Floor Insulation
Strength & thermal performance
20 | 24 | 30 kg/m3
High to extra high density
1.0 to 18.182
Thermal R-Value range
B1 Fire Rating
Fire Retardant Polystyrene
WHY CHOOSE POLYFLOOR EPS INSULATION BOARDS
Specify & Order
PolyFLOOR Insulation with Confidence
Verified compressive performance
By Specifying PolyFLOOR you know that you are getting the high-density polystyrene to carry the floor slab loads required in this application.
Thermal Performance for Any Project
With PolyFLOOR you can get the thermal values you need for any high-end residential home, building, cold room or freezer room project.
Cost-Effective Insulation
Your are getting the exact density you need for the application and not paying for over engineered solutions.
SOUTH AFRICAN BUILDING REGULATIONS
Building Code Requirements for Floor Insulation
Regulation XA requires applicable buildings to use energy efficiently and to have a building envelope appropriate to the building's use, internal environment and geographical location. Compliance is demonstrated through the prescribed SANS 10400-XA route, a rational design by a competent person, or approved thermal modelling against a reference building.
SANS 10400-XA:2021 · CLAUSE 5.4.1
Underfloor heating requires minimum R‑1.0 insulation
Where an underfloor heating system is installed, the floor must be insulated with insulation having an R-value of not less than 1.0 m²·K/W to reduce heat loss to the surrounding and adjacent ground.
ONLY HIGH-DENSITY EPS IS SUITABLE
PolyFLOOR Density, Compressive Strength & Safe Working Loads
POLYFLOOR is designed for use beneath concrete floor slabs, providing the compressive strength required to support the slab and its imposed loads. Each density has a defined safe working load, allowing the correct board to be specified for the application.
Please note:
Low-density polystyrene is not suitable for this load-bearing application and may compress or fail under the slab.
Density Options
Nominal Density
Compressive Strength
Cross-Breaking Strength
Safe Working Load
PolyFloor
20 DV
20 kg / m3
110 kPa at 10%
150 kPa
45 kPa at 1%
PolyFloor
24 DV
24 kg / m³
160 kPa at 10%
205 kPa
70 kPa at 1%
PolyFloor
30DV
30 kg / m³
200 kPa at 10%
250 kPa
100 kPa at 1%
20 kg/m2 is generally sufficient for residential homes
24 kg / m3 is used where higher compressive strength is required
30 kg / m3 is used where extreme compressive strength is required
THERMAL PERFORMANCE FOR EVERY PROJECT
Thermal Resistance (R-value) by Board Thickness and Density
Values are expressed in m²·K/W. A higher thermal resistance value indicates greater resistance to heat flow.
Thermal R-Values
20 DV
35 mm - 1.000
40 mm - 1.143
50 mm - 1.429
75 mm - 2.143
80 mm - 2.286
100 mm - 2.857
125 mm - 3.571
150 mm - 4.286
200 mm - 5.714
300 mm - 8.571
600 mm - 17.143
Thermal R-Values
24 DV
35 mm - 1.029
40 mm - 1.176
50 mm - 1.471
75 mm - 2.206
80 mm - 2.353
100 mm - 2.941
125 mm - 3.676
150 mm - 4.412
200 mm - 5.882
300 mm - 8.824
600 mm - 17.647
Thermal R-Values
30 DV
35 mm - 1.061
40 mm - 1.212
50 mm - 1.515
75 mm - 2.273
80 mm - 2.424
100 mm - 3.030
125 mm - 3.788
150 mm - 4.545
200 mm - 6.061
300 mm - 9.091
600 mm - 18.182
TURN THE DESIGN INTENT INTO A CONTROLLED SPECIFICATION
As the Architect, Control What Is Specified—and What Arrives on Site
A sound design can still fail when a vague insulation note permits the wrong product to be priced, purchased or installed. Specify POLYFLOOR as a performance-controlled floor-insulation product, define the thermal and loading requirements, and require verification before the material is accepted or concealed.
You cannot use cheap low density polystyrene for this application. It will fail.
DESIGN CONTROL
Your specification determines what the contractor must price and supply.
Name POLYFLOOR, state the exact density, thickness and performance, and make every substitution subject to written professional approval.
MANDATORY SITE CONTROL
Check what arrives on site before any board is installed.
The architect or appointed professional must verify the delivered product against the approved POLYFLOOR specification and supporting documentation before installation begins. Recheck the completed insulation before the concrete pour. The client's floor, the integrity of the design and your professional reputation are all on the line.
SPECIFYING POLYSTYRENE FLOOR INSULATION CORRECTLY
How to Specify POLYFLOOR on Drawings and in the BOQ
Use the project engineer's confirmed values in every placeholder below. The drawing, specification and BOQ must describe the same product performance so the requirement survives pricing, procurement and construction.
