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Reroofing Guidelines

Introduction : Reroofing is categorized according to one of the following four methods;
  • roof repair
  • roof restoration (resaturation and rejuvenation)
  • roof retrofit (recover)
  • roof removal and replacement
Roof Repair is repair work of actual leaks and obvious deteriorated areas on an identified, localized basis. Good repair work generally requires highly skilled roofing experience in defect identification and proper repair procedures. Barrett materials are well suited for roof repair work utilizing traditional repair methods.

Roof Restoration, or resaturation, is an intermediate step between repair and retrofit, and generally includes a repair procedure for all flashing and a resaturant type liquid with an optional fabric or mat over an entire roof area.

This procedure is rarely cost effective in the long term. Barrett generally does not recommend the use of their materials for this type of application except as a short-term or temporary solution.

Roof Retrofit, or recover, is refitting the existing roof system with a new membrane cover and all related flashing, over the top of the existing roof membrane. New insulation is generally used to separate the new membrane from the existing membrane.
Reroofing directly over an existing roof membrane is not recommended by many material manufacturers and roofing experts since defects in the old roofing system can be transferred to any new roof covering and there is always a high risk of trapping moisture from the existing roof under the new roof membrane. Complete roof removal eliminates these risks.
Barrett's policy regarding reroofing over existing membrane is a more enlightened approach based upon decades of experience and success in identifying and remedying defects in an existing roof.
In general, a retrofit roof may be successfully completed if the original roofing system is securely attached to the deck, is not significally deteriorated, the structural deck and insulation are in satisfactory condition and the system does not contain excessive amounts of moisture.
Making a decision between the options of retrofit or removal of an existing roof assembly should be based on a complete engineering study including a moisture survey and consideration of all extenuating circumstances which might preclude or necessitate a complete tear-off.
If the decision is made to roof over (retrofit) an existing membrane, the following procedures are generally followed prior to the application of Barrett retrofit reroof system.
    1. It is generally a code violation to install more than one "retrofit roof membrane" over an exisiting (singular) membrane.
    2. lf the existing roof surface is gravel surfaced the aggregate is scraped with mechanical equipment, powerbroomed and blown clean or vaccumed. The surface should be relatively smooth. All surfaces must be free of dust, dirt and debris.
    3. All wet or deteriorated insulation, as determined by an approved moisture survey, must be removed and replaced with new insulation material. All existing insulation material should be vented with random cuts through the existing membrane at approximately fifteen feet centers in all directions.
    4. All blisters, buckles, ridges, folds, and other deformations must be cut out and patched to provide a smooth, even surface.
    5. All old flashing is cut out and stripped from all walls, curbs and other projections, the substrates cleaned, repaired or otherwise conditioned to conform with the flashing requirements of the new construction. All old edge detail work must be reviewed and a new edge detail considered for specific job conditions.
    6. All roof curbs, roof drains, edge conditions and other roof projections shall be raised or lowered as required for new elevations, if any. All flashings shall have a minimum height of 8 inches. Treated wood nailers are installed as required.
    7. All new expansion joints, if required by the engineering survey, and all existing expansion joints being renewed shall have treated wood nailer curbs installed as required
    8. Any drainage system changes, including new gradient slopes, new roof drains or scuppers, are to be designed to conform with current code requirements.
    9. A new membrane system, insulation and flashing accesssories are installed in compliance with Barrett specifications.
Roof Removal and Replacement is the installation of a new membrane system after complete removal of all roof components above the structural deck. This is generally considered the safest and surest method to guarantee long-term performance.
As with the retrofit procedure, an engineering study should be conducted with consideration of component expansion/contraction cycles, roof drainage, vapor retarder requirements, temporary roofing requirements, roof projection flashings, perimeter flashing elevations, structural system loadings, asbestos audit and energy conservation analysis.
A roof removal plan generally requires special provisions for keeping the building watertight during construction as well as for dealing with potential odor, dust and noise pollution.
Many components of an existing built-up system can be recycled. If recycling is desired contact Recycle Inc.
Summary : The Barrett Company can provide a number of options and alternatives for reroofing projects with economical, long-term proven and guaranteed results. Each reroof is as unique as a fingerprint. Before starting any reroof project, the owner should consult with an RCI Registered Roof Consultant or a licensed architect or engineer. Only approved projects are eligible for a Barrett warranty. For more information contact Barrett Technical Services at 1•800•647•0100.

 

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http://www.barrettroofs.com
Last Updated : 03.17.06
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