Replies

1. 
   Brewskie | Jan 08, 1999 09:15pm | #1

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   Tell us a little more about the construction of your house.

   Is it block, frame? What is the stucco attached to?

   If the stucco is over block then one coat may be suffecient. The plasterer can go over the block with a tight coat then "double-back" with a second texture coat.

   However, if it is over metal lath then you need to talk to your plasterer about ethics. Because this is a three coat system.

   As for the light and dark areas. It sounds like the stucco may have had a poor curing period by drying too fast in some areas. This may also be caused by the plasterer wetting the base coats too much, before applying the finish coat, and the wall has dried poorly. But you said your plasterer applied the plaster in one coat so this may not be the problem.

   When plaster is applied you need to have good ventilation. Sometimes, if you're not carefull, localized areas of the stucco will dry and/or curing too fast. The areas that have dried correctly have remained darker.....like the color it should be. Whereas, the lighter areas is where the stucco has dried out too fast, washing out the color. So not only do you need adequit ventilation but it also has to be evenly disbursed across the wall surface.

   The only way to fix these walls will be to fog coat them or do a re-scrub over them.

   A fog coat is lime, cement and pigmentation (no sand). This is sprayed over the stucco to give it a uniform color appearance. Most manufacturers of stucco have this in their stock. Be sure you get the real thing tho....Some manufacturers will try to sell you a paint and call it fog coat....DO NOT DO IT!!! Paint will ruin the value and look of stucco! And once it is painted it will have to be sand-blasted if you ever want the true look of stucco again and paint will seal the plaster and not allow it to breathe as it should.

   To do a re-scrub is just to give the wall a new coat of the same stucco as the first time. Be sure the wall has been scraped and wet before applying it.

   Another cause of color deformation is freezing and improper application.

   If stucco freezes before it cures it crystalizes. During this crystalization process the pigments are suspended. When the plaster thaws the color becomes washed out. One way to tell if the plaster has done this is to scrape it with a nail or something. If it is rather powdery and it has glittery stuff on it (after it has thawed) then you do have a problem and the stucco has to be scraped off and re-applied.

   Improper application will cause what is known as "burn". Painters get this problem occasionally also. It's caused by not keeping a wet edge as you plaster across the wall. When the plasterer goes back over the stuff he just applied it may burn, causing a section down the middle to have a darkened streak where the two joints meet. The way to keep this from happening is to wet the wall according to the temperature and humidy of where the plaster is being applied.

   If the temperature is high and the humidy is low the plasterer will need to apply more water to the wall to keep it from drying out and burning as he works. If the temperature is low and the humidy is high then the plasterer will need to apply less water to the wall. It takes experience and trial and error to get it right. The first batch in the morning is usually when the plasterer will know how the wall is going to behave and he can adjust the water accordingly.

   I know you had a contractor do the work. But the info I gave you here may help you to be aware of how this should be done.

   Brian Ewing

   OrnamentalPlaster.com

2. 
   Don_MacShane | Jan 08, 1999 09:15pm | #2

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   I need help desparately with a stucco problem. I have just finished having the
   interior walls of my new house stucco-ed
   and the following problems has occurred.
   First, in some areas the wall looks like
   a different color ( much darker) as if there is moisture behind the stucco. Second, there are spider like lines in some areas where the stucco was applied. A little backround! The house
   is being built during the rainy season down here and the moisture is unbelievable. Second, the sub who has done this job(Costarican, not American)
   claims one coat of stucco on interior walls is suffient? Is there any way to repair this problem. Any suggestions will be greatly appreciated.