What Are Post Shores and Props?
Definition: A post shore, or prop, is an adjustable vertical support made of an inner tube that telescopes inside an outer tube, with a threaded collar or adjustment nut for fine height control and a pin for coarse adjustment. Steel plates or heads at each end transfer load from the formwork or structure above to the floor or ground below. Post shores are used individually or in rows to support slab formwork, beams, and existing structures during construction and renovation.
Post shores are the simplest form of shoring. Each prop supports a single point, so crews can set, adjust, and remove them one at a time without building towers or frames. That makes them fast to install, easy to work around, and well suited to typical floor-to-floor heights. Their compact footprint also leaves the floor below more open for other trades than frame or tower shoring.
Post shores are made from steel or aluminum. Steel props are economical and durable, while aluminum post shores offer higher capacity at lighter weight and are common with engineered slab forming systems. Props are also widely used for reshoring — re-supporting newly stripped slabs while the concrete continues to gain strength — and for propping existing structures during renovation, demolition, and repair. Through Scaffold Exchange, you can find vendors across the U.S. who rent and sell post shores and props and compare their inventory, rental rates, and availability in your area.
Key Components of a Post Shore
Post shores vary in size and capacity by manufacturer, but most share the same basic components.
Inner & Outer Tubes
Telescoping steel or aluminum tubes that set the overall height range of the prop. The inner tube slides inside the outer tube for coarse adjustment.
Collar & Adjustment Nut
A threaded collar or nut on the outer tube that provides fine height adjustment, allowing the shore to be snugged tight against the formwork above.
Pin
A steel pin passed through holes in the inner tube to lock the coarse height setting. Only manufacturer-supplied pins should be used.
Head Plates & Fork Heads
Flat plates, U-heads, fork heads, or drop heads at the top of the shore that cradle beams or formwork and transfer load into the post.
Base Plates & Tripods
Base plates spread load into the slab or sill below. Removable tripods hold props upright during erection until the formwork is in place.
Common Applications & Job Site Uses
Post shores and props are used across residential, commercial, industrial, and renovation work throughout the United States — anywhere temporary vertical support is needed.
Supporting elevated slab formwork at typical floor heights
Beam and girder formwork support
Reshoring newly stripped slabs during curing
Propping existing floors during renovation and repair
Temporary support during wall openings and demolition
Supporting precast elements and composite metal decks
Residential construction and foundation work
Drop-head slab systems that allow early stripping
How Post Shores Compare to Other Shoring Equipment
Post shores are the simplest shoring option. Here is how they compare to other shoring equipment and which jobs each suits best.
Purpose-built shoring towers
- Interchangeable posts, ledgers, and jacks
- Higher capacity and height than single posts
- Towers can be flown or rolled as units
- Best for complex or tall slab shoring
Heavy-duty steel shoring frames
- Welded frames stacked into towers
- High vertical load capacity per leg
- Larger footprint than post shores
- Best for heavy slabs and high shoring heights
Adjustable single-post shores
- Telescoping steel or aluminum posts
- Fast to set, adjust, and remove individually
- Compact footprint, open floor below
- Best for typical floor heights and reshoring
Other shoring and reshoring equipment
- Timber, specialty, and custom shoring
- Reshoring for slabs during curing
- Covers equipment outside standard categories
- Best for unique or project-specific needs
Support for elevated slabs
- Carries slab formwork and fresh concrete
- Remains until the slab reaches strength
- Often followed by reshoring
- Best for multi-story elevated slab pours
Find Post Shore & Prop Vendors Near You
Use the Scaffold Exchange map to search by location, filter by equipment type, and connect directly with local suppliers who rent and sell steel and aluminum post shores and props.
OSHA Compliance & Safety Standards
Post shores used to support concrete formwork on U.S. job sites are governed by OSHA 29 CFR 1926 Subpart Q, Concrete and Masonry Construction. Standard 29 CFR 1926.703 sets general shoring requirements and specific rules for single post shores, including additional requirements when shores are tiered one on top of another. Industry guidance is provided by ACI 347, Guide to Formwork for Concrete.
- Shores inspected before erection — damaged equipment not used
- Base plates, shore heads, and adjustment screws in firm contact and secured
- Erected shoring inspected before, during, and after concrete placement
- No height adjustment to raise formwork after concrete is placed
- Tiered shores designed by a qualified designer, aligned, spliced, and braced
- Shores left in place until concrete has gained sufficient strength
1926.703
Requirements for Cast-in-Place Concrete — U.S. Construction Regulations
OSHA Interpretations & Rulings →
