Fenestration Manufacturers Association

Standard Practice for the Installation of Windows with Flanges for Masonry Construction

Introduction: During the hurricane season of 2004 – 2005, the southeast United States received significant water damage through fenestration. The Florida building code commission has asked the Fenestration Manufacturers Association of Florida to create standards that would improve the current installation methods. This document was created by the Fenestration Manufacturers Association, and is now offered to ASTM to establish a consensus process.

1. Scope

1.1 This standard covers the installation of all windows in buildings of no more than 3 stories in height. It is expected that that all referenced components shall meet code requirements in force. 1.2 This practice applies to flanged windows which employ an integral or applied mounting flange that is attached and sealed to the window perimeter frame and are designed as an appendage that will cover previously- installed bucks and/or integrate with a masonry sill. 1.3 This standard covers the installation process for windows from pre- to post-installation. It does not include fabrication techniques that would be required to join individual windows to each other, either horizontally or vertically. It does not cover any other factory or field fabrication which joins or combines multiple windows. The instructions for mulling windows together and any accessories required must be supplied by the window manufacturer. 1.4 This standard provides minimum requirements for window installation, illustrating an effective, watertight manner based on state-of-the-art techniques. Actual conditions in buildings may vary. In some cases the window manufacturer will have to be consulted if the field or building conditions are other than as described in this standard. If the standard conflicts with the manufacturer’s instruction, the manufacturer’s instruction will take precedence. 1.5 This standard does not address safety concerns, either from the installation process or present at the building site. It is the responsibility of the user of this standard to ensure that all appropriate health and safety practices have been implemented. 1.6 This standard’s techniques have been developed specifically to stop liquid water from entering through the window masonry opening. The major emphasis is focused on sealing the surrounding area of the window’s masonry opening in such a manner as to eliminate liquid water from penetrating the wall through the CMU, masonry, and sill of the window opening.

2. Standard References

2.1. AAMA 711 Voluntary Specification for Self-Adhering Flashing Used for Installation of Exterior Wall Fenestration Products 2.2 AAMA 800 Voluntary Specifications and Test Methods for Sealants 2.3 AAMA 808.3 Voluntary Specification for Exterior Perimeter Compounds 2.4 AAMA 809.2 Voluntary Specification Non-Drying sealants (Type II) 2.5 ASCE 7 Minimum Design Load for Buildings and Other Structures 2.6 ASTM E2112 Standard Practice for Installation of Exterior Windows, Doors and Skylights. 2.7 ASTM E 631 Standard Terminology of Building Constructions 2.8 ASTM C 920 Specification for Elastomeric Sealant 2.9 ASTM C 1085 Specification for Rubber-Based Solvent-Release Sealant (Type II) 2.10 ASTM C1063-03 Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster 2.11 ASTM C926-98a (2005) Standard Specification for Application of Portland Cement-Based Plaster 2.12 ICBO Evaluation Service: AC 212 Acceptance Criteria for Water Resistive Coating

