Spray Foam Insulation & BREEAM — Mat 01, Ene 01 and Hea 04 Credit Contributions

BREEAM is the UK’s dominant sustainability rating system for non-domestic buildings. For specifiers and contractors targeting BREEAM Excellent or Outstanding on a commercial project, every credit counts — and insulation contributes across at least four credit categories, not one.

This article walks through the four BREEAM credit areas where closed-cell spray foam insulation can make a measurable difference, what evidence the assessor actually wants, and where mineral wool wins on a single line but spray foam wins on the total score. It’s aimed at architects, M&E consultants and BREEAM AP-qualified specifiers who need to defend the insulation specification at design-stage assessment.

The four BREEAM credit areas spray foam touches

For a typical UK commercial warehouse, distribution centre, school or hospital project, the Ene 01 contribution is the headline win — operational CO₂ savings translate directly into credit on the largest weighted category in the scheme. Mat 01 is a partial credit for spray foam (it’s not the lowest-embodied insulant), but the Ene 01 gain typically more than offsets the Mat 01 loss.

Mat 01 — Environmental impacts of materials

Mat 01 awards credits based on the building’s whole-life embodied environmental impact, calculated using BREEAM’s Mat 01 calculator (which reads from the green Guide to Specification or the project’s Environmental Product Declarations).

For an insulation product, the input figures are kgCO₂e per kg of insulant, multiplied by mass of insulant on the project.

Typical embodied carbon figures (cradle-to-gate, kgCO₂e/kg):

• Rock wool: ~1.0–1.2
• Glass wool: ~1.4–1.7
• Closed-cell PUR spray foam: ~3–5
• PIR rigid board: ~3–5
• EPS expanded polystyrene: ~3–4

On the per-kg metric, mineral wool is the lowest-impact insulant by a clear margin. But mass per square metre is the relevant figure on the building, and that depends on the U-value target and density:

• Closed-cell foam at 30–35 kg/m³ × 140 mm = ~4.5 kg/m²
• Rock wool at 30 kg/m³ × 225 mm = ~6.75 kg/m²
• Glass wool at 18 kg/m³ × 225 mm = ~4.0 kg/m²

Multiply by embodied carbon:

• Closed-cell foam: 4.5 × 4 = ~18 kgCO₂e/m²
• Rock wool: 6.75 × 1.1 = ~7.4 kgCO₂e/m²
• Glass wool: 4.0 × 1.55 = ~6.2 kgCO₂e/m²

Glass wool and rock wool are roughly 2–3× lower in embodied carbon than spray foam per square metre installed. This is the line where mineral wool wins outright on Mat 01 — there’s no defensible counter-argument.

The mitigations for spray foam’s higher Mat 01 footprint are:

1. Optimised thickness. A closed-cell spray foam at λ = 0.022 needs ~60 % of the thickness of mineral wool for the same U-value. The kgCO₂e-per-m² gap shrinks (but doesn’t close).
2. Verified EPDs at product level. Newer spray foam systems with HFO blowing agents have lower embodied carbon than legacy HFC-blown formulations. Verify the specific datasheet’s EPD before submitting Mat 01.
3. Operational offset. Spray foam’s airtightness contribution drives more operational CO₂ savings over a 60-year building lifecycle than the embodied difference. BREEAM’s Mat 01 only counts embodied; operational savings are picked up in Ene 01.

Mat 03 — Responsible sourcing

Mat 03 awards credits for materials with verified responsible-sourcing chains — typically under BES 6001 (BRE Global Framework Standard for Responsible Sourcing) or equivalent.

For insulation, this is less about the material and more about the supplier. Major UK mineral wool producers (Knauf, Rockwool, Isover) all hold BES 6001 certification at varying levels. PIR board producers (Kingspan, Recticel) similarly hold or are working toward it.

For closed-cell spray foam, supplier RSC certification varies. Verify before submitting — don’t assume the spray foam used carries a specific certification unless the manufacturer’s documentation states it explicitly.

Duratite can confirm the responsible-sourcing certification of the specific spray foam product on a project at quote stage. Request a free site survey to get the certification details for your specification.

Ene 01 — Energy efficiency (the headline credit)

Ene 01 is the largest weighted credit in BREEAM. It rewards operational CO₂ reduction below the BREEAM notional building.

Tighter fabric U-values reduce conductive losses. Tighter air permeability reduces convective losses. Both directly reduce the BER (Building Emission Rate) calculated in SBEM, which feeds into the Ene 01 score.

This is where closed-cell spray foam pulls ahead of the alternatives:

• At the same U-value target, closed-cell spray foam, mineral wool and PIR all produce identical conductive heat-loss figures — same Ene 01 contribution from U-value alone.
• At airtightness, closed-cell spray foam routinely tests at 3 m³/(h·m²) at 50 Pa or below in a properly-applied installation, with no separate VCL or air barrier membrane required. Mineral wool and PIR can match this only with significant additional VCL/membrane work — and on refurbishments, often can’t match it at all.

The airtightness gain is worth typically 5–10 % CO₂ reduction in operation on a heated UK warehouse. On an Ene 01 calculation, that translates to 2–4 additional credits depending on the BREEAM scheme version.

Practical Ene 01 numbers for a 2,000 m² warehouse:

• Roof at U = 0.18, walls at U = 0.26, airtightness 5 m³/(h·m²) → 8 m³/(h·m²) baseline → BREEAM Ene 01 partial credits typical
• Same roof at U = 0.15 (140 mm closed-cell foam), walls at U = 0.21, airtightness 3 m³/(h·m²) → BREEAM Ene 01 full or near-full credits typical

The exact credit count depends on the project’s geometry, glazing ratio and use class. A BREEAM Assessor will run the Ene 01 calculator at design stage and confirm.

Hea 04 — Thermal comfort

Hea 04 awards credits for modelled thermal comfort in occupied spaces — defined by ISO 7730 Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD).

Closed-cell spray foam’s airtightness contribution again helps:

• Reduced draughts → lower air movement at workstation height → lower PPD
• Reduced internal surface temperature swing on cold mornings → lower PMV variance → fewer dissatisfied occupants

For warehouse mezzanine offices, retail spaces, schools and hospitals in the UK climate, the airtightness bonus from spray foam typically delivers an extra 1–2 Hea 04 credits over a same-U-value mineral wool spec.

Wat 04 (incidental) — Water-related impacts

Spray foam doesn’t directly score Wat credits — but on roof refurbishments where the existing membrane is failing, applying closed-cell foam over the existing roof and topping with a silicone roof coating (e.g. Gaco S42) eliminates leak-related water loss and damage that the building owner would otherwise budget for. Not a BREEAM credit area for new construction, but a real-world cost saving worth raising with the client.

Putting the BREEAM total together

For a typical UK BREEAM Excellent commercial new-build, the closed-cell spray foam vs mineral wool comparison net total looks something like:

The exact differential depends on the project, but on most heated UK commercial buildings the airtightness gain on Ene 01 outweighs the embodied carbon loss on Mat 01.

For unheated buildings (cold storage, agricultural sheds without heating), the Ene 01 gain shrinks and mineral wool’s embodied advantage often wins outright — pick mineral wool for those.

Evidence the BREEAM Assessor will ask for

For each credit area:

Mat 01:
– Product EPD (Environmental Product Declaration) for the specific spray foam used
– Mass per square metre of installed foam, calculated from thickness and density
– Contribution input into BREEAM Mat 01 calculator at design stage

Mat 03:
– Supplier’s BES 6001 certificate (or equivalent) at the time of supply
– Chain of custody documentation linking certification to the specific product on the project

Ene 01:
– SBEM output showing BER vs TER, including the airtightness design figure
– ATTMA TSL2 as-built airtightness test report from a UKAS-accredited tester
– U-value calculations to BR 443 for each insulated element

Hea 04:
– Thermal comfort model (CIBSE TM52 / TM59 for overheating, ISO 7730 for PMV/PPD)
– Internal surface temperature outputs

A BREEAM-credentialled contractor like Duratite supplies the project-specific evidence at handover — datasheets, EPDs, U-value calcs, airtightness test results, photo records — packaged for the BREEAM Assessor’s submission.

Frequently asked questions

Q: Does spray foam automatically score better on BREEAM than mineral wool?
A: No. Mineral wool wins outright on Mat 01 (embodied carbon) and often on Mat 03 (responsible sourcing). Closed-cell spray foam typically wins on Ene 01 (airtightness) and Hea 04 (thermal comfort). The net total depends on the building — heated buildings tend to favour spray foam, unheated favour mineral wool.

Q: Is BREEAM applicable to refurbishments or only new construction?
A: Both. BREEAM UK New Construction covers new-build and major refurbishment / extension. BREEAM In-Use covers existing operational buildings on a separate scheme. Spray foam contributes similarly across both — Ene 01 / Hea 04 gains are the strongest driver in either context.

Q: What about embodied carbon if I’m pursuing LETI / RIBA 2030 targets?
A: LETI and RIBA’s 2030 Climate Challenge targets weight embodied carbon more heavily than BREEAM does. On a project with hard embodied targets (e.g. ≤ 600 kgCO₂e/m² super-structure), mineral wool is often the only viable insulant. For LETI-stretch projects, run the embodied calculation early and don’t spec spray foam without a clear operational-savings justification.

Q: Does spray foam contribute to BREEAM Wst credits?
A: Indirectly. Spray foam application has near-zero off-cuts compared to board (typically 8–15 % wastage) — small but real Wst 01 contribution. The bigger Wst gain is using spray foam in refurbishment to overspray existing insulation rather than stripping and disposing.

Q: What about non-BREEAM schemes — LEED, WELL, NABERS UK?
A: LEED has equivalent credits in the EA (Energy & Atmosphere) and EQ (Environmental Quality) categories — the same airtightness and thermal comfort gains apply. WELL focuses on occupant outcomes — closed-cell foam’s thermal comfort and indoor air quality (post-cure) profiles are neutral-to-positive. NABERS UK is operational-rating focused and rewards the same airtightness-driven energy savings as BREEAM Ene 01.