How do you choose the thickness of roof panels for garage conditions?

If you plan later heating, describe it at the design stage. A material selected solely for the initial function may require reconstruction. The walls, door and floor must also be checked. A thicker roof alone will not turn the whole garage into a well-insulated workshop.

The core dimension and the overall height with the trapezoidal steel sheet may differ. In a specific family, a 60/100 mm panel has a 60 mm core and a height to the profile apex of 100 mm. The 100/140 mm variant has a 100 mm core. Do not compare these designations as a single insulation value.

Enter the full description in the order. The seller should specify the correct thermal parameter and cross-section. Two panels described by the abbreviation “100 mm” may have a different construction. A drawing and product identification help avoid a mistake before delivery.

For selected roof PIR panels, cores of 40, 60, 80, 100 and 120 mm have U-values of 0.50, 0.34, 0.25, 0.20 and 0.17 W/(m²·K) respectively. These are data for one family. They do not constitute a universal thickness recommendation for every garage or every manufacturer.

A lower U-value reduces heat flow through the panel under the same conditions. However, the design and target temperature determine the choice. In a heated garage, the door and the frequency of its opening must also be calculated. They can have a significant share in the balance.

Water carried in on the bodywork and wheels can evaporate inside. If surfaces are cold, the risk of condensation increases. An insulated panel can improve thermal conditions, but does not remove the source of moisture. Adequate air exchange is needed.

Do not block ventilation openings with random shelving or insulation. Also check water drainage and the condition of the floor. Persistent dampness requires identifying the cause. Roof thickness is one element of the solution, not a substitute for the entire moisture management.

Check snow and wind loads, purlin spacing and bearing width. A panel with good U-value may still require a different support arrangement. Span cannot be determined from core thickness alone. The facings and span scheme are also important.

If the garage stands against a higher wall, allow for local snow conditions and water runoff. A roof connected to the house requires detailing of the junction and the required safeguards. Do not copy the arrangement from a detached carport of similar floor area.

Thickness also does not determine the permissible roof pitch. This results from the roof system, the joints and any openings. Increasing the core from 60 to 100 mm does not permit laying the panel on a horizontal structure without checking drainage.

Gaps in the insulation at the eaves, corners and wall junction create weaker points. A leaky joint allows air flow. A duct penetration requires proper sealing and protection of the core. Increasing the thickness in the middle of the roof slope will not fix these errors.

Allow for the installation of the door drive, lighting and services. Their weight should be transferred to the appropriate structure. Do not hang equipment on the lower facing alone without checking. Accidental holes can also impair tightness and the durability of the surface.

Assume 30 m² of ordered panels and an agreed net price difference of €5.09 per m². The surcharge will be €152.70 net. This is purely a comparative calculation. Also check for changes in the length of connectors, flashings and any lifting arrangements.

Assess the surcharge together with the usage plan. For a periodically heated workshop, it is worth calculating the target thickness straight away. For a cold garage, other characteristics may be more important. In both cases, the structural and fire requirements of the specific project must be met.