In composite floor construction, edge trims often go unnoticed, but these small steel components play a major role in concrete containment, site safety and structural finish. At RMD Profiles we supply bespoke slab edge trims with every decking package and frequently support contractors with design assistance to ensure precise fit, performance and compliance.
So what makes edge trims so critical?
What Is a Slab Edge Trim?
A slab edge trim is a folded galvanised steel component that forms the perimeter of the concrete slab on steel decking. It serves multiple roles:
- Forms the concrete edge during casting.
- Prevents grout loss.
- Supports toeboards or handrails in safety planning.
- Completes the slab visually for architectural finish.
At RMD, we design trims to match MetFloor, ComFlor and TATA profiles, with adjustable depths (typically 100 to 300mm) to suit slab thicknesses.
Good Practice from SCI P300 and BS EN Standards
The SCI P300 publication outlines that temporary works such as edge formwork must maintain concrete level and prevent loss during casting. Edge trims satisfy this, particularly where soffit formwork is absent thanks to the steel decking for concrete beneath the slab.
According to BS EN 1994-1-1 and supporting guidance, trims should:
- Allow at least 50mm bearing onto structure.
- Be fixed securely with restraint straps every 600mm.
- Withstand construction loads until the concrete cures (SCI P300).
Why Bespoke Slab Edge Trim Saves You Money
Too often, generic edge trims cause problems on-site:
- They do not align with the decking profile.
- They lead to concrete overspill and delays.
- They require on-site cutting and waste.
Our team at RMD avoids this by:
- ✅ Designing the trim alongside the decking layout.
- ✅ Matching the top edge with slab level.
- ✅ Providing prompt delivery, with a 24 to 48 hour turnaround if required (subject to stock).
- ✅ Assisting with layout drawings and loading limits.
Case Study
See how edge trim featured in our St Andrew Street project for slab control on a tight, city-centre site with no margin for mess or misalignment.
When Should You Use Slab Edge Trim?
Always consider edge trim in:
- Open slab perimeters
- Temporary edge protection zones
- Precast interfaces
- Stairwell voids
- Where the decking does not return to a steel flange
Ask our team to include it in your decking supply only or supply and fix package.
Slab edge trim is more than a ‘nice to have’. It is an essential part of concrete metal deck construction that improves speed, safety and quality. At RMD we offer trims made to order and ready to install as part of our Edge Trim & Flashing service. Want a quote for edge trim alongside your decking? Just send your drawing or DWG today and we will solve it.