How to Insulate a Steel Building for 2025 Compliance

December 12, 2025

How to Insulate a Steel Building for Maximum Energy Efficiency

Steel buildings offer superior strength and durability, but they require proper insulation to be energy-efficient and comfortable. As the premier provider of steel buildings nationwide, we emphasize that correct insulation is essential for controlling the internal environment and meeting modern regulatory standards.

Here is an updated guide on why and how to insulate your steel structure in 2025.

1. Do I Need to Insulate My Steel Building?

If your steel building is sited in the UK, the answer is a clear and legally binding "Yes."

Thermal Performance: Steel is an excellent conductor of heat, meaning without insulation, internal warmth quickly escapes in winter, and external heat rapidly builds up in summer. Proper insulation is essential for energy efficiency and cost-saving.
Regulatory Compliance (Part L): Any new commercial, industrial, or habitable steel building must meet current Building Regulations Part L (Conservation of Fuel and Power). This requires achieving very specific, low U-values (a measure of heat loss) that are impossible to meet without high-performance insulation.
Condensation Control: Insulation helps keep the internal steel surface temperature above the dew point, preventing the formation of condensation, which can damage stored goods and the building structure itself.

2. What is the Best Insulation Material to Use?

For modern, regulatory-compliant steel structures, the industry standard is the use of Composite Insulated Panels(often referred to generically by the brand name of market leaders like Kingspan).

Design: Composite panels are factory-manufactured units consisting of a rigid insulating core (typically PIR or Mineral Wool) sandwiched between two external steel sheets.
Efficiency: This system installs the insulation outside the steel frame, effectively creating a continuous, high-performance thermal envelope. This prevents thermal bridging (heat loss through the frame itself), drastically reducing energy consumption.
Alternative Method (Built-Up/Twin Skin): For certain budget or historical applications, a traditional twin-skin system (two layers of metal sheeting with a soft insulation quilt between them) can be used, but composite panels offer superior performance and installation speed.

3. Simplified Installation of Composite Insulated Panels

The primary advantage of composite panels is the speed and simplicity of installation, which streamlines the construction process.

Step	Action	Detail
1. Preparation	Ensure the purlins (secondary steel framing) are correctly installed and aligned.	Use correct PPE and confirm weather conditions are safe (avoid high winds).
2. Panel Lifting	Panels are lifted and aligned, starting from the eaves/base.	Installation is typically done vertically or horizontally, depending on the panel design.
3. Sealing	Apply butyl tape or a similar sealant to the panel overlap seams (joins) as per manufacturer instructions.	This is critical for achieving a weatherproof, airtight seal and maximizing thermal performance.
4. Fixing	The panels are secured directly to the steel purlins using specialized self-drilling, self-tapping screws (known as 'teks' or stitcher screws).	The screw position, spacing, and length are dictated by the panel manufacturer (e.g., Kingspan instructions) to ensure structural integrity and thermal performance.
5. Finish	All joints, corners, and building apertures (windows/doors) are sealed with specialized trims and flashings to ensure a weather-tight finish.

Expert Advice from Atlantic Steel Buildings

Achieving the required thermal performance and fire rating for your structure is non-negotiable in 2025. When you purchase a steel building from Atlantic Steel Buildings, we don't just supply the frame and panels; we provide expert guidance.

We will advise you on the best U-values, panel core type (PIR or Mineral Wool), and thickness to meet your specific needs and ensure full compliance with current regulations.

Contact us on 01872 560488, or complete our quote request form on our website to discuss your insulation and building requirements.

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“The whole service we got from Atlantic was brilliant – from their Architect that got the planning to the supply of the building we wanted. The installers were brilliant too.”

Peter Cook, Cornwall.

2 weeks ago

We had an excellent service from Atlantic Steel who supplied and fitted our 6500 sq ft workshop. The process was straightforward and the result is very good. We have recommended Atlantic Steel to two other interested parties and would not hesitate to use them again.

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1 month ago

“We had first class service from Atlantic Steel and their product was very high quality. Their installers were fantastic and did a great job. We have recommended them to three other parties so far. We would definitely use Atlantic again.”

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