Repairing A Wind-Damaged Copper Sheetmetal Roof Ridge & Installing A New Ridge Cap
- Procedure code:
- Hspg Prepared For Nps - Sero
- Thermal and Moisture Protection
- Sheet Metal Roofing
- Last Modified:
REPAIRING A WIND-DAMAGED COPPER SHEETMETAL ROOF RIDGE AND
INSTALLING A NEW RIDGE CAP
THIS PROCEDURE HAS THE POTENTIAL TO ALTER THE HISTORIC APPEARANCE
OR CHARACTER OF A BUILDING. IT SHOULD ONLY BE PERFORMED BY AN
EXPERIENCED PROFESSIONAL AND ONLY UPON APPROVAL FROM THE REGIONAL
HISTORIC PRESERVATION OFFICER (RHPO) OR DESIGNATED REPRESENTATIVE.
THIS PROCEDURE SHOULD BE PERFORMED UNDER THE DIRECTION OF AN
HISTORICAL ARCHITECT OR ENGINEER TO DECIDE THE MOST EFFICIENT AND
LEAST DESTRUCTIVE MANNER FOR EXECUTING THE WORK.
A. This procedure includes guidance on repairing a copper
sheetmetal roof ridge by removing the damaged section and
welting on a new metal capping over timber battens.
GENERALLY, THIS WORK SHOULD BE ACCOMPLISHED BY A
EXPERIENCED ROOFING CONTRACTOR.
B. Wind loading is increased at the ridge of a roof. Cracks
in the pans close to the ridge, or cracks on the ridge
seam itself, are indications of wind displacement. The
cracks occur because the standing seam, typically found
at the ridge, lacks the necessary strength to withstand
C. Typically a ridge roll is preferred over a standing seam
ridge because it provides more strength at the ridge to
withstand the forces of wind loads. Therefore,
replacement of a standing seam ridge with a ridge roll is
often the recommended treatment for wind damage of the
D. Safety Precautions:
1. Wear rubber-soled shoes that have non-slip or grid
type tread (preferably sneakers with a high top for
good ankle support). Avoid wearing loose clothing.
2. Wear a safety belt or harness and secure it to a
substantial chimney or to a window on the opposite
side of the house. Leave only enough slack so you
can work comfortably in one area, and adjust the
slack as you work on other sections of the roof.
3. Be sure the roof is clear of debris and water.
4. Do not work on wet or snow covered roofs. Work on
5. Steep roofs: On roof slopes greater than 4 inches
rise per foot, special consideration must be given
to both footing and materials handling.
a. Secure chicken ladders or cleats at the top
for adequate footing.
b. Hang and secure approved safety lines with
rope of sufficient strength.
c. Carry a limited number of materials so that
balance and footing are not impaired.
d. Use scaffolding, ladders, and working
platforms as required to execute the work.
Ladders shall not be supported on hanging
gutters. These gutters may be distorted which
can affect the slope to drain.
E. See 01100-07-S for general project guidelines to be
reviewed along with this procedure. These guidelines
cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO).
A. bay--a unit of sheet covering as laid between rolls or
B. capping--a copper strip, covering the top of a batten
roll, welted to the edges of the sheets which are dressed
up the side of the roll.
C. cleats or clips--strips, cut to lengths to suit roll or
seam, placed at intervals and securely fixed to the roof
base, the ends being welted in with the edges of the
sheets to hold the copper roofing in position.
D. batten--a shaped timber core against the sides of which
the sheet metal is dressed or turned up.
E. standing seam--a double welted joint formed between the
sides of adjacent bays and left standing.
F. welting--joining copper sheets at their edges by folding
together. Welting may by single or double folds, such
joints being termed single or double welts respectively.
1.03 SYSTEM DESCRIPTION
A. A firmly secured metal roof lays flat against the
decking, and good workmanship ensures that the seams and
cross welts are well clipped. There should be no cracks
extending along the ridge line, and the ridge seam should
be securely fastened.
1.04 QUALITY ASSURANCE
A. Qualifications: Metal roof systems and accessories
should be applied by qualified sheet metal mechanics
using methods devised or approved by the manufacturer of
the metal. Details may vary depending on the properties
of the metal, local custom, and architectural effect
1.05 DELIVERY, STORAGE, AND HANDLING
A. Storage and Protection:
1. Material storage: Keep uninstalled roof materials
under cover, dry, free from scratches,
condensation, and distortion during delivery,
storage, and handling.
2. Historic material to be used as example of original
construction shall be stored as directed by the
3. Manufacturer's delivery or job markings on metal,
and adhesives for manufacturer's labels shall be
either a neutral or slightly acidic material. In
no case shall such material be alkaline; any
staining of the metal by alkaline materials will be
cause for the rejection of the piece.
A. The amount of maintenance required will depend on the
kind of roofing used and the exposure hazards. It will
also depend on the degree of waterproofing quality and
exterior appearance that is acceptable.
1. Small pieces of metal with exposed fasteners and
simple laps may require more maintenance than full-
length zipped panels.
2. Factory enamel coatings and concealed fasteners add
immeasurably to the appearance and life of a metal
roof, and reduce the maintenance cost to the
B. In addition to scheduled inspections, inspect after each
exposure to unusually severe weather conditions such as
strong winds, hail, or long continuous rains.
PART 2---PRODUCTS (for sources also check relevant periodicals, web research, and local business directories)
A. Revere Copper
C. Metal Sales Mfg. Corp.
D. Vulcan Supply Corporation
E. Fine Metal Roof Tech
A. Long screws
B. Cleats or clips, metal to be compatible with roofing
C. Sheetmetal, same type and weight as existing
D. Rosin Paper
E. Timber Batten
A. Chicken ladder, safety belt or harness.
B. Straight snips for cutting straight or slightly curved
lines in sheet metal 24 gauge or lighter.
A. Inspect the ridge for buckling or starcracks near the
seam. Inspect the ridge seam to ensure that the seam is
securely fastened, welted or clipped.
B. Whenever possible, make inspection from ground or from
above if possible.
C. Inspect the underside of the roof deck from the attic to
A. Surface Preparation:
1. Carefully examine, measure, and record existing
sheetmetal patterns at edges, hips, ridges, and
other special conditions.
2. Be careful not to damage old metal wall and vent
flashings that may be used as a pattern for cutting
templates. If metal cap flashings at the chimney
and other vertical masonry wall intersections have
not deteriorated, bend them up out of the way so
that they may be used again. Carefully roof in
these areas to avoid damaging reusable base
3. For installation of new material, verify the type,
thickness, weight/gauge prior to installation.
4. Prior to installation, remove all oil, dirt, and
other debris from the surface. All surfaces shall
be dry and free from frost.
5. Work on only a quantity of roofing which may be
repaired on that same day.
3.03 ERECTION, INSTALLATION, APPLICATION
NOTE: For a detail of this procedure, see the book Practical
Building Conservation by John & Nicola Ashurst, English
Heritage Technical Handbook. Vol. 4: Metals. New York:
Halsted Press, 1988, p. 61.; or check for newer editions of this title.
A. Cut out the entire length of standing seam ridge,
undamaged as well as damaged sections.
B. Turn back and fold up the edges of the ridge bays to form
upstands which will be welted onto the new ridge cap.
C. Screw new timber battens through the roof deck into the
ridge beam or rafters.
D. Nail 2 inch wide clips along the ridge, placed at two per
bay. Pass under the ridge roll and turn up on each side,
or nail on the side of each section of the roll before
E. Welt on a new metal capping.
A. At the end of each work day, provide building protection
for any exterior roofing element removed during repair.