Hurricane season is once again exposing a myth about residential windows and doors — that they are completely waterproof.
The truth is, the doors and windows that protect your home from weather will leak in a wind-driven rain such as a hurricane. Most windows installed in the last five years in Central Florida have a design pressure (DP) rating of 35-50 pounds per square foot. According to the American Architectural Manufacturers Association, a window with a DP of 35 will have water intrusion in a wind-driven rain of 45 miles per hour, while one with a DP of 50 will have water intrusion in a wind-driven rain of 54 miles per hour.
The reason why windows have water intrusion in wind-driven rain is simple — you don’t install submarine windows in a home. This also means your windows will leak when your home is pressure washed or someone sprays a water hose directly into the meeting rails and crevices of the windows. To make a window totally waterproof you would have to use heavy gaskets with an extra tight locking mechanism, which would be unattractive and too difficult for most homeowners to operate.
During the winter, window companies receive a lot of calls for leaky windows, which are not leaking at all. There are thousands of homes in Central Florida that were constructed with single-pane glass and aluminum frames. The thin piece of glass or aluminum is the only thing that stands between the inside of your home and the cold air outside during winter.
On those rare Central Florida days when the temperature inside your home is warm and the temperature outside is cold, these older style windows will sweat just like a cold soda can in a warm room. Homeowners see puddles of water on their window sill or water running down their wall and mistakenly believe that the windows are leaking.
The only remedy is a set of new windows, or in some cases a dehumidifier and fan.
Look at the roof overhang on your house and the direction the doors are facing. Weather typically rolls in from the north-northeast, which is the side where most wind-driven weather events occur. An exterior door facing the north with little roof overhang is a prime candidate to leak. Wind-driven rain will penetrate the cracks between the door and jamb and in many cases wet the floor.
Homeowners will believe the door is defective, but in every case, the problem is that the door has too much exposure to rain or is poorly installed. A door should be installed plumb and level with a slight, even reveal around the door. Plumb means it’s not bowed in or out. Level means it’s even across the top. The reveal is the little gap between the door and jamb — it should be the same around the door. A door is prone to leakage if it is exposed to the north, has little overhang, and is improperly installed.
Another problem area is water intrusion underneath the door. The optimum way to install an exterior door on a cement slab is to recess the door’s threshold in the cement with a slope by the depth of the threshold (normally an inch and a half). This is done to prevent water from leaking underneath the threshold into the home.
Unfortunately, when enclosing a lanai many re-modelers set the exterior door directly on the slab with no recess. There is only a small bead of caulk, which is preventing water from rolling directly into the room. In time, caulk shrinks, the door settles, and water will leak under the door. For this type of installation to be successful, the homeowner must be diligent in keeping the door completely caulked, but few do. Throw in little to no roof overhang and you have a lanai that constantly has water coming in underneath the threshold.
Water will find a way into your home, and only through good initial building decisions and maintenance can you mitigate its effect. The quality of the installation matters just as much as the product itself when it comes to water intrusion. One myth that is true when it comes to water intrusion: water will always find the weakest point to enter your home.
Don Magruder is the CEO of RoMac Building Supply. He is also the host of the Around the House TV show on LSTV and LakeSumterTV.com at 1 and 6:30 p.m. Monday, Wednesday and Friday; at 9 a.m. and 4 p.m. Tuesday and Thursday; and at 7 a.m., Noon and 6 p.m. Saturday.