T18 or T35 façade sheets: coordinate profile, supports and window details

The designation suggests the depth family, not the complete section. Compare broad flats, ribs and effective cover width in drawings. Two products called T18 may differ in details affecting appearance and jointing.

Consider a shallower profile for a finer scale and a deeper one for stronger divisions on a large wall. This is a visual judgement to test on a sample. Similar colour or naming does not confirm technical interchangeability.

Stiffness also depends on thickness, steel and support arrangement. Wind suction is particularly important at corners. Support spacing and fixings must follow the design and product data, not the T35 label alone.

Check the load path all the way to the building wall. A stiff sheet cannot compensate for weak substructure anchors. Separate responsibilities for sheet, rails and anchorage in the quotation to avoid a design gap.

Mark the exposed face on the section before buying. Roof and façade variants may present different profile flats. Confirm coating position and installation direction; “graphite T18” is too general a specification.

Coordinate vertical or horizontal ribs with windows and field lengths. Either direction needs correct drainage at interruptions. Prepare a full wall layout to avoid arbitrary short pieces during installation.

Account for rain, sunlight and local pollutants in the specification. Industrial exposure or aggressive substances may restrict choice. Colour does not describe corrosion resistance; obtain data for the actual finish.

Matt and dark finishes do not conceal every unevenness. View the sample outdoors in the planned rib direction beside the windows. Compare maintenance and warranty conditions as well as appearance.

Sheet can form the outer skin of a designed assembly. Behind it, provide the cavity, substructure, insulation and wind protection. These perform different functions; installing sheet on the wall cannot replace them.

Protect air inlets and outlets without restricting required openings. Interruptions at windows, the base and other details also need fire-related consideration. Do not arbitrarily substitute materials specified as part of the assembly.

Match sheet lengths to façade fields and handling methods. Fewer joints do not justify bending overlong pieces during lifting. Mark corners, sills, heads and base drainage on one coordinated drawing.

Align fixing lines with rails and structural requirements. Do not remove necessary fixings for a cleaner appearance. Clear drilling and cutting swarf and check edges before rust stains the new finish.

Compare effective coverage together with substructure, fixings and trims. Around many windows, detailing can be a significant cost. Include cutting, transport and labour separately rather than comparing sheet prices alone.

Approve the profile after comparing the sample with the layout and checking performance. Either T18 or T35 can work when it suits the building’s scale. A considered arrangement matters more than rib depth alone.