This Sanibel Pool Cage Needed Reinforcing for 170 mph
A Sanibel homeowner came to us with a screened pool enclosure that was already built but had never been permitted. The house could not get its certificate of occupancy until the enclosure had an after-the-fact permit, and they needed engineering to submit to the City of Sanibel.
Step one: draw what is actually there
We drew the cage from the owner's sketches and measurements and the original layout of the house, then sent a check set back so the owner could confirm it matched what was standing in the yard. It did: a two-bay aluminum enclosure about 46 feet across the back and 19 feet tall at the walls, with a hip roof on top, 2x8 top rails, 2x8 mid girts (the horizontal members that run between the posts) and a 6x6 center post.
Then an independent Florida-licensed engineer went out to the house and looked at it in person. On an after-the-fact job, that visit matters. Drawings show what is there. Only a site visit tells you how it was actually put together.
What the inspection found
The enclosure, as built, needed reinforcing to carry the design wind for Sanibel: 170 mph under the Florida Building Code (ASCE 7-22, Exposure C).
An aluminum screen enclosure is light, and nothing about how it looks tells you whether its members were sized for the wind at that address. That takes an engineer and the numbers, the same way coastal structures on the islands are designed for wind and flood.
The fix was two items, not a new cage
The repair drawing added two things:
A new 2x10 self-mating beam fastened under each long horizontal rail, both the top rail and the mid girt, on the back wall and both side walls. A self-mating beam is a deep, two-piece aluminum beam used in screen enclosures; adding one under the existing rail stiffens it.
A 2x2 member added along the bottom of each of the four roof hips.
Everything else stayed as built. The reinforcing is drawn and noted on the structural sheet as new work, so an aluminum enclosure contractor can install it straight from the drawing, and the rest of the set documents the existing enclosure for the City.
"Is this a requirement or a recommendation?"
The owner asked exactly that when the signed and sealed set arrived, and it is a fair question. It is a requirement. An engineer cannot sign and seal a document that is not code compliant, so the reinforcing is not advice. As Michael D. Stewart, P.E. put it to the owner: "We don't provide recommendations, it's a specification."
The second question was whether to hold the permit application until the work was done. No. The order is:
Submit the signed and sealed set with the after-the-fact permit application.
Wait for the City's review and the permit.
Install the reinforcing shown on the drawing.
Call in the final inspection; once it passes, the permit is closed.
The inspecting engineer also asked to see the reinforcing once it is installed, before he issues his final letter.
If you have an unpermitted pool cage
Expect a site visit. Engineering for an after-the-fact permit needs someone to look at what was built, not just draw it.
Expect that it may need work. "It has been fine for years" is not the test. The test is the design wind for your address under the current code.
The fix may be targeted. Here it was a beam under two rails on three walls and a member at each hip, not a new enclosure.
The drawings do two jobs. They document what is there for the building department, and they tell your contractor exactly what to add.
What to do
Gather what you have: photos of the enclosure from all sides, any old survey or plans of the house, and the basic dimensions (width, depth, height, post spacing).
Get the engineering done before the application goes in, so it goes in with signed and sealed drawings.
Once the drawings are done, give them to your aluminum enclosure contractor so any reinforcing can be scheduled when the permit is issued.
Do not skip the final inspection. That is what closes the permit.
Frequently asked questions
Can an unpermitted pool cage be permitted after the fact?
It can be. An engineer documents the enclosure as built and specifies any reinforcing it needs. You submit that with an after-the-fact permit application, install any required work, and call in the final inspection.
Will I have to tear it down?
Not in this case. The existing enclosure stayed, and the drawings added two reinforcing items. Whether yours can stay depends on what the inspection finds.
What wind speed does my pool cage have to meet?
It depends on where the house is. The design wind speed comes from the ASCE 7 maps the Florida Building Code uses. This enclosure on Sanibel was designed for 170 mph.
Should I install the reinforcing before I apply?
In this case, no. Once the permit is issued on the signed and sealed drawings, the work goes in, and the permit closes after the final inspection passes. If you are unsure how your building department handles it, ask before you start.
If you have a pool cage, lanai or addition that was built without a permit, we provide the engineering an after-the-fact permit needs: we document what is standing, specify any reinforcing it needs, and give the building department signed and sealed drawings it can approve. We do this work across Lee and Collier counties, from Cape Coral to Fort Myers Beach and the islands. Call or message us at (239) 292-7670 and we will tell you where to start. We have never lost a structure to a hurricane.
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