3. Definitions Page 1 of 5 3.1 Back dam, n. The rear upturned leg of a masonry sill. This leg can be created from a variety of materials, including a pre-cast sill, a device that is placed on the masonry block to form a back dam, or as a result of being poured and cast into the opening, provided that the height of the back dam is at least 6 mm (1/2-inch). 3.2 Barrier wall, n.—a wall system that is intended to manage all water to the exterior surface. 3.3 Buck, n. – A code compliant member which is typically installed on a minimum of three sides of the window opening cavity (top and two sides) for the purpose of acting as a provision of a mounting surface for the installation of windows. 3.4 Compatible Materials –materials that maintain physical and functional properties when in direct contact or close proximity to each other. 3.5 End dam, n. Portion of sill construction which is the side upturned leg. This leg can be created from a variety of materials, including pre-formed or field fabricated members which are sealed to the sill. The use of sills that have right and left end dams already built into the material or a variety of liquid-applied sealers and flexible flashing material, which can be applied to the sill and the masonry opening in such a fashion as to make end dams seal together with the bottom of the sill. End dams must be of a height equal to the height of the back dam or higher. 3.6 Mounting fin, a.k.a. integral fin, n—a permanent appendage protruding from the body of a window or door, used as either an installation attachment feature or part of the water-resistive barrier interface between the product and the wall, or both. The term “fin” is also known as “flange”. A fin projecting from the frame of the window, parallel to the plane of the wall, for the purpose of securing the window to the building structure. NOTE: Flange-mounted, a.k.a. frontal-flanged, adj.—refers to a type of window which has a flange projecting parallel to the plane of the wall, located at the most exterior surface of the window for the purpose of installing the window against a backstop, buck, receptor, groove, or other such stepped features that are incorporated into the rough opening to act as a backstop for the flange only, to seat a window into a masonry opening. 3.7 CMU Sealer aka. Liquid-applied waterproof coating, n. – Protective, breathable coating that minimizes amount of liquid water into given substrate. 3.8 Masonry Window Cavity, n. – that portion of a masonry opening which consists of the two sides and top, which is located under the lintel and is as wide as the lintel and is as deep as the CMU or masonry opening. 3.9 Masonry Window sill, n. aka window masonry sill – A product designed with slope for the purpose of draining water away from the window opening to the exterior of the building and shall meet the building requirements. 3.10 Sealant (construction), n. – an elastic material capable of sealing a surface, or acting as a filler between two or more substrates. The sealant shall have the joint movement, adhesion and exhibit minimal shrinkage as required for construction applications. 3.11 Shim, n - a thin, flat material made of a material of a durometer of 90 or higher used to level or plumb a fenestration product frame during installation. Discussion-Lateral shims are placed in the rough opening adjacent to the frame jambs. Setting shims are placed in the rough opening beneath the sill.

4. Significance and Use

4.1 This practice recognizes that the effective performance of installed fenestration products is dependent in part upon following proper installation procedures and appropriate workmanship. 4.2 This practice recognizes that the coordination of trades and proper sequencing are essential for effective fenestration installation. The general contractor shall be responsible for the necessary coordination of trades and proper construction sequencing of the installed fenestration product. 4.3 Improper installation of units contributes to excessive air, water, sound leakage, and condensation. This promotes the deterioration of wall constructions, insulation, fenestration products, and their respective finishes. 4.4 This practice presumes a working knowledge of applicable federal, state, and local codes and regulations; specifically, but not limited to required means of egress, requirements for safety glazing materials, and structural requirements of applicable codes. 4.5 This practice presumes a working knowledge of the tools, equipment, and methods necessary for the installation of specified fenestration products. It further requires familiarity with flashing and sealing, glazing procedures, finishes where applicable, and an understanding of the fundamentals of construction that affect the installation of these units. 4.6 This practice presumes that the products that have been furnished for the installation and their locations within the structure comply with all the applicable building codes and regulations. 4.7 This standard recognizes that the installer must have a working knowledge and an understanding of the fundamentals of the methods necessary for the installation and application of caulking, sealants, and coatings as required for the installation of the window, including their compatibility with other products.

of 5 5. Related Issues and Procedures

5.1 Continuity—Continuity shall be maintained between all elements in the fenestration product and the surrounding wall.

5.2 Joints and Anchorages—Joints and anchorages between the building masonry openings and fenestration product shall be designed to accommodate differential thermal expansion, structural requirements and moisture migration within the window/wall assembly.

5.3 Construction Sequence—Effective integration and continuity of the fenestration product and other components of the masonry walls is dependent on proper construction sequencing.

5.4 Construction Damage—Masonry openings which have cracked, missing/mis-aligned or damaged masonry, sill, mortar joints or missing block shall be repaired or replaced, prior to application of any waterproofing materials and the installation of the window.

