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Eliminate Ponding Water on Your Flat Roof

Oct 19, 2015 | Roofing Services

When you have a flat roof on a building or house, building and maintaining the roof is necessary to avoid long-term problems. Flat roofs are notorious for having areas where ponding occurs, and we’re going to discuss some of the problems that can occur with that ponding and what you can do about it.

Ponding Water on a Portland Flat Roof

Having a flat roof on any structure can be a maintenance nightmare. And adding to the problem is the situation when a flat roof holds water. There are many problems that can occur with ponding water, so let’s explore a few. First, water can be hefty, and that extra weight that water can bring with it can cause disastrous results to the structure of the building. The weight can cause areas to fail and sink more, adding more weight and further compounding the problem. This weight can be wrong for the structure, the foundation, and the roofing membrane. In some cases, they could cause catastrophic failure altogether.

Tapered Insulation roof plan to divert water to drains

In addition to the structural problems that standing water can attribute to are other problems like insect breeding opportunities, debris buildup situations, bird and animal waste collection, mold and mildew, ice buildup, and damage to the roofing membrane and drains. The number one killer of a flat roof is ice. The most dangerous thing that can happen is when the ponding water has the opportunity to freeze and for ice to break apart your roofing membrane. When the water standing on a flat roof freezes, it expands by 12%. Therefore, any areas where water has made it into the cracks of your roof will expand 12% more than what it already is.

The solution to the above problem is never to have water on the roof in the first place. Flat roofs can easily be turned into a pitch to the roof by adding components that would, in effect, ‘taper’ the roof, adding what equates to a downhill for runoff. Typically, foam or insulation will be cut to a pitched angle, and water will be diverted to the drains. This requires some forethought, and a plan must be drawn up so that the insulation can be ordered appropriately and installed later. An insulation plan, like the one to the right, will give you an excellent water runoff, with little or no standing water. A Portland roofing contractor can provide a professional estimate and layout for this water diversion system. Usually, this is done when a new roof is installed.

Ponding water does not need to be something that you live with. With a roof taper appropriately designed for your home or business, all the water can go down the drains, eliminating any weight, insect breeding areas, ice dams, or stagnant water odors. In addition, because foam is lightweight, you’ll add very little weight to your existing structure. Accompany this with a new PVC membrane roofing system, and you will have a lifetime-warranted maintenance-free roofing system.



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