A roof should be an effective covering over a building, that shields it from rain, snow, sunlight, temperature, and wind. But we wish it were that simple, once designers and architects have had their day. We often wonder whether some of them understand a thing about drainage. Read on as we discuss the worst types of roof design we work with in Calgary.
Our Criteria for a Roof that Drains Successfully
The primary job of any roof is to repel moisture, so this does not enter the living space below. However, what happens to that moisture is equally important, because the overall design must lead the flow away from the building to protect the underground structure.
Overhanging eaves are part of this solution. But most modern buildings also have networks of valleys, gutters, and down pipes to control the water flow. The slope of the roof is also important, so that the water flowing down the roof matches the capacity of that network.
Unfortunately this balance is sometimes disrupted, by the aesthetic preferences of the architect, designer, or home builder. When water pools in valleys, or cascades over eaves troughs, homeowners contact Valiant Exteriors, and ask us to pop around and assess the situation.
The Worst Types of Roof Design We Encounter
- Valleys where sloping roof sections come together can accumulate too much water. They can splash some of this under the surrounding tiles, and cause damp below over time.
- A nearby chimney or skylight can worsen this situation, by damming up the water flow in the valley further. This can go even higher up the slope, and get past any membrane that may be there.
- Further problems can occur when the water reaches the end of a gully. If the flow is manageable, then the eaves troughs should cope. However, if they can’t, then the water will go who knows where.
- These three situation can worsen quite considerably, if deep snow or ice blankets the roof. That’s because the overflowing water can freeze, adding further to the bulk building up.
When We Thought Roof Design Could Not Get Worse
Just when we thought roof design could not get worse, a new client asked for advice on one of the poorest types of roof design we have seen. As you will notice in the image from Google Earth, pairs of roofs come together in channels that are impossible to widen.
Our only option was to replace the 5″ gutter with a 6″ gutter, and also use extremely large 4”x 4” steel down pipes. This solved the immediate problem.But the client had to live with a horrible design, by someone who may have never climbed up on a roof.
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