Complete Tender BOQ Specification for Exterior Polyurethane Faux Beams

Project Overview and Scope of Work

The specification should begin with a clear statement of the project's scope, identifying the building type, the areas where faux beams will be installed, and the overall design intent. This section provides context for all the technical requirements that follow and helps contractors understand the scale and complexity of the work.

For exterior applications, the scope should explicitly identify which building facades or exterior structures are included in the beam installation. Entry porticos, covered patios, lanai, gazebos, and exterior dining areas are common locations for exterior faux beams. Each location may have different exposure conditions—proximity to direct rainfall, sun exposure, wind exposure, and temperature variation—and the specification should address each location separately if conditions vary significantly.

The scope should also specify what is included and what is excluded from the beam contractor's scope. Typically included are supply and installation of beams, mounting hardware, adhesive, sealants, and finishing materials. Typically excluded are structural modifications to the building, electrical or mechanical work that may need to be relocated to accommodate beams, and any decorative accessories not specified as part of the beam system.

Identify whether the project is new construction or renovation. In renovation projects, existing conditions may require additional preparation work, and the specification should note that the contractor is responsible for conducting a pre-installation survey to identify any conditions that may affect the installation approach. Any conditions discovered during the survey that require additional work should be documented and priced as a variation order before proceeding.

Material Requirements and Performance Criteria

The material specification is the heart of the BOQ and must be precise enough to prevent substitution of inferior materials while remaining flexible enough to allow reasonable equivalent products from different manufacturers. The following parameters should be specified numerically wherever possible.

Base Material: The specification should require beams manufactured from polyurethane resin specifically formulated for exterior use. The polyurethane shall have a minimum density of 280 kilograms per cubic meter and a maximum density of 400 kilograms per cubic meter. Materials shall be sourced from manufacturers with a minimum of five years' continuous production experience in architectural polyurethane products.

UV and Weather Resistance: Exterior polyurethane beams must be formulated with UV stabilizers and hindered amine light stabilizers (HALS) to resist degradation from ultraviolet radiation. The specification should require third-party test data demonstrating color retention of at least 90 percent after 2,000 hours of accelerated UV exposure testing per ASTM G154 or equivalent. The material should show no surface chalking, cracking, or delamination after this testing period.

Impact Resistance: The beam material should have a minimum impact resistance of 2.0 joules measured per ISO 179 or equivalent, to ensure durability in exterior environments where accidental impacts may occur.

Moisture Absorption: Maximum moisture absorption should not exceed 2 percent by weight after 24 hours of immersion at 23 degrees Celsius, ensuring dimensional stability and resistance to water damage in humid exterior conditions.

Fire Performance: Where exterior beams are installed under covered structures in areas subject to building code requirements for fire-rated materials, the specification should require beams with a flame spread index not exceeding 25 and a smoke developed index not exceeding 450 when tested per ASTM E84 or equivalent. Test reports from an accredited laboratory should be submitted for verification.

Profile, Dimensions, and Finish Specification

This section describes the physical and aesthetic requirements for the beams. All dimensions should be stated in millimeters, and tolerances should be specified.

Beam Profile: Beams shall replicate the appearance of [SPECIFY SPECIES: e.g., rough-sawn Douglas fir / hand-hewn oak / reclaimed barn timber] with a profile matching drawing number [SPECIFY DRAWING NUMBER]. Cross-sectional dimensions shall be [SPECIFY DEPTH] millimeters by [SPECIFY WIDTH] millimeters with a tolerance of plus or minus 2 millimeters.

Lengths: Beam lengths shall be as specified in the beam schedule on drawing number [SPECIFY DRAWING NUMBER]. All beam ends shall be square-cut unless otherwise indicated. Field cutting of beams shall be permitted only where dimensions cannot be achieved with standard lengths, and all cut ends shall be sealed with a compatible polyurethane sealer before installation.

Texture: The beam surface texture shall be [SPECIFY: smooth planed / lightly wire-brushed / deeply sculpted / hand-hewn] as indicated on finish schedule [SPECIFY SCHEDULE NUMBER]. Texture depth shall be consistent across all beams in a given run.

Finish System: The complete finish system shall include a primer coat, a base stain coat, a grain enhancement coat where specified, and a minimum of two topcoat layers of exterior-grade water-based polyurethane with UV inhibitors. The final color and sheen level shall match the approved sample held by the architect, reference sample number [SPECIFY SAMPLE NUMBER].

