Our 1987 Oakville detached had original 4-inch aluminum eavestroughs — still functional but overflowing at the garage corner every heavy rain, and constantly clogged with Norway maple seeds. We finally replaced them all.
The overflow diagnosis: The eavestrough contractor we hired did a proper diagnosis. The 4-inch gutter on the garage side was receiving drainage from 850 sqft of roof — well over its rated capacity of 700 sqft. The cause was actually a valley that concentrated flow from two roof slopes into that one section. Solution: oversized 6-inch gutter on that run, 5-inch on the rest of the house. We also added a second downspout on that side.
The leaf guard question: We had three companies give opinions. Honest consensus: if you have Norway maples (we have two), no leaf guard keeps maple keys out completely. The micro-mesh guards do the best job but still require one cleaning per fall. The surface tension guards catch the keys in the curved channels and build up. We installed micro-mesh (Alu-Rex T-Rex) on all runs except the garage (where we use the gutter as a wash-through for the concentrated flow — no guard on that run).
What was installed:
- 5-inch seamless aluminum K-style, 185 linear feet: $2,590
- 6-inch oversized run (garage side, 22 feet): $440
- New downspouts x4 (including second garage side downspout): $580
- Alu-Rex micro-mesh guard on 163 linear feet: $3,100
- Splash pads at downspout discharge: $80
- Total: $6,790
One full fall season with the new system: eavestroughs held without overflow in every rain. One cleaning needed in November — took 20 minutes with a leaf blower. Previous system needed cleaning 3-4 times a year.