Flat roofs do drain but not nearly as efficiently as a roof with any kind of pitch.
Flat roofs and rain.
For clarity flat roofs actually have a slight slope to allow rain water to drain off the roof but they seem flat when compared with more traditional steeply sloped roofs.
Flat roofs must be slightly sloped towards the middle or the edges to allow water to drain properly.
Calling this type of structure flat is a bit of a misnomer because no roof is ever really flat.
Therefore water has a tendency to puddle and remain on the roof which could lead to the roofing material breaking down or to eventual leaks particularly along the seams.
Excessive rain heavy snow and built up ice all pose extra challenges for flat roofed homes.
A rooftop garden or additional outside living space are the top reasons people choose flat roofs.
Of course this is a con.
This causes water to stand which can cause major problems.
If high winds are the cause of roof damage always wait until the winds subside before doing any work.
They are ideal for climates that don t experience large quantities of rain and moisture.
Flat roofs operate with the same basic principle but of course their lower angles mean that gravity isn t quite as effective in shedding water rapidly.
Along with the benefits of a flat roof come unique challenges.
High winds and heavy rain can damage a flat roof or cause it to leak.
Unfortunately there is no way for water to naturally drain away from flat roofs because they are flat.
Flat roofs and rain it seems go hand in hand.
Together they also lead to three problem areas for a commercial building manager to monitor.
A more appropriate name is low slope roof.
The risk of rain although called a flat roof a flat roof is actually very slightly pitched meaning that rain is able to drain away.
But it is possible to.
All roofs must be slightly sloped to allow for proper drainage.
The slope should be a minimum of 1 in 80 but in practice a minimum slope of 1 to 40 should be used to allow for deflection of the roof and for normal building tolerances.
Across wide expanses of low slope roofing natural deflection in steel or wood supporting pieces within the roof deck can cause ponding.
While not frequent per se the low slope of a flat roof does make it more prone to certain problems particularly when it interacts with the elements.
The second disadvantage is the lack of roofing material options.
Once water is able to penetrate the roofing membrane it will soak any decking and insulation.
Flat roofs have unique architectural characteristics that make them desirable in many situations.
