#8 x 2 in. Philips Square Drive Flat-Head Full Thread Yellow Zinc Coated Multi-Material Screw (161 per Box)

A:  Yes, should hold and have a secure hold.

A:  With the information given, we would recommend a #10 x 2-1/2 full thread Unidrive screw. These screws are available in a 1lb box at Home Depot. MFG Part# 4101010500606. Thank you for being a SPAX customer!

A:  The #8 2" SPAX screws that I have that have a green label as does the box in the picture states on the face of the box:For interior use in wood, masonry, concrete, metal and plastic. This particular screw would do everything you want EXCEPT it is for interior use. You state that your use is on a roof. You need and exterior screw. You should be able to find a SPAX sister screw to the ones shown that are for exterior use..

A:  Sorry, but I've never needed a full thread screw and have not spent any time finding which are full and which are standard thread patterns. I'd rather tell you I do not have any knowledge in that area than come up with a response and be winging it.

A:  The information shown on the SPAX box reads:For interior use in wood, masonry, concrete, sheet metal and plastic.For windows you'd need an exterior screw.. I'm not sure on the other applications you mention whether or not they are for outside use. For any outside use, get an exterior screw.

A:  Yes can use

A:  Yes is a very good in all those materials

A:  Yes

A:  Hello, Both of these of these screws can be used in masonry applications but they must be pre-drilled. Secondly, as long as the screw is not exposed to the elements a yellow zinc coating will be fine. If the screw is exposed to the elements, we would recommend an HCR-X coated screw. Thanks for being a SPAX customer.

A:  already answered

A:  When you have a question about a product, read what is on the box or packaging. For this particular SPAX screw, the information on the box reads:For interior use in wood, masonry, concrete, sheet metal and plastic. It is also a full thread screw.

A:  The information on the box reads:For interior use in wood, masonry, concrete,sheet metal and plastic.You need to get a box of SPAX screw that are for exterior use. Other than that, the answer is yes.

A:  While this 2" screw would work for fastening underlayment plywood to a subfloor, I personally would prefer to use a nail gun and nails intended to use for fasten underlayment to a subfloor.

A:  I did end up purchasing these for the subflooring and they worked wonderful! You really don't know what's under the subfloor until you remove it, at least we didn't. We just bought this house and it's quite a few years old (built somewheres in the early 1900's). We had to sister some 2"x8"s to some of the floor joists to make the subfloor more level (we're adding hardwood flooring eventually). We also added some blocks between the floor joists to help make it a very sturdy subfloor. We needed to use a 90 degree adapter for our electronic driver because there was no way to get our electronic driver between the floor joists. I think the square head on these really helped. The square bit did a great job grabbing into the screw and we didn't end up stripping any heads at all. Definitely worth the extra money!

A:  Yes is very good for that

A:  Yes

A:  For use in fastening 23/32" underlayment plywood to a subfloor, they'd be as good a screw as any. But, for that particular usage, I'd prefer to rent a power nailer and use underlayment nails specifically made for that job.

A:  already answered

A:  Hello, Yes, the #8 x 2" or the 2-1/2" would be a great choice for this application. Thanks for being a SPAX customer, The SPAX Team