SashcoThrough The Roof Sealant, 10.5 oz Cartridge, Clear (Pack of 1)

Q: can this be applied over silicone

Says right on the container: "Remove any silicone with a silicone caulk remover".

Q: Is this a silicone or a rubber-based product? Or something else?

It says it's a co-polymer rubber in one of the descriptions.

Q: Why would this sealant and the through the roof cartridge sealant be "frequently bought together"? Is there a difference in what they do?

I bought the two together so that with the cartridge it could be squeezed into tight fitting cracks. And I bought the stuff in the can so that it could be brushed over to possibly seal anything that was missed with the cartridge. Kind of a double up in order to catch a leak that has been hard to find.

Q: Hi! Can I apply this with a foam brush?

Schmitt, you could over a small area, but the foam will fall apart. a 3 to 4 inch bristle brush is ideal for large areas. My wife has used a 2 inch brush on some seams on her car.