Need help preventing future water damage and rot

Hi,

First, I apologize if this is the incorrect forum for this.

I recently purchased my first home and I have severe trim rot along the side of my house with the garage. I pulled it off and found out why it was so bad - it appears that water can travel along the other side of the house and get in behind which also caused the plywood to rot... Here's pictures to show you what I mean (click to enlarge):





The hole in the retaining wall in picture 2 is for the gutter I just removed to remove the trim. But water seems it get in from picture 2 (there was a trim piece all the way down, but I removed it). I'm not sure how I can fix this side properly so water doesn't get down and behind again (assuming I'm correct..). I can fix the rotted plywood and replace the trim but this doesn't really fix the problem. I thought this was going to be easy!

Thanks in advance for any suggestions!

 

this probably isn't what you want to hear, but you probably need to take down that retaining wall, and install a corner flashing behind your trim, running a bead of sealant behind the metal flashing so that water can't get behind it. You'd probably also want to use a wider corner trim on top of the cement so that you have some overlap. It can be attached on the left side (into the cement) with countersunk 3/16" x 1 3/4" tapcons.

We also now know that Tyvek and cedar shingles do not play nice together. The tanins in the cedar eventually degrade the Tyvek, making it lose it's water resistant properties.

You might also ensure that there aren't penetrations through the siding that are leaking (all those electrical conduits). Often the main meter is hard to seal behind since it usually can't be disconnected.