This was one of my favorite projects, the house is around 115 years old and is on the National Historic Register. Although beautiful on the inside; the exterior, specifically the roof, had been neglected. 90% of the roof is completely out of sight so it was easy for deterioration to get out of control. The client called with a small leak in the front part of the house.
Before: you can see the upper flat roof is covered in blisters and various peeling coatings.
The front has a small mansard (learn more: François Mansart 1598–1666) which is a steeply sloped, almost wall like roof. This small roof section has three round louvered vents made from tin set into asphalt shingles, the vents had missing and rusted through areas and were contributing to the leaks. The vents were probably original to the house but the asphalt shingles were probably installed 15 years ago when the original slate roof developed leaks.
Missing pieces had left the roof open to driving rain:
Since the house is registered all architectural elements need to be replaced exactly or with period specific materials. If you can see it from the street it has to look like a snapshot in time. The asphalt roof can be easily replaced with slate but the dormer vents were more of a challenge.
We removed one vent to bring back to the shop for precise measurement; of course we closed the hole in the roof.
After 3 months we had three new copper reproductions, these are identical in every way down to 1/16th of an inch to the originals. Since these are made from 16oz and 20oz copper they wont need paint and they’ll never rust.
Now the easy part: We replaced the old black flat roof with new White TPO over dense insulation board. This roof will make the upper floors of the house much more comfortable in the summer by reflecting most of the sun.
The mansard was covered with small 12×6 Buckingham slates; these slates will easily last 100+ years. Once the copper vents were set in place the whole job really came together. Eventually the copper louvers will turn to a bronze color, 10-15 years from now they will start to develop a green patina. In 100 years the roof will be replaced again, I hope the next roofer enjoys the job as much as I did.
This was one of my favorite projects this spring; the existing slate roof was on it’s last leg and had been the victim of some lousy repairs over the years. You can see where some of the slates have just turned to powder, when more than 25% of the slates have gone bad the most prudent thing to do is schedule a complete replacement.
The light gray blobs between the slates is old roof cement; this was someone’s attempt to stop a leak; sealing between slate keyways will usually make the leak worse-not better.
At least 60% of the existing slates have lost the will to live; some have turned to powder that hasn’t blown away yet.
Tear Off: we removed all the existing slate, we checked the roof deck and made a few minor repairs. Despite the condition of slate the roof has surprisingly few leaks.
Underlayment and layout of the new roof:
First step is the installation of new 20 oz copper drip edge, this has two purposes; first it becomes our square edge to start layout, secondly it keeps water from backing up and rotting the facia and soffit. Once the drip edge is installed it pretty much disappears but its a critical part of the roof and must last as long as the slates will; hence super heavy 20 oz copper.
Next we installed waterproof underlayment at the eave to a point 24″ inside the warm wall of the house; this will protect the roof from ice dams. then we install two layers of 30# felt to temporarily protect the structure from rain and to give us a clean smooth surface to lay out our slates. We take a long time during layout; before any slates are installed we make sure that they line up evenly on each side of the house. Failing to perform these calculations can leave the house with full slates on the left side and little tiny slates on the right; instead of even sized slates on both sides; look at some houses; you’ll see what Im talking about.
My client chose Del Carmen slate, they are quarried in western Spain and are rated S1. The S1 rating means they will have a useful life of no less than 100 years; they come in many different sizes, these are 16×10 ultra heavy. The previous roof was a thin soft slate in 24×12; I thought they were too big and looked like dinner plates on the roof. It took roughly 350 more slates of 16×10 than it would have if I installed the same 24×12’s; more slates look better, and the thicker profile of the ultra heavies give the roof a rich texture.
End of day three; although the roof is very steep we made very good progress. The cloudy gray dust is slate marl (dust) that gets on the slates when the quarry cuts them in Spain, a few hours of rain will rinse it off and let the rich color come through.
The front porch got a new roof with less obtrusive copper loop snow guards; they still keep ice from sliding off the roof but are a little less visible than the larger ones we had to use on the main roof. We also installed a new copper gutter on the upper main house roof.
The trees cover my gorgeous roof; I’m sad to report that this is pretty much the best angle to see it. This picture was taken about a month after we finished the job, the copper is starting to turn a dark bronze color and the true deep rich color of the slate is coming through.
Before: this is the day before we ripped the old roof off.
After: back to beautiful again. I love slate; I’d love to put it on your house, call me if you love slate too.
We have been repairing the roof on this house for years. The house was roofed with a tile that was designed to look like slate; it was made up of slate dust and cement formed into a uniform slate shape. The product failed miserably and the company that produced it was sued out of existence.
Before:
The darker spots you see are where I made repairs to the roof; since the original product is no longer available I had to use real slates for repairs.
There is a flat roof on top of this house, the old roof was black EPDM rubber. Although it never leaked, it’s matte black surface got incredibly hot. There were also two fans on thermostat controls that would try to keep the attic interior cool.
Once the old roof was removed we checked that the plywood roof deck was sound, this house had no leaks and it’s roof deck was in great shape. We installed new waterproof underlayment to provide temporary coverage and to give us a new clean surface to lay out our slates. The large copper flashing around the flue pipe was fabricated in the shop, since the material we are installing will last for 50+ years it becomes critical to have all flashing components last just as long. Copper flashings will last for at least 80 years.
The Owner chose Eco-Star Majestic Slate in Federal Gray; I think is was a perfect choice and it complements the stone and brick you will see later in post.
