The Williams Coffer Slab System has been designed for use in both commercial and residential applications and can be engineered to suit any project where concrete slabs are required.

The System described:

The Williams Coffer Slab System consists of removable plastic coffer blocks suspended between a series of parallel ribs spanned across the area where a concrete slab is required. Depending on the application, the ribs will be either pre-cast concrete lattice ribs or wooden purlins. When erected, the coffer blocks and ribs form a shutter on which the concrete slab can be cast.

Where wooden purlins are used as the ribs, tensile strength is provided to the concrete slab by means of steel reinforcing positioned in the beams formed between the coffer blocks. The primary reinforcing is placed above and across the wooden purlins. The secondary reinforcing is placed above transverse to the ribs.

Where pre-cast concrete lattice ribs are used, the primary reinforcing is cast into the ribs with the steel lattice. The secondary reinforcing is fixed above and transverse to the ribs.

Steel mesh is placed above the coffer blocks to control cracking and to add additional strength. The deck is generally supported by load bearing walls and beams.

Whether to use wooden or pre-cast concrete ribs depends on the length of the span and the application. However, wooden purlins would generally be used for residential and concrete ribs for commercial applications. The span of the slab using wooden purlins will seldom exceed 7 meters, whereas a slab using concrete ribs could span as much as 10 meters.

For Commercial applications – spans
up to 10 meters

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For Residential applications – spans
up to 7 meters)

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The Williams Coffer Slab is a superior insitu concrete slab solution. The unique design of this system offers substantial benefits to the user; examples of which are:

  • Lightweight construction
  • Ease of installation
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  • Cost effectiveness
  • Superior strength
     

Lightweight Construction:

Despite the depth of the Williams Coffer Slab being almost 40% greater than that of the conventional wet deck, the amount of concrete used is considerably less as a result of the voids created by the coffer blocks. As a consequence of the lighter slab and greater effective depth, considerably less reinforcement is required. Deflections are also minimised. This weight advantage can be used to achieve longer spans and a lighter support structure. The system requires less support work than any other insitu slab

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Ease of Installation:

The coffer blocks used in the Williams Coffer Slab are manufactured from plastic, making them light and easy to handle. The assembly of the coffer blocks is done on the ground before being lifted into position between the supporting ribs. The result is less labour and quick and easy installation.

Cost Effectiveness:

The Williams Coffer Slab using less material, less labour, requiring less support work and being quick and easy to install, results in substantial cost savings. This makes the Williams Coffer Slab System an extremely cost effective concrete slab.

Superior Strength:

The Williams Coffer Slab has superior strength compared to alternative concrete slabs due to the geometric shape of the coffer void, the depth of the slab and the 2 way spanning reinforcing steel bars and steel mesh. The strength of this system means that, depending on loading, spans up to 7 meters can be achieved using wooden purlins and 10 meters using pre-cast concrete lattice ribs without excessive deflections.

Holes can be drilled through the wooden purlins
for the electric conduit and plumbing pipes

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Holes can be drilled through the wooden purlins
for the electric conduit and plumbing pipes

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For Residential applications – spans
up to 7 meters)

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The ceiling of a house painted and fitted with lights

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