rotted wooden panel repair

Q: I was told by a neighbor that the corner boards on the back side of my house are starting to rot. (The paint there is beginning to peel.) Is there some way that I can tell if a particular spot is actually rotted? –Lane M., Roxboro, NC

A: Hi Lane, testing for rot is actually very easy. More often than not, people suspect that they have bad rot when they actually only have damp wood.

(Tools and materials are linked below strictly for informational purposes–no marketing revenue is generated through these links.)

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The best way to test an area for rot is to simply poke it. Rotted wood will be soft to the touch. You can also use a sharper object, like a screwdriver or awl, to test the area. If you can’t sink the blade of the tool in more than 1/8”, the wood has probably not given over to rot yet.

wood rot test with screwdriver

If the area is wet but not soft, then it’s probably not necessary to replace anything. However, you should do everything you can to figure out where the moisture is coming from, and prevent the area from getting any wetter.

There are a couple typical sources for excessive moisture on exterior trim:

An overhead gutter is not channeling water effectively. 

Sometimes gutters may be overspilling because they are full of leaves and twigs and need to be cleaned out. Other times, the gutter has become pried away from the fascia, and water is falling behind it. Check the gutter above your problem area to make sure it is moving water like it’s supposed to.

Water may be splashing up from ground level.

This is a very typical situation with damp corner boards. Either direct rain or water spilling off the roof bounces up from a hard ground surface and soaks lower parts of the house.

To solve this, you can add an aggregate drainage material, like mulch or washed stone, to the ground below to capture excess water. You might also consider adding an aluminum diverter to the roofline above this area to channel water away.

If you can reduce the amount of water that hits the problem spot, and get it to dry out a little, you can protect it in the future by caulking and painting it properly.

Here’s a good link for info on prepping an exterior trim spot for fresh paint.

If you have any questions about what I’ve discussed here, feel free to write to me through the Contact page of the website.