On a steel-framed building, the floor often comes down to two options: composite metal deck with a concrete topping, or precast hollowcore planks. Both work, both get specified, and suppliers on each side will tell you theirs is better.

The useful thing is that this comparison has been studied by the industry bodies, with independent cost consultants doing the pricing. So rather than give you our opinion, here is what that data actually found.

Composite Metal Deck vs Hollowcore: What the Studies Compared

Two published studies put both floors on the same steel frame and cost them side by side.

• Business park office: commissioned by the BCSA and Tata Steel. Gardiner & Theobald priced a three-storey office of around 3,200m², and Mace worked out the programme.
• Secondary school: part of the Costing Steelwork series from the BCSA and Steel for Life. AECOM costed a real three-storey secondary school in Knowsley, Merseyside, at 2023 prices.

Both were funded by the steel sector, and that is worth saying. But both floors being compared sit on a steel frame, so the question was never steel against concrete. It was which floor to put on the steelwork.

Composite Metal Deck vs Precast Cost Comparison

On both buildings, composite deck came out around 10% cheaper than precast planks on the frame and upper floors.

Frame and upper floors cost per m² of gross internal floor area. See sources below.

The saving is not all in the floor. A composite floor is lighter, so the frame and foundations can be lighter too. In the office study, the composite option had the lowest substructure cost of any frame. A shorter programme brings preliminaries down as well. That is why both studies insist on comparing total building cost, not just the frame and floor package.

Programme: Which Floor Builds Faster?

On the office, Mace found composite deck gave the fastest frame and the fastest overall build, by one week.

We would rather be straight about that margin than dress it up. Deck goes down faster, because several sheets come up in one crane lift, where precast goes in one plank per lift. Some of that gain is given back at stud welding, which takes longer than grouting plank joints. Net, deck was still a week ahead.

Why Composite Metal Deck Saves Time and Money

• Less weight to lift. The concrete topping on deck is pumped rather than craned, so the crane only handles light bundles of sheet. That lighter dead load is also what lets the frame and foundations come down in size, which is where the studies found much of the saving.
• Fewer vehicle movements. The topping concrete still arrives by mixer, and a composite slab generally needs more of it than a precast screed, so the saving is in the floor units themselves.
• A faster route to a working platform. Once edge protection is up, the first sheet is pushed out and becomes the platform for laying the rest of the bay. The fixed deck then carries the stud welders and the concrete gang without waiting on the crane.

Composite Floor Decking Design, Supply and Fix

We design, supply and fix composite floor decking across the UK, with through-deck stud welding as part of the package. Send us your structural GA drawings and we will price a deck layout for your frame, so you can compare it with precast on your own project rather than someone else’s.

Sources

• Secondary school cost model (AECOM, BCSA, Steel for Life) – SteelConstruction.info cost comparison studies
• Business park office study (BCSA, Tata Steel, Gardiner & Theobald, Mace) – Building magazine: multi-storey offices