5.5 Sealants – All gunnable sealants shall comply with ASTM C 920 Class 25 specification or greater for proper joint expansion and contraction. In addition, the sealant shall be chemically curing to minimize cracking, loss of adhesion and shrinkage. Solvent and waterborne products such as latex, acrylic, other water and solvent based tri- polymer blend products shall not be used due to the high shrinkage and low joint movement for the installation of windows. If pre-formed tapes are used they must meet ASTM C1281 specification. Prior to using the sealants seek input from sealant manufacturer for proper joint design and sealant selection.

5.6 Stucco and Other Cladding - Prior to window installation, no claddings will be installed.

5.7 Shims: Shims are required under all anchors. Non-treated wood or organic material shall not be used as shims.

NOTE 2: When wood bucks are used, the front surface of the wood buck shall be 100% coated with a sealant to protect it from possible water absorption from the stucco material that it will be in contact with. If additional material is used to make the buck thicker for the purpose of making the masonry opening smaller, these additional members will be pressure- or chemically-treated wood, and shall be 100% covered by a sealant and then flattened with a putty knife or sealant knife to form a flat, consistent covering on top of the buck. The coatings applied to the wood buck material will need to be extended onto the sill member, ensuring 100% continuity between the buck and the sill member, with no air or water gaps.

5.6.4 Anchorage of bucks/receptors/devices: Anchorage of the buck /receptor/device into the CMU shall be accomplished in accordance with the wind-loading requirements of the locale of the window installation. Refer to ASCE-7 for Florida wind-load zones.

NOTE 3: The number, type and spacing of fasteners required for the installation of the bucks/devices/receptors is directly related to the wind-load requirements and in accordance to local codes.

6. Window Installation Procedures

6.1 Pre-Installation Inspection 6.1.1 Verify that the masonry rough opening meets this standard with regard to being square, correct size, plumb and true. Notify contractor to remedy any discrepancies per this standard. 6.1.2 Before installation can occur the installation contractor is responsible for inspection of the masonry opening for missing mortar, cracks in the sill, and any other defect which has produced a hole or allows passage of liquid water through the masonry opening. Note: In certain cases the installer shall inspect and verify that a CMU sealer has been applied on all three sides of the masonry opening (2 sides and the top) and that a mechanism/device or coating has been installed to make the sill portion of the window opening impervious to liquid water penetration, which includes the formation of an end dam to tie the sill and the masonry jambs together to form one homogenous area.

of 5 6.2 Pre-Installation Requirements performed by others, per manufacturers instructions.

6.2.1 Masonry Rough Openings

6.2.1.1 The builder will supply the masonry openings. Size and tolerances of masonry rough openings shall be determined from the window manufacturer’s instruction. 6.2.1.2 The masonry opening shall be square, plumb, and level prior to the installation of the window. Masonry openings diagonal dimension must be square; no more than a 6 mm (1/4-inch) tolerance diagonally will be allowed. Horizontal and vertical dimensions of the rough opening can be no smaller than described above and up to 3 mm (1/8-inch) larger. 6.2.1.3 The installer will treat the masonry opening with a CMU sealer for the purpose of sealing the CMU window cavity from absorbing liquid water. This application will be put on before the installation of the buck materials.

6.2.1.4 After application of CMU sealer, the contractor will install or cause to be installed by others, a waterproof sill mechanism across, on top of, or in replacement of the masonry sill, which is sealed to the window masonry opening cavity’s previously-installed CMU Sealer. See Section 2, Standard References. 6.2.1.4.1 The water-resistive coating shall be applied on all three sides of the masonry opening (2 sides and the top) and a mechanism/device or coating shall be installed to make the sill portion of the window opening impervious to water penetration from liquid water, which includes the formation of an end dam to tie the sill and the masonry jambs together to form one homogenous area.

NOTE 1: Upon completion of all steps in 5.0, the masonry opening will have been treated with materials, either liquid or solid, which will prevent liquid water from absorbing through the CMU or concrete sill, or any of the masonry mortar joints, cracks, or defects.

