rotten window frame - roof master

How to Prevent Rotten Window Frames

It is common to find a rotten window frame in old homes, especially in wet climates. Rot can develop in window frames due to various reasons. Any wood left exposed to the elements without suitable treatment leads to rot formation.

Wood is a porous material. Therefore, moisture can easily penetrate the small gaps or cracks on the surface, causing it to rot. This can lead to mold growth, which harms your house and poses a health threat. 

The article looks at the causes of window frame rot and how to prevent it.

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Why Does Rot Happen?

Most windows are engineered to endure the test of time and external elements. Nevertheless, some window frames might start showing signs of decay before expected. Here are various factors that cause your window frames to rot.

Water Damage

One of the leading causes of rotten window frames is water damage, whether from extreme weather or other external factors. For example, installing your A/C system directly on top of your window can lead to the disintegration of the window frame over time. 


If you want to uphold your window frame performance irrespective of when you fitted them, maintaining a certain level of upkeep is vital. Window frames rot due to various reasons, but one of the most leading causes is pests.

A termite infestation is destructive, but it might be too late when you notice the deterioration. To ensure durable window frames, the best thing you can do is be proactive about their maintenance.


Most window frames come with a small, precise opening at the bottom known as a weep hole. The essential feature diverts the water from the sills, and you should always keep it clear.

How to Prevent Window Frame Rot

Window frame designs add to the appeal of your house. However, rotten window frames lead to poor appearance and loss of value of your home. Below are various ways to prevent your window frames from rotting.

Locate and Repair Cracks and Holes

Always inspect the window frames for tiny cracks in the surface and minor holes made by pests. Look for signs of brownish or yellowish wood that is soft to the touch and identify the rot. You will subsequently need to repair the defects to stop the window frame from rotting more.

Clean out the cracks and remove paint and rotted wood using a wood chisel. Sand the cavity with medium-grit sandpaper until its surface becomes smooth.

Mix equal measure of epoxy filler onto a plastic surface as you follow the manufacturer’s directions. Use a putty knife and press the wood filler at the edge of the dug area. 

Slightly overfill the area to permit contraction and then sand it after about fifteen minutes until the fixed location is level with the rest of the surface.

Priming, Painting, and Waterproofing

Among the best ways to prevent window frames from rotting is by painting them using three coats of primer and letting them dry thoroughly between each coat. The primer will fill gaps in a wooden frame and sturdily stick to the surface while offering a bond for the paint to adhere to.

Additionally, apply two coats of exterior, weather-resistant latex paint to the window frame and allow it to dry thoroughly between each coat. Latex paint thwarts rotting since it dries fast to a flexible finish. Latex also allows for contraction and expansion as a result of different weather conditions without cracking.

Finally, prevent your window frames from rotting by painting them using numerous coats of waterproof wood sealer per the manufacturer’s directives. Wood frame sealers halt the absorption of wetness by the wood that otherwise would cause it to expand and contract, causing the paint to break up and peel away.

How to Repair a Rotting Window Frame

It is possible to repair a rotten window frame before the damage extends over the entire building. Here are the steps to follow when fixing a rotten window frame.

Assess the Damage

Not all window frame rots are visible, but the best way to assess the damage is by probing it using a flat-head screwdriver.

Remove the Rotten Material

After the assessment, use a knife or a flat-head screwdriver to scrape out the rotten wood or cut off the affected part. Dig deeper through the decaying wood until you reveal the healthy part of the wood.

Drill Holes and Apply a Wood Consolidator

Drill small and evenly spaced holes into the healthy wood for the filler to hold securely onto the wood. Dust off the debris and apply the consolidant to the affected areas using the manufacturer’s guidelines. Please fill all the drilled holes as you give it time for absorption before applying the second coat.

Apply the Filler

Smear the filler on the affected parts as you mold it to fit into the shape of the window frames. Use a putty knife to firmly press the filler in and allow it to dry.

Smooth Out the Repair

Use rough-grit sandpaper or a sanding block to level out the surface once the filler is dry. Remember to clean away the dust and wood leftovers using a dry rag.

Prime and Paint

Prime the area and give it time to dry. You can then apply one to three coats of paint depending on the results you intend to achieve.

Final Words

Rot can harm your window frames and affect the insulation level and overall appearance of your house. Therefore, addressing the issue on time will save you a lot of money on energy bills or costly repairs. If you are not sure about the degree of the rot, seek help from an expert at Roof Master.

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