We seal miters and end cap leaks all the time! Sealant like many most things in this world, eventually wear away. Aluminum gutters expand and contract with temperature changes, causing the sealant to move, and eventually fail, Sunlight exposure also plays a big role in how long miter joints last. We guarantee our miter and end cap seals for 2yrs.
Leaky miters and end caps get really unsightly over time. They become moldy and dirty looking. More importantly, leaky miters will stain driveways, sidewalks, and masonry stone, as well as rot out cedar siding and fascia/soffit boards. Letting a leaky miter or end cap go to long can cost thousands in repairs.
SIGNS YOUR MITER IS LEAKING:
Leaking miters and end caps are very easy to spot. Stains on fascia, soffit, siding, brick, or stucco are sure signs of a leaky miter or end cap. Water dripping from a miter, or end cap is also a sure sign of a leaky seal.
We clean the joint area the best we can. Often times, homeowners or handyman guys get up there and put flex seal, or bathroom caulk, bubble gum, pretty much anything they can find to seal the joint, which makes cleaning the joint next to impossible. For the love of god, hire a professional.
Costs: We seal miters at ~$50 each joint location if we do all the joints on the structure.