| Author | Message | ||
     Nan Taylor New member Username: Nbtaylor Post Number: 9 Registered: 04-2007 |
Sorry for the delay - here's the picture of the slate pieces.  | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 77 Registered: 01-2007 |
Is there any pictures of the slate you found on the roof. If there was any ture over lapping slate, it would have been only on a few areas of the roof. It look like there is alot of work to do! | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 8 Registered: 04-2007 |
The slate pieces were stuck in tar at the side of one of the flat roof areas. The roofers said the flat roof areas (now covered with a rubber membrane)was originally covered with galvanized steel with soddered seams. The slate pieces were not evenly cut, but were stuck along the side of one of the flat roofs, next to the asphalt shingled sloped area. Attached are two photos of the rubber-membraned flat roof areas where the tile was found and you can see the asphalt shingles nearby. They seem to think as the slate began to leak, they ripped it off and applied the rubber membranes to the flat areas, and asphalt shingles to the sloped areas. I've also attached a shot of the back sloped area so you can see how it tied in with the dome. The white trim is painted metal.    | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 67 Registered: 01-2007 |
Is it more like a tile floor? Was there anything under the slate tared together? | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 66 Registered: 01-2007 |
Flat Slate roofs with tar. So is it overlapping pcs? Or is the slate cut square and tarred together like what was done on many older building. There are pictures in the Vermont structural Slate CO Book. I ask because you said they took rudder of a flat area and that is where it was, not the pitch areas? What about a picture? | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 7 Registered: 04-2007 |
Yesterday we removed an old rubber membrane from one of the flat roof areas and - guess what - we found several pieces of grey slate stuck in some tar near a sloped roof area. Interestingly, this Carnegie Library roof now appears to have had three types of roofing material - cold tar on the flat areas, grey slate on the sloped areas and the copper dome. Thanks for all your help. | ||
| Joe Jenkins Senior Member Username: Joe Post Number: 99 Registered: 07-2006 |
Slate is nailed with two nails per slate on vertical rows equivalent to the spacing of the slate exposure. Three layers of asphalt on top may obscure the roof deck nail pattern quite a bit. Walter's suggestion of photographing the deck so we can look at it is a good one. | ||
| Walter Musson Junior Member Username: Walter_musson Post Number: 19 Registered: 07-2006 |
Nan, With that many layers you'll have a tough time using the nail pattern to tell if slate were there before. Your roofers should take some good digital photos to help in the detective work. | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 6 Registered: 04-2007 |
We have a new development. Due to a recent roof leak and warmer temperatures in northern Michigan (finally), we are doing some roof repairs next week. Roofers will begin to remove the 2-3 layers of asphalt shinges from one sloped roof area that may have had slate. What type of nail pattern would we look for if slate was there? How do we tell the difference between the nail pattern of the asphalt shingles versus the slate? I'm being told the nail holes may be similar in size and difficult to distinguish from the multiple layers of asphalt shingles. | ||
| Joe Jenkins Senior Member Username: Joe Post Number: 95 Registered: 07-2006 |
I should elaborate a little on my previous comment. Wood shakes were popular roofing materials prior to the widespread use of slate. So we find them on buildings that were built pre-1880 (approximately). This date varies from region to region across the country. 1906 was the peak of slate roofing and there was no incentive to use wood at that time on a public building when much superior stone was available. The Carnegie Library I worked on as a consultant was in northern California, built in 1915. There is no roofing slate produced in northern CA, so this area was about as far from a working roofing slate quarry as you could get in 1915. Yet, they made sure they had the best roof on the building. That seemed to be the style of Carnegie, who was from the Pittsburgh area where everything was slate roofed. | ||
| Joe Jenkins Senior Member Username: Joe Post Number: 94 Registered: 07-2006 |
If the library was built in 1906 and it's a Carnegie library, there is a *very* high probability that the original roof was slate, if the roof is a sloped roof with adequate slope. Wood shingles were often used as cant material under the starter course of slate roofs, so you could find traces of wood shingles. Probably the only way to know for sure, other than old photos or memories of old-timers, is to look at the nailing pattern on the roof deck. The flashings may have some clues as well. | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 56 Registered: 01-2007 |
Asphalt in the USA was started in 1900's then about 1916 it was sold through mail order. | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 55 Registered: 01-2007 |
There should be someone how did the work or was around during the other roofs that were installed. I am not a 100% sure but, asphalt is old enough that the first lay chould have been installed in the 40's or 50's. The old asphalt I have run in to in Vermont, has been under metal standin seam then the asphalt, then wood shingles. They are more gritty and fall apart. | ||
