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CERTIFICATIONS for ROOFING CONTRACTORS
CHOOSING A ROOFING CONTRACTOR
ASBESTOS CEMENT & FIBER CEMENT ROOFING
ASPHALT ROOF SHINGLES
BUILT UP ROOFS
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY INSPECTION & REPAIRS
CHOOSING A ROOFING CONTRACTOR
CLAY TILE ROOFING
CONCRETE ROOFING
CORRUGATED ROOFING
ENERGY SAVINGS in BUILDINGS
FIRE RETARDANT PLYWOOD
FLAT ROOF MOISTURE & CONDENSATION
HEAT TAPES & CABLES on Roofs for Ice Dams
LOW SLOPE ROOFING MATERIALS
MASONITE WOODRUF FIBERBOARD ROOFING
MEMBRANE & SINGLE PLY ROOFS
METAL ROOFING TYPES
MODIFIED BITUMEN ROOFING
ROOF INSPECTION SAFETY & LIMITS
ROOF VENTILATION SPECIFICATIONS
ROOF VENTING ENERGY SAVING DETAILS
SLATE ROOF INSPECTION & REPAIR
SLATE ROOF PHOTO LIBRARY
SLATE ROOF PATTERNS
  CLOSED LAP
  CONVENTIONAL
  CURVED ROOF
  DIAMOND
  DIAGONAL
  DUTCH LAP
  FRENCH
  GRADUATED
SLATE ROOF COLORS
  GREEN SLATES
  RED SLATE
  RIBBON SLATE
STEEP SLATE ROOFS
  MANSARD ROOF
  STEEPLES
SLATE ROOF HARDWARE
  SNOW GUARDS
SLATE ROOF DEFECTS
  BROKEN CRACKED ROOFING SLATES
  DELAMINATING
  FLASHING
  LOOSE LOST SLIDING SLATES
  MINERAL INCUSION
  STAINING SLATE
  THICKNESS
SLATE ROOF REPAIRS
WORN OUT SLATE ROOFS
  SOFT DETERIORATED SLATES
  BEYOND REPAIR
Slate Roof References
Slate Sources, Repairs
SLATE ROOF INSPECTION CLASS
SOD ROOFING
SIDING WOOD
STAIN DIAGNOSIS on Building Exteriors
STAIN DIAGNOSIS on Roofs
STANDARDS for ROOFING
STONE ROOFING
THATCH ROOFING
THERMAL EXPANSION of MATERIALS
THERMAL MASS in BUILDINGS
THERMAL MASS in UPSTAIRS
TILE ROOFING
WARRANTIES for ROOF SHINGLES
WOOD SHAKE & SHINGLE ROOFING
WORKMANSHIP & WIND DAMAGE

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A Photo Library of Slate Roof Defects
InspectAPedia®  -    

  • Photo Guide to Slate Roof Inspection
  • Photo library of slate roofing materials & slate conditions
  • Slate wear indicators
  • Examples of worn-out slate roofs
Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at InspectAPedia.com/appointment.htm.

This slate roofing photo library shows various kinds of roofing slate defects. This photographic dictionary of roofing slates is a supplement to our detailed article (links at page left) describing procedures for evaluating the condition of slate roofing. The main article reviews types of slate, common defects, inspection topics, and some repair tips. © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

This article assists home inspectors, building buyers or building owners, and roofing contractors in evaluating the condition of slate roofs by providing photos of various slate materials, patterns, defects, and conditions. Readers should also see How to Inspect & Repair Slate Roofs for a detailed "how to" article on inspecting, evaluating, and repairing slate roofs.

A Photographic Guide to Defects in Slate Roofs

Photo guide to Cracked, Broken Slate Roofing Inspection & Repair

  • Broken roofing slates


    Cracked, broken slates
    , probably not leaking but note the diagonal crack in the slate below the course with a missing slate half










  • Cracked roofing slates


    Cracks: Slate crack repair
    , copper was slipped up over a slate which had split just below the butt joint of slates in the next course








 

Photo Guide to Delaminating Roofing Slates

  • Photo of delaminating roofing slate


    Delaminating roofing slate
    , if the delamination is only in the upper surface layer of the slate the material may have substantial remaining life.


