Installing floor deck to the supporting structure will typically be carried out using low velocity powder (‘shot-firing’) or gas-actuated cartridge tools. In certain circumstances, the use of self-tapping screws may be necessary depending on the application

Common applications and support materials

Composite steel beams

When steel beams are to receive thru-deck welded shear studs, Hilti X-U 15 shot-fired fixings or X-P14 G3 MX gas-fired fixings should be used to secure the deck during installation.

Non-composite steel beams

Where studs are not required for composite action, the Hilti X-ENP 19 should be used. These fixings are required for the increased resistance of the nails, as typically beams will have been designed with a restrained top flange

No studs and lateral restraint?

Where decking is required to provide lateral restraint and no thru-deck welded shear studs are specified, the fixing type should be checked by the engineer to ensure adequate shear resistance is provided by the fixing type and frequency, refer to TGN Section 4.4 for more information.



Masonry & Concrete

Fixings to masonry should be either Drill & Hammer Anchors (Spit P370) or shot-fired fixings (Hilti X-SW or Spit CR9).

Timber & Glulam

When fixing to timber or glulam beams, shot firing is not recommended. Instead self-drilling screws should be used, such as; Hilti S-MD55Z, Fixfast DF12 5.5mm.

Side Stitching

To stop the deck profile spreading during concreting, the sheets must be fixed together. For SMD floor deck, self-tapping screws (typically Hilti S-MD01Z 4.8 x19) must be installed at a maximum of 1.0m centres, refer to item A in Fig. 4.6b below.

Fixing Spacings

Decking must be fixed at a maximum spacing of 300mm centres (300/333mm dependent on profile) at the end of each sheet and 1 per 600mm (For TR60+ 333mm or 666mm respectively) at intermediate supports.


Fixings should be located a minimum of 20mm from the end of the sheet and where more than one fixing per trough is specified, the spacing between fixings in the direction of deck span is to be >45mm. The table below indicates the spacings for the various SMD floor deck profiles: