How to seal gap between gutter and decking roof?

[fan8956]

Hi, currently the rain will go along the edge of gutter and leak through the gap onto the decking floor. I tried to use silicone but it has nothing to hold on to. Inside the gap, it is narrow space between gutter and the wood instructure. So I need something that can
- fill and seal the gap

- good for outdoor

- easy to apply as hard to access the opening and the gap is deep inside

- reasonable price as I will need to fill this ~7m long gap

- a bit flexible as the gutter can move up and down with force

I am thinking either some kind of putty sealant so I can fill and seal it in one go, or some kind of spary foam to fill the gap then apply silicone to seal it. Do you have any recommendation please? Thanks in advance.

[EricL]

Hello @fan8956 

I propose attaching Metal Mate 20 x 20 x 3mm 3m Aluminium Equal Angle - Silver under the gutter (not the roof) to prevent any rolling water from entering the gap. The aluminium angle will act like a shield as any water hitting or rolling towards it will get redirected to the roof. If you wish to use spray foam behind the aluminium it is possible and will help with the prevention of water from entering the gap. I suggest using Selleys 310g Translucent Roof And Gutter Silicone Sealant to attach the angle to the bottom of the gutter. My best advice is to wash the outside face of the gutter with detergent and water to remove the mould on the surface.

If you need further assistance, please let us know.

Eric

[fan8956]

Hi Eric, thanks for your time to help me out. That is a great idea！