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Brick is usually nothing more than a rectangle or square of hardened clay-bearing soil. The standard size is three-and-five-eighths inches deep, two-and-a-quarter tall and 8 inches long.

In a Life After People, bricks like these can't last even half a century without human maintenance.

But let's say that the standard brick is bigger--three-and-five-eighths inches deep, seven-and-five-eighths deep and fifteen-and-five-eighths long. Let's also say that the brick is made not of clay, but solid rock, preferably marble or granite.

In a temperate zone, akin to New York or Chicago, if a brick house does have bricks as described above, how long will the house's outer skin stand in a Life After People?

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    $\begingroup$ Look at bricks that have lasted, like some of those from ancient Mediterranean cultures. "Solid rock" would not be a brick but natural stone. $\endgroup$ – JDługosz Oct 27 '15 at 5:53
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There's two factors that you need to worry about: chemical weathering and mechanical wearing.

Chemical Weathering

For chemical weathering purposes, perhaps the best rock to last through the centuries would be slate.

Remnants of rock after chemical weathering -> silt
Silt compressed into rock -> Shale
Shale metamorphosed -> Slate

Since slate is compose of only mineral grains that survived chemical weathering, it is of necessity highly resistant to chemical weathering. Unfortunately, it really isn't resistant to mechanical weathering. So if not subjected to mechanical weathering, your best bet is slate. It would likely last several centuries for rain to erode the house.

Mechanical Weathering

To resist mechanical weathering you want a rock that is very hard and tough. Granite (and related rocks like andesite & rhyolite) are composed of multiple different minerals. In combination they act like a composite material with the different materials providing some of their better qualities to the overall structure.

Unfortunately, several of the minerals in granite are highly susceptible to chemical attacks. Stroll through a cemetery and look at the granite headstones. After a few decades the chemical weathering begins to make reading those headstones quite difficult.

But if you took a hunk of slate and bashed it into a hunk of granite, the granite is going to win - every time.

For water to erode the structure will likely take 1-2 centuries.

The Winner

Since you stated this is a post-human world, I'll make the assumption that weathering is the primary factor for your building - which means Slate is the ultimate winner.

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  • $\begingroup$ 1) How common is slate? 2) How do you mean by bashing? $\endgroup$ – JohnWDailey Oct 27 '15 at 4:14
  • $\begingroup$ Are plants (roots etc) part of your mechanical weathering analysis? What about the joints, between bricks? $\endgroup$ – Lyndon White Oct 27 '15 at 4:19
  • $\begingroup$ I think you need to think about the mortar that's holding the bricks together. $\endgroup$ – Howard Miller Oct 27 '15 at 6:36
  • $\begingroup$ For chemical weathering I was thinking about just exposure to the atmosphere and rain. For mechanical weathering I was thinking about plants and other things actively rubbing against the materials. "Bashing" means hold one type of rock in one hand and the other type in your other hand and smash them together until one is dust. Slate is fairly common. I selected slate over shale because it is just as chemically resistant but is better mechanically resistant than shale. $\endgroup$ – Jim2B Oct 27 '15 at 12:33

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