6.3 Installation of Buck, Receptor, or Device - The installer will install or cause to be installed a window buck, receptor, or device which will act as a mounting surface on both sides and the top for the seating of the window into the masonry cavity. Bucks, receptors, or devices will be no more than 1 ½” thick. 6.3.1 Apply a 9 mm (3/8 inch) bead sealant or appropriate gasket under the buck/receptor/device material to ensure against the passage of liquid water behind the buck/receptor/device. 6.3.2 The bucks will be in line with the sill material, allowing the flange of the window to be 100% situated against the back rabbet created by the installation of these devices. 6.3.3 The bucks/receptors/devices will be installed in such a fashion as there are no edge gaps between the bucks and the masonry sill member.

6.4 Installation Procedures

6.4.1 Carefully remove all loose construction debris from the buck and sill areas. 6.4.2 With the rear of the window’s flange exposed and cleaned, carefully run a continuous 9 mm (3/8 inch) bead of sealant up both sides and across the top of the inside of the flange. Connect that bead of sealant across any joinery of the window frame at all four corners to the furthest inside plane of the window frame, to ensure that that window joinery has been sealed from the exterior. NOTE 4: Do not run a bead of sealant across the bottom flange. A discontinuous bead of sealant will be allowed, to easily allow water that has entered the window sill to exit. Any finish applied to the sill shall not interfere with the drainage of liquid water. The water must drain to the exterior surface of the façade. 6.4.3 Place the window into the masonry opening, seating the back-sealed flange against the buck /device/receptor. 6.4.4: Carefully tool the squeezed-out portion of the sealant to make it flat over the wood buck/device/receptor, ensuring that there is no interference with the installation of the cladding or stucco after it has been anchored. 6.4.5 Following the window manufacturer’s instruction, and an awareness of the local codes and wind-load requirements, install fasteners per instruction/drawings. NOTE 5: When penetration of the CMU or masonry material is required for structural integrity the installer must use manufacturer’s specified fasteners. NOTE 6: Install shims in such a manner that will allow for an air seal. 6.4.6 Apply backer rod and an interior perimeter bead of sealant or other window manufacturer approved material between the window and the substrates to ensure a complete water seal.

of 5 NOTE 7: This sealant shall be tooled in such a way as to not interfere with the placement of any interior trim on the inside of the window masonry opening. NOTE 8: Compatibility must be known between the low-expanding, low pressure foam and the sealant, if foam is used, to ensure there is no reaction between the two materials.

6.5 Combination, Bayed or Bowed Windows: Window products which are mulled together, joined, or set side- by-side must be installed using manufacturer’s instructions, which include the use of a mullion that has been selected to meet the wind load for the location and the size of the window.

6.5.1 Mullions shall be installed and sealed in accordance with manufacturer’s instructions. Anchors must be 100% shimmed; anchors which have no support between their structural clip of the mullion and the masonry will not be allowed.

6.5.2 Window sills shall not be altered in any fashion that would cause the back dam of the sill to be lowered from its designed height to install a mullion. Sills should be designed to allow water drainage to the exterior of the façade. If a sill is not designed to allow proper water drainage to the exterior façade additional steps shall be taken to ensure drainage away from the exterior facade.

7.0 Post-Installation Procedures 7.1 The installer shall ensure that the fenestration product frame and sash are installed square, plumb and level within the manufacturer’s specified tolerances. 7.2 Check of Operable Elements—The installer shall ensure that all sash move freely within their frames and that weather stripping or compressible seals make full contact with mating surfaces. 7.3 The installer shall ensure that operable hardware such as locks, cranks, latches and hinges operate smoothly and that all locking mechanisms engage and operate properly. 7.4 Drainage holes shall be inspected for blockage and freed of any obstructions to allow drainage at the time of installation. Note: Post-Installation by others – In the process of installing cladding locate the window’s weep holes and make sure that no trim, stucco, sills, or any other appendage is either closing, blocking, or interfering with the weep holes of the window, which provides drainage to the outside.

8. Keywords 8.1 Buck; CMU; Masonry Opening; Receptor; Sealant; Sill pans; Window; Window installation.