“[With] fully adhered [systems], you’re totally reliant on the substrate that you’re adhering the membrane to [in order to] hold the roof on. You’re not using fasteners and plates or bars, you’re just gluing the membrane to the substrate – sometimes, that’s right to the deck material, insulation, and in some cases, an existing membrane. While mechanical fastening involves the expense of increased labor time and materials, fully adhered systems can be quite economical – especially when considering self-adhered products like peel-and-stick TPO.

Again, it’s important to think about the roof deck and its role in this decision. “We don’t recommend mechanically attaching a roof – any kind of roof – to a concrete deck. We just don’t think it is the right thing to do (hammer-drilling holes in a concrete deck to attach the roof). Now, we do recommend adhering single-plies to a concrete deck with an adhesive. We think that’s an appropriate solution. While it’s not uncommon to mechanically fasten a roof to a concrete deck, fully adhered systems have been found to provide excellent wind uplift resistance in these applications. Additionally, various peel-and-stick TPO membranes must have a suitable substrate in order to bond properly.