Notches in a (wooden) Ceiling Joist

Factual Questions
1

I know it’s hard to explain 3D objects in words, so I’m sorry this is so wordy.

The previous owner of my house had an outdoor patio cover/roof put in and to do so they cut the rafter tails, which were only about 10 inches long, with a horizontal cut from the bottom edge of the roof toward the exterior wall. So imagine these rafter tails cut horizontally from roof line back to the wall. https://youtu.be/Lm8Afm7He4U?t=147
The horizontal cut ends (leaves the rafter) right at the exterior wall, so that each rafter tail now looks like a small right triangle, with a skinny tip of the triangle being at the edge of the roof. (This may not have been up to code.)

The patio cover was later removed and since there is no gutter water just comes off the roof, and near our back door a bunch of rain spills. I want to put up a fascia board to hold gutters, so I’ve done some research and I plan to “sister” another 2x4, about 3-4 feet long, to the rafter. That is, I plan to attach another 2x4 to the rafter, parallel with it and touching it, with some of it sticking out of the exterior wall and some of it going up into the attic. It is similar to https://youtu.be/UttfbMXjzik?t=26 except the top of my exterior wall is not stucco. Instead, between the rafters (and at the top of the exterior wall) is a 2x4 piece of wood about 2 feet long. (Some of these have a vent hole with a screen.) So to make room for the new 2x4 I can cut 1 1/2 inches off of the end those pieces of wood between the rafters, to fit the new 2x4 (which is really 1 1/2 inches wide).

Here’s the problem though. The bottom of the rafter is going through a ~half inch deep notch in the ceiling joist (is that the right name?) that rafter is sitting on top of, just before the rafter goes through the exterior wall. So if I try to put the new 2x4 next to the rafter, the new 2x4 will be sitting higher up, since there is no notch in the joist. If make the notch in the joist wider to accommodate the new 2x4 the notch will be 3 inches wide (2 times 1 1/2). I believe that’s too wide, because I’m told (online research) that a notch’s width can’t be more than 1/3 the total depth of the ceiling joist. I don’t know for sure what the ceiling joist’s dimension are, but I would guess it’s less than 9 inches in depth. Is that a reasonable guess? I don’t know how to see the joist to figure it out. If I assume it’s less than 9 inches in depth, I can’t widen the notch, right?

FYI, to avoid taking off the roof I was going to slide the new 2x4 up into the roof without taking off the roof. So I can’t just put a (birdsmouth) notch in the new 2x4 and lower it down from above. The only solution I can think of is to cut the new 2x4 length-wise to make it a little skinnier for the entire length of the board that will be fitting into the attic. Then I could slide it into the attic from the outside, through the hole I cut in the board between the rafters. But then it will be sitting on just the corner edge of the ceiling joist. Is that okay if it’s just is going to be holding up a fascia board and gutters? Is there a better solution?

2

Any reason you want the new 2x4s to pierce the exterior wall? Can you just have them flush with the outer wall and use a couple of bolts to attach them to those existing “triangles”? I can’t imagine the weight of a gutter and fascia board to be that much especially distributed over several rafters.

3

Hampshire is correct. These sistered boards are not structural. Cut the pieces to fit in place and trim off the outboard ends to be vertical. Screw them to the existing rafter tails using exterior construction screws.

Dennis

4

Thanks for the replies. I agree that the sistered boards are not structural. However, a few things.

First, I was told the current system isn’t to code, I believe because the last tongue and grove board of the eave is held up by only the end of the triangle. So if a person were to stand on it it might not support their weight. The triangles have sides of something like 3.5", ~9" and ~10". They’re pretty small. It’d be hard to attach something to them.

Similarly, a guy giving me a quote on the gutters said that adding a fascia board and gutters would only increase the weight on that last eave, making things worse. (But he also did give me a quote for hanging gutters instead of using a fascia board. Later when I questioned him he agreed it’d still have the problem of adding weight.)

I found out that the board that was notched wasn’t the joist, it was a 2x4 (a little less than 2 feet long) that was nailed between the rafters, on top of the joist. It’s not structural, so I started to work on them and have cut 4 of them (nearest the back door where the water comes pouring down). But your ideas are MUCH easier. Do you think they’re fine?

5

I assume whatever fascia you attach would be nailed to the sister boards you install, not the last board of the roof. So it has no effect on the weight on the eaves or roofing. I would suggest putting a sister board on each side of each triangle. Solid gluing and bolts should make that more than adequate to hold the weight of one man, and the roof board will not give way unless several of those triangles break. It’s a risk but I don’t see it as a serious one. I assume fascia and eavestrough will not add that much weight, unless you plan to use excessively thick fascia.

I guess it’s up to you to decide how important it is to match current code. Depends on city inspetors, and also how picky local home inspectors are should you want to sell.