Loft boarding is a popular way to gain extra storage without extending your home. But if not done correctly, it can have a serious impact on your Energy Performance Certificate (EPC) score—and not in a good way. In fact, poorly installed loft boards often compromise the thermal performance of your insulation, reducing the effectiveness of your entire roof space.

In this article, we explore how loft boarding can damage your EPC rating, the common mistakes homeowners make, and how to get it right without losing valuable energy efficiency points.

🏠 Why Loft Insulation Matters So Much in an EPC

Your loft or roof insulation is one of the most heavily weighted components in a SAP-based EPC assessment (used for residential properties). Around 25% of heat is lost through the roof in an uninsulated home, so assessors pay close attention to:

  • The depth and condition of insulation

  • Whether it’s continuous or compressed

  • If it’s been compromised by boarding or other installations

Find out more about residential assessments on our EPC Assessors London page.

🧱 The Problem with Incorrect Loft Boarding

When boards are installed directly over insulation, the insulation gets compressed. This drastically reduces its thermal performance. Even worse, some homeowners remove insulation to make room for boards—undoing a vital energy upgrade.

❌ Common mistakes include:

  • Laying boards directly on joists without raising them

  • Squashing loft insulation down to fit beneath boards

  • Removing insulation to create flat storage

  • Failing to insulate areas around loft hatches or downlights

📉 How This Affects Your EPC Score

EPC software assumes that insulation is performing at its declared thickness—typically 270mm for mineral wool. But if it’s compressed under loft boards, an assessor must downgrade the insulation level to what’s actually effective.

This results in:

  • A lower EPC rating (A–G scale)

  • Reduced property value and appeal

  • Potential non-compliance with MEES regulations for landlords

Worried your home might be affected? Book an assessment to find out where you stand.

✅ How to Board a Loft Without Hurting Your EPC

If you want to board your loft and keep your EPC score intact, follow these energy-efficient practices:

🔼 Use Loft Legs or a Raised Platform

Install loft legs or a raised timber frame above your insulation so that boards sit on top of the insulation, not squashing it.

💨 Maintain Ventilation

Loft boarding should never block air gaps or soffit vents, as poor ventilation can lead to condensation and mould, further harming EPC ratings.

🔒 Insulate the Loft Hatch

Don’t forget to insulate and draught-proof the hatch itself. It’s a small but crucial point often flagged by assessors.

🛠 Hire Professionals

DIY jobs often overlook thermal bridging or moisture traps. Consider hiring trained installers who understand how to protect insulation integrity.

Need a re-inspection after upgrading your loft? Contact us at EPCrate.co.uk for advice.

🧾 Final Thoughts: Storage vs Efficiency

Loft boarding is a great convenience—but if not installed correctly, it can backfire by wrecking your EPC and increasing your energy bills. A well-insulated and correctly boarded loft supports:

  • Lower heating costs

  • Higher property value

  • A better EPC rating

🔍 Not sure if your insulation is up to standard?
✅ Book an EPC inspection today
📋 See pricing for residential EPCs
📞 Contact us for insulation upgrade guidance