A Quick Fix for Difficult Dry Rot Repairs
Use a metal skin to cover and seal difficult dry rot problems
We began noticing the corner of our garage cupola showing signs of dry rot.
Dry rot is like a cancer it never looks as bad on the surface as it really is underneath, so at the first signs it’s time to take action before more damage can occur.
Since the cupola is rather large and heavy on a steep pitched roof, it wasn't a job my husband was anxious to tackle.
To totally repair the corner meant the entire cupola would have had to been taken apart and brought to the ground for shop replacement of the corner.
After climbing up and looking it over he noticed, the corner had a way to seal the top and bottom to prevent further moister from entering.
This is an important element in deciding to use a sheet metal skin over an area that has dry rotted.
With that we decided to bend a piece of sheet metal to make a wrap skin around the corner and the ¾” exposed edges.
With a very inexpensive sheet metal brake and very little experience in sheet metal work, we made the metal corner wrap.
To cut sheet metal use a square and a dull knife to scribe the edge. Continue to scribe until the sheet can be bent back and forth several times to release.
This makes a much straighter and cleaner edge than trying to cut with tin snips. Use the tin snips to trim the edges for a close fit.
The edges will still be very sharp and will cut you before you know it so be careful.
You may be able to rent a sheet metal brake or have a sheet metal fabricator make you a skin. It’s still far less than hiring a contractor to replace something like this cupola.
Since we made our skin corner wrap from galvanize metal, it needed to be degreased and etched in order to hold the matching paint. If not the paint would soon peel off.
We used a solution of ammonia to degrease and then hand sanded the surface with Emory sand paper to etch it so we could paint it.
After a dry fit we drilled some small nail holes and then gave it three coats of paint. We then dabbed Liquid Nails construction adhesive on the inside. Use galvanized nails to attach so they won’t rust.
After installing we then caulked all the edges, caulk the other entire surface cracks on the cupola, and then did a final coat of paint.
We were done within four hours; actually to put up the ladder, throw a rope over the ridge to hold onto and bend the sheet metal only took about an hour.
We did other projects in between, letting the caulking and then the paint dry took the longest.
We like this method better than using the wood filler approach. At least we know the area is now totally sealed off from future moisture.
The wood filler approach seems to be like filling a pot hole, it is only as good as the adjoining surface can be sealed off.