volume and speed. Roof designers calculate roof slopes to allow a controlled flow of water into the eavestroughs. This means that, under normal circumstances the lines of gutters should not overflow, even at the valleys.

However, this could still happen during torrential rain. Although it should not prove a problem to the building structure, provided the roof overhangs are wide enough. However, some water may tumble down on the homeowner, tempting them to install roof splash guards.

The general idea is these raised, inner gutter corners splash the water back from the hips and valleys, to where it can harmlessly spread across the broader roof surface. The industry that supplies splash guards believes:

• This prevents the rainwater splashing the siding, windows and doors below.
• It also helps keep rainwater away from flooding flower beds and foundations.
• As a result, the proponents believe there is less water-pooling and mildew.
• And finally, there should be less rot in fascia boards, soffits and roof timbers.

Splash Guards May Not Extend Roof Life

Would that life was as simple as that! The counter-argument requires little explanation. The general idea is a roof covering extends over the gutter, so rainwater can flow harmlessly away.

However, the truth is that where this is not the case, then capillary action will draw the water over the gutter inside-edge, which is the point where many lower-roof problems begin.

We typically don’t install these devices. That’s because splash guards may force water under roof sheathing, and behind fascias during periods of heavy rain. We believe this can arguably cause more harm than letting some water overflow the gutter.

We favour taking a holistic approach to waterproofing Calgary homes. Diverting rainwater is one thing, but it begs the question ’where does the water go after that?’ Call us on (403)829-1661 to learn more about the way we solve problems, permanently. Full stop.

More Information

Seamless Gutters Should Mean That

How Sheathing Under Siding Matters

Vulnerable Parts of a Roof (Bill Bradley BY CC 3.0)