Metal Building Insulation — Thermal Systems & Insulation for Metal Buildings

Both rock wool and glass wool are mineral fibre blanket insulation with similar thermal performance at the same thickness. Rock wool has slightly better fire performance — reliably classified non-combustible Class A — and provides better acoustic attenuation for noise-intensive environments. Rock wool is heavier and typically slightly higher in cost. For industrial buildings, government facilities, or any project with a stated fire safety requirement, rock wool is the more conservative specification. For general commercial warehouses, offices, and agricultural buildings without specific fire requirements, glass wool is the standard choice at good value for the performance level.

Insulation thickness is determined by the U-value target, which depends on building use, the local outdoor design temperature, and whether air conditioning is present. We produce a thermal calculation for every insulated building project as part of the initial design proposal. For occupied buildings in tropical West African and Southeast Asian climates, the standard configuration is 75–100 mm glass or rock wool for a non-air-conditioned building, or 100–150 mm for an air-conditioned building where reducing cooling load is an economic priority. Specifying 50 mm as a cost-saving measure in tropical climates typically results in a cooling energy penalty that recovers the cost difference within the first year of operation.

Insulated sandwich panels are the mandatory specification for cold storage buildings at any temperature below ambient. For above-ambient applications, the choice between sandwich panels and blanket-plus-liner depends on performance targets, fire classification requirements, and programme considerations. Sandwich panels integrate outer face, insulation core, and inner face into one factory-assembled product, eliminating the on-site blanket-laying and liner-closing sequence. They achieve a given U-value at smaller overall thickness. The trade-off is higher material cost. Where higher thermal performance, a tighter building envelope, or cold storage capability is required, sandwich panel is the appropriate specification.

A vapour barrier is a low-permeability membrane on the warm side of the insulation that reduces the movement of moisture-laden air into the insulation cavity. Without it, warm humid air from the building interior migrates into the insulation, cools as it approaches the outer panel, and condenses. Over time, this moisture accumulation degrades insulation performance and accelerates corrosion on the inner face of the outer panel. In tropical climates with high ambient humidity, the vapour drive is higher than in temperate climates — making vapour barrier specification more important, not less. We include vapour barrier specification in all insulated building packages for tropical climate projects as a standard design provision.

For a building erected without inner liner structural provisions, retrofitting a blanket insulation system requires opening the outer envelope, adding liner support rails to the secondary structure, installing insulation, and re-closing the envelope. This is a substantial construction operation — the cost is typically similar to the original insulation package cost if it had been included at the design stage, and the thermal result is rarely equivalent to an integrated installation. For insulated sandwich panel systems, the only retrofit path is removing and replacing the outer envelope. We treat insulation specification as a design-stage decision and include it in every initial project proposal for buildings in climates where thermal performance is operationally relevant.

Yes. Cold storage buildings at any temperature below ambient require continuous insulated panel envelopes as a structural prerequisite. The thermal load through an uninsulated envelope makes the refrigeration plant required to compensate uneconomic to purchase and to operate. For chill stores at 0–8°C, PU sandwich panels from 80–100 mm are the standard specification. For deep freeze stores at −18°C to −25°C, 150–200 mm PU or PIR panels are required. Panel thickness must be calculated from the target temperature and local ambient climate — not from a generic cold store table. This is addressed in detail on our Steel Cold Storage Buildings page.