Rainfall in South Florida does not arrive gently. An afternoon storm can drop two inches in an hour, and the wet season runs from May into October — overlapping almost exactly with hurricane season, which officially starts on 1 June and ends on 30 November.
A drainage system that copes with ordinary rain will not necessarily cope with that. The difference between the two shows up on the building, and it shows up in a specific order.
The fascia goes first
When a gutter overflows, the water does not fall cleanly away from the house. Surface tension pulls a good part of it backwards, behind the gutter and down the face of the fascia board.
That board is usually wood. It is painted, not sealed, and it is now getting wet from behind where nobody can see it and where it never dries properly. Rot starts at the hanger screws, spreads along the grain, and the first visible symptom is often the gutter itself starting to pull away — because there is nothing solid left to hold the screws.
By then you are not buying a gutter. You are buying carpentry, then a gutter.
Then the soffit
Water tracking behind the fascia gets into the soffit, the underside of the overhang. Vented soffit panels are designed to let air into the roof space, which means they will also let water in.
Signs it is already happening: staining on the soffit panels, panels sagging out of their channel, or a smell of damp under the overhang after rain. In a roof space, the same water shows up as dark patches on the underside of the deck.
Then the wall and what is behind it
Water running down an exterior wall finds every opening — a hairline crack in the stucco, the gap around a hose bib, the seal at a window head. Inside the wall cavity it has nowhere to go and nothing moving the air, which in this climate is all mould needs.
Efflorescence, the chalky white bloom that appears on block and stucco, is the visible marker that water has been moving through the wall and leaving its minerals behind. It is cosmetic in itself. It is a warning about what is not cosmetic.
Then the ground, which is the expensive one
Water discharging against the house soaks the ground next to the slab over and over. The soil swells wet and shrinks dry, and the slab edge moves with it.
That movement is what produces hairline cracks in a floor, a door that binds in its frame during the wet season and releases in the dry, and tiles that lift along a line. These are the repairs nobody budgets for, and the cause is usually something that cost a few hundred dollars to fix before it started.
Outside, the same water scours a trench under the drip line, undermines the edge of a driveway or a paver path, and carries mulch and soil out across the walkway with every storm.
What correct drainage actually looks like
- Capacity matched to the roof. The run is sized for the area draining into it, not for what fits the look of the house.
- Enough outlets. One downspout for roughly every 30 to 40 feet of run, more where the catchment is large.
- Fall towards the outlets. About a quarter inch per ten feet, so nothing stands in the trough.
- Secure hanging. Hidden hangers into sound fascia every two feet, so a storm does not take the run with it.
- Discharge well clear of the building. Four to six feet minimum, onto ground that drains, sloping away.
- Nothing blocked. Capacity you cannot use is not capacity.
Before the season, not during it
The useful window for this work is spring, before the wet season builds. Once the storms are arriving weekly, every gutter company in Miami-Dade and Broward is booked, and the work gets done between downpours.
If you only do one thing, walk the perimeter during the next heavy rain and watch where the water goes. Overflow, a stream running down a wall, or a puddle sitting against the slab tells you more in five minutes than an inspection on a dry day.
Joya General Services Gutter LLC designs and fits rainwater drainage across Opa-locka, Miami and Fort Lauderdale. Call (786) 302-1221 and we will come and tell you what your roof is actually doing with its water.