The Benefits of Using First Fix Formwork’s Deck Box

The Deck Box, manufactured by First Fix Formwork, is a product widely used in the construction industry. Used to create an opening in the concrete slab for service penetrations to pass through, it can be made to suit your specific requirements at any width, length, or depth (subject to practicality) and is supplied with a structural ply lid.

Manufactured and assembled in a factory off-site, it is created from a mild steel frame that is coated with zinc. The perforations in the steel frame allow the grout of the concrete to penetrate the sides, providing a profiled key for the infill to bond to. It is delivered to site, ready to install, where it can then be nailed to the deck for the concrete to be poured around it.

What are the main benefits of the Deck Box product?

The Deck Box predominantly saves you time onsite. Because it is manufactured off-site and is delivered ready to install, this means that no diamond drilling is necessary to get the correct-sized hole and no shuttering is required to be assembled onsite. It also doesn’t need to be broken out once the concrete is set, all you need to do is simply pop the lid off when you’re ready to put the services through.

It’s easy to use. The product is labelled clearly with your drawing reference. And because it is a singular product with no hassle involved, this reduces the waste removal from site.

The Deck Box not only ensures a safer work environment but also gives you that extra peace of mind. It is supplied with a strong lid which minimises the risk of trips and falls onsite. It’s also highly beneficial to know that once the QF2 Fire Protection Compound is installed and the concrete is poured around the box, you can walk away knowing that the installation is complete… and fully fire tested!

QF2 Fire Protection Compound in conjunction with the Deck Box

Like any other aperture for services penetrating a fire compartment, the Deck Box must be suitably firestopped to achieve effective compartmentation. And that is where we step in: Our QF2 Fire Protection Compound has been specifically fire tested in conjunction with the Deck Box.

Our compound forms part of the QuelStop System and is used as a gap-filling material for cables and pipework that penetrate fire compartment walls and floors. One of its main benefits is that it does not shrink like concrete, but expands upon curing, locking itself into the surrounding structure to form a load-bearing and fire-rated seal. This, if installed in line with the tested scope of application, prevents the passage of fire from affecting other areas of the building.

> See also: What is fire protection compound?

What is the difference between the Deck Box and a cast in fire collar (like our QuelCast product)?

If you are familiar with the concept of cast in fire collars, you may be wondering what the difference is between the use of a cast in fire collar and firestopping products within the aperture formed by the Deck Box? First of all, whilst cast in fire collars create the aperture for penetrating services (typically plastic pipes), they are service penetration seals themselves as they contain intumescent material. Deck Box, on the other hand, only creates the aperture for penetrating services, so that firestopping solutions can be installed around them within the Deck Box. The main benefit of using the Deck Box over the use of cast in collars is that it provides more flexibility in terms of the different types of penetrating services that can be firestopped using this solution. It can also be used to create larger apertures, giving an element of flexibility, or more tolerance, in the positioning of the services.

Which of our standard details relate to the Deck Box?

Our QF2 Fire Protection Compound has been tested with the Deck Box, cast into the concrete slab as a blank seal as shown on detail QF2-CF150-00B. This detail can be used in conjunction with other QF2 standard details to cover scenarios where services penetrate concrete floors.

If you have any further questions about the information above, please email; for any questions regarding the Deck Box, please email

Craig Wells

This article was written by Craig Wells

Sales Director

Learn More About Craig Wells