Mike Wray
The right insulation can be a gamer changer!
When it comes to floor insulation, Celotex PIR boards remain one of the most widely specified solutions across UK construction projects. Available from National Insulation Supplies, these boards are trusted by contractors for their high thermal performance, ease of installation, and compliance with Building Regulations.
Celotex boards are typically manufactured in 2400mm x 1200mm sheets and come in a wide range of thicknesses, from 20mm up to 200mm, making them suitable for everything from concrete slab floors to suspended timber systems.
Below, we break down the best-selling Celotex insulation boards for floors, based on trade usage, versatility, and performance.
Best Selling Celotex Floor Insulation Boards
Best Overall: Celotex GA4000 PIR Insulation Board
The Celotex GA4000 is by far the most popular choice for floor insulation and for good reason. It’s a general-purpose PIR board suitable for ground floors, beam-and-block systems, and suspended timber floors.
- Thermal conductivity: 0.022 W/mK
- Thickness range: 50mm-100mm+
- Applications: floors, walls, roofs
- BBA certified for multiple uses
Its strong thermal performance means you can achieve target U-values with less thickness, which is critical on projects where floor build-up is limited.
Best for: Most trade floor insulation applications
Best for Thin Floor Build-Ups: Celotex TB4000 PIR Board
The TB4000 range is designed for thin insulation layers, making it ideal where floor height is restricted.
- Thickness: typically 20mm-40mm
- Same PIR core as GA4000
- Lightweight and easy to cut
Best for: Refurbishments, retrofits, and low floor build-ups
Best for Integrated Solutions: Celotex PL4000 Insulated Plasterboard
While more commonly used on walls, PL4000 is sometimes used in floor-related internal upgrades where combined insulation and lining is beneficial.
Best for: Internal upgrades where speed and finish matter
Best for High Thickness & Performance: Celotex XR4000 Range
The XR4000 range is typically used when higher thermal performance is required, especially in new builds.
Best for: Projects needing thicker insulation to meet Part L
Product Comparison Table
| Attribute | ||||
|---|---|---|---|---|
| Best Use | General floor insulation | Thin floors | Internal lining | High performance floors |
| Thickness Range | 50-100mm+ | 20-40mm | 25-70mm | Up to 200mm |
| Thermal Conductivity | 0.022 W/mK | 0.022 W/mK | 0.022 W/mK | 0.022 W/mK |
| Floor Applications | ✅ | ✅ | ⚠️ Limited | ✅ |
| Trade Popularity | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ |
How to Choose the Right Celotex Floor Insulation
When selecting a board for floor insulation, trade professionals typically consider:
1. Floor Type
- Concrete slab: GA4000 or XR4000
- Suspended timber: GA4000
- Refurb projects: TB4000
2. Required U-Value
Lower U-values require thicker boards or higher-performance ranges.
3. Floor Build-Up Height
Restricted height? Go thinner (TB4000).
New build? Use thicker PIR boards for compliance.
4. Installation Method
Celotex boards are lightweight and easy to cut, making them ideal for fast on-site installation.
FAQs
1. What is the best Celotex board for floor insulation?
The GA4000 range is the most widely used due to its versatility and strong thermal performance.
2. Can Celotex be used under concrete floors?
Yes, Celotex PIR boards are suitable for concrete slab and beam-and-block floors, provided they are installed correctly.
3. What thickness Celotex do I need for floors?
Typically:
- 50-75mm for refurbishments
- 100mm+ for new builds to meet Part L
4. Is Celotex better than mineral wool for floors?
For floors, PIR boards like Celotex provide higher thermal performance per thickness, making them more space-efficient.
5. Are Celotex boards compliant with UK regulations?
Yes, Celotex boards are BBA certified and designed to meet UK Building Regulations when correctly specified.
Conclusion
For trade customers, Celotex remains a go-to solution for floor insulation thanks to its balance of performance, cost, and ease of use.
- Use GA4000 for most projects
- Choose TB4000 where height is restricted
- Opt for thicker PIR boards when targeting higher energy efficiency
By sourcing from National Insulation Supplies, contractors can access a full range of sizes, fast delivery, and trade-friendly pricing.
Get Expert Advice
Not sure which option is right for your property or have a any insulation related question?
Get expert advice and quote tailored to your needs and budget. Contact our sales team at 02030 045 451 – we’re here to help!