How to fix wood rot around windows | Treatment guide

Last Updated: 5 September 2022

accoya wood windowsIn the past, wooden windows have simultaneously been a point of pride and annoyance for Cheshire homeowners. While their classic aesthetic is undeniably appealing, especially within heritage homes and period properties, the natural process of rotting can sometimes still prove to be a persistent pest.

So, what should one do in the event of wood rot within your windows? We at Reddish Joinery have put together this complete guide to treatment for wood rot.

Why does rot occur in wooden windows?

Before delving into the nitty gritty of rot preventative measures and fixes, it’s worth highlighting why wooden windows are susceptible to rot in the first place. Simply put, timber and water are not good friends.

If not properly maintained or protected, when rainfall or any type of moisture lands on the surface of your wooden window’s sills, it’ll find its way into any available cracks and gaps, eventually going on to break down the established cell structure of the wood.

Though not completely absent, the original 19th-century windows were constructed using old growth wood, making rot less likely to occur.

Because of the ever-increasing demand, modern wooden windows are unfortunately engineered using lesser materials and methods, requiring extra efforts on behalf of the homeowner to better fend off the risk of moisture infestation.

However, this is not the case with Reddish Joinery’s wooden windows, sourcing our timber from either African Sapele hardwood or engineered Accoya.

Airtight units that prevent the build-up of moisture

Giving all our customer’s wooden windows a fighting chance against rot from the very start, each member of the Reddish Joinery team has been specially trained to install units to be as airtight as possible. Effective wood rot treatment is essential in maintaining the health of your window. An equally vital method of reducing the risks of rattles, draughts, and general poor insulation levels, such a stringent approach to fitting will help minimalise moisture impact too.

There’s no avoiding that your windows will get wet from time to time, but the secret to preventing rot is to let it dry out. To achieve this, our modern wooden windows incorporate trickle vents internally that allow concentrated air to flow through, letting the soaked wood easily dry. This is something previously not possible with original timber frames.
Window in a state of disrepair

How to fix wood rot around windows

You will need:

• Chisel or a wide screwdriver
• Drill with a ¼ inch bit
• Wet rot wood hardener and wood filler (Ronseal do both)
• A plastic or metal knife
• Brush
• Paintbrush, wood paint & painter’s tape
• Various grades of sandpaper

Method for wood rot repair on windows

1. Determine the amount of rot

Your first step is to identify the rot and the amount of rotten wood there is. If there is an excessive amount of rot (over 10% of the frame), it’s best to forget about repairs and replace the windows. This is because excessive amounts of rot will cause instability in the window frame, which poses a security risk.

2. Remove the rotted areas

Using your chisel or screwdriver, begin dislodging the rotted wood from the framing until you find the healthy wood underneath. Once you’ve finished dislodging the rot, use the brush to wipe away any leftover debris.

3. Drill some holes

Drill some holes into the healthy wood using a ¼-inch bit, spacing the holes about an inch apart. Doing this ensures that the wood filler will have a firm hold of the wood. Next, clean away any newly created dust and debris.

4. Apply the wood hardener and filler

Apply your wood hardener to the affected area and ensure to fill the holes you drilled. Leave to dry before applying a second coat. This will reinforce the wood before applying the filler.

Next, apply a generous amount of filler and mould it to the shape of the frame. Firmly press the filler into place using a plastic or metal knife and leave to dry for the amount of time recommended by the manufacturer’s instructions. Make sure the filler is dry before progressing to the next step.

5. Sand the area down

If the filler is dry, take the various grades of sandpaper and begin sanding down the repaired area so it’s level with the rest of the frame. Start with a coarse grade and progress to a smoother one for a better finish.

6. Paint the wood

Firstly, the wood paint that you use should be suitable for exterior use. For a consistent finish, make sure to use a colour that matches your current window frames too. Before you start painting, place strips of painter’s tape along the frame to protect the glass, before proceeding to paint the frames.

Although this method allows you to replace rotted wood around a window, it’s highly likely that rot will have weakened the frame, potentially compromising the security of the window. So, whilst rot repair may provide a temporary solution, we recommend replacing the windows to be certain the security of your home will be unaffected.

Is this method suitable for repairing rotted windowsills?

rotten windowsill Yes, you could use this method to repair a rotted windowsill. However, if the sill has large areas of rot, the structural integrity of the window might be compromised.

You might be able to replace a rotted windowsill yourself, although we would recommend a full window replacement by a professional installation company such as Reddish Joinery. This is primarily to ensure that it doesn’t pose a security risk.

Can I avoid wood rot around my windows?

Although, you cannot completely avoid the risk of rot from developing in traditional wooden windows there are some steps you can take to prevent the growth of wood rot.

Wipe, wipe, and wipe again

The most active thing you can do as a homeowner to keep your wooden windows rot-free is to keep a watchful eye on the frames. Should they ever suffer from even the slightest amount of moisture build-up, wipe it away straight away. Only the occasional one is needed, and it could save you a lot of hassle in the long term. Inspect for any present cracks, peels, or gaps, and where these problems do occur, sand them down and re-paint.

Where possible opt for rot-resistant wood: Accoya!

If you don’t have the time or want to regularly maintain your windows, we’d recommend having wooden windows installed using a composite material like Accoya.

Specifically engineered and treated to enhance the internal cell structure of the wood, they’re a slighter bigger investment, but one that looks just as authentic is highly sustainable and allows homeowners to enjoy the appearance of timber but the strength and performance of aluminium.
grey white accoya window front

Wooden windows that continue to look good

Reddish Joinery remain intent on giving homeowners in and around Cheshire the best chance possible of enjoying the benefits only wooden windows can offer. Take our tips on board, and we’re confident you will!

For more information, call the team today on 0161 969 7474 or send us an online message for your free, no-obligation quote.

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