Backstop NT – Smooth SpecificationsDUK180
Backstop NT™ - Smooth
A High Performance, Roller Applied
Water-Resistive Membrane and Air Barrier
Backstop NT - Smooth
Specifications
DRYVIT UK LTD.
MANUFACTURER’S SPECIFICATION
SECTION 07240
DRYVIT Backstop NT - Smooth Air and Moisture barrier
1
Backstop NT – Smooth SpecificationsDUK180
PART I - GENERAL
1.01 SUMMARY
This document contains all the Manufacturer’s requirements for the proper design, use, and installation of the Dryvit Backstop NT - Smooth air and moisture barrier. This document is intended to be used in conjunction with:
A. DUK181 – Backstop NT - Smooth Application Instructions
B. DUK455 – Backstop NT - Smooth Product Sheet
C. DUK177 – Backstop NT - Texture Application Instructions
D. DUK176 – Backstop NT - Texture Specifications
E. DUK453 – Backstop NT - Texture Product Sheet
1.02 DESCRIPTION
A. General: The Dryvit Backstop NT - Smooth is a non-cementitious, polymer based, water resistant, protective coating used as a secondary weather barrier and air barrier for use over approved exterior substrates, in conjunction with Dryvit’s Backstop NT - Texture and Dryvit Grid Tape joint treatment. Backstop NT - Smooth may be used as a component of Dryvit’s Outsulation, Outsulation Plus Exterior Insulation and Finish Systems.
B. Design Requirements
1. Acceptable surfaces for Backstop NT - Smooth include:
a. Core treated exterior grade gypsum sheathing meeting ASTM C79
b. Fiberglass mat faced exterior grade gypsum sheathing meeting ASTM C1177
c. Exterior, cement and calcium silicate sheathing.
d. Minimum 13 mm (1/2 in), 4-ply, APA Exterior Grade, CD-X plywood, installed with the C face out.
Caution: Backstop NT - Smooth is not recommended for use over Oriented Strand Board (OSB), pressure treated or fire retardant treated wood products.
2. Backstop NT - Smooth is not intended to be used as waterproofing for exterior horizontal surfaces or below grade applications.
3. Backstop NT - Smooth shall not be exposed to weather for longer than 30 days prior to being covered.
4. The substrate system shall be designed so that maximum deflections do not exceed L/240.
C. Performance Requirements: Backstop NT - Smooth shall meet the following performance criteria:
1. Water Vapor Transmission: ASTM E96 – Vapor Permeable
2. Flexibility: ASTM D522: Passes 3.2 mm (1/8 in) mandrel
3. Tensile Bond: ASTM C297 – Substrate failure
4. Tensile Strength –
ASTM D2370 – (100+psi)
5. Elongation – ASTM D2370 – 17%
6. Wind Driven Rain –
FS TT-C-555B – No moisture penetration
7. Moisture Resistance –
ASTM D2247 – No deleterious effects
8. Flame Spread/Smoke Development–ASTM E84 – Flame Spread less than 25.
1.03 SUBMITTALS
A. Product Data – The contractor shall submit to the owner/architect manufacturer’s product data sheets describing products, which will be used on this project.
B. Samples – As required for the specific Exterior Insulation and Finish System specified.
1.04 QUALITY ASSURANCE
A. Qualifications
1. Product Manufacturer: Shall be Dryvit UK Ltd. All materials shall be manufactured or sold by Dryvit and shall be purchased from Dryvit or its authorized distributor.
a. Materials shall be manufactured at a facility covered by a current
ISO 9001 certification. Certification of the facility shall be done by a registrar accredited by the American National Standards Institute, Registrar Accreditation Board (ANSI-RAB).
2. Contractor: Shall be experienced and competent in the application of the Dryvit Exterior Insulation and Finish Systems and shall possess a current trained contractor certificate* from Dryvit.
1.05 DELIVERY, STORAGE, AND HANDLING
A. All Dryvit materials shall be delivered to the job site in the original, unopened packages with labels intact.
B. Upon arrival, materials shall be inspected for physical damage, freezing, or overheating. Questionable materials shall not be used.
C. Materials shall be stored at the job site in a cool, dry location, out of direct sunlight, protected from weather and other damage. Minimum storage temperature shall be 4 °C
(40 °F).
1.06 PROJECT CONDITIONS
A. Environmental Requirements
1. The air and wall surface temperatures shall be minimum 4 °C (40 °F) and rising at the time of application of
Backstop NT - Smooth. These temperatures shall be maintained, with adequate air ventilation and circulation, for a minimum of 24 hours thereafter, or until the products are dry.
1.06 PROJECT CONDITIONS
A. Environmental Requirements
1. The air and wall surface temperatures shall be minimum 4 °C (40 °F) and rising at the time of application of Backstop NT - Smooth. These temperatures shall be maintained, with adequate air ventilation and circulation, for a minimum of 24 hours thereafter, or until the products are dry.
B. Existing Conditions – The contractor shall have access to electric power, clean water, and a clean work area at the location where the Dryvit Backstop NT - Smooth materials are to be applied.
1.07 SEQUENCING AND SCHEDULING
A. Installation of the Dryvit Backstop NT - Smooth shall be coordinated with other construction trades.
1.08 LIMITED MATERIALS WARRANTY
A. Backstop NT - Smooth is covered by and subject to the terms and conditions of Dryvit’s limited materials warranty applicable to the specific Dryvit system used.
