Why Do I Have A Rotted Windowsill, And What Can I Do?

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You take a look at your windows and realize there’s signs of rotting. Either you notice damage and the wood peeling apart, or your window frames are soft and discolored. Unfortunately, even the smallest signs of a rotted windowsill can point to much more extensive issues below the surface. In southern Louisiana and across the Deep South, we unfortunately run into this problem often. There’s usually a common major reason: wooden or aluminum-clad window frames. This is what causes the problem and the best way to fix it.

Why wood and aluminum clad windows rot in the Deep South

Architecturally, wooden window frames look good and they also have a historic feel to them. However, wooden frames down here in the South are not maintenance-free, especially in southern Louisiana and the humid Gulf South.

Our climate down here, such as excessive rainfall and a hot, heavy sun, take a toll on all wooden home fixtures. This makes them considerably more vulnerable to disrepair. Windows, as the barrier between your home and the outdoors, allow for even more long-term, extensive damage.

To protect wooden window frames, you need to have protective paint on them at all times and keep up to date with regular maintenance. Even then, you can run into problems that lead to a rotted windowsill. Here’s why.

Humidity and rainfall

If and when water seeps into the wood underneath the protective surface (such as polyurethane or paint), the wood will suck up all of the moisture from the rain and wet humid air like a sponge.

If your wooden window is not maintained regularly and properly even for one big rain, it could swell up, rot out, and be otherwise subject to decay.

Our strong, hot sun

Oftentimes, because of reasons mentioned above, people choose aluminum-clad wooden windows and doors as an alternative to standard wood. In this case, they use polyurethane or paint as protective surfaces, enjoy the look and feel of the wood on the inside, and can paint the exterior aluminum cladding however they want.

People mistakenly think this option is more durable. However, durability is not the only factor that comes into play. The major issue we have with these types of windows in this region is that aluminum is a conductor of heat.

When the sun is out, the aluminum on the outside gets hot. So hot, in fact, that it effectively “cooks” the wood on the inside. This causes the wood within the frame to expand during the day and contract at night. The expansion and contraction of the aluminum on the outside with the wood on the inside can cause seams to split between the two fundamentally different structures.

And then, to bring it full circle, it rains and water seeps into the split seams behind the aluminum cladding, rotting the wood frames from the inside out. Also, wood windows, rarely incorporate water evacuations into their designs, so any water that gets past the initial barrier, have nowhere to go but into the window and wall.

So while, aluminum cladded wood windows might sound great because of the lack of need to repaint, they oftentimes require complete replacement as well as water remediation work in the same time it would have taken to need a second coat of paint. With little effort, you can find many class action suits against wooden window manufacturers for this very problem.

What are the best windows for the Deep South?

High end wooden windows, while much more expensive than alternative types of windows, can be a great product. For arid cooler climates, they can be an excellent option that holds up beautifully and help achieve aesthetic that just isn’t possible with windows made of different material types in most cases. However, they’re simply not a product that can hold up in our climate unfortunately.

In climates with excessive heat and moisture, it will always be an ongoing fight against windowsill rot and additional structural damage requiring constant inspection, upkeep and finish maintenance. For this reason, we advise our community’s homeowners to skip the wooden or aluminum-clad windows. Instead, we focus on maximum performance, which means that we only install high-quality vinyl windows for our hot, humid climate.

For our Deep South climate, there’s no comparison. It’s as The Spruce points out: “In the last 25 years, wood dropped from accounting for almost half of all windows sold to less than 20%. Guess which material took wood’s place? Vinyl.”

Vinyl window frames provide durable protection for years to come. They require no ongoing maintenance. And, they’re not vulnerable to windowsill rot or damage from our hot, humid climate. The corners of all frames are thermally welded to create a complete consistent barrier that isn’t achievable with aluminum, wood, or fiberglass. You can learn more about the differences between vinyl vs. wooden windows here.

We know windows

At LAS Shutters + Windows, we’ve been crafting and installing windows in the Gulf South community for over 60 years. Our focus is building windows that work for our climate—not arid dry climates like Arizona or the cold of Wyoming.

Because of this focus, we’ve developed products that outperform our competitors. From hurricane windows that protect your home from extreme storms to beautifully functional shutters, our products are proven to last in our Deep South climate.

For a free estimate or more information about our high-quality vinyl windows, contact LAS today.

Request an Estimate from LAS

Originally posted on May 3, 2014.

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