DRAWING NOTE
Density, Thermal Values, Compressive Strength Matter
POLYFLOOR [20DV / 24DV / 30DV] fire-retardant EPS floor-insulation boards, [THICKNESS] mm thick, nominal density [DENSITY] kg/m³, installed continuously below the reinforced concrete floor slab. Provide minimum insulation-layer thermal resistance R-[VALUE] m²·K/W and coordinate all joints, edges, penetrations and damp-proof membrane with the approved floor detail.
BOQ DESCRIPTION
Suggested unit: m² of insulation by stated thickness and density.
POLYFLOOR fire-retardant expanded-polystyrene floor-insulation boards, [GRADE] with nominal density [DENSITY] kg/m³, thermal conductivity not greater than [λ] W/m·K, compressive stress at 10% deformation not less than [VALUE] kPa and safe working load at 1% nominal compression not less than [VALUE] kPa; [THICKNESS] mm thick, providing insulation-layer R-value not less than [VALUE] m²·K/W; supplied for close-butt-jointed installation below the concrete floor slab in accordance with the drawings and approved specification.
WHY INSULATE BENEATH THE CONCRETE SLAB?
Benefits of Floor Insulation for Homeowners and Building Owners
Floor insulation is not only a technical line item. It changes how the building feels, how hard its heating and cooling systems must work, and how effectively the complete thermal envelope performs over the building's life.
01 · COMFORT
More comfortable floor surfaces
Reducing heat transfer between the slab and the ground helps moderate internal floor-surface temperatures—particularly noticeable on winter mornings and in barefoot living areas.
02 · HVAC DEMAND
Less avoidable heating and cooling load
A better-insulated floor reduces one path of unwanted heat flow, allowing the HVAC system to focus on maintaining the intended indoor conditions.
03 · OPERATING VALUE
Long-term value beyond the initial cost
Correct floor insulation is a small part of many premium builds but can support lower energy demand and better comfort year after year. Judge it over the life of the building.
04 · COMPLETE ENVELOPE
Direct more heat into the occupied space
Insulation beneath a heated floor limits downward heat loss, improving the effectiveness of the heating system and supporting the required thermal performance.
05 · UNDERFLOOR HEATING
Long-term value beyond the initial cost
Insulation beneath a heated floor limits downward heat loss, improving the effectiveness of the heating system and supporting the required thermal performance.
06 · BUILT IN FOR LIFE
Make the decision before the concrete pour
Below-slab insulation is difficult and disruptive to add later. Specifying the appropriate R-value, thickness and density during design protects the opportunity permanently.
TECHNICAL INSULATION TERMS
PolyFLOOR Technical Glossary
Plain-language definitions for comparing, specifying and verifying EPS floor insulation. Units and calculation boundaries matter: a material property is not automatically the performance of the complete floor.
MATERIAL-LAYER CALCULATION
R = d ÷ λ
d is board thickness in metres and λ is thermal conductivity in W/m·K.
COMPLETE-ASSEMBLY RELATIONSHIP
U = 1 ÷ RT
Use only where RT is the total resistance calculated for the complete assembly by the applicable method. It is not the board-only R-value.
DV designation
The EPS density designation used by South African suppliers. The number corresponds to nominal density: 20DV = 20 kg/m³, 24DV = 24 kg/m³ and 30DV = 30 kg/m³.
Nominal density
Mass per unit volume, expressed in kg/m³. Density helps identify the product option, but it is not by itself the allowable load for a floor design.
Thermal conductivity (λ or k-value)
A material property indicating how readily heat passes through the EPS, expressed in W/m·K. A lower value means less heat conduction through the material.
Thermal resistance (R-value)
The resistance of a stated material layer to heat flow, expressed in m²·K/W. For the same material, increasing board thickness increases R-value. Higher is better.
Thermal transmittance (U-value)
The stated stress associated with 1% nominal compression in the supplied typical property data. The project engineer must still confirm the serviceability and long-term loading requirements.
Cross-breaking strength
A measure of the board's resistance to bending or flexural failure. It supports product comparison but does not replace the structural design of the complete floor.
Fire-retardant (FR) grade
An EPS material formulation intended to limit flame spread under the relevant test conditions. FR grade is not a fire-resistance rating for the complete floor assembly.
Calculation boundary
The parts included in a performance calculation. PolyFLOOR's board R-value covers the insulation layer only; complete-floor performance also depends on the remaining construction and ground conditions.
TECHNICAL SUPPORT BEFORE YOU SPECIFY OR ORDER
Need Help? Ask Us. We Are the Poly Experts.
Tell us what you are building, where the project is located, the required thermal performance and the expected floor loads. We will help the homeowner, architect, engineer or contractor identify the appropriate POLYFLOOR density, thickness and supply route for professional confirmation.