The price of the panels is not the price of a finished house. The panels may be part of the building envelope, but the building needs a structure, foundations, joinery and installations. Comfort and the way the interior is finished also matter. It is therefore worth building the budget for a complete solution, with a clear scope for each stage. The term “house with sandwich panels” does not describe a single construction technology. It may refer to various structures in which the panel forms part of a wall or roof. It is necessary to establish what carries the loads and how the elements are connected. A self-supporting cladding panel does not automatically replace the entire frame.

A masonry wall is not always a ready substrate for new panel cladding. First the masonry must be assessed and the way loads are transferred determined. Only then are profiles, anchors and fasteners selected. During refurbishment, unevenness, the condition of lintels and space for sealing the entire building envelope also matter. Begin by establishing what the wall is built from. Solid brick, block and concrete require different fixing solutions. Plaster alone says little about the load-bearing capacity of the substrate. Exposing a few locations may reveal hollow joints, friable areas or earlier repairs. The parameters of a new material must not be assumed for an old wall without assessing its condition.