Gutters and hurricane season

The Atlantic hurricane season runs from June 1 to November 30. In Central Florida that window overlaps almost exactly with the wet season, which means the same months bring both the ordinary afternoon thunderstorms that gutter has to handle every week and the occasional named system that it does not. Distinguishing between the two is the whole point of this guide.

What gutter is designed for

Rainwater management. A gutter system exists to collect roof runoff and move it away from the building envelope, and it is sized and hung against rainfall, not against wind. It is a light aluminum channel fastened to a wooden board with screws. In a serious wind event, that is not the part of the house doing the structural work, and it is not supposed to be.

Ordinary Central Florida storms are the design case, and they are demanding enough. NOAA Atlas 14 puts the one-hour, ten-year figure for Orlando at 2.91 inches of rain, against sizing tables published at an inch of rain an hour. A system that handles that comfortably is doing its job. See the sizing guide.

What fails, and why

Gutter damage in a wind event is rarely wind acting directly on the trough. The common causes, in order:

1. Falling limbs. By a wide margin the leading cause. A branch coming down across a run will tear it off the fascia regardless of how well it was hung. This is a tree problem, not a gutter problem.
2. Weight. A trough packed with wet debris in a storm holds a great deal of water, and the combined load pulls hangers. A gutter that was cleared in late spring goes into hurricane season carrying far less risk than one that was not.
3. Soft fascia. Hangers hold only as well as the wood they are screwed into. Fascia that has been softened by years of water backing over a blocked trough is where a run detaches under load.
4. Old spike-and-ferrule hangers. Nails driven through the gutter face into fascia back out over time. In a heavy event they finish backing out.

Notice that three of those four are maintenance and installation quality rather than product specification. That is where preparation effort pays.

Preparation worth doing

• Clear the gutters in late spring. After the live oak has finished shedding in March through early May, and before the wet season is properly underway. This is the single highest-value item on the list, because it removes the weight problem before it exists.
• Confirm the downspouts run. Flush each one. An outlet that has silted up will back a full trough into the fascia during a multi-day rain event.
• Look at limbs over the roofline. Anything resting on or directly above a gutter run is the most likely cause of damage. Tree work is a separate trade from gutter work, and it wants booking early, both because arborists fill up as the season approaches and because any pruning is better done before new metal goes up rather than after.
• Check the discharge. Extensions and emitters carry more meaning during a multi-inch event than during an ordinary shower. A splash block against the slab is a weak point precisely when it matters.
• Fix known problems before June. A sagging run, a loose downspout, a leaking mitre: all are minor repairs in April and all are worse in September.

What is not worth doing

Taking gutters down before a storm. This comes up and it is almost never sensible. Removing a system takes a crew, storing it takes space, rehanging it costs nearly what hanging it did, and the house then has no rainwater management during the exact event that produces the most rain.

Buying a gutter product on wind claims. A wind rating printed on a gutter or guard brochure is a manufacturer's own marketing number, and it says nothing about the fascia board on your house, which is where the run will let go. Hanger type and fascia condition decide how a system comes through a storm, and neither of them is a product you buy.

Emergency pre-storm cleaning. Not because it is useless, but because it is the most expensive time to buy it and the least available. The same work in April costs less and is easier to book.

Afterwards

The useful post-storm check is done from the ground. Look along each run for a new dip or a section standing away from the fascia, check that downspouts are still strapped and still connected at the elbows, and look for debris sitting on top of guard where a limb came down. Water marks on a fascia board or a new stripe of washed-out bedding under a downspout both point at something worth looking at properly.