Structural Bracing Standards

Safety Recommendations

WAM Engineers certified loading limits, sliding trough placements, 60mm height allowances, and step-by-step guidelines for safe dismantling.

Prop Requirements by Span Length

The values below are professional, certified guidelines for masonry up to 2 blocks high with core fill only above the temporary head. More block height above means more loading weight and may require additional or closer bracing spacing.

Rapid Head Span Length	Required Acrow Props	Support Placement Description
0.4m – 1.8m	None Required	Self-supporting high-strength structure. No acrow props needed.
2.0m – 2.8m	1 Acrow Prop	Requires 1 prop centered under the sliding steel beam.
3.0m – 3.6m	2 Acrow Props	Requires 2 props placed at even 1/3 division points under the span.
3.8m – 5.0m	3 Acrow Props	Requires 3 props placed at even 1/4 division points under the span.
Over 5.0m	4+ or Dynamic	Requires 4 props or specialized scaffold support. Consult Cameron.

Note on Height Calculations: All Rapid Heads add 60mm (0.06m) to the total height of your site setup. When selecting your acrow prop sizes, you must subtract this 60mm height from your available clearance to ensure your props aren’t too long to slip in comfortably!

The 50mm Seating Rule

We strongly recommend adjusting the integrated sliding trough so that it sits fully on the bearing blocks by at least 50mm on each end. This guarantees optimal, balanced load distribution and ensures seamless sliding extraction once the masonry blocks reach self-curing strength.

Dimension Table

Acrow Prop Size Ranges

Use this measurement chart to map your masonry floor-to-ceiling heights against our standard rental prop ranges. Allow 60mm clearance for the top head flange.

Prop Variant

Stubbys

For low-set openings and restricted height service paths.

500mm – 750mm

Prop Variant

Size #00 Props

For window sills and compact doorway spans.

775mm – 1200mm

Prop Variant

Size #0 Props

Excellent for mid-level openings and short windows.

1175mm – 1800mm

Prop Variant

Size #1 Props

Standard residential ceiling height window support.

1680mm – 2600mm

Prop Variant

Size #2 Props

Standard residential and commercial doorway heights.

2030mm – 3200mm

Prop Variant

Size #3 Props

For tall commercial garage doors and high structural ceilings.

2675mm – 3950mm

Prop Variant

Size #4 Props

For large industrial portals, wide shopfronts, and heavy masonry.

3150mm – 4950mm

Instruction Manual

How To Remove Heads Safely

Learn the safe and correct way to remove Rapid Heads and props on site. This quick guide walks builders and block layers through releasing, lowering, and piling procedures to keep everyone safe and avoid structural damage.

Relieve Tension

Ensure cement block mortar is completely dry. Relieve the weight from the acrow prop by slowly turning the screw collar counter-clockwise. Never kick or hammer a prop loose under high load.

Extract Prop

Supporting the acrow prop column with two hands, remove the locking pin, lower the inner tube fully, and extract the prop column away from the ceiling cavity.

Slide Sliding-Trough

Slide the Rapid Head sliding-trough backwards by hitting the striking bracket gently with a mallet. This shortens the total structural footprint immediately, separating it from the block.

Pile and Stack

Stack your temporary steel heads flat on wooden support blocks at a safe, central location out of water pooling. Keep collar threads cleaned to ensure simple, low-maintenance transport.

Australian Site Warning

A table explaining safety metrics is supplied on delivery.

Please refer under all circumstances to the manual booklet supplied upon setup delivery for heavily stacked blocks.

Go to Equipment Order Form

Engineering Compliance Certifications

Signed and reviewed by WAM Engineers Pty Ltd. Pass building codes.

Call 0421 695 408