Frequently, when I get to the repair of rotten rafter tails, modifications have already been done in an attempt to solve the problem. Often, the owner of a home, at one time or another, has a gutter company remove the original wooden gutters and install aluminum gutters. To do this, the notch in the tail is cut plumb, because the size of modern aluminum gutters has a greater depth than original wood gutters and doesn't fit in the notch.
When that retrofit is made, two compromises happen:
- The original wooden gutters had rigid and supportive strength that tied everything together. In some cases, this system would even cantilever past the last rafter tail and support the gable-end lower portion of fascia from sagging under its own weight. Removing the wood gutters removes that rigid supportive strength.
- Because aluminum can conduct moisture, putting it against raw end-grain is a recipe for moisture wick and further decay. If you take a close look at these rafter tail ends, you can see a round decayed area where the gutter spike was located. Because of this, I've had the very rewarding experience of removing 40-foot aluminum gutters in one pull.
This story has played out in many historic homes. There's often a disconnect between trying to fit old and new technology together, a lack of understanding from the modern tradesman in how to make modifications without compromising structural integrity, or the homeowner makes the choice not to spend the money. But there is proper, simple methodology that can be employed to ensure a modern fix will be one of long-lasting quality.
Step 1: Access to the Soffit
To begin, asses the project and choose the right scaffolding method for the situation. The point is to have a scaffolding run all the way along the working length from end to end.
Step 2: Plan the Process
In this case, to help solve the problem of rafter tail decay and separate any moisture-conductive aluminum gutter from tail ends, we're going to install 1½" cedar fascia. We're going with an 1½" thick material because it gives us more support strength for the heavy, sagging gable end fascia, and more meat to cut out of the rafter tail ends, giving us a better chance of eliminating the decay.
Step 3: Choose the Material
In order to have the face of the fascia in the same location as the rafter tail ends, we have to cut 1½" from the tails. Since the roofing is a finished product, we can't deviate from where the gutters were located. Even though the modifications we are making are not original, I still want to use original looking components.
In this case, we will use an s4s clear cedar (which means it's smooth on all four sides). Most modern "fascia" materials are sold as rough-face, tight-knot cedar that is graded to the rough side. This grade of material doesn't fit the continuity of a historic building that has all smooth exterior surfaces.
Step 3: Use a String to Mark the Rafters
Once planning is done and scaffolding is set up, we simply measure the two end rafters and make a mark. Once we set a nail and install our string line, we check for settling in the rafter run. Old houses settle; that's a fact. This also means that the rafters settle as well. In other words, they are not in a straight plane with each other in a long run. There could be a rise or a sag or a combination.
In such cases, it's not prudent to use a chalk line to snap line for marking the tail cuts, because the line will have a tendency to curve around the sag in the plane of the tails. It's much more exacting to hang a tightened string line that's far enough down that it doesn't touch any rafters.
Plumb up to mark the rafters, and once cut, the fascia will be dead straight, even if there is a bow up or a sag down. To cut the rafters in this case, I have found it really simple and accurate to use a jigsaw and finish the cut with a sawzall with a metal blade or a multitool. If there is any decay seen on the cut rafters, we will soak it with end cut solution. If the damage is really bad, sometimes it's appropriate to add a sister tail or remove the tail and dummy another one in.
Step 4: Cut the Fascia
Eliminate a void: Take the time to rip the top of the fascia at the angle of the roof. It's a better fit, provides more surface against the rafter tail, and more support at the soffit.
Step 4: Install the Fascia
Once the fascia is cut to length, start installing it from one end and work to the other. In these cases, we like to use 6" exterior screws, because they're long enough to pass through any soft wood into hard, secure wood for ultimate holding power. We're not concerned with the large heads on the screws for beautification, because the gutter will hide them.
As a part of installing the fascia, it's necessary in this case to lift up the sagging gable end fascias for the new fascia to fit more snugly. Then, we secure the gable fascia into the end of the new 2" x 6" fascia creating a strong, unified system. If you were to put weight on the roof, you'd notice a big difference in solidity with this system.
Repair cases like these are unique fixes from one home to the next, not only due to original designs, but also because decay is completely random in its damage. This was a relatively easy project, but these projects can get to be very complicated and require a high level of expertise to complete.
In the end the unique look of this home will be preserved, even though we modified the look of the fascia a bit. With new gutters on the face of the fascia, from a distance it will look very close to the original, simple design. The bonus is that aluminum gutters need little maintenance, and this fix will last longer than the original.