EPS Bulk Insulation · R-Value Calculator

Achieved R & U, required thickness per grade, board count — FRCel EPS bulk boards (12SD–30DV)

Application

Grade & thickness

mm
Cut-to-order: 10 mm minimum; envelope up to 6000 × 1240 mm, 10–960 mm thick (2026 brochure). Priced stock thicknesses: 10/15/20/25/30/35/40/50/75/100/120/125/150/175/200/225/250/300+ mm.

Target R-value

m²K/W
No SANS 10400-XA climate-zone → thickness table is published for these boards — enter the added-R target from your project's XA assessment. Verified anchor: 100 mm EPS @20 g/l gives R 2.86 (2026 brochure).

Board count

m²
%
Verified standard sizes (internal sheeting list — sizes only): widths 1200 / 1220 mm; lengths 2000 / 2440 / 2500 / 3000 / 4800 / 5000 / 6000 / 7500 mm. Boards are cut to order — confirm the sheet size with Technopol.

1 · Achieved R-value & U-value

Thermal resistance R (insulation layer)
–
Thermal transmittance U (layer only)
–
Achieved R vs target R
Cross-check — published anchors reproduced by R = t/λ: 100 mm 20DV → R 2.86 · 100 mm 30DV → 3.03 · 50 mm 30DV → 1.52 · 100 mm 12SD → 2.22 (2026 Bulk Insulation brochure / lab sheet).

2 · Required thickness per grade for the target R

Gradeλ (W/mK)Required t (mm)Nearest stock (mm)R at stock

3 · Boards required for the area

Coverage per sheet
–
Sheets required (incl. waste)
–

Sources & flagged assumptions

λ, density and strength are the authoritative six-grade lab sheet “Typical Physical Properties for Expanded Polystyrene” (text-verified). EPS 15 naming conflict — shown resolved: the website's “EPS 15” row (λ 0.038 W/mK) is actually the 16DV grade; the true grade-15 (15SD) is λ 0.040 W/mK. Both are listed separately here — confirm the supplied grade with Technopol. R and U are for the EPS layer only — surface film resistances, air gaps and the rest of the construction are excluded; assess the total-element U-value per project. “Nearest stock” rounds up to the next priced thickness; any thickness ≥ 10 mm is available cut to order. Grade 32DV (cold-store floor guideline) has no published λ and is excluded. Max-thickness / envelope conflict: 6000 × 1240 mm, 10–960 mm (2026 brochure) vs 10–1030 mm (2D Shapes) vs 600 mm max on the price list — confirm the publishable maximum with Technopol.
Disclaimer. Indicative calculator for concept design and comparison only — not a substitute for a competent-person SANS 10400-XA assessment. R = t/λ uses the published maximum thermal conductivity at 10 °C mean temperature. For sustained floor loads design to the safe working load @ 1% strain, not the 10% crush value. Fire: EPS is combustible. Technopol FRCel EPS carries a reaction-to-fire classification of Class B-s1,d0 to SANS 53501-1 (Ignis report IT 23-08-00009) — a reaction-to-fire class, NOT a fire-resistance (minutes) rating; keep away from open flame during storage and installation. © Technopol SA (Pty) Ltd · Leaders in EPS since 1993 · www.technopol.co.za · info@technopol.co.za · (011) 363-2780/1/2