Sheet Metal Screws vs. Wood Screws
I'm getting ready to mount my solar panels to my 5ver roof. It's 3/8" plywood. I'm planning two screws per bracket and four brackets per panel. I bought stainless steel screws for the mounting and pla...
Forum Discussion
allen8106 wrote:GaryKH wrote:
I will second the use of well nuts, as they were designed for this type of application. It is best practice to fasten into a rafter, if possible. Use a stud finder to locate where they are. Use dicor around the well nut to seal against the wood (redundant as the rubber will seal, but for secondary backup). Use a poly butyl tape for under the bracket and tighten so that it squeezes out. Complete the job with dicor sealant over the bolt head and around the (trimmed excess of butyl tape) outside. Make the sealant rounded over, so that there are no sharp edges, it functions better that way. JMO
I've never used a well nut but based on the instructions I saw I don't think you want to drill into a rafter. The well nut appears to be designed to flatten out under the panel it is placed in. Can't do that if you drill into a rafter.
You are correct in that they can be used through sheet goods. It can also be used in a blind hole. In a blind hole (in the rafters), it expands and grips the sides of the hole. Very strong!
