I saw the strangest thing today and I can't believe it is true. Apparently, I own a property that has a flat "hot tar" roof over multiple layers of "tar paper"(?) -- and the roof decking under under the tar paper is just two layers of sheetrock. There is no wood decking -- just a double layer of sheetrock nailed to roof rafters on 16-inch centers and the roofing material on top of that. Has anyone ever heard of or seen that?
Here are the details:
I own an end-of row two-apartment building. I am not sure when it was built, but some records indicate that it may have been built in 1930, another indicates possibly 1935. And, a third anecdotal report is that maybe it was built around 1945 because all of the walls and ceilings are constructed with studs and ceiling joists on 16-inch centers with a double layer of 1/2-inch sheetrock. There are no plaster walls, and someone said that around 1945 they had just started using sheetrock and, because it was new, they did double layers of sheetrock. I am only explaining this is case it gives any clues as to the type of roof construction that was used back then.
I bought the property a few years ago and the second floor tenant that I inherited just moved out a few days ago, so I am re-doing the second floor apartment. The ceiling of the second floor apartment was a drop ceiling and I took just that out. There were no signs of any roof leaks on the drop ceiling, but after I took down the drop ceiling I could see that there used to be water leaks by looking at the old sheetrock ceiling. And one small part of the old sheetrock ceiling was damp and warped. So, I started taking down the sheetrock ceiling to find the leak and to repair the ceiling. The sheetrock ceiling is a double layer of sheetrock that is nailed to the bottom of the ceiling joists. Above the ceiling joists are the roof rafters, and nailed to the top of the roof rafters is a double layer of sheetrock. That double layer of sheetrock on top of the rafters is the actual roof decking. Some of that sheetrock had been water damaged in the past and was pulled down is spots. So I can see the underside of the actual tarp paper roof base and the hot tar roof on top of that. I can even see roof nails coming through the roofing material and through the double layer of sheetrock.
So, again, the is absolutely no wood roof decking under the hot tar and tar paper -- is is just those asphalt/tar products on top of a roof deck that is only made of two layers of 1/2-inch sheetrock nailed on top of 2x6 roof rafters on 16-inch centers. This is how it is for the entire roof (I checked other areas to confirm this).
Has anyone else ever seen this or heard of this?