Repairing A Leaky Sliding Window On Your Boat

A leaky boat window is a common problem that can lead to significant damage and expenses if left unaddressed. While it may be tempting to smear caulking around the window frames, this is often ineffective and merely a waste of time. Instead, the root cause of the leak must be identified and addressed properly to prevent further issues. This may involve repairing or replacing the window frame, resealing the windows, or even redesigning the boat's structure to provide adequate support and reduce leakage.

Remove the glass from the frame

Before removing the glass from the window frame, it is important to note that the process may vary depending on the design of the window. In some cases, it may not be possible to completely remove the glass, so extra care must be taken to protect it from damage during the repair process.

If you are able to remove the glass, start by taking out the window from the frame. This will make it easier to access the glass and reduce the risk of breakage. Once the window is out, carefully detach the glass from the frame. This may require unscrewing or prying out any fasteners or seals holding the glass in place. Be gentle and use the appropriate tools to avoid damaging the glass.

If the glass is held in place by a sealant or adhesive, you will need to cut through it. A sharp craft knife or a Stanley knife can be used for this purpose. Carefully run the knife along the interface between the glass and the frame, being mindful not to scratch or damage the glass. You may need to cut through the sealant from both the inside and outside of the frame, working your way around the perimeter.

In some cases, the window frame may be held together by fishplates, which are thin strips of metal located in the bed of the channel and secured by screws. To separate the frame halves, release the fishplates by removing the screws from at least one side. Clamp one end of the frame and wrap a piece of strong, thin material (such as polyester) around a rounded filler knife. Insert the knife between the frame and glass, and gently knock the two halves apart with a mallet, being careful not to distort the frame or glass.

Once the glass is removed, clean the frame and glass surfaces thoroughly. Use a combination of washing in hot soapy water, Cif, white spirit, and meths to ensure a clean surface, free of any oil or silicone residue. This step is crucial to ensure that the new sealant or adhesive will bond properly.

Clean the window frame and glass

Before you start repairing your leaky sliding window, it's important to clean the window frame and glass thoroughly. Here's a step-by-step guide to help you through the process:

Step 1: Remove the Glass

If possible, take the glass out of the frame carefully. If the window design doesn't allow for this, make sure you protect the glass from damage during the cleaning and repair process.

Step 2: Clean the Window Frame

Use a mild, non-detergent soap or a marine-grade cleaner specifically designed for boat windows. Avoid harsh chemicals like ammonia, alcohol, and bleach, as these can damage the window frame. You can use a soft cloth or cotton fabric to wipe down the frame gently. Make sure to clean all the mating surfaces, including the fiberglass parts, and remove any corrosion with sandpaper.

Step 3: Rinse and Dry

Rinse the window frame with fresh water to remove any remaining dirt, soap residue, or cleaning solution. Use a clean, soft cloth, such as a microfiber towel, to dry the frame thoroughly.

Step 4: Clean the Glass

If you were able to remove the glass, lay it on a flat surface and clean it separately. Use a boat glass cleaner or a mild, non-detergent soap, and spray or apply it to the glass. Then, use a soft, clean cloth to wipe down the glass, working in left-to-right motions. Rinse the cloth and repeat until the glass is clean. Finally, use a new, clean cloth and warm water to remove any remaining soap residue.

Step 5: Reinstall the Glass

If you removed the glass, carefully put it back into the frame before proceeding to the next steps of the window repair process.

By following these steps, you will ensure that your window frame and glass are clean and ready for the next stages of repair, helping you achieve a high-quality result and preventing further issues down the line.

Reseal the glass and re-bed the frame

Resealing the glass and re-bedding the frame is the only real solution to a leaky boat window. This process can be lengthy and labour-intensive, but it will hopefully keep your boat watertight for years to come.

First, you need to remove the window frames from the boat. This can be a challenging task, especially if the frames are well-sealed with silicone. You'll need a screwdriver, stripping/filler knives, sharp Stanley knife blades or craft knives, blue masking tape, and duct tape.

On the outside of the boat, use blue masking tape to label each frame component and glazing pane with its window number, orientation, and whether it's left or right. This will be crucial for reassembly. Cut the silicone sealant internally with sharp blades at the window/GRP frame moulding interface. Then, go around the exterior of the frame edge with both narrow and wide stripping/filler knives, cutting into the silicone. You may need to leapfrog several scrapers around the frame perimeter, gently breaking the seal with the hull.

