Would a 40 mm second-grade roof panel suit a small warehouse?

In a hypothetical warehouse in Drawsko Pomorskie, equipment may come back from use wet. Drying capability and air exchange will be needed. A panel with a core limits heat flow but does not remove water from the interior. Increasing the roof thickness alone will not fix a lack of ventilation or a damp substrate.

In a roof panel, the nominal thickness does not have to mean the total section height. The outer trapezoidal sheet cladding increases the height at the rib. For thermal comparison, the declared value specific to the panel is used. Do not calculate it from the highest point of the profile alone.

In one verified PIR roof family, the 40 mm variant has Uc 0.49 W/(m²·K). This is the value of a specific product, not of all panels bearing that name. When assessing a heated room, walls, floor, doors and details must also be taken into account. The required configuration must be established in the design, without automatically assuming a thin core is sufficient.

The condition of the top cladding, the side lap and the panel ends is particularly important for tightness. A dent in the joint zone can make it difficult to assemble the components correctly. Damage to the coating requires an assessment of whether it can be protected. Not every blemish can be treated as a minor aesthetic defect simply because the roof is barely visible from the ground.

For second grade, ask for a description of the deviations and the scope of confirmed properties. Do not accept a general statement that ‘it will be fine for a warehouse’. Even a small building must have functioning connections and adequate load-bearing capacity. Missing documents or an unclear panel condition must be clarified before purchase, not after the material has been brought onto the structure.

The commercial length of the panel is not the permissible purlin spacing. The design must take into account loads, cladding thicknesses, colour and single- or multi-span arrangement. A small warehouse footprint does not exempt it from this check. Likewise, the number of fasteners does not follow from one universal rate per m².

The minimum pitch may depend on whether the panels are continuous or joined transversely. Requirements for rooflights and other penetrations also apply. Making an additional joint from short sections must have proper support, overlap and sealing. This detail should not be based on a random piece of sheet metal and a large amount of sealant.

For example, 38 m² of material at a contractual €25.23 net gives €958.74 net. If a better-fitting variant requires purchasing 34 m² at €28.47, its cost is €967.98. The difference is only €9.24. These are solely calculation assumptions, not market prices or a current offer.

With such a small difference, additional cuts, seals or one special flashing can change the result. Also count transport and lifting. Do not subtract the value of every offcut from the cost if there is no planned use for it. What matters most is the expenditure on a correctly executed roof slope, with complete drainage and protection of the core ends.

Use tools approved for cutting the panels, without overheating the coating. After drilling and cutting, remove swarf, including from the profile recesses. Check the pressure of the washers and the continuity of the seals before these areas are covered. Flashings should direct water to the outlet, not create random ponding.

After completion, check the gutter, corners and connections to the existing building. Access to the roof for inspection requires compliance with the rules specified for the covering and structure. Do not treat the panel as a general-purpose working platform. Even an inexpensive warehouse benefits from careful installation, because repairing a leak above stored equipment can cost more than the initial difference in quotes.