Exterior: Georgia Slate Roof

“There’s one thing unique about this house and no longer reproducible – – God only knows how much it’d cost you if you had to get it – – and that’s the roof.  That is Rockmart slate.” – James C. Wise, Meredith House Architect

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Those words from the architect to the Thompsons in 1973 (Track 6, about 3 mins) have created the most consternation for the current owners.

Mr. Wise went on:  “I can’t even remember the fellows name, but he used to – – he had two families from Pennsylvania.  That’s where the original slate quarries were for slate roofs.  And, this really was an art.  The only way you can quarry slate – – you can’t use high explosives – – you have to use black powder, which is slow.  Break it out in chunks.  Then, you have to – – there’s an art in it.  Now, Pennsylvania slate is very thin.  And, this is a minimum of – – 3/16th of an inch – – I mean Pennsylvania slate – – this is a minimum of 1/2 inch.  But, you have to know what you are doing to see the seams and split it. . .  It’s random thickness.  That slate is no longer available.  He used to quarry it and put it on for about $10/11 per square – – and it’s put on with copper nails. . .  Rockmart, Georgia.  I can’t remember the fellows name but he set off a charge.  It didn’t do and he went back in to set off another charge to refuse it and a big chunk of slate came down and killed him.”

Mr. Wise added:  “There’s no telling what it would cost to reproduce that roof.  It might cost $500 or $600 a hundred square feet.  [In 1938, he charged] $10 to 12 a hundred square feet. . .  That’s a hand operation.  They’d split it.  As they applied it, they had a little steel bar and a little hammer that had a punch on one end.  They’d put the piece of slate up here.  They’d take that pointer – – instead of a claw hammer, they had a punch on one end – – and then they’d knock the holes – – punch the holes – – and then use copper nails to put it on.  So, this is very hard slate.”

The original slate roof, installed in 1938, as described by the architect remained on Meredith House through 2016.

The Leaks

In 1973, the Thompsons commented to Mr. Wise that they thought the roof was in “remarkably good condition” but described having a “few leaks.”

In 2010, we first  wandered into Meredith House while it was on the market.  We noticed evidence of more than “a few leaks.”  At the time of the sale, there were NO overt, active leaks.  The home inspector recommended a separate inspection by a qualified slate roofer, since slate roofs exceeded his area of roofing expertise.  An experienced and well-respected slate roofer recommended replacing the roof but offered to provide limited repairs if necessary.

Between 2010 and 2015, the slate roof repeatedly failed.  A leak emerged in the carriage house.  A leak emerged over the foyer.  A leak emerged (during a holiday party) in the Great Hall.  A leak emerged in a bathroom.  A leak emerged in a bedroom closet.  With each leak, an experienced slater roofer was dispatched to the house and made various repairs (some more extensive than others).

During this period, we listened to the architect’s words that the roof was the “one unique” feature of the house and “no longer reproducible.”  Three different roofers came to Meredith House to evaluate repairing the roof.  All claimed the roof was “shot.”  Two refused to perform any repairs citing the poor condition of the roof.  Each roofer was willing to replace the roof with shingle or slate.  None were willing to take on replicating the pattern of the original roof but put up slate in a standard pattern.  One roofer referred to it as a “work of art.”  It was a leaking work of art, but a work of art nonetheless.

Finding an Artist

So, what do you do when you need to reproduce a work of art?  You find an artist.

So, how do you find the right artist for the reproduction?  You look for similar works the artist has reproduced.

In researching installation and restoration of slate roofs, I came across Joseph Jenkins of Pennsylvania, author of the Slate Roof Bible.  Jenkins also published a magazine, Traditional Roofing Magazine.  Traditional Roofing Magazine published an article in the Fall 2003 edition on the reproduction of the slate roof for Glenridge Hall.

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This article brought Ron Stokes of R.W. Stokes Company to my attention.  We were familiar with Glenridge Hall from benefit functions and garden tours.  R.W. Stokes is the only Slate Roofing Contracting Association member located in the State of Georgia.  Unfortunately, the 1929 English Tudor Revival estate was demolished to make way for a multi-family development project.  After all the research and a meeting with Ron, R.W. Stokes Company was THE slate artist for Meredith House.

