Edison Coatings wrote:
>
> I am just a chemical engineer
>
And I am just a guy that gets to play with stuff.

I agree that control of water flow through maintenance of gutters, 
leaders, roof systems etc. is way more of a factor in the deterioration 
of brownstone facades than coatings. Though I really am solidly against 
the wholesale use of cut-n-stucco techniques.

I have encountered situations, one in particular, where the sandstone 
(not brown in this case) was coated so many times by maintenance staff 
that it was the coating that held the stone together. Once the coating 
was removed the stone crumbled, whereas everywhere else on the facade 
where maintenance could not conveniently reach the stone was in 
noticeably better, though admittedly poor, condition. So, I would prefer 
appropriate maintenance if it is to occur at all. In my experience 
though knowledge is not very well communicated to maintenance. Which 
brings up questions as to how knowledge of anything gets disseminated 
into the built environment. Many times experts are not brought in to see 
evidence in the field as there is no motivation to involve them -- then 
the question is how do they learn?

> If you don't have tons of water pouring into the wall system, letting 
> it out just isn't that big a deal.
>
Yeah, all you need is good flow, a few well placed holes.
>
> ...they just aren't seeing the predicted damage. DUH! But hey, don't 
> acknowledge those of us who questioned the conclusions on this 
> subject 25 years ago.
>
I agree with your sentiment re: the back-n-forth on clear coatings. It 
is curious to me that a quarter century can go by and yet there is no 
conclusive consensus. One expert doctor will say it is good to beat 
children, another expert doctor will say that it is not. Personally I 
find the lack of consensus, and the constant reiteration of pro and con 
to be the more interesting subject.

I remember a time when to say 'abrasive blasting' was suicide and that 
was when I was playing with plastic media to remove epoxy paint from 
granite at Carnegie Hall. Then came micro-abrasives and soda blast and 
all sorts of chummy stuff.

][<en



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