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 are 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. Wooden frames in the South, especially in Louisiana and the humid Gulf South, require maintenance due to the climate.

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

Water can seep into wood even if it has a protective surface like polyurethane or paint. The wood will absorb moisture from rain and humid air like a sponge.

If you don’t take care of your wooden window, it can swell, rot, and decay after just one heavy rain. Regular maintenance is important to prevent damage.

Our strong, hot sun

Many people choose aluminum-clad wooden windows and doors instead of standard wood for various reasons. In this situation, they use polyurethane or paint to protect the surfaces. They like the wood on the inside and can paint the outside aluminum however they like.

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 aluminum and wood can expand and contract differently, causing seams to split between them.

To bring it full circle, when it rains and water seeps into the split seams behind the aluminum cladding, the wood frames rot from the inside out. Wood windows usually do not have drainage systems. This means that any water that gets inside can end up inside 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 at 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.

rotted windowsill

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. In dry and cooler areas, metal windows are a great choice for a beautiful look that other materials can’t match. They are durable and can create a unique aesthetic. However, they’re simply not a product that can hold up in our climate, unfortunately.

In hot and humid climates, you will always need to keep an eye on windowsill rot and other damage. Regular inspections and maintenance are necessary to prevent further issues. For this reason, we advise our community’s homeowners to skip the wooden or aluminum-clad windows. We only use high-quality vinyl windows for our hot, humid climate to ensure maximum performance and efficiency.

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 frame corners are welded together with heat to create a strong barrier. This barrier cannot be achieved 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.

Posted in: Energy Efficiency Home Improvement Home Owner Advice Windows

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