توصیه های اجرای شینگل
Do not make a roof system or manufacturer selection on the basis of a warranty. Select a system for its suitability to the project, as discussed in System Selection Criteria above.
Do not automatically specify a warranty. Rather, select a system for its suitability for the project, as discussed in System Selection Criteria and Specific Roof System Selection above, and then determine if the Owner’s best interests are served by a warranty.
If specification of a warranty is being considered, review the warranty section of NRCA’s Low-Slope Roofing Materials Guide (or the Steep-Slope Roofing Materials Guide). Ensure that the manufacturer’s standard language is not onerous BEFORE specifying that manufacturer. Make sure that the specified warranty includes:
- Defects in materials and defects for the entire roofing system with all materials and accessories included.
- Coverage up to the basic wind speed identified in the building code.
- No Dollar Limit coverage without prorating.
For government projects, if a warranty is desired, recommend that a Government attorney identify provisions of the manufacturer’s standard warranty that are unacceptable, so that warranty provisions acceptable to the Government can be specified. The following are examples of changes to standard warranties that should be considered for all projects:
- Delete warranty language that takes away the Owner’s rights
- Delete warranty language that excludes other rights and remedies
- Delete warranty language that sets a maximum dollar limit
- Delete or modify the unfavorable items listed above in “Warranty Limitations.”
KEY ELEMENTS OF SPECIFICATION
After a suitable roof system has been selected, appropriate specifications and drawings need to be prepared to help ensure that the roof designer’s design concept is understood and executed by a professional roofing contractor. The fate of many prematurely failed roofs is often set by poorly prepared documents (Figure 14). The importance of the designer’s diligence in preparing specifications and drawings cannot be overemphasized.
The following elements are critical in communicating project requirements to the contractor:
- Roof Plan(s) and Details
To produce good specifications, the roof designer should first acquire a suitable guide specification.
MasterSpec® is a reliable source of master specifications, which must be edited by experienced specification writers.
Also, the following Unified Facilities Guide Specifications (UFGS) are available:
Roof decks: 03 31 00.00 10 (cast-in-place concrete), 03 51 13 (pre-cast concrete), 05 30 00 (steel), 06 10 00 (wood)
Insulation: 07 21 16 (blanket [attic]), 07 21 23 (loose fill [attic]), 07 22 00 (rigid)
Built-Up Roof: 07 51 13
Modified bitumen: 07 52 00
Protected Membrane Roof (using a variety of membrane types): 07 55 00
Single-ply: 07 53 23 (EPDM), 07 54 19 (PVC)
Sprayed Polyurethane Foam: 07 57 13
Metal Panels: 07 41 13 (structural), 07 61 14.00 20 (steel standing seam roofing), 07 61 15.00 20 (aluminum standing seam roofing), 07 41 13 16 (copper roof system)
Flashing and sheet metal: 07 60 00 (flashing and sheet metal) and 07 62 10 (copper flashing)
Asphalt Shingles: 07 31 13
Slate: 07 31 26
Tile: 07 32 13 (clay and concrete)
After obtaining a guide specification, it is critical that the roof designer tailor it to the specific project. Information that is not applicable should be deleted. Applicable information should be adjusted if needed. Additional specification criteria should be added as necessary to suit the project. The following should be considered when developing Parts I, II, and III of the roof specifications:
- Fire and Wind: Specify fire and wind resistance requirements. For wind uplift, specify the test method required to demonstrate required resistance (see Wind Safety Section 4.4 Roof Systems). (Note: For shingles, slate and tiles, normally the resistance for the corner areas is specified for use throughout the entire roof area because these products are typically used on small roof areas. For large slate and tile roofs, if there is sufficient cost savings, both corner, perimeter and field resistances can be specified.)
- Submittals: Specify submittal of catalog data for all products, including installation instructions and, where applicable, maintenance and repair instructions. Specify submittal of samples only when necessary to evaluate the product. For example, it is normally not necessary to specify the submittal of an EPDM sample, because black sheets are typically specified and there is no factory-applied surfacing to evaluate. However, it may be appropriate to specify submittal of samples of a granule-surface SBS modified bitumen sheet in order to select the desired color and to qualitatively evaluate the granule coverage and embedment.Specify that the following be submitted: Demonstration of specified contractor qualifications, manufacturer review letter, manufacturer inspection reports, certification reports demonstrating that materials comply with referenced standards, certificates of analysis (when specified), and documentation demonstrating enrollment in the MBMA certification program (when specified).
These items are discussed below:
- Contractor Qualifications: Specify that the contractor have a minimum number of years of experience with the type of system specified (five years is usually a reasonable requirement). Also specify that the contractor is approved, authorized or licensed by the roof covering material manufacturer to install its product. For public bid work, this may make it difficult to find multiple manufacturers.
- Manufacturer Review: Require the roof covering materials manufacturer to review the specification and drawings and advise in writing of their acceptance thereof, or to submit in writing their concerns and recommendations to resolve these concerns. Specify submittal of the review letter within a short time after contract award, so that if changes are needed there is sufficient time to develop them before the roofing begins.
- Manufacturer Inspection: Require the roof covering materials manufacturer to inspect the roof application on the first or second day of application, and to perform an inspection upon completion of the application. Require submittal of the inspection reports.
- Standards Compliance Certificates: To help ensure that products furnished to the project comply with referenced standards, specify that certificates demonstrating compliance be submitted.
- Certificates of Analysis: For those products where certificates of analysis are available, consider specifying certificates of analysis that provide quality control test results for specific manufacturing lots (lot numbers are printed on the product package label).
- Certification Program: If a metal roofing system is selected, consider specifying that the manufacturer be certified through the MBMA Metal Roofing Systems Quality Certification Program. Further information about the program is provided in the MBMA Metal Roofing Systems Design Manual.
- Pre-roofing Conference: Specify a two-stage pre-roofing conference. The first conference should be held a few or several weeks prior to the start of roofing, depending upon job size and complexity. The second conference should be held just prior to application. The purpose of the conference is discussed later in this section.Specify that the conference be attended by the general contractor, roofing contractor’s project manager, superintendent (on large projects) and foreman, a representative of the roof covering materials manufacturer, and the mechanical, electrical, and lightning protection system (LPS) contractors if mechanical, electrical, or LPS work is associated with the roofing work. If a third-party inspection firm will be on the job, the inspector should also attend.
Quality Control Documents: If a BUR, modified bitumen, EPDM or sprayed polyurethane foam system is specified, specify application compliance with the applicable quality-control document co-produced by NRCA:
- Quality Control Guidelines for the Application of Built-Up Roofing
- Quality Control Guidelines for the Application of Polymer Modified Bitumen Roofing
- Quality Control Guidelines for the Application of Spray Polyurethane Foam-based Roofing
- Quality Control Guidelines for the Application of Thermoset Single-Ply Roof Membranes