Can You Install Loft Boards Without Damaging Your Insulation?
- Matthew Driver
- Jul 25
- 5 min read
Loft boarding is an excellent way to maximise your home's storage potential, turning an under utilised loft into a practical, organised space. But before grabbing your drill and heading up the ladder, there's one crucial question that needs answering:
Can you install loft boards without damaging your insulation?
The short answer is: Yes – but only if you do it the right way.
In this comprehensive guide, we'll explore how to board your loft safely without compressing your insulation, why this matters, and how raised loft flooring solutions like Loft Leg and Loft Leg XL provide a safe, energy-efficient solution.
Why You Should Never Compress Loft Insulation
Modern homes are built with energy efficiency in mind. One of the key elements in reducing heat loss is loft insulation, typically laid in rolls between and over the ceiling joists. Current UK Building Regulations recommend a minimum of 270mm of insulation in a loft, comprising two layers:
100mm between joists
170mm over the joists
This thickness improves thermal performance and can save you hundreds on heating bills annually. However, if you install loft boards directly onto joists without considering this depth, you’ll compress the top layer of insulation, drastically reducing its effectiveness.
❌ What Happens When You Compress Insulation?
Thermal Performance Drops: Loft insulation works by trapping air; when compressed, it loses its insulating properties.
Increased Heating Costs: Poor insulation means more heat loss and higher energy bills.
Risk of Damp and Mould: Reduced airflow and compressed insulation can lead to condensation forming in the loft, which can damage timbers and create an unhealthy environment.
Voiding New-Build Warranties: Many home warranties (e.g. NHBC) prohibit alterations that compromise thermal performance or structural integrity.
The Solution: Raised Loft Boarding Systems
To safely board your loft without compressing the insulation, you need to raise the height of the loft floor above the insulation level. This creates a space allowing the insulation to retain its full thickness.
Enter the Loft Leg system — a purpose-designed, cost-effective solution for raised loft boarding.
Introducing Loft Leg: The Original Raised Loft Floor Support
Loft Leg is an award-winning product designed and manufactured in the UK. It allows you to create a raised floor in your loft above the insulation, preventing compression and ensuring energy efficiency.
Key Features:
175mm Tall: Perfect for homes with standard 270mm insulation.
Easy to Install: Screws directly into ceiling joists; no specialist tools required.
Durable & Strong: Manufactured from strong recycled plastic and tested to withstand significant loads.
Made in the UK: Manufactured to ISO 9001 standards.
How It Works:
Position Loft Legs in a grid pattern on top of the ceiling joists.
Screw them in using standard wood screws.
Fix loft boards (typically 18mm chipboard) to the top of the Loft Legs.
This method raises the floor above the insulation, creating a safe platform for storage while maintaining the insulations performance.
What If You Have Extra-Deep Insulation?
If your home has deeper insulation because you're in a new build the Loft Leg XL is your solution.
Introducing Loft Leg XL: The Elevated Option for Modern Roofs
Loft Leg XL is a taller version of the standard Loft Leg, specifically designed for newer homes where 300mm+ insulation is common.
Key Features:
300mm Height: Accommodates deeper layers of insulation.
NHBC Warranty Friendly: Used correctly, Loft Leg XL helps maintain compliance with new-build warranty conditions (check with your provider).
Compatible with standard loft boards and larger chipboard sheets
Perfect For:
New builds with truss roofs (where insulation is deeper).
Homes aiming for even better thermal performance with extra insulation.
Property owners who want a solution that preserves warranty compliance.
Step-by-Step Guide: Installing Raised Loft Boards with Loft Leg
Want to know how it all works? Here’s a quick walkthrough of the installation process:
1. Inspect and Prepare the Loft
Measure your insulation depth.
Check joist conditions and layout.
Clear away debris or obstructions.
2. Layout the Loft Legs or Loft Leg XL
Place in a grid layout, spacing each support no more than 600mm apart.
Ensure alignment for standard 1200mm x 320mm loft boards or 2400mm x 600mm sheets.
3. Fix Loft Legs to Joists
Use screws to securely attach each Loft Leg to the joist.
Avoid electrical wires or pipes beneath.
4. Lay the Loft Boards
Use P5 T&G chipboard loft panels or sheets
Secure to Loft Legs using screws.
Leave a 10mm gap between boards and walls.
5. Create Access Points
Make sure you have clear access to pipes, wiring, or water tanks.
Use Loft Lids to keep downlights protected from insulation.
Frequently Asked Questions
Can I lay loft boards directly over insulation?
Only if the insulation is below the joist level — and that’s rare in modern homes. If the insulation is above the top of the joists you need to raise the boards.
Are Loft Legs strong enough to support heavy items?
Yes. Each Loft Leg is tested to support around 500kg per square metre when correctly installed. We would not recommend putting this kind of weight in your loft – we recommend storing no more than 25kg/m2.
Does installing Loft Legs require cutting the insulation?
The first layer of insulation will not generally require cutting as it sits between the joists. As the Loft Legs sit directly on joists the top up layer may need small slits cutting into it so it can be pushed over the Loft Legs.
Will raised loft boarding affect ventilation in my loft?
No. The insulation will be unaffected, eaves ventilation should always be monitored.
Insulation, Airflow and the Science Behind Raised Boarding
Let’s get a bit technical. Loft insulation works by trapping pockets of air, reducing convective heat loss. When insulation is squashed or compressed (e.g. by an incorrectly fitted loft board), its ability to trap air is significantly reduced.
According to the Energy Saving Trust:
“Compressing insulation reduces its thermal performance, meaning you won’t achieve the energy savings you expect.”
New Builds & NHBC Warranty Compliance
New build homes typically come with a 10-year warranty under schemes such as NHBC, Premier Guarantee or LABC. Many of these schemes state that:
Insulation must not be compressed or removed.
Any modifications must not adversely affect thermal performance.
Boarding should be installed in a way that maintains insulation depth and ventilation.
Using a raised system like Loft Leg XL ensures you can create storage without invalidating your warranty.
Tip: Always check your specific warranty provider's guidance. Loft Leg XL is specifically designed to comply with these types of requirements.
Optional Add-ons: Improve Your Loft Storage Setup
To further enhance your loft, consider these compatible products:
✅ Loft Lids
Plastic enclosures that safely cover downlights, maintaining safe airflow and preventing overheating.
✅ Loft Light
Battery-powered or wired lights to safely illuminate your new storage area.
✅ Loft Hatches & Ladders
Ensure safe and convenient access to your raised loft floor.
Conclusion: Yes, You Can Board Your Loft Without Damaging Insulation
Installing loft boards without damaging your insulation is not only possible — it’s essential. By using purpose-built raised flooring systems like Loft Leg or Loft Leg XL, you can:
✅ Maintain full thermal performance
✅ Avoid costly heating bills
✅ Create safe and stable storage space
✅ Stay compliant with building regs and warranties
Whether you’re in a traditional home with 270mm of insulation or a brand new property with deeper insulation, Loft Leg has a solution that protects your insulation and creates usable storage space for years to come.
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Get in touch—we're here to help 01282 861001.
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