I did an elevation certificate yesterday and there were to crawlspace doors that were wood-frame with insect screening and wood lattice.
Can I use the gross area of the wood frame(not cont the wood lattice)?
I'm thinking "yes" because lattice is permissible in Building Type 5.
What do you think?
Everything you ever wanted to know about flood vents straight from FEMA TB1.
Edit: I did see a note in FAQ section of FEMA's site that indicated that in areas where flood waters can be expected to contain debris that the insect screens may reduce the usable area of a vent by 50%.
Flood Openings Means Openings
So you must calculate the total open area within the lattice.
That latticework is allowed assumes that there are large areas of lattice, such that sufficient open area is provided.
Paul in PA
It doesn't sound like you really have a diagram 5 building. You can't claim the 2 crawl space openings as being diagram 5 just for the openings, it must be for the entire area below the elevated floor.
The situation you describe requires the NET area be calculated. And remember you can only count the area of the opening which is below the BFE.
Thanks guys.
I know the building type is 8. I was just thinking that if lattice didn't impede flood waters in type 5, maybe it wouldn't in a type 8.
No biggie, I measured the net, too. I just wanted to check.
Doors aren't usually considered flood vents.
I recommend to clients all the time to convert a crawlspace door into a vent.
> I did an elevation certificate yesterday and there were to crawlspace doors that were wood-frame with insect screening and wood lattice.
> Can I use the gross area of the wood frame(not cont the wood lattice)?
> I'm thinking "yes" because lattice is permissible in Building Type 5.
>
> What do you think?
The wood lattice would decrease the area of the opening. Also, only the area of the flood opening below the BFE is to be counted.
I understand all that. Thanks.
I guess my main question was why is lattice not counted against the net opening in a type 5, but it is in a type 8.
That's an odd question. As I see, it is impossible for a building type 5 to have any flood openings. If there is a garage or enclosure of solid walls below BFE (which would require openings) then by definition the building can't be a 5.
Thanks Steve - Big Help- Used the ENTER button to print out.
Carlton
Steven
2 cents here - If the enclosure is a crawl space, area for storage or car is above the adjacent finished grade then the flood vents can be more than 1 foot above grade as long as the vent is within 1 foot of the enclosure floor. FEMA TB1 page 11
Carlton
I think you misread his post.
He said the question was:
"... why is lattice not counted against the net opening in a type 5, but it is in a type 8."
My point is, there can't be any countable openings in a type 5, so how can we conclude that lattice is treated differently between a type 5, and a type 8? I think the only reason why insect screening and lattice is specifically mentioned in some the docs about type 5s is to make the point that FEMA doesn't want anything that's valuable, or heavy and rigid that could be swept away and cause damage elsewhere, to be installed below a type 5. But as far as it not counting against net openings for a type 5, I'd say there is no such thing as openings in a type 5.
