Exterior abrasion

This is something I noticed while waiting to use the ATM at my bank. I have always known the power that water has as far as how it can carry away cars in floods and how rivers and rapids are. But water, given time, can wear away rock and other sediments such as this formed block used to build this wall. Ascetically speaking, they should have figured a way to keep the water from draining off of the bricks. I have seen items that resemble a tongue affixed to the opening. Just something I thought should be shared among my fellow inspectors.

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I would have to think that was something other than water.
Condensate, maybe. De-humidifier. Ext.

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Yes. Roof drains (spouts) would’ve been elsewhere. My point was that, given time, water can cause some serious damage and lead to problems down the road.

Water has incredible power.

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Acid Rain. LOL

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True, but that looks like spalling to me.

That is split face block and colored CMU and not very resistant to erosion of the surface unless properly water sealed.

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Spalling and possible organic growth.

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I agree, that’s a very common method for discharging water from a roof but that’s not a common type of damage. It may be that chemicals from some material on the roof are being leached out and included in runoff and are causing that damage. Maybe it’s a siphoning type drain and water discharges at a velocity that exceeds the capacity of the discharge pipe outlet diameter to handle. At any rate, it seems unusual.
In my opinion it’s erosion and not spalling. During spalling, pieces separate as flakes containing both sand and cement. In erosion, cement erodes from between sand particles by water flow action and finally the sand particles are carried away. Erosion can be accelerated by anything that hastens the rate at which cement dissolves; possibly high water temperature/pressure, or chemicals that act as solvents to cement.

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I just happened to speak to a service tech for the bank/store and when asked he told me that’s a common drain tubing that ties the a/c and a dehumidifier for the ATM.

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That makes a lot more sense now,

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Condensate discharge starts to make sense as Marcel surmised. The discoloration looks organic, possibly originating in a fouled condensate system that’s been incubating corrosive bacteria or simply some water- and dirt-retaining algae, in any case causing microbiologically induced corrosion. Disinfection of the lines and a small diverted under the grate would probably solve the problem.