The Dormer: Structural Repair and moving a window.
Hidden Problems
One of the many attractive features of our current house was the built-in book case at the stair landing half way to the second floor. We thought this was the perfect location for our many photo albums. There was some evidence of a leak around the old window, which we had replaced. There was also some damage on the drywall ceiling where water had come in due to an improperly installed eaves trough. That problem, too, had been fixed shortly after we moved in.
The laminate top of the book case had been damaged as a result of the eaves trough leak, so I decided that I would remove the book case and build a new one (or not replace it at all). That was when I discovered that damage was far more extensive than I had ever suspected.
These photos show two views of the book case, one from the first floor looking up and the second from the upper floor looking down. Once the book case was removed, it was obvious that the drywall which it concealed was badly water damaged. Once the drywall was removed, the extent of the water damage was revealed.
The two horizontal 2x4s were the top plate of the main floor structure and the bottom plate of the dormer structure. They were so severely rotted, that I was able to crumble them with one hand with very little effort. The studs were also significantly damaged.
The "Mickey Mouse" Fix
I attached a 2x4 across the studs and propped it up with a 3 or four other 2x4s supported by the floor of the landing (not shown). I then surgically removed all the damaged portions of the top plate and the studs. The new top plate in this area is somewhat lower than the original so that it could be securely fastened to 4x4 posts on either side of the landing area using Simpson Strong Ties. The studs were sistered and toe screwed to the new top plate. The sheathing was reattached to the new structure from the inside using L-brackets (also by Simpson).
I was fortunate that all the damaged wood was easily accessible once the wall was opened up. The rest of the dormer is part of the bedroom and the top plate supports the floor joists. That repair would have been truly nightmarish.
More Problems
I was concentrating so much on replacing the rotted wood that I missed another obvious problem. At some point in this house's past, the original windows in the dormer were replaced with larger windows, but the installer did not properly modify the structure. Instead, he basically cut the opening and slapped the window in place. You can see how the studs had been cut to accommodate the window, but without a proper header supported by jack studs, the window is actually supporting some of the weight of the roof.
Time to Call in the Pro
With a major structural issue such as this, I knew it was time to seek the assistance of a professional contractor, and I have to say that it was money well-spent. While my work was "adequate," it was far from perfect. It was merely one Mickey Mouse fix on top of another, and, of course, I had not addressed the structure around the window.
The Proper Fix
The window was removed and set aside. The 2x4 studs that were completely in this area were removed. The other studs were cut off at floor level.
A 2x6 bottom plate was installed, supported both by the studs and the floor of the landing. Next, the 2x6 top plate was added to the existing top plate. Then the new studs were installed. The header over the window, comprising of 2 2x8 with OSB sandwiched in between as a spacer, came next, followed by the sill and remaining studs. What was once a mish-mash of sloppy workmanship is now a strong and sturdy structure. As an added bonus, we took the opportunity to move the window over so that it is now centered in the landing area.
