Historic Preservation - Technical Procedures
Repairing Small Holes In Roof Flashing
Ohj - Feb. 1981
Thermal And Moisture Protection
Sheet Metal Flashing And Trim
Repairing Small Holes In Roof Flashing
REPAIRING SMALL HOLES IN ROOF FLASHING
A. This procedure includes guidance on making small
temporary repairs to roof flashing by patching small
holes with sheetmetal. See also 07631-03-R for
additional guidance on patching sheetmetal. For more
extensive flashing repairs, see 07620-02-R.
B. Flashing is an integral part of a roofing system and
protects against water infiltration at roof hips and
valleys; penetrations such as chimneys; where roofing
meets a vertical surface such as a parapet or at a porch
roof; or at drip edges.
C. Copper, with copper nails, galvanized sheet metal with
hot-dipped galvanized nails, or terne-coated stainless
steel with stainless steel nails are the primary
materials used for flashing.
CAUTION: THE DIFFERENT METALS SHOULD NOT BE MIXED.
RAINWATER RUN-OFF FROM COPPER FLASHING WILL CORRODE BOTH
GALVANIZED SHEET METAL AND STAINLESS STEEL THROUGH
GALVANIC ACTION. GREAT CARE SHOULD BE TAKEN TO USE A
FLASHING MATERIAL COMPATIBLE WITH THE REST OF THE ROOF
D. Safety Precautions:
1. Wear rubber-soled shoes that have non-slip or grid
type tread (preferably high top sneakers for good
ankle support. Avoid wearing loose clothing.
2. Wear a safety belt or harness secured to a
substantial chimney or to a window on the opposite
side of the building. Leave only enough slack to
work comfortably in one area, and adjust the slack
as work proceeds 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, or on a
brittle roof surface. Work on cleated walkboards.
5. On steep roofs:
a. Secure chicken ladders or cleats at the top
for adequate footing.
b. Safety lines should be tied and secured with
c. Carry a limited amount of materials so that
balance and footing are not impaired.
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 before performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO) or designated representative.
1.02 SYSTEM DESCRIPTION
A. Flashing is performing as it was intended when there are
no cracks, splits or torn areas. It should not show any
signs of corrosion. Where flashing meets a vertical
surface, all cap flashing should be secure and the
flashing itself should be soundly anchored.
A. Check flashings as a part of the annual roof inspection
(preferably in late autumn). Repair defects immediately
because flashing is a critical part of the roof fabric.
Small leaks in the flashing which are neglected may lead
to major faults in the roof system. See also Section
3.01 Examination below.
A. Flashing material: 16 oz. or 20 oz. sheet copper; lead-
coated copper; 26 gauge galvanized steel. Metal should
match remaining metals on the roof.
B. Flashing cement or roofing compound
C. Clean, soft cloths
D. See also materials/manufacturers listed in Part 2 of
A. Safety belt or harness; protective gloves and gear.
B. Chicken ladder; ladders and scaffolding.
C. Straight snips for cutting straight or slightly curved
lines in sheet metal 24 gauge or lighter.
D. Stiff bristle brushes
E. See also equipment listed in Part 2 of 07631-03-R.
A. Flashing is usually a weak part of the roofing system
and, therefore, should be inspected regularly for damage
1. Outside, inspect flashing for splits, holes or
2. Inside, inspect the underside of the roof deck for
evidence such as water stains or damp wood; inspect
the ceiling and walls around fireplaces and chimney
flues for stained or spalling plaster or wallpaper,
or peeling paint.
3. Look for daubs of roofing cement on the flashing -
this is an indication of previous leaks. This type
of repair is not recommended and may not have
completely stopped the leak.
4. Look for uncaulked openings at the tops of flashing
where water may enter.
A. Surface Preparation: Select sheetmetal type to be used
making sure it is compatible with the remaining flashing
on the roof.
3.03 EXECUTION, INSTALLATION, APPLICATION
A. See 07631-03-R for three different methods of patching
small holes in sheetmetal. The methods described in that
procedure are recommended for patching metal gutters, but
may also be used for making temporary patches to
flashing. For guidance on making more extensive repairs
to flashing, see 07620-02-R.
END OF SECTION
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