| ron kugel Junior Member Username: Slateworks Post Number: 20 Registered: 09-2006 |
Nan I would say your original roof would be the wood shakes that have been exposed upon the removal of the shingles,seems they would of also found some evidence of slate if it had been installed on the roof(in the attic space,in the overhangs under the sheathing, nailing pattern has others have suggested ect..),not 100% but a strong possibility it was never on the roof..the age of building would be about right for shakes and then shingles, but at the same time the Carniege buidings that I know of have slate on them. Yes you must Repair or replace what was original. I do not know if you could check with the other Carniege caretakers to see if records were kept for other building sites? Good Luck | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 5 Registered: 04-2007 |
Unfortunately the only documentation we've been able to find are reports that state: "roof repairs were done," or similar phrasing. There have been no details on the specifics of the roof materials that were used for repairs. When did asphalt shingles first come on the market? | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 54 Registered: 01-2007 |
Is there info on when they decided to install the first layer of asphalt. May slate was the first choice but was to much at that time. So that is why they didn't use it. Maybe paper work in that way may help to get a long lasting roof system. | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 4 Registered: 04-2007 |
According to the Standards for Rehabilitation, it's inappropriate for us to add something that was never there. This building will be reviewed as a National Register property in May and I think we should stick to what we know to be historically accurate. Thanks for your helpful expertise. | ||
| Slate Affair Inc. Senior Member Username: Slate_man Post Number: 53 Registered: 01-2007 |
Well I would say we found what was there, it was the wood shingles then two layers of asphalt. Will you put slate on if there is no prof. I would suggest a full copper roof (blocks or standing seam) because of the roof pitch, this would go with the other copper detail you talk about. | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 3 Registered: 04-2007 |
I checked yesterday in the photo archives for better pictures and can't find anything. We have not seen any sign of slate in the building, including the attic area. There are multiple layers of asphalt shingles. Not sure if this helps, but based on an engineer's assessment in 2004, the multiple parts of the roof include: the copper dome, flanking copper pedestal, pitched roof areas (where the slate would have been)and flat roof sections that are covered with a polymer membrane. | ||
| Slate Affair Inc. Advanced Member Username: Slate_man Post Number: 50 Registered: 01-2007 |
There could have been three roof system over the years. Two wood and one asphalt. OR is there two layers of asphalt? The building is only a 100 years old and I would think that you would have the slate roof on there know and not the wood shingles. Is there better picture then the one I found on your web site? Has any one looked for any slate in the building? (Basement, crawl space, shed , attic.) | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 2 Registered: 04-2007 |
Thanks for your input. Currently there are asphalt shingles on the roof and the general contractor who worked with the roofer told us about the evidence of wood shingles. I'll contact the roofer directly and ask if he noticed a nail hole pattern. Unfortunately, historic pictures are telling us nothing. The building sits on a hill, and the shots predominately show the copper dome. However, I could scan them for a closer look. I've been told that a brick building more likely had a slate roof than a wood one. Is that true? | ||
| Slate Affair Inc. Advanced Member Username: Slate_man Post Number: 44 Registered: 01-2007 |
What is on the roof know wood or something else? That could have been put on after the wood. The building isn't that old. | ||
| Joe Jenkins Senior Member Username: Joe Post Number: 85 Registered: 07-2006 |
Slate was often installed directly over wood shingles. If the slate had been later removed, there could still have been traces of the wood shingles. You can probably determine whether slate was once installed by looking at the nail pattern on the exposed roof deck, as Walter suggests. We did a restoration on an old Carnegie Library in California. It had VT purple slate on it. | ||
| Walter Musson Junior Member Username: Walter_musson Post Number: 18 Registered: 07-2006 |
Usually it would be the other way around- slate replacing wood,but it could have been as you suggested. Where are you located? A good roofer while removing some of the wooden roof- if it's still there-might be able to tell from the pattern of nail holes in the boards whether slate was ever there. Aren't there old pictures or documents about the construction which would shed some light on this/ | ||
| Nan Taylor New member Username: Nbtaylor Post Number: 1 Registered: 04-2007 |
Our historical society is restoring a 1906 former Carnegie Library and we're trying to determine the original roofing material. We've found evidence of wood shingles, but not slate. However, restoration contractors have told us the roof could have been slate originally and the slate removed and replaced with wood shingles. How can we tell? If slate existed at one time, we'd like to recreate it. The exterior walls are brick with ornamental metal, and there is a copper dome. Is there any way to tell from either the exterior or interior that a slate roof once existed? |
