Steel in the Floor

Elevated Slab Reinforcement

See inside a concrete slab - where the steel goes, how chairs hold it in place, and why the 2-inch cover matters. Simple visual guide for Florida Keys elevated floor construction.

8"
Slab Thickness
#5
Rebar Size
2"
Clear Cover
Get Slab Design View Rebar Schedule
Chairs
Bottom Steel
Top Steel
Pour
Slab Specifications
Thickness 8"
Bottom #5 @ 12"
Top #4 @ 12"
Cover 2" min
2" cover
2" cover
Reference Guide

Rebar Schedule

Typical reinforcement requirements for elevated slabs in Monroe County.

Slab Thickness
Bottom Rebar
Top Rebar
Spacing
Cover
6"
#4
#4 at supports
12" O.C.
1.5"
8"
#5
#4
12" O.C.
2"
10"
#5
#5
10" O.C.
2"
12"
#6
#5
8" O.C.
2"
Components

Slab Layers Explained

Chair Supports

Plastic or metal supports that hold rebar at the correct height. Spaced every 3-4 feet to maintain consistent cover.

Reinforcing Steel

Two layers of rebar - bottom carries the load, top prevents cracking at supports. Both directions make a grid.

Concrete Cover

The concrete between the rebar and the surface. 2 inches minimum in coastal Florida protects steel from salt.

Common Questions

Elevated Slab FAQs

How thick should an elevated slab be in the Florida Keys?
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Elevated slabs in Monroe County are typically 6-8 inches thick for residential construction. The thickness depends on the span between supports and the loads. Longer spans or heavy loads may require thicker slabs up to 10-12 inches with additional reinforcement.
What rebar size and spacing is used in elevated slabs?
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Typical elevated slabs use #4 or #5 rebar at 12-inch spacing in both directions for the bottom mat. Top reinforcement is added over supports. The exact spacing depends on the slab design but 12 inches on center is common for residential Florida Keys construction.
What is the required concrete cover for rebar in coastal Florida?
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In coastal environments like the Florida Keys, concrete cover must be 2 inches minimum for reinforcement. This protects the steel from salt and moisture. Chair supports hold the rebar at the correct height during the pour to maintain this cover.
Why are chair supports important in slab construction?
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Chair supports (also called bar chairs or rebar supports) hold the reinforcement at the correct position in the slab. They ensure proper concrete cover above and below the steel. Without chairs, rebar sinks during the pour and loses its structural effectiveness.
Slab Quick Reference
Min Concrete 4000 psi
Coastal Cover 2" min
Chair Spacing 3-4 ft

Get Your Slab Design

PE-stamped elevated slab calculations for your Florida Keys project. Includes reinforcement schedules, pour specifications, and structural details.

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