We realized there was some rot on the exterior of the house when we bought it two years ago, and I knew obviously I would want to deal with it eventually.
As I've been looking more around the outside of the house, getting ready for new projects (planning on painting the exterior soon) I'm noticing just how much and how bad this rot actually is.
Before I go ripping this wood off the side of the house and trying to replace it, I want to know what the actual cause may have been so I can prevent this from happening to this extent in the future. The house was only built in the early 1990s, so I feel like it's not nearly old enough for this extent of damage to happen naturally, but I really don't know.
I'd also like to point out that all that foam/silicon/paint trying to fix or hide the issue has been there from the outset; I have not touched this at all yet.
Any ideas or suggestions are greatly appreciated, thanks all.
http://imgur.com/gallery/XXtdMXU
Best Answer
The cause is simply nature. You've got wood that's outside. It gets wet, the wet stays in the wood, the wood rots. This happens when wood is left outside in an area where water can get stuck and the wood wasn't properly installed (no caulk) and isn't properly maintained (not regularly painted/caulked).
Much of the rot seems to start near places where wood was penetrated (nails, etc) which would make sense as an initial entry point for water.
The fact that it's on a corner near a downspout is probably a contributing factor. You should watch this area of the house during heavy rain to see if the gutters/spout are leaking.
To repair - replace the wood, replace it with new wood, seal the seams between wood pieces with paintable exterior caulk. Properly prime and paint the wood with exterior paint. Apply new paint regularly as per manufacturer (the paint that is) guidelines. Also check caulk regularly for potential need to replace.