    Also ask how many of the roof slates are delaminating at all - note the neighboring slates on this roof are sound.






  • Repair on loose roof tiles

    Surface delamination on slates
    : Notice the surface delamination on some of these slates. A close inspection is needed to evaluate slate delamination when it looks like this. We need to know if the slate is basically sound, hard, and secured to roof, or if alternatively the delaminations are throughout the slate body, making it soft.

    See our photos at SOFT DETERIORATED SLATES where we show close up photos of slate that looked pretty good on the roof but when touched, disintegrated easily




Photo Guide to Slate Roof Flashing Details










Photo Guide to Loose, Sliding, Lost Roofing Slates & Slate Nails 

  • Repair on loose roof tiles|

    Nails: sliding slates
    , mean the nails are lost - perhaps from corrosion.

    Don't underestimate the implication of many slates which have moved only a little bit - all may have lost their nails.

    Notice also the surface delamination on some of these slates.







  • Loose roof slates

    Nails: Slate fastener failure
    , might be indicated by the slate at right if it is sliding down - can you move it back up?

    If you can, this slate has lost its nail and is not connected. Use a slate hook or copper tab to secure the loose slate in place.











  • Sliding roof slates

    Nails: Roof Tiles (not slate)
    , repaired using copper strips - the strip ends holding tiles have been bent back by sliding snow - expect movement, leaks, and extensive nail failures.

    This defect also occurs on slate roofs repaired using this method. This demonstrates the advantages of slate hooks in lieu of copper strips when replacing lost slates.






  • Slate damage photo

Slate damage at chimney and lower edge, probable leaks at chimney. Why to the slates seem loose particularly around the chimney?

Often the building framing settles away from the masonry chimney as framing ages, sags, or settles due to shrinkage or later rot or other in-building damage. But the chimney, built of masonry, tends to remain the same height.

On many old houses the framers actually connected roof framing right to the chimney. Later when the building sagged, settled, or moved, the framing pulls away from the chimney causing damage to the roofing slates and flashing, and leading to leaks in this area.

Another common source of slate roof damage around a chimney is wear and movement caused by flashing leaks and, in freezing climates, frost.

Photo Guide to Slate Roof Defects: Mineral Inclusions & Staining in Slates


Stains and Wear Indicators on Slate Roofing, a Photo Guide

  • Stains on roof slates help diagnose their condition and life expectancy


    Staining on roofing slates
    : Slate edges showing moisture absorption, but generally good condition, these slates have a good remaining life












  • Effloresence marks on slate roofing
    White Efflorescence on roofing slates:
    the white markings shown on these roofing slates, is a mineral deposit left behind as water evaporates. Water penetrating the slate material absorbs minerals and leaves some of them, probably Ca and Mg on the slate surface.

    Many slate roofers and slate inspectors assert that as the white stains progress from the edges of individual slates towards their center, one can estimate the remaining roof life. If 50% of the slate remains inside of the white area, the slate may have about half of its life remaining.

    We recommend that this condition be confirmed by close inspection as well since other slate deterioration factors could be at work.

 

Thickness of Roofing Slates, Close up Photo of Slate Edges in Good Condition

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SLATE ROOF PATTERNS
  CLOSED LAP
  CONVENTIONAL
  CURVED ROOF
  DIAMOND
  DIAGONAL
  DUTCH LAP
  FRENCH
  GRADUATED
SLATE ROOF COLORS
  GREEN SLATES
  RED SLATE
  RIBBON SLATE
STEEP SLATE ROOFS
  MANSARD ROOF
  STEEPLES
SLATE ROOF HARDWARE
  SNOW GUARDS
SLATE ROOF DEFECTS
  BROKEN CRACKED ROOFING SLATES
  DELAMINATING
  FLASHING
  LOOSE LOST SLIDING SLATES
  MINERAL INCUSION
  STAINING SLATE
  THICKNESS
SLATE ROOF REPAIRS
WORN OUT SLATE ROOFS
  SOFT DETERIORATED SLATES
  BEYOND REPAIR
ROOFING INSPECTION & REPAIR

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More Information on Building Diagnostic Inspections and Repairs

Slate Roofing References

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06/30/2009 - 01/23/1991 - InspectAPedia.com/roof/Slate_Roof_Defects.htm - © 2009 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark