W38 (YX38-152-914) is an FM-approved steel roof deck geared specifically for the waterproof single-ply roofing.

The wave crest is wider than the opening, thus suitable for the combination of FM approved thermal insulation materials and flexible waterproof membranes to form a complete wind-resistant and waterproof roofing system.

Different from the ordinary metal roof deck, W38 allows the purlin spacing to be extended under the same load, so as to take full advantage of its excellent section properties.