How do I seal a gutter?

February 12, 2025

Sealing Your Gutters: Keep Leaks at Bay with the Right Products

Leaking gutters can be a real headache. A small crack or gap might not seem like a big deal at first, but when rain starts pouring, you’ll quickly realise how much damage a leak can cause. Water can seep into your walls, damage your foundation, and create the perfect breeding ground for mould. Fixing this is much easier than dealing with the aftermath, and the good news? You don’t need to call in a professional. With the right sealant and some guidance, you’ll have your gutters sealed and watertight in no time.

Why Do Gutters Leak?

Gutters take a lot of wear and tear—harsh sun, heavy rainfall, falling branches, and the occasional backyard cricket ball. Over time, this exposure can lead to cracks, rust, or separation between gutter sections. Some of the most common reasons gutters start leaking include:

Cracks and holes from rust or impact damage.
Separated joints where sections of guttering pull apart due to movement or poor installation.
Clogged gutters that overflow and cause water to find its own escape route.
Old or failing sealant that no longer holds up against the elements.

Luckily, these issues don’t spell doom for your gutters—you just need the right approach to fix them up properly.

What You’ll Need to Seal Your Gutters

Before getting started, gather these essentials to make the job as smooth as possible:

A durable silicone sealant made for gutters, like Soudal All Purpose Silicone 300ml.
A caulking gun for even application.
A wire brush or sandpaper to clean and prep the area.
A damp cloth to wipe away dust and debris.
Gloves to protect your hands.
A sturdy ladder to access the gutters safely.

Step-by-Step Guide to Sealing Gutters

Step 1: Clean the Gutter Thoroughly

Start by removing any leaves, dirt, or debris from the area you need to seal. Scrub away rust and old, failing sealant with a wire brush or sandpaper. If the surface isn’t clean, the new sealant won’t adhere properly.

Step 2: Dry the Surface

Ensure the gutter is completely dry before applying sealant. Wet or damp surfaces will prevent the silicone from bonding effectively.

Step 3: Apply the Sealant

Using a caulking gun, apply a generous bead of Soudal All Purpose Silicone 300ml along the crack, hole, or seam. This silicone sealant bonds to aluminium, PVC, stainless steel, zinc, galvanised surfaces, timber, concrete, and more, making it ideal for gutter repairs.

Step 4: Smooth the Sealant

Use your gloved finger or a sealant tool to smooth out the silicone, ensuring it covers the entire area with no gaps or air pockets.

Step 5: Let It Cure

Allow the sealant to cure fully before testing with water. Silicone sealants usually take around 24 hours to set properly, but always check the manufacturer’s instructions for specific curing times.

Step 6: Test for Leaks

After the sealant has fully cured, pour some water into the gutter and check for any leaks. If needed, apply a second layer for extra security.

Why Soudal All Purpose Silicone 300ml Is the Ideal Gutter Sealant

Not all sealants are created equal, especially when dealing with tough outdoor conditions. Soudal All Purpose Silicone 300ml offers some key benefits that make it perfect for gutters:

Weatherproof & waterproof – Resists water, rain, and extreme weather conditions.
Superior adhesion – Bonds to most common building materials.
UV resistant – Won’t crack or degrade under direct sunlight.
Flexible & durable – Allows for slight gutter movements without breaking.
Low odour – More pleasant to use compared to strong-smelling alternatives.
Anti-mould properties – Prevents mould and mildew build-up inside your gutters.

Prevent Future Gutter Leaks

Once your gutters are sealed properly, a little maintenance will keep them in top shape. Clean them regularly to prevent clogs, check for signs of wear and tear after storms, and apply a fresh layer of sealant every few years to reinforce joints.

With a bit of effort now, you can avoid hefty repair bills later and keep your home protected against water damage. And if you need the right sealant and tools, Strathalbyn H Hardware has you covered.

Happy sealing!
Candeece