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Slate, Tile & Cedar Roof Repair & Replacement & Related Metal Work Must Be Rendered By An Expert |
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Coppersmith works on custom copper in St. Davids.font> |
The
environment of the rooftop is as harsh as that of any place
on earth. The temperatures can vary 100 degrees in a single
day and the seasonal swings can double that number in some
climates.
More
threatening to these natural rooftops than the regular assault
of the elements is the band of sloppy servicemen that are
the transients that frequent the roofing profession. Haphazard
slate roof repairs are rampant in this day and age of fast
food, the fast buck, and the fly by night roofer. A can
of flashing cement and a trowel is all the unscrupulous
contractor needs to generate almost immediate income. With
little or no expertise and a ladder, these guys are making
slate roof nightmares every day.
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....Well it is actually the guy that uses it
on your slate or tile roof as a method of
repair. Take a look at the destruction that
can be wrought by the unskilled, uncaring, or
unscrupulous contractor: |
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ACIDIC MASTICS AND ASPHALT CEMENTS DESTROY METAL FLASHINGS |
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Asphalt roofing products such as Asphalt Roof Cement, in their "active state," will leach out acidic material that will destroy some construction metals.
The image to the left is depicting a "step flashed" Copper Valley that was "mucked." The Slates were removed and the metal pieces were removed as one mass, cemented together by the asphalt. |
To the right is a photograph of the same Step Flashing mass (as above) being dismantled. Notice the damage from the Acid Wash in the center of the Valley. |
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To the left is a photo of another valley from a Tile Roof that was sealed at the Ridges, etc. The mastic type sealant was pigmented to give it a matching hue to the Tile Roofing. A Mortar would have been preferable to the non-setting mastic. The Valleys had holes everywhere!
The mastic seemed to have been falling down into the valleys and lodging there and leaching an acid wash for years. The pliable nature of the mastic allowed it to embed itself into the irregular surfaces of the tiles. Mortar by contrast, if dislodged, will tend to bounce and fall from the roof. Mortar is far less caustic to metal than acidic mastic. |
A closer look at the non-setting mastic sealant & the resultant damage is to the right and an even closer look is shown below. Notice that the acid wash first causes a wearing away of the protective patina, then the damage continues to pit the metal. Notice all of the holes in this metal valley.
Note: Ours was the third valley re-lining on this tile roof in 80 years!
How do we know this?
One side of the roof had two layers of metal that had been eaten away in the same manner. We removed this mastic material to prevent future damage. |
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ROOF CEMENT (MUCK) REPAIRS CAUSE LEAKS & DESTROY ROOFS |
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A
guy with a ladder and a can of muck slathered
this valley and made a small leak into several
gushers. As air pockets crack and become
fissures, they direct water velocity laterally
and in unpredictable directions. This roof was
leaking worse than before almost by the time
the check cleared the bank. The poor consumer
is left holding the bag again. This guy is out
of the business and working at his night job.
Take
notice of the pimples and fissures in this
recent coating application used as a method of
repair for this slate roof. |
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The immediate concern for those with mucked roofs is the fact that these materials trap and direct water flow to cause lateral flow and leaks in the very areas meant to be repaired. The next matter to be of serious concern is that of the destruction an acidic material like roof muck can cause. |
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Asphalt Roofing Products & Mastics are acidic in nature and applying them over some metals like Terne Coated Steel and Copper leads to degradation of the metal. It is the wash from atmospheric moisture that picks up the acidic material and releases it in a continual way with every morning dew. Every time it rains or snows, this same effect is also realized, but the concentrations are less than with simple morning dew. The metal eventually wears away and the leaks increase over time.
The pans of this terne metal lined Built-In
gutter have expanded and contracted for many
years of service and finally have given way at
the seams. After the use of damaging aluminum
fibrated coating, the next transient repairman
mucked the seams of the tin and the course of
slate above. These areas have begun leaking
worse than before. Total replacement of the
linings and the slates is now the only viable
option.

“While yer at it, muck that pipe too,” and ruin
another seven or eight slates.

Aluminum roof coating is not a fix for a
leaking valley, or for any other leaking roof,
for that matter. Old terne coated ferrous roof
metal that is prone to oxidation will only
rust away under the porous fissures that
quickly develop and hold moisture when such
coatings dry.
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This
slate roof valley on this 100 year old Vermont
Slate Roof has been maintained. It is coming
due for replacement and all of the original
slates should be able to be reused. |
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New
metal valley linings on worthy slate roofs should
be a labor of preservation and the level of
workmanship displayed should leave the lasting
statement of a caring craftsman. |
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Common Types
of Roofing Slate Found in the Northeastern United
States: |
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Shapes
These are
some of the common shapes used in
slate roofing:
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Deep
Bevel
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Shallow
Bevel
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Deep
Scallop
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Shallow
Scallop
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Pointed
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Round or
Fish
Scale
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Square
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The
above courtesy of Durable
Slate Company |
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