1.09 DESIGN RESPONSIBILITY
A. It is the responsibility of both the specifier and the purchaser to determine if a product is suitable for its intended use. The designer selected by the purchaser shall be responsible for all decisions pertaining to design, detail, structural capability, attachment details, shop drawings, and the like. Dryvit has prepared guidelines in the form of specifications and product sheets to facilitate the design process only. Dryvit is not liable for any errors or omissions in design, detail, structural capability, attachment details, shop drawings, or the like, whether based upon the information prepared by Dryvit or otherwise, or for any changes which purchasers, specifiers, designers, or their appointed representatives may make to Dryvit’s published comments.
PART II PRODUCT
2.01 MANUFACTURER
A. All materials shall be obtained from Dryvit or its authorized distributors.
2.02 COMPONENTS
A. Dryvit Backstop NT - Smooth: A fully formulated, non-cementitious, water based material applied over approved substrates to provide water resistance and air barrier properties.
B. Dryvit Grid Tape: A 100 mm
(4 in) wide, open weave fiberglass mesh tape used to reinforce sheathing joints and exposed edges of sheathing.
C. Dryvit Backstop NT - Texture: A fully formulated, non-cementitious, water based material with texture, used to fill joints in substrates.
D. Dryvit Flashing Tape: A high-density, polyethylene backed, tape with a rubberized asphalt adhesive.
E. Dryvit Flashing Tape Surface Conditioner: A water-based surface conditioner and adhesion promoter for the Dryvit Flashing Tape.
PART III EXECUTION
3.01 EXAMINATION
A. Prior to application of Backstop NT - Smooth, the contractor shall ensure that the substrate is of a type listed in Section 1.02.B.1.
B. Ambient and surface temperatures are minimum 4 °C (40 °F) and rising.
C. The substrate shall be flat within 6.4 mm (1/4 in) in a 1.2 m (4 ft) radius.
D. Sheathing gaps shall not exceed 6.4 mm (1/4 in). Larger gaps shall be corrected by replacing sheathing material.
E. The contractor shall notify the general contractor and/or architect and/or owner of all discrepancies. Work shall not proceed until discrepancies have been corrected.
3.02 SURFACE PREPARATION
A. The substrate shall be prepared so as to be free of foreign materials such as oil, dust, dirt, paint, wax, water repellents, moisture, frost and any other materials that inhibit adhesion.
3.03 INSTALLATION
A. General: Backstop NT - Smooth is used in conjunction with Dryvit Backstop NT - Texture joint treatment and shall be applied in accordance with current, published Dryvit Backstop NT - Smooth Application Instructions, DUK181.
B. For sheathing substrates, spot all fastener heads and apply Backstop NT - Texture with Grid Tape at all sheathing joints, inside and outside corners in accordance with Backstop NT - Texture Application Instructions, DUK177. Allow to dry a minimum of 1 hour or until dry to the touch. Cool humid conditions will require longer drying time.
C. Backstop NT - Smooth is shipped in 19 L (5 gal) pails and is ready to use without additives.
D. Using a Wind-lock BM-1 or
BM-8 mixing blade, or equivalent, powered by a
13 mm (1/2 in) drill, at 400-500 RPM, mix the Backstop NT Smooth material to a smooth homogeneous consistency prior to use.
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Backstop NT – Smooth SpecificationsDUK180
E. Using a 19 mm (3/4 in) nap roller, apply the Backstop NT - Smooth over the entire wall face, including previously treated joints, at the recommended coverage rate.
F. Allow to dry a minimum of
4 hours prior to application of Flashing Tape and adhesively applied EPS insulation board. Cool damp weather will require longer drying times. During cool, damp weather, Flashing Tape Surface Conditioner may be necessary for proper Flashing Tape adhesion.
G. Install the specified Dryvit Exterior Insulation and Finish System per published installation instructions for the specific system being used.
3.04 FIELD QUALITY CONTROL
A. The contractor shall be responsible for the proper application of the Dryvit materials.
B. Dryvit assumes no responsibility for on-site inspections or application of its products.
3.05 CLEANING
A. All excess Dryvit materials shall be removed from the job site by the Contractor in accordance with contract provisions.
B. All surrounding areas, where Dryvit materials have been installed, shall be left free of debris and foreign substances resulting from the Contractor’s work.
3.06 PROTECTION
A. The Dryvit materials and the project shall be protected from damage and weather until dry.
1. The Dryvit Backstop NT -Smooth shall not be exposed for longer than 30 days prior to being covered with the Exterior Insulation and Finish System.
Printed in UK R5:01-31-07 1
© Dryvit UK Ltd.
Backstop NT – Smooth SpecificationsDUK180
DISCLAIMER
Information contained in this specification conforms to standard detail and product recommendations for the installation of the Dryvit Backstop NT - Smooth product as of the date of publication of this document and is presented in good faith. Dryvit UK Ltd. assumes no liability, expressed or implied, as to the architecture, engineering or workmanship of any project. To ensure that you are using the latest, most complete information, contact:
Dryvit UK Ltd.
Unit 4 WrenPark
Hitchin Park
Shefford, Bedfordshire
SG17 5JD
Tel: 01462 819555
*The Trained Contractor Certificate indicates certain employees of the company have been instructed in the proper application of Dryvit products and have received copies of Dryvit’s Application Instructions and Specifications. The Trained Contractor Program is not an apprenticeship. Each trained contractor is an independent company experienced in the trade and bears responsibility for its own workmanship. Dryvit UK Ltd. assumes no liability for the workmanship of a trained contractor.
Dryvit UK Ltd.
Unit 4 WrenPark
Hitchin Park
Shefford, Bedfordshire
SG17 5JD
01462 819555
Printed in UK R5:01-31-07 1
© Dryvit UK Ltd.