The Pattern and Scale

The original roof installed in a variable-width, graduated pattern.  That is, the slate pieces at the bottom of the roof was longer and wider than the pieces at the top.  For illustrative purposes, the diagram below was prepared by Ron Stokes to determine the original pattern.  What emerged was a complicated pattern of slate sizes and organization.

 

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Original Slate Pattern, Meredith House

As can be seen, Meredith House utilized seven different lengths of slate ranging from 24″ near the bottom of a pitch to 12″ at the top (of note, only six sizes were used in each pitch).  The roof comprises nearly 100 squares of slate.  Based on the architect’s comments about slate thickness and an estimate of slate weights, the original roof had total gross weight of about 200,000 pounds.

By comparison, Glenridge Hall utilized six different lengths of slate ranging from 24″ near the bottom to 12″ at the top.  The roof comprised about 170 squares of slate.

Rockmart Slate:  The Good, the Bad, and the Ugly

The bad news was that roofing slate is no longer quarried in Georgia.  The Rockmart Slate Company makes a decorative landscaping product, called “Slate Scape,” from the quarry.  Other slate pulled from quarries was ground up for aggregate and used as a concrete filler.  Thus, there was no way to replicate the roof with new slate roofing sourced from Georgia.  That was the bad news.

According to the second edition of Jenkins’ Slate Roof Bible, Rockmart slate is known “as black, or ‘blue-black’ (actually great), and is very similar to the slate of eastern Pennsylvania’s Lehigh-Northampton ‘hard vein’ district” (p. 92).  Some Rockmart slate was “quite hard and durable a century later,” while some “varieties seem to be softer, becoming rather soft after a century” (p. 94).  This different occurred even within the same quarry.  I suppose it was “luck of the draw.”  Meredith House did not draw from the better quarry pit.  The slate had become quite soft after just 75 years.   Thus, there was no way to replicate the slate roof by reusing unbroken pieces of the original slate.  That’s the ugly news.

Slate comparison
Faded Rockmart slate (top), New Black Slate (bottom)

The good news was Ron Stokes worked diligently to find a comparable color and texture match to the Rockmart slate.  The solution was black slate from the Virginia Slate Company.  This produced fairly good match.

The puzzle was deconstructed.  Various sized slate was ordered.  The old slate was removed.  All rotten wood was replaced with similarly sized boards.  Much of the decking was remarkably well-preserved.  The flat section of the roof (rolled asphalt on top of original metal) was removed and replaced with soldered copper.  New flashings were laid.  Thirty-three pallets of slate ultimately arrived.  The new slate was painstakingly replaced in the same pattern as it had been removed.

What emerged was a non-leaking work of art.

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“God only knows how much it’d cost” – James C. Wise, Meredith House architect

In 1973, Jim Wise seemed to relish in how inexpensively he’d acquired the slate for Meredith House.  He said – – not once but twice, “$10 to $12 per hundred square feet.”  He guessed that in 1973 the same roof might cost $500 to $600 per hundred square feet.  In 2016, the same roof cost over $1500 per hundred square feet.

God is no longer the only one that knows how much it’d cost to reproduce the roof.

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Old versus New

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Repurposing Rockmart Slate

Some reports indicate that around one quarter of all landfill space is occupied by construction debris.

About 200,000 pounds of Georgia slate was being removed from Meredith House.  The slate could not be reused on the roof.  Less than ten percent was salvaged intact and will be utilized to roof small woodsheds or other projects.  The rest crumbled as it was removed.

A plan was hatched to repurpose this slate.  Keep the historic Georgia slate on the grounds.  Thus, much of the slate was crushed with a skid-steer and laid in paths and walkways around the grounds.  None of the original slate ended in a landfill.

Final Thoughts

In the end, a fine architectural shingle could have been installed on Meredith House for one-fifth the cost of the current project.  However, that would have violated the architect’s design, destroyed the residence’s historic integrity, and removed the “one unique thing” about Meredith House forever.

One thought on “Exterior: Georgia Slate Roof

  1. I am so glad that the Meredith House is in your hands. I’m not sure someone else would have done so much research to preserve the integrity of the roof and spent what had to be thousands of dollars to have it restored as near possible to its original condition. It is gorgeous! Incredible. Lisa

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