✅ Premium Celotex Insulation

We use Celotex GA4000 and XR4000 PIR insulation with industry-leading thermal conductivity (λ = 0.022 W/mK). This means superior insulation performance in thinner panels compared to alternatives.

✅ Sterling OSB Construction

11mm or 18mm Sterling OSB3 boards provide proven structural performance and enhanced moisture resistance. Stronger and more reliable than standard OSB.

✅ Building Regulations Compliant

All our SIP panels meet or exceed UK Building Regulations Part L 2021. Our 122mm panels achieve U-value 0.209 W/m²K, easily meeting the 0.18 W/m²K requirement for walls.

✅ Fast UK Delivery

1 Week+ delivery to anywhere in the UK. We manufacture in-house, so we control quality and lead times. Depending on your order size, we could have your order dispatched within 3 days.

✅ Free U-Value Calculator

Our exclusive online U-Value calculator helps you choose the right panel thickness for your project. Instant calculations based on official Celotex data.

✅ Competitive Pricing

Starting from just £88.90 per panel. Bulk discounts available. We offer the best value-for-money SIP panels in the UK without compromising on quality.

50% Faster Build Time

SIP panels are manufactured off-site to exact specifications, dramatically reducing on-site construction time. What takes weeks with traditional methods takes days with SIPs.

Superior Thermal Performance

Celotex PIR insulation (λ = 0.022 W/mK) provides exceptional thermal efficiency. A 122mm SIP panel outperforms a 300mm+ traditional cavity wall for U-value.

Exceptional Airtightness

Continuous insulation with minimal joints eliminates thermal bridging. SIP buildings achieve airtightness levels of 1-3 ACH @ 50Pa vs 5-10 ACH for traditional builds.

Lower Heating Bills

Superior insulation and airtightness reduce heating costs by 40-60% compared to standard construction. Savings pay back the panel cost within 3-5 years.

Structural Strength

Sterling OSB facings bonded to rigid PIR core create incredible structural integrity. SIP panels can span further than traditional stud walls with less material.

Sustainable Building

Less waste, fewer deliveries, reduced energy consumption. SIP construction generates 50% less construction waste than traditional methods. Lower carbon footprint.

Insulation Core

• Material: Celotex PIR (Polyisocyanurate)
• Types: GA4000 (50-100mm) & XR4000 (110-200mm)
• Thermal Conductivity: λ = 0.022 W/mK
• Fire Rating: Class B-s1,d0 (Euro class)
• Facers: Dual aluminum foil vapor control

OSB Facings

• Material: Sterling OSB3
• Thickness: 11mm or 18mm (both sides)
• Thermal Conductivity: λ = 0.13 W/mK
• Grade: Structural OSB/3 EN 300
• Moisture: Enhanced moisture resistance

Panel Dimensions

• Standard Size: 1220mm x 2440mm (4ft x 8ft)
• Thickness Range: 72mm to 172mm
• Custom Sizes: Available on request
• Weight: Varies by thickness (approx 20-30 kg/m²)
• Manufacturing: UK-made, precision cut

How much do SIP panels cost in the UK?

UltraSIPs panels start from £88.90 per panel for our 72mm and 97mm options, with our most popular 122mm panels priced at £98.70. Thicker high-performance panels (142mm and 172mm) range from £115.50 to £133.40. We offer bulk discounts for larger projects. Calculate your total project cost by multiplying the number of panels needed by the unit price, then add PIR splines and fixings.

What U-value do I need for Building Regulations?

UK Building Regulations Part L 2021 requires maximum U-values of 0.18 W/m²K for walls, 0.16 W/m²K for pitched roofs, and 0.18 W/m²K for flat roofs. Our 142mm panels (U-value 0.179) and 172mm panels (U-value 0.144) meet all these requirements. For garden rooms under 30m², Building Regulations typically don't apply, so our 97mm or 122mm panels are perfect. Use our free U-Value Calculator to check compliance.

How long does delivery take?

We manufacture all SIP panels in-house in the UK, which means we control lead times. Standard delivery is 1 week+ to anywhere in the UK. For custom sizes or large orders, allow 2-3 weeks days. We'll provide a confirmed delivery date when you place your order. 2-3-day delivery may be available for standard sizes—contact us to check availability.

Can SIP panels be cut to size?

Yes! While our standard panels are 1220mm x 2440mm, we can cut panels to your exact specifications before delivery. This reduces waste and speeds up installation. Provide us with your cutting list when ordering, and we'll precision-cut your panels in our factory. Custom cutting may add 2-3 days to delivery time but saves significant time on-site.

What's the difference between Celotex GA4000 and XR4000?

Both Celotex GA4000 and XR4000 have identical thermal performance (λ = 0.022 W/mK). The only difference is thickness range: GA4000 is available in 50-100mm thicknesses for general applications, while XR4000 extends from 110-200mm for projects requiring higher insulation levels. Both types feature dual aluminum foil facers that act as vapor control layers.

Do I need 11mm or 18mm OSB?

11mm Sterling OSB is suitable for most residential applications including garden rooms, extensions, and standard houses. 18mm OSB provides greater structural strength for larger spans, commercial buildings, or where Building Regulations require enhanced structural capacity. Both achieve the same thermal performance per millimeter. Our team can advise on the right choice for your specific project.

Are SIP panels suitable for roofs?

Absolutely! SIP panels are excellent for both pitched and flat roofs. For pitched roofs, use our 172mm panels (U-value 0.144) which easily meet the 0.16 W/m²K requirement. For flat roofs, 142mm panels or thicker are recommended. The continuous insulation eliminates thermal bridging common in traditional roof construction, and the panels are strong enough to support roof loads with minimal additional framing.

Can I install SIP panels myself?

Yes, SIP panels are very popular with self-builders! With basic carpentry skills and the right tools, you can install SIP panels yourself. They're much simpler to work with than traditional construction. We provide installation guides and technical support. For best results, we recommend having at least two people for panel lifting and positioning. Electrical and plumbing chases can be cut easily with standard tools. Many customers complete garden rooms in 2-3 weekends.