But there is one definitive downside to those flat roofs.
Flat roof has standing water.
3 use the utility knife to cut a 12 inch diameter circular patch out of the rolled asphalt roofing.
The design of a flat roof can sometimes prevent rain and precipitation water from draining properly making standing water a common problem.
Standing water on a flat rooftop is a problem since rooftops are designed to quickly drain out any water as soon as possible so it does not leak into cracks and passageways.
This is because the flat roof can hinder drainage from rainwater which results in standing water on the roof.
Ponding water on a flat roof may cause long term negative effects.
Because these roofs don t drain water that well they are prone to developing what is known as ponding water.
When the drainage system of your roof is inadequate or obstructed this will tend to keep the water on the roof especially since there is no roof slope to naturally drain the water away with the aid of gravity.
It s best to have a pitch of 0 5 12 or 1 12 that can help drain water towards the appropriate gutter systems.
There can be a host of reasons why ponds of water may appear on your roof after bouts of rain so it s important to know what remedial action to take if your property is suffering.
This often occurs following a storm heavy rain or after snowfall when the sun is out and melting the snow.
The consequences of your flat roof collecting standing water.
This means that once the rain stops you have about 2 days to get rid of the standing water or puddles that are on the roof.
If you are getting standing or ponding of water then it looks like your flat roof was installed at the foundations with an insufficient fall or the decking has not been rebated where the drip trims have been attached which created a lip that s holding the water on the roof.
Ponding water is known in the roofing community as water that stands in a puddle on the roof for more than 48 hours at a time.
One of the most common reasons why a flat roof tends to hold standing water is due to the fact that there is an ineffective drainage system.
Besides water one of the main damaging forces your roof has to stand up to is ultraviolet rays from the sun.
Another problem with leaving pooled water on your roof is the ability of water to act as a magnifying glass.
If your commercial building has a flat roof sometimes there is a problem with ponding water.
This is especially prevalent after a lot of rainstorms.
Your flat roof is built to withstand regular ultraviolet rays for many years.
After a few weeks the mold could be so significant that the wood starts to warp.
Standing or ponding water on a flat roof is defined in the roofing industry as a situation wherein water from rain melted snow or other means stands to remain on the surface of a roof for longer than 2 days.
This is because flat roofs do not drain water as effectively as their pitched counterparts.
After the 2 days the water is going to start sinking into the roof system.
Depending upon the structure you could start to see mold grow on wood.