I tell clients “I never want to see you again”; and I mean it in the best possible way. I’ll never leave any component on a roof that might cause a problem in the future, we replace every bit of flashing, every pipe collar and even decorative pieces. I fabricated the turret caps in the shop from 16oz copper.
There are two small flat seam copper roofs on the house, they are basically sheets of copper that are folded at the seams and soldered with tin/lead along the seams. After a month or two the roofs will turn a bronze color, within 12-20 years they’ll turn to a perfect green patina.
Here you see the second flat seam copper roof and a really good close up of the slate.
Once we removed the old black rubber roof we installed new polyisocyanurate insulation board, this is a dense foam board that provides a high r-value and a clean smooth surface to lay out our new roofing membrane. The small silver plates are used with epoxy coated screws to anchor the insulation to the roof deck.
Since the house is taller than any tree around it we took full advantage of the sun. The new roof membrane we installed is white TPO; a thermoplastic that uses no adhesives or sealants (low voc) in its installation. The seams of the roofing and the associated flashings are welded with a hot air welder; once finished they require no further maintenance or caulk over the life of the roof. The previous black rubber roof easily reached 160 degrees in full sun, our new bright white TPO roof is only a few degrees above ambient air temperature because of its naturally reflective surface.
The old roof had two electric attic fans, one was noisy and the other had stopped working altogether. I replaced them with these solar powered units; the panels face Southwest so they are in full sun from 11am to around 5pm (hottest time of day). They are virtually silent, require no electricity and will be working hardest when the sun is at its most fierce. The bright white roof and solar powered fans will make the upper floors of this house a happier place to be.
These copper snow guards were placed at 12″ intervals around the entire perimeter of the roof. Snow guards keep sliding snow and ice on the roof until it either melts or breaks up into harmless pieces. This house had no ice protection before and sliding snow and ice had done a lot of damage to the gutters.
All finished.
This was a very eco-friendly job; the slates are made from almost 90% recycled materials, the flat roof is energy star rated and there are two solar powered fans keeping the roof cool.
This was a tough job; it had very steep slopes with beautiful landscaping beneath, virtually none of the old tiles could hit the ground when the old roof was removed. The week we did this job the temps were in the high 90’s; covering trees and shrubs with tarps on days that hot will have them overheated and cooked by days end. We removed just a few of the old cement tiles at a time, delivered them up to the flat roof where they were taken down the front to the dump truck; basically handling the material four times instead of the normal two. I must say I’m very proud of the roof and also that all of the trees, shrubs and plants are safe and sound.
I’ve been installing Eco-Star slate for the past twelve years, my oldest job looks just as good as the day i put it on. If you have a failing real or synthetic slate roof this product might be perfect for you. Call 703-299-8888 and ask for Tom if you would like to discuss the possibilities.
This is a slate roof in Alexandria, VA. The homeowners had been having some sporadic leaking and hired a company to correct the problem. The solution they came up with was not carefully examining the slates for cracks or checking flashings for pits or holes; that would have been the right thing to do.
What they chose to do was spread no less than five gallons of tar over the entire roof plane; making any legitimate repair impossible. When the roof is covered in tar it locks all of the slates in place, you can’t gently remove one or two without destroying all that adjoin it. Think of it like playing Jenga with all of the pieces glued together, not fun I think you’ll agree. Although some are cracked, most of the slates that are covered in tar were still in pretty decent shape. What happens in the following pictures could have been avoided and the homeowners could have saved a good pile of cash.
Copper Apron Flashing Covered With Tar
The roof was leaking right at the angle change and could have been repaired very simply. All that was necessary was to remove the courses of slate above and below the copper apron flashing; install new copper flashing and new slates. But instead someone with bucket of tar and not even a pair of gloves trashed the whole roof.
I knew he didn’t have gloves because I could see finger prints in a few spots; kind of like the La Brea Tar Pits of poor workmanship.
New Slate with copper snowguards
The old trashed slates were removed and we had to replace a few rotted pieces of 1×6 roof decking. Once the old roof was removed it was plain to see that the leaking was from one place only, however with the roof covered in tar the water was coming in the house in three spots.
We installed new copper drip edging at the eave and along the rakes to keep water from wicking back into the roof. We also installed these copper loop snow guards, the snow guards prevent accumulated ice from sliding off the roof. The guards keep the ice on the roof until it can melt away without destroying anything below.
Finishing Up
New copper valley flashing, new copper apron flashing and new slate roof tied properly into the old slate roof. No can of tar, no mess, just another stone roof ready to serve for a hundred years. By using copper nails to fasten the slates and copper flashings there is nothing on this portion of roof to rust or corrode.
Finished Slate Roof
The slates we installed on this job are from the Buckingham Slate Quarry, it’s about four hours from Washington DC and it produces some of the best roofing slate in the world. Buckingham Slate is graded S1 and has a service life of 125-150 years if properly applied and cared for. The slates above our new roof are not Buckingham and will probably require replacement in the next ten years or so. This will not be a problem, our new roof and apron flashing can stay right in place and the rest of the roof can replaced around it.
If your slate roof is giving you some trouble call a qualified roofer with some demonstrated slate experience. A bucket of tar might seem like a bargain now but it will cost you a fortune in a few months. Even if your roof isn’t having any problems it should be inspected every year, a quick inspection will head off any problems before they get out of hand.
