Replies

1. 
   hammer1 | Jul 23, 2007 04:05pm | #1

   The latest info regarding surface prep is not to use chlorine bleach to remove mildew, as was typically done in the past. Oxygen bleach is preferred. Pressure washing can be used but it can cause problems if done incorrectly. I don't see any need for pressure washing in most cases. The oxygen bleach can be applied with a garden sprayer and washed down with a garden hose using a gentle spray.

   A 100% acrylic solid color stain is a good choice, you may need two coats to cover the existing color. Longevity involves more than just the coating. There can be issues regarding interior vapor barriers, present coating on the siding, improper flashing, overhanging trees, close bushes and exposure. Cedar needs to breathe. Coatings that restrict this can cause problems. Your existing coating and it's condition may have an impact.

   Beat it to fit / Paint it to match

1. 
   steveNH | Jul 23, 2007 11:22pm | #2

   Thank you for the reply to my query.  The age of the house pretty much means there is no vapor barrier (e.g., Tyvek), so there may be moisture movement in and out.  Is the recommendation for oxygen bleach environmentally-driven, or is there a paint adhesion issue?  Assuming the solid color acrylic is properly applied, how does its life expectancy compare to oil-based stains?  With the solids content, is there a greater risk of peeling?

   Thanks again.

    

    

1. 
   hammer1 | Jul 24, 2007 05:01pm | #4

   Part of the issue with chlorine is environmental but it can also be hard on metals like nails and flashing. Chlorine also can turn the surface of the wood into pulp, oxalic acid can do the same. Both oxygen and chlorine are effective mildew removers but neither works well on tanin stains which can be a problem with red cedar. If you have these brown stains, oxalic acid is used but it doesn't remove mildew. From your original description, it sounded like the existing coating was in good shape and you were looking for a color change. Not knowing what the original coating was, the acrylics often have better adherence on a variety of surfaces. The color retention and resistance to fading are very good, red colors are a different ballgame. It's generally more resistant to blistering and peeling. It's also more friendly to the environment than oils. Head to head in controlled tests, the 100% acrylics seem to out perform oils on things like trim and siding. It is flexible and breathes which are good qualities on cedar. I have had better performance on my own place with the acrylics. Many manufacturers as well as the cedar bureau recommend it. http://www.cedarbureau.org/installation/finishing.htmBeat it to fit / Paint it to match

2. 
   Piffin | Jul 24, 2007 02:59pm | #3

   As with any other exterior painting, some sanding and scraping is usually required, but shakes are hand split and you would do damage to the appearance by sanding on them, so careful pressure washing will probably be the prep method.

   but I have almost never seen shakes stained or painted. Are you sure that you don't mean cedar shingles? These would be much easier to stain and are more commonly treated that way.

    

    

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1. 
   steveNH | Jul 26, 2007 05:25am | #5

   Thanks for the clarification.  They are indeed shingles - variable width.  Does that change your assessment?

1. 
   Piffin | Jul 26, 2007 01:10pm | #6

   For shingles I would use sander to prep and keep the water away from it. I would prefer a latex solid color from Cabot 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!