Gutter sealant (silicone): What You NEED To Know

Are you looking to install new gutters or perhaps repair existing gutters and need gutter sealant?  Check out the below article for all the info you need to know about gutter sealant, including what it is, how to apply it, and what I believe is the best gutter sealant to use.

Sika silicone based gutter sealant
Sikaseal roof and gutter sealant are available at bunnings and most other hardware stores

What is gutter sealant?

Gutter sealant is used during roof and gutter repairs and installation.  Often silicone-based, gutter sealant is used to provide adhesion when joining gutters, downpipe fitting, and gutter end caps.  It’s also often used to install roof vents, skylights, and flashings too.

Other names for gutter sealant?

Apart from sealant, you’ll find that some refer to gutter sealant as gutter silicone, adhesive, sealer, and lastic.

What can it be used on?

Gutter sealant can be used on a number of roofing products, however, in Australia, it’s commonly used on steel roofing and gutter products such as Colorbond and BlueScope steel, including gutters, flashings, and sheet metal.  Other products sealant can be used on include aluminum, brass, copper, zinc, rigid PVC, and different types of tiles (Concrete, glazed and clay)

What colours does gutter sealant come in?

You’ll find gutter sealant comes in a range of different colours including most of the common colorbond colours.  However, with gutters, the best-suited colour is grey as this will match the inside of most colorbond and zincalume gutters.

How do you remove old gutter sealant?

There are a number of methods you can use, however from my experience I’ve found the most effective is by using an extendable stanley knife blade.  With the blade fully extended you can flex the blade and run it under the old silicone to remove it.  

Note, this is unlikely to remove all the old sealant though it will ensure you have a clean enough surface to apply the new sealant.

And as always, please be careful if you do use this method as having the stanley knife blade fully extended can be dangerous.

How do you apply gutter sealant?

So you’ve got to the stage of applying your gutter sealant.  Depending on the job you’re doing there are a couple of different ways to approach this, hence to assist I will be providing an in-depth step-by-step guide for joining gutters, installing downpipe pops, or sealing end caps.

However, in the meantime, until this is ready below are a few points to keep in mind when applying gutter sealant:

  • Always ensure the area you’re applying silicone to is dry.  If you’re doing a gutter repair and you find there is a lot of water in the gutter, then a tip is to block off the water on either side of the area you’re working on using a sponge or rag place in the gutter.  Once it’s blocked off you can then dry it out and do the repair;
  • When joining gutters and inserting a downpipe pop always put a layer of sealant in between AND on top; and
  • When rubbing in the top layer of sealant use your fingers to work in the silicon in a circular motion.  Why a circular motion you may ask?  This will ensure that the silicone is worked into the joint to ensure there are no holes or gaps in the joint.

How long does gutter sealant take to dry?

Generally, you want to allow at least 24hrs for the gutter sealant to dry, however, this time can vary depending on factors such as the temperature and humidity.

In Australia, though you’ll find it dries pretty quick due to our hotter climate.  From my experience, I’ve found sealant will become touch dry within a couple of hours.

How long does gutter sealant last?

When it comes to the longevity of gutter sealants, most sealants have a guarantee of 25 years.  However, saying this, in Australia where the climate can vary a lot during winter and summer I’ve seen sealant deteriorate quicker than this.  Therefore,  if appropriately applied I believe this to be more than 10 – 15yrs in the Australian climate.

Can you apply gutter silicone wet?

Technically, Yes, there are brands of gutter sealant that can be applied in the wet – however from the products I’ve used I’ve found these to be hard to apply and to be honest messy in doing so.

Therefore, unless it’s an emergency-type situation and it’s more of a gutter leak that you need to fix then I’d strongly recommend that you avoid applying in the wet or wait for a sunny day.

What is the best gutter sealant?

Favourite silicone based gutter sealant

When it comes to the best gutter sealant in Australia, although most sealants are similar, my preference has always been Sika silicon-based gutter sealant.  I’ve found this silicone has proved itself over time and is well priced compared to others on the market.

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