Replies

1. 
   Guest_ | Feb 20, 2000 07:33pm | #1

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   .Blackhawk.

   where do you live?

   around here, if the roof is wood and 25 years old, when you do a close inspection , you'll find that the shingles are too deeply penterated by rot and too brittle to do much with.

   If you do find good wood, think about a very low pressure spray solution to clean them...some zinc strips along the ridge.... and cut back or prune the overhanging branches
   which are usually the source of the organic material supporting the moss.....

   A thorough cleaning will probably remove too much material and the roof will need replacing...

   ...if you decide to replace with red cedar or any other wood product, install your new roof over a breathing layer, such as Shingle Breather, or skipped sheathing..

1. 
   Guest_ | Feb 28, 2000 03:41am | #2

   *Contact the Forest Products Department at Oregon State University and see if you can get a copy of the Extension Publication entitled "Care and Maintenence of Wood Shingle and Shake Roofs". I wrote it when I was there several years ago. It costs about $.75 and maybe shipping and covers the various chemicals, washing solutions etc.If you cannot, get back to me and I'll try to answer specific questions Stanley Niemiec [email protected]

1. 
   Guest_ | Feb 28, 2000 04:35am | #3

   *Bear in mind that the algae that grow on roofs are windborne, so even killing that which is there won't keep it from coming back if the growing conditions remain. I would think that 25 years is about it for a shake roof, and replacement should be in your near future plans, particularly if you have rot.

1. 
   Guest_ | Feb 28, 2000 09:21pm | #5

   *Bleach and chemicals like copper sulfate will kill the moss -- it will not prevent its return which is why there are preservative solutions (eg zinc or copper napthanate sp?) that will provide some level of long-term prevention (2-5 years). Avoid any oil product that does not have a fungicide/mildicide included, as the oil will provide a food source for molds, mildew and moss. Once the moss has been "killed" you have to get it off the roof. Most commercial services use a high pressure washer but if you don't exercise judicious care you can excessively erode the surface of the shingles/shakes. A hose will work especially if you use a broom. Zinc strips will help retard moss growth but so will copper. Copper is more effective than zinc as an anti-biocidal agent. You can get copper ground wire and run it just below the ridge cap and then depending on the size of the roof at various intervals. The best thing that you can do (as someone else mentioned) is to trim/remove overhanging branches. These shed debris and retard/shade the drying of the roof surface.I hope this helps

2. 
   blackhawk | Feb 28, 2000 09:21pm | #4

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   How or what is the best way to remove moss and mildew from a cedar shake roof?
   The roof is approx. 25 years old and seems to be in good shape. Thought about using diluted oxalic acid or bleach.