Mission Valley Roofing, Inc.

RECOMMENDED ROOFING PROCEDURES

GENERAL
All re-roofing shall conform to the applicable provisions of Chapter 32 of this code.

Roofing materials and methods of application shall comply with the U.B.C. Standards or shall follow manufacturer's installation requirements when approved by the building official.

INSPECTIONS
New roof coverings shall not be applied without first obtaining an inspection by the building official and written approval from the building official. A final inspection and approval shall be obtained from the building official when the re-roofing is complete. The pre-roofing inspection shall pay particular attention to evidence of accumulation of water. Where extensive pounding of water is apparent, an analysis of the roof structure for compliance with Section 3207 shall be made and corrective measures, such as relocation of roof drains or scuppers, re-sloping of the roof or structural changes, shall be made.

An inspection covering the above listed topics prepared by a special inspector may be accepted in lieu of the pre-inspection by the building official.

A.)  Built-Up Roof Covering

1.) GeneralBuilt-up roof covering shall be completely removed before applying the new roof covering.  New roofing conforming to Section 3209 shall be applied except that when the new roof is to be applied directly to a nailable deck which has Residual Bitumen adhering to it, a rosin-sized or other dry sheet shall be installed prior to the installation of the new roof system.

EXCEPTION: The building official may allow existing roof coverings to remain when inspection or other evidence reveals all of the following:

a.) That the roof structure is sufficient to sustain the weight of the additional dead load of the roof covering.

b.) There is not more than one existing roof covering on the structure.

c.) The existing roof covering is securely attached to the deck.

d.) The roof deck is structurally sound.

e.) The existing insulation is not water soaked.

1.)  General

When reroofing without removal of existing roof covering is permitted by the building official and when the conditions specified in the exceptions to Subsection (a) above have been met, the reroofing shall be accomplished in accordance with the section.

2.)  Over Gravel-Surfaced Roof Coverings

Over gravel-surfaced roof coverings, the roof shall be cleaned of all loose gravel and debris.  All blisters, buckles and other irregularities shall be cut and made smooth and secure.  Minimum 3/8-inch insulation board shall be nailed or securely cemented to the existing roofing with hot Bitumen over which a new roof complying with Section 3202 shall be installed.  When insulation board is to be attached with hot Bitumen, the existing surface shall be primed.

Alternatively, on nailable decks only, all existing gravel shall be spudded off to provide a smooth surface.  All blisters, buckles and other irregularities shall be cut and made smooth and secure.  A rosin-sized or other dry sheet shall be installed and a base sheet as defined in the code shall be mechanically fastened in place.  New roofing conforming to Section 3202 shall be applied.

3.)  Over Smooth or Cap Sheet Surface

Over smooth or cap sheet surfaced roof coverings, all blisters, buckles and other irregularities shall be cut and made smooth and secure.  In the case of non-nailable decks, a base sheet shall be spot cemented to the existing roofing.  New roofing conforming to Section 3203 shall be applied.

In the case of nailable decks, a base sheet shall be nailed in place.  In those cases where residual materials may cause the new base sheet to adhere to the old roof, a rosin-sized dry or other sheet shall be installed under the base sheet.  New roofing conforming to Section 3203 shall be applied.

C.)  Construction Details

1.)  Flashings and Edgings

Vent flashings, metal edgings, drain outlets, metal counter-flashing and collars shall be removed and cleaned,  rusted metal shall be replaced.  Metal shall be primed with cutback primer prior to installation.  Collars and flanges shall be flashed per the roofing manufacturer’s instructions.

2.)  Intersecting Walls

All concrete and masonry walls shall be completely cleaned and primed to receive new flashing.  All vertical walls, other than concrete or masonry, shall have the surface finish material removed to a height of approximately 6 inches above the deck new roof surface to receive new roofing and flashing.  All rotted wood shall be replaced with new materials.  Surface finish material shall be replaced.

3.)  Parapets

Parapets of area separation walls shall have noncombustible faces, including counter-flashing and coping materials.

EXCEPTION:  Combustible roofing may extend 7 inches above the roof surface.

4.)  Cant StripsWhere space permits, cant strips shall be installed at all angles.  All angles shall be flashed with at least two more layers than in the new roof with an exposed finish layer of inorganic felt or mineral surfaced cap sheet.

SHINGLES AND SHAKES

A.)  General

Based on inspection of the existing roofing, the building official may permit the recovering of existing shingle or shake roofing in accordance with the provisions of this section.

Not more than two overlays of asphalt shingles shall be applied over an existing asphalt shingle roof.

Not more than two overlays of asphalt shingle roofing shall be applied over wood shingles.   Asphalt shingles applied over wood shingles shall have an overlay underlayment of not less than Type 30 non-perforated felt.

On structures with a slope of 2:12 or greater and having no more than one existing built-up roof with gravel surface, the gravel must first be spudded off to provide a smooth surface.  All blisters and irregularities shall be cut and made smooth and secure and an underlayment of not less than Type 30 non-perforated felt shall be installed.  If the built-up roof has a smooth or cap sheet surface, all blisters and irregularities shall be cut and made smooth and secure and an underlayment of not less than Type 30 non-perforated felt shall be installed.

Not more than one overlay of wood shakes shall be applied over an existing asphalt shingle or wood shingle roof (with one layer of 18-inch, Type 30 non-perforated felt interlaced between each layer of shakes).

Not more than one overlay of wood shingles shall be applied over existing wood shingles.

New roof covering shall not be applied over an existing shake roof.

Rusted or damaged flashing, vent caps and metal edgings shall be replaced with new materials as necessary.  

TILE

Tile roofs may be applied over existing roof coverings when approved by the building official.  Such installation shall be substantiated by structural data indicating that the existing or modified roof framing system is adequate to support the additional tile roof covering.

Existing tile roofing shall be removed and cleaned. Damaged or rusted flashing and cracked or broken tile shall be replaced.  Tile shall be applied in accordance with the requirements of Section 3208 (b) 5 (application of clay or concrete tile) and in conformance with the original manufacturer's specification.

EXECEPTION:  When the original manufacturer's specifications are no longer available, the tile may be reinstalled to match the prior installation except when clay and terra-cotta hips and ridge tile shall be reinstalled with portland cement mortar.