sheet rock decking - InspectionNews

Jim Robinson · #1 (**permalink**) 06-04-2009, 12:34 PM

This was a first for me. This whole house had a lot of fun things. It would have been a great experience for new inspectors. Anyhow, there were some big dips in the roofing between rafters. A little is not unusual, but these were 3-4", which is a lot in my book.

After I got into the attic space, I see what appears to be sheet rock as the roof decking. Sure enough, that was exactly what it was. There were at least two layers of what I think is 1/2" sheet rock. I couldn't tell if there was anything above this, Almost no nails sticking through the sheet rock.

Have any of you come across this before, and what did you say about it?

Scott Patterson · #2 (**permalink**) 06-04-2009, 12:39 PM

Looks like exterior gypsum sheathing, I have never known it to be approved for roof decking.

Jim Robinson · #3 (**permalink**) 06-04-2009, 12:44 PM

It wasn't working too well in that application, either. I've got some more fun stuff from this house, but trying to get my report finished in the meantime.

Jerry Peck · #4 (**permalink**) 06-04-2009, 12:50 PM

Quote:

Originally Posted by Scott Patterson

Looks like exterior gypsum sheathing, I have never known it to be approved for roof decking.

My thoughts precisely ...

... however, thinking about it, I seem to remember a discussion years ago about some which was used for roof sheathing, ...

... and the more I think about it I recall having seen some in Miami many many years ago.

My recollection is that it was used for roof sheathing during or after the war (WW II) when plywood was in short supply for being used for planes and boats, then new homes for the GIs returning home, and it proved to be fatally flawed for that use.

Was the house a 1940s house?

A.D. Miller · #5 (**permalink**) 06-04-2009, 12:51 PM

Quote:

Originally Posted by Jim Robinson

This was a first for me. This whole house had a lot of fun things. It would have been a great experience for new inspectors. Anyhow, there were some big dips in the roofing between rafters. A little is not unusual, but these were 3-4", which is a lot in my book.

After I got into the attic space, I see what appears to be sheet rock as the roof decking. Sure enough, that was exactly what it was. There were at least two layers of what I think is 1/2" sheet rock. I couldn't tell if there was anything above this, Almost no nails sticking through the sheet rock.

Have any of you come across this before, and what did you say about it?

JR: There seems to be no end to the stupid things some contractors will do.

Jerry Peck · #6 (**permalink**) 06-04-2009, 12:55 PM

What I recall having seen back when was just what Jim's photos show. All Things Gypsum<br>A Brief History of Gypsum Board in North America - Column - Walls and Ceilings____
"During the ’40s, gypsum wall sheathing and gypsum roof sheathing products were used along with gypsum board in domestic and overseas military construction. By 1945, the military had used approximately 2.5 billion square feet of gypsum board. In 1946, gypsum products were used extensively to fuel a housing boom;"

This is a current use, but note that it has wood roof sheathing over the gypsum: http://www.gypsum.org/pdf/GA-276-05.pdf

Jim Robinson · #7 (**permalink**) 06-04-2009, 01:01 PM

I think the house was built around 1972. There may be some wood on top, I couldn't really tell.

#8 (**permalink**) 06-04-2009, 02:01 PM

Quote:

Originally Posted by Jim Robinson

This was a first for me. This whole house had a lot of fun things. It would have been a great experience for new inspectors. Anyhow, there were some big dips in the roofing between rafters. A little is not unusual, but these were 3-4", which is a lot in my book.

After I got into the attic space, I see what appears to be sheet rock as the roof decking. Sure enough, that was exactly what it was. There were at least two layers of what I think is 1/2" sheet rock. I couldn't tell if there was anything above this, Almost no nails sticking through the sheet rock.

Have any of you come across this before, and what did you say about it?

Back in the day when the green fire rated ply started to deteriorate and was no longer available, builders tried various methods to satisfy the 4' fire rating on each side of a townhome party wall.
There are some builders who got stung so bad that they use trusses that are 5/8" lower in this area and use drywall sheathing under the roof decking instead of using the new and improved red fire rated ply

Hope this helps

Tim

Marc Robin · #9 (**permalink**) 10-31-2009, 10:25 AM

I came across this same thing yesterday in a house that was built in the '40s. This thread came up when I googled 'sheetrock roof'. A label was still attached to the underside of the sheetrock decking. Ultimately, the roof was decked with plywood and covered with comp shingles; my concern is, how well are the nails fastened after penetrating an inch plus of old sheetrock and other "stuff".

Derek Kelly · #10 (**permalink**) 10-31-2009, 12:02 PM

I saw this exterior board used on commercial flat
roofs.1 or 2 layers,then there foam board etc.
I also used it on the exterior of buildings, not on
house roofs.Thats unbeleivable!!!