If there is a functionality issue with the aluminum where the joint is moving around no amount of sealant.
How to seal aluminum gutters.
If possible go with a caulk that is specifically formulated for gutters.
For sealing and joining lap seams in aluminum or vinyl gutters and downspouts we recommend a permanently flexible and water resistant sealant.
Gutter sealer comes in squeezable or in calking gun tubes and the price can run you from about 5 to 10 depending on the amount and quality.
You should never need to apply sealer to the outside of the gutter.
You can buy gutter caulking compound online.
Time after time we see the failed efforts of well intentioned diy ers head up the ladder and attempt to silicone and spray their way to success.
If your gutters are painted in another color choose a clear caulk.
Simply squeeze into cracks and holes then apply a further coating around the entire gutter joint.
Gutter sealing happens from the inside of the gutter.
One of the most common repairs we complete out in the field is to seal leaky gutters.
This old house general contractor tom silva has a fast fix for a dripping rain gutter.
In the category of professional caulking compounds the polymer and tri polymer caulks are excellent choices for repairing leaky gutters and sealing new gutter installations.
If the metal gutter parts have rusted through you can quickly and easily patch it.
Use a putty knife to spread the cement generously around.
See below for a shopping list and tools subscribe to this old house.
It creates a powerful and waterproof protective seal making it perfect for repairing not only gutters but also doorframes windows vents toys appliances gaskets weather stripping and even clothing.
This means the caulk will not shrink as it cures.
Patch small holes with roofing cement.
Allow the insides of the gutters to dry out and brush leaking seams clean.
If the hole is small you can use plastic roofing cement.
Gutter caulks are designed to work in the conditions gutters face and as such they last much longer than non gutter caulks.
Applying sealer to rain gutter joints.
If it is large use a piece of galvanized metal flashing.
Apply silicone or special gutter caulking compound along the seams on the inside and outside to seal the leaks as shown above.
A waterproof sealing product such as ge clear gutter caulk available on amazon is easy to use.