Where the cage meets the roof
The screen enclosure is the most Floridian thing about these houses and the least considered part of the roof. It is attached to the structure, it moves independently of it, and the line where the two meet is a seam like any other.
- 1 The ridge. The highest, hottest course, and the one the sun works on all day.
- 2 The field. Tile or shingle above, and the underlayment that actually keeps water out below.
- 3 Valleys. One channel carrying what two slopes shed, at the pace this coast rains.
- 4 Flashing. Where the lanai and the enclosure meet the house, and where neither trade owns the seam.
- 5 Penetrations. Every vent and curb is a hole the underlayment has to seal, and the first place it stops.
- 6 Eaves and metal. Drip edge and fasteners, which salt air reaches years before it touches the covering.
A junction with two owners
Enclosures are usually installed by a different trade at a different time from the roof, often years apart. Each side does its own work correctly, and the connection between them belongs to neither. That is exactly the condition under which a detail is sealed rather than built.
Attached lanai roofs make it more pointed still, because a lower roof running into a wall is one of the hardest details on any house to get right. Done properly the flashing is let into the wall and outlives the covering. Done quickly it is caulked, and caulk in this sun is a maintenance item, not a permanent one.
How it shows up
The symptom is almost never at the junction. Water entering at a lanai tie-in runs along the top plate or a beam and appears as staining several feet inside the house, which sends the first inspection to the wrong place.
A second common sign is a lanai ceiling that stays marked after the rain stops. That is usually read as condensation and is often not.
Getting it into the quote
It comes down to one question asked out loud: does this price include rebuilding the flashing where the enclosure and the lanai meet the house, or does it assume the existing detail is sound? Both answers can be legitimate. Only one of them is what most homeowners think they are buying.