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I have been thinking about adhesion recently and, more specifically, have been thinking about adhesion to porous surfaces. I am a big fan of being able to adhere things together, on flat surfaces, with industrial strength adhesive. What are some of your ideas of how to go about adhering a flat surface to a porous one, or a porous surface to a porous surface? I have thought about the following ideas:

Adhesive foam that fills in the gaps of the porous surface, although this is difficult to remove and also will result in significant tension at the junction. Simple adhering double sided tape that is less firm than typical tape, allowing it to slightly adhere to the insides of pores. Using some substance to fill in a porous space, that results in a more flat space to use typical adhesion on. What are some of your ideas? I'm thinking about the following example (My question): You want to mount something to a porous material rooftop (i.e. asphalt) but you are limited in the fact that the object is heavy and you cannot pierce the rooftop, how would you go about doing this?

Thanks!

konnor
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  • Hello, and welcome to Stack Exchange. There are many more variables than porous-versus-sealed; a good answer will probably be broader than you think. – Daniel Griscom Jun 24 '16 at 19:23
  • @Konnor welcome to the stack exchange. You would not want to glue something to the asphalt roofing. You would want to screw or nail into the rafters and seal it. – Ed Beal Jun 24 '16 at 19:24
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    Could you simply identify the object you're trying to mount? The right approach depends on weight, shape, roofline, wind concerns, etc. and your current parameters are too broad. Generally speaking, surface adhesion on asphalt roofing is problematic because the aggregate covering the surface is itself not very strongly adhered, and you'd risk pulling that off / falling off with it. – Shimon Rura Jun 24 '16 at 19:58
  • Real questions are much easier to answer than vague generalizations. – Ecnerwal Jun 24 '16 at 20:15

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Heavy things are easier, actually. Standard approach for a "non-penetrating" roof mount is to simply let gravity hold it, with suitable "load-spreaders" to keep the weighted feet from damaging the roof surface, and sometimes EDPM rubber to add friction. Easier on "flat" (low-slope) roofs, or on the peak of pitched roofs.

If you thought that adhesive was a good idea in that case (most don't, is roof damage can result when the thing needs to be removed, or when forces beyond what you planned for remove it anyway) hot roofing tar would be ideal - it's most of what "asphalt" is, so it's compatible, and it will act a whole lot like hot glue. Of course, you are then depending to whatever extent you have uplift forces on how well the layer of roofing you glued to is glued or otherwise fastened to the layers below it - which is another reason this approach is not normal.

Ecnerwal
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