I've been thinking about revising the way I flash the fascia, and came up with this concept today.
Just want to see what others are doing, or would do.
Trevor
JeromeS
Mar 7, 17 9:12 pm
Where is the building felt?
Trevor Pan
Mar 8, 17 9:45 am
Hi James,
I've spec'd out an adhesive membrane instead of traditional felt.
cadomestique
Mar 8, 17 2:52 pm
Not needed IMHO
A little water wind driven/ice dams/condensation etc gets under shingles and needs to filter out at the bottom. If you hermetically seal edge it does not have a way to go out but down.
If anything this detail works in that spirit. The cement board, which is more durable than wood extends beyond the framing.
With regards to the flashing tape, it prevents the plywood edges from getting wet, which was the main concern.
It's actually not hermetically sealed. The edge has more protection than usual. Air is free to access the bottom of plywood freely. Now, I do see an issue of aesthetics. Might need to think of how to dress that up.
Anyhow, any other thoughts?
Perhaps a little misleading is the space shown between the layers. That's just graphical. Do you think it's better to have the layers closer together from a graphical standard?
bowling_ball
Mar 8, 17 10:11 pm
I don't see anything really worrisome about your detail, but it's also not necessary.
Wood Guy
Mar 9, 17 6:47 pm
3M 8067 is a great product. If you live in a place where wind-blown water is an issue, I agree that an extra layer of protection there is a good idea.
I usually spec ice and water shield to go down first, wrapping over the top of the fascia, then the dripedge, then the shingles go over the dripedge. That used to be the way that Grace preferred for their product, though they now show several options. You can seal the dripedge to the I+WS with roofing cement if you want to but it's not necessary.
The idea is the same that I use for all roofs and walls: the structure should be waterproof before any cladding is installed. The cladding should be installed to shed water, but the WRB layer should be waterproof as well.
Trevor Pan
Mar 9, 17 7:51 pm
Hi wood guy,
good to hear. I just noticed the edge of my plywood at my own home had got wet over the years. I'll definitely include it. But we'll see if the owner goes for it . . .
Hi,
I've been thinking about revising the way I flash the fascia, and came up with this concept today.
Just want to see what others are doing, or would do.
Trevor
Where is the building felt?
Hi James,
I've spec'd out an adhesive membrane instead of traditional felt.
Not needed IMHO
A little water wind driven/ice dams/condensation etc gets under shingles and needs to filter out at the bottom. If you hermetically seal edge it does not have a way to go out but down.
Interesting link related:
http://www.woodworks.org/wp-content/uploads/2015-Jan-Bronski-Durable-Design-Lessons-from-Historic-Wood-Structures.pdf
That was a great article. Thank you.
If anything this detail works in that spirit. The cement board, which is more durable than wood extends beyond the framing.
With regards to the flashing tape, it prevents the plywood edges from getting wet, which was the main concern.
It's actually not hermetically sealed. The edge has more protection than usual. Air is free to access the bottom of plywood freely. Now, I do see an issue of aesthetics. Might need to think of how to dress that up.
Anyhow, any other thoughts?
Perhaps a little misleading is the space shown between the layers. That's just graphical. Do you think it's better to have the layers closer together from a graphical standard?
I don't see anything really worrisome about your detail, but it's also not necessary.
3M 8067 is a great product. If you live in a place where wind-blown water is an issue, I agree that an extra layer of protection there is a good idea.
I usually spec ice and water shield to go down first, wrapping over the top of the fascia, then the dripedge, then the shingles go over the dripedge. That used to be the way that Grace preferred for their product, though they now show several options. You can seal the dripedge to the I+WS with roofing cement if you want to but it's not necessary.
The idea is the same that I use for all roofs and walls: the structure should be waterproof before any cladding is installed. The cladding should be installed to shed water, but the WRB layer should be waterproof as well.
Hi wood guy,
good to hear. I just noticed the edge of my plywood at my own home had got wet over the years. I'll definitely include it. But we'll see if the owner goes for it . . .