Replies

1. 
   rvillaume | Jun 29, 2004 02:31pm | #1

   I don't know if this is "roofer approved", but I've used a weak muriatic acid wash before with a stiff brush.  Sometimes took a couple times to get it mostly clean.  Rinse well.  If there's copper flashing, you want to cover that otherwise it will turn black.

1. 
   DIYER | Jun 29, 2004 04:38pm | #2

   I'm not even sure you can get muriatic acid anymore, seems like they've pulled it off the shelves in most stores, I know they don't carry it at the Depot anymore

1. 
   rvillaume | Jun 29, 2004 04:52pm | #3

   Maybe, but we don't have HD around here so wouldn't know about that.  I'd bet you can still get it at masonry supply stores, but I am going to check around.  Just used the last of what I had. 

2. 
   rjw | Jun 29, 2004 10:43pm | #4

   >>with a stiff brush

   On fiberglass shingles?

   Ouch! Sounds like a great way to lose the stone and shortly after the shingles themselves.

   "It is as hard for the good to suspect evil, as it is for the bad to suspect good."

   -- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)

1. 
   rvillaume | Jun 30, 2004 02:46am | #5

   How about "stiff brush with a light touch?"

   Seriously, I've not had a problem with this, but you've got a point.  If it hasn't been too long since the guy's been there, you don't have to rip into it.

   Edited 6/29/2004 7:58 pm ET by RVillaume

2. 
   EricPaulson | Jun 30, 2004 03:54am | #6

   Bob,

   It's not as caustic as it soound. I may erode the granules slightly at full strength, but I dont believe that it will harm fiberglass or the asphalt especially if it is not left to sit and is rinsed off.

   This is probably a good solution to gettting the mortar haze off. I've used it to remove pee stains from terra cotta and hardwood floors quite successfully.

   Use of eye and face protection is highly recommended!

   EricEvery once in a while, something goes right!

1. 
   rjw | Jun 30, 2004 04:39am | #9

   I'm corcerned about the abrsion of the brush, not the acid.

   "It is as hard for the good to suspect evil, as it is for the bad to suspect good."

   -- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)

2. 
   WayneL5 | Jun 30, 2004 04:05am | #7

   If you wish to try something less strong first, try vinegar.  I don't give it high chance of working, but if the stains are light, it might.

   With either vinegar or muriatic you don't want to use lots of it and have it run off the roof to be wasted or kill the plants around your shrubs.  Nor eat away at your foundation.  Try covering the stains in a couple of layers of heavy fabric, like burlap, and saturate it.  The fabric will hold the acid in place and you can use much less.  Capture the runoff in a plastic bucket under the downspout.

   A masonry supply house will have laitance remover, which may be milder than muriatic.  It's worth asking.

1. 
   jalex | Jun 30, 2004 09:24am | #10

   Thanks for the suggestions. It's a new house, so there is no landscaping to worry about. However, there are copper gutters and valleys, so muriatic acid is probably out. I will try the vinegar tomorrow, but will test it on some scrap copper first. Thanks again.

1. 
   DanH | Jun 30, 2004 05:40pm | #11

   Place a rag or heavy paper towel over the stain and pour the acid (strong vinegar or weak muratic acid) on that. This will keep the area damp and keep the acid from running off. Leave it for 10-15 minutes minimum, then hose off.

3. 
   bkhy | Jun 30, 2004 04:12am | #8

   no problem---have roofer replace the stained shingles & deduct the cost from the mason's payment.however,give the mason a chance to fix it himself.