wood rot around windows

We noticed a crack form on the outside of our house under some windows, the wall inside between the windows may have a slight bulge (tough to gage visually).
I got a good look at the area today. The windows have boards nailed above and below. The caulk had deteriorated allowing water to get in behind the boards (and I will assume that is unintended and thus bad). The boards are pretty well rotted. I applied caulk to hopefully prevent additional water from seeping in but the boards will need replacement. The siding below the bottom board is showing a large crack that was not there two years ago (it's now filled in with caulk too). The foundation isn't showing cracks but the previous homeowner appears to have applied a thin layer of something over the sides of the foundation (or maybe that's been there - house built in 86).
Buying lumber and sawing it to proportion is not difficult for me. I can also seal up any holes where water might seep in when I replace the old with the new. I'm more concerned about what I might find when I remove the rotten boards (or what I should try to find).
What can I expect, what should I look for, any reason I should consider having a professional to handle this?
Thanks!
-- gorf
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There are a great number of windows that were and are installed incorrectly. All windows should be flashed in such a way as to direct water outside the building. The head flashing should push it out onto the window top and to the outside of wall siding and keep water away from the wall sheathing. This should happen down each side. There should be a sill pan under the window that catches any water that did make it into the window system and turns it out away from the building envelope and to the exterior portion of the siding.
If you have signs of moisture damage to the sheathing below the window or any signs of mold growing under the siding or in the sheathing or insulation, get a good carpenter involved.
Look at the Journal of Light Construction site and look up an article on the proper way to flash windows in their archive. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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Visit www.pella.com and download installation instructions. Even if you have crappy windows, Pella instructions shows the importance of flashing them right during installation.
Also visit www.bia.org and read tech notes about installing windows in brick walls. Again you will see importance of flashing.

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Yes, consult a professional -- but hire him only if he suggests the right kind of repairs. . . 1. Siding can usually be removed easily. His plan should remove whatever siding is necessary to survey the structure for rot damage and replace all damaged timbers, once and for all. 2. Windows should have flashing applied over them, i.e. thin metal under the siding (and out of the weather) that turns forward to make a tiny shelf above the window. If your man does not point this out, do not hire him.
The main reason you should hire a professional is because your earlier repairs did not weatherproof the house to your own specifications.
--
Don Phillipson
Carlsbad Springs
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