gypsum in attic

[SAL IACONO]

Why would they install this here?

[Jim Robinson]

I saw that once a year or two ago. I didn't understand it either. Probably some type of cost saving over plywood back in the day. The stuff I saw didn't hold up very well.

[Brandon Whitmore]

What type of structure was that? I'm guessing it's not a single family residence, and it has to do with fire rating. It looks like there is plywood or OSB over the drywall, correct?

[David Bell]

I don't ever recall seeing a 2 hour rated roof. Should have a fire damper to the vent if thats the case.

[Jerry Peck]

House was built sometime in the 1940s or early 1950s?

Gypsum was used for roof sheathing for a while as plywood was scarce (having been used to make boats for the war, etc.).

Fortunately that practice never lasted.

I should add: at least that is what I heard when I first saw that many years ago.

[chris mcintyre]

House was built sometime in the 1940s or early 1950s?

Gypsum was used for roof sheathing for a while as plywood was scarce (having been used to make boats for the war, etc.).

Fortunately that practice never lasted.

I should add: at least that is what I heard when I first saw that many years ago.

Now that you say that, if you zoom in there does appear to be a layer of shingles between the gypsum and the plywood :eek:. I guess they don't build em' like they used to.

[David Bell]

Being from that era, are there any asbestos issues in the gypsum?

[Stacey Van Houtan]

Also if the home was not within a certin range of a fire hydrant this was used to reduce Insurane cost.

[A.D. Miller]

Fortunately that practice never lasted.

JP: True, in residential buildings. Not so in commercial.

[Jerry Peck]

Also if the home was not within a certin range of a fire hydrant this was used to reduce Insurane cost.

Actually, if a home was not close enough to a fire hydrant the insurance would increase (there would not be a discount), and, even more important and more often missed is ... if a home was TOO CLOSE to a fire hydrant the insurance would also increase - because the firefighters would not be able to get to that hydrant and would have to go to the next further away hydrant.

I know because we had a house with a hydrant in the front yard, and there was a surcharge because the next closer hydrant was beyond the distance for the discount and that hydrant was not counted as it was TOO CLOSE.

[Stacey Van Houtan]

Actually, Jerry, I think you just want to disagree with me :D I will expand on this. In some areas it the home is too far from a hydrant or they are not present a gyp. board underlayment will reduce Ins cost. And in multi family it can eliminate the need for thu roof parapet walls. See Attached
www.fema.gov/library/file?type...file=fs_05_roofs.txt...

[SAL IACONO]

Gentlemen,
This was a single family structure with a hydrant with in 500 ft. There is an addition in the back. Is it possible they buit the roof up to tie the addition roof together? There were no shingles below the ply wood. Thanks for the answers!