You can create a duct tape loop outside the boat to prevent the window frame from crashing when it pops out. Once the frames are removed, you'll need to disassemble and clean them. Ensure all surfaces are free of oil and old silicone so that the primer and new sealant can bond properly. Cut into the old butyl or sealant with a sharp blade, and clean the glass and its edges with hot soapy water, white spirit, and a solvent such as Cif.

Now, it's time to reassemble the glass into the frames. You may need to use rubber chocking to provide movement for the glass within the frame. Apply primer to the inside and outside faces of the frame/glass interface and let it set. Then, fill the frame with a two-pack butyl sealant, pressing it into the frame firmly and filling the bottom channel. Insert the glass, creating a new void around the frame, and insert rubber chocking pieces at intervals to support the glass. Force butyl into this side, working around the frame and avoiding voids. Smooth and trim the edges.

Finally, bed the refurbished frames back into the boat. Check the fit of the window and alignment of screw holes. You may need to adjust the hull window opening slightly. Apply a bead of bedding compound or sealant on the inside of the window flange, forming a doughnut shape around the screw holes. Present the window to the hull and gently press it against the hull, creating a 'witness' around the perimeter. Tighten the screws, working around the perimeter and leaving a small gap between the hull and frame. The sealant should not be completely squeezed out, or it will leak.

Use a non-hardening caulking to stop leaking

If your boat's window frames are made of black anodized or painted aluminium, you may experience leaks due to the metal's high heat conductivity. As the frames heat up in the sun, they can expand and break the caulking seal, or cause the caulking to become brittle. To prevent this, you must use a non-hardening caulking that can move with the expansion of the frames.

Non-hardening caulking, also known as soft-set caulking, is a flexible sealant that does not cure or harden completely. It is designed to remain pliable, allowing for movement and preventing leaks. This type of caulking is commonly used in applications where there is likely to be movement or vibration, such as boats, vehicles, and machinery.

When selecting a non-hardening caulking for your boat windows, look for a product that is specifically designed for marine use and is compatible with the materials of your boat, such as aluminium, fiberglass, wood, and glass. The caulking should also be able to withstand a wide temperature range and be resistant to water and UV radiation.

To apply the non-hardening caulking to your boat windows, follow these steps:

• Remove the window frame and clean all mating surfaces thoroughly. Use a solvent such as toluene, lacquer thinner, or acetone to remove any old bedding or corrosion.
• Apply the non-hardening caulking generously to the frame, making sure to fill any gaps or cracks.
• Insert shims along the edges of the frame to prevent the frame from being drawn completely flush. This will ensure that the caulking doesn't get squeezed out and provide a gasket for the frame to seal against.
• Draw the frame tight against the shims and allow the caulking to cure for a few days to a week.
• Remove the shims and retighten the fasteners. This will create a tight seal and allow for future adjustments if needed.
• Trim away any excess caulking with a razor blade, holding the blade at a 30-degree angle off of vertical.
• Finish up by applying a final glazing to the exterior of the window frame if needed.

By using a non-hardening caulking and following these steps, you can effectively stop leaks around your boat's sliding window and maintain the value and appearance of your vessel.

Use a do-it-yourself kit to repair the window

If you're looking for a more permanent solution to your leaky sliding window, you might want to consider a do-it-yourself kit. These kits are designed to provide a long-lasting solution to window leaks, increasing the life and resale value of your boat. One such kit is offered by FixLeakyBoats, which promises a "permanent repair for annoying window leaks".

The FixLeakyBoats kit includes everything you need to repair your window, including custom-fabricated marine-grade aluminium extrusions, the latest adhesive and sealant technologies, templates, outside frames, fasteners, sealant, and simple instructions. The company also offers support during the installation process if you have any questions.

Before you begin, it's important to note that you'll need to completely remove the window frames and clean all the mating surfaces thoroughly. Use toluene, lacquer thinner, or acetone to clean off any old bedding, and be sure to clean the fiberglass mating surfaces as well. If there is corrosion on the surface, sand it off completely to ensure that water doesn't wick through the aluminium oxides and ruin your efforts.

Now, let's go through the steps of using the FixLeakyBoats kit:

• Using the provided templates, mark the areas where you will drill holes for the new window frames.
• Drill the holes using a power drill, a drill bit, and a counter sink.
• Install the new window frames using the provided fasteners and follow the simple instructions included in the kit.
• Apply the sealant to the window frames, ensuring a tight seal to prevent future leaks.
• Allow the sealant to cure for the recommended amount of time before testing the window.

By following these steps and using the FixLeakyBoats kit, you can repair your leaky sliding window on your boat, improving its appearance and performance.

Frequently asked questions