Order Your Bulk Polystyrene Nationally Online In Seconds! 

Specialist National Suppliers Of Polystyrene Sheets, Blocks, Polystyrene Insulation, Extruded Polystyrene ISO Ceilings Boards, XPS Cornice Blocks, Beads / Regrind & Void Formers In South Africa & For Export


Polystyrene - Johannesburg

011 678 5626

Polystyrene - Cape Town


021 200 5926

Polystyrene - Durban

031 940 7056

Polystyrene - East London & PE

087 095 3259

National Email

PolySlab Void Formers For Concrete Slab Construction

Looking For Polystyrene PolySlab Blocks For Your Suspended Slab Construction Projects?

If you are a concrete slab construction company or just need polystyrene decking blocks for one of your projects we can certainly assist you in South Africa or for export.

We Don't Design or Install Concrete Slabs :

  • Please note that we only supply the POLYSLAB Blocks.
  • We don't design concrete slabs.
  • We don't install concrete slabs.

POLYSLAB - Rib & Block Void Former Or Decking Blocks

  • POLYSLAB Blocks are expanded polystyrene decking blocks or void formers used in rib & block slab construction.
  • POLYSLAB Blocks are used instead of traditional ash blocks and they are placed between the concrete lintels to create a base on which the final concrete slab can be cast.

Benefits of using PolySlab Blocks instead of Ash Blocks

  • POLYSLAB Blocks are lightweight and easy to lift in multi-story building projects.
  • They significantly reduce they final weight of the concrete slab.
  • They increase the rate at which concrete slabs can be prepared and constructed.
  • Lightweight slabs reduce the amount of jacking supports required and the time that such supports need to remain in place.
  • This means that work can resume faster during the curing period of the concrete slab.
  • They increase the thermal and acoustic properties of the concrete slab.

Most Requested Block Sizes & Dimensions:

  • Below you will see our standard blocks dimensions.
  • To avoid wastage and costs the blocks are all 1200mm long.
  • We can custom-cut blocks if necessary.

Most Requested POLYSLAB Block Thicknesses:

  • Once again, we don't specify block thickness. Your engineer will have to specify the block thickness and density requirements based on their actual engineering design.
  • The most common block thicknesses based on the concrete slab thickness can be seen below.
Final Concrete Slab Thickness PolySlab Block Thickness
170mm 110mm
200mm 150mm
255mm 190mm
300mm 230mm
340mm 285mm

POLYSLAB Design Properties:

  • Your engineer can use these properties to finalise your concrete slab design.
Density Compressive Strength Cross-Breaking Strength
X-Grade 60 kPa @ 10% compression 80 kPa @ 1% compression
20DV 110 kPa @ 10% compression 150 kPa @ 1% compression

Shipping & Collections:

  • This product is shipped directly from factory.
  • Due to COVID 19 we are not allowing collections at our factories for this product.

Getting A Quote:

In order to get a quote on POLYSLAB Decking Blocks you will have to email us the following:

  • The size of the blocks you require.
  • The density of the blocks you require.
  • The number of blocks you require (including potential wastage)
  • Your exact project location (so we can determine which factory is closest and what the delivery will cost will be)

Please Note:

  • We don't work off plans and we don't measure quantities.
  • Before we release any PolySab Blocks from our factories, we will require a letter from your engineer confirming the density and thickness specification.
  • Feel free to get your engineer to call us if need be.

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Let's Explore Your Green Building & Polystyrene Requirements Together!

Recent Projects Supplied

Cape Town Convention Center Extension Concrete Roof Insulation Project

1400m2 of 120mm Extra-High Density Concrete Roof Insulation (PolyRoof Insulation) Laid On Top Of Torch-On Waterproofing With Paving Overlay

Hydroboard Insulation_edited.jpg
PolyVoid - Structural Fill Blocks.jpg

Nelson Mandela Children's Hospital Raised Slab Project 

3000m2 of 50mm Extra-High Density Concrete PolyVoid Fillers To Raise An Existing Concrete Slab By 1m. Extra-High Density Polystyrene Has Incredible Compressive Strength Properties.


Polystyrene Product Company

Polystyrene Product Company Was Established In 2016 And Today It Is One Of The Leading National Suppliers Of Bulk Polystyrene To The Construction And Manufacturing Industries In South Africa And For Export.

National Sales & Head Office


Unit 8, Lower Ground Level, Commercial City, Tungsten Rd, Strydompark, Randburg, 2194

VAT Number: 4220273447

CO. Reg Number: 2016/072709/07

Main Office Number:

011 678 5626


Main Email: