Green roofs are a rising star in eco-friendly architecture. From sedum mats to fully planted rooftop gardens, they promise better thermal regulation, reduced rainwater runoff, and enhanced biodiversity. But do they actually improve your EPC (Energy Performance Certificate) rating?
Let’s unpack whether EPC assessors consider green roofs a form of insulation—and how that impacts your final score.
🏡 What Are Green Roofs, Exactly?
A green roof is a roofing system covered with vegetation and growing medium, layered over a waterproof membrane. Types include:
Extensive green roofs (thin, lightweight, minimal maintenance)
Intensive green roofs (deeper, can support shrubs and walkways)
Semi-intensive roofs (a blend of the two)
They reduce thermal fluctuation, provide acoustic insulation, and absorb heat—all things that seem EPC-friendly.
🧾 But Do EPCs Actually Count Them?
Short answer: Not directly.
The UK’s Standard Assessment Procedure (SAP), which underpins domestic EPCs, does not explicitly factor green roofs as a standalone insulation layer. EPCs assess:
U-values (heat loss) of roof, walls, floors
Type and thickness of traditional insulation (e.g., mineral wool, foam boards)
Material properties logged in the EPC database
Unless the green roof is formally included in U-value calculations—via verified data or building regs compliance—it likely won’t impact the EPC score significantly.
🔗 Learn how U-values affect EPC scores
📉 Why the EPC Model Overlooks Green Roof Benefits
Thermal mass and evapotranspiration benefits aren’t recognised in SAP.
Shading effects (which reduce overheating) are not credited unless tied to passive solar control systems.
Moisture retention and acoustic benefits are beyond the scope of EPC assessments.
SAP assumes standard construction unless data-backed alternatives are provided.
So even if your green roof reduces heating and cooling bills in real life, your EPC rating may not reflect that.
🔍 Can You Make It Count?
Yes—but only with supporting documentation.
To have your green roof considered, you need:
U-value calculations that include the green roof layer
Proof the structure meets Part L of the Building Regulations
Supporting data on material composition and thickness
A qualified EPC assessor in London can then enter custom roof data into the software instead of using default assumptions.
📅 Book a detailed EPC with documentation support
🧠 When Do Green Roofs Make a Real EPC Difference?
✅ In new-builds, where U-values are carefully modelled
✅ On flat roofs, where green coverage reduces thermal bridging
✅ In non-domestic EPCs, where SBEM allows more bespoke inputs
❌ In older homes with default roof assumptions and no thermal bridging accounted for
💬 “I Installed a Green Roof—Why Didn’t My EPC Improve?”
This is a common frustration. Most homeowners expect their green roof to reflect in the EPC because:
It feels cooler in summer
Heating costs have dropped
It adds environmental value
However, without formal insulation values being entered into the EPC software, these benefits remain anecdotal in the model.
If your green roof replaced poor or no insulation, you may see an EPC gain—but only if the new U-value is recorded and verified.
🛠️ How to Maximise EPC Gains with Green Roofs
Pair your green roof with formal insulation underneath.
Get your installer to provide thermal performance data.
Request a custom roof entry in your EPC assessment.
Avoid relying on EPC defaults—get a tailored report.
🔗 Speak to our EPC team to document your green roof
✅ Final Verdict: A Green Roof Can Help Your EPC—If Done Right
Green roofs have real thermal benefits, but EPC models won’t acknowledge them without evidence. Treat your green roof as a supplement, not a substitute, for traditional insulation.
For those committed to both sustainability and compliance, green roofs are a smart investment—but remember to bridge the gap between real-world performance and EPC modelling.
📞 Want to make sure your green roof is EPC-compliant?
👉 Book your EPC with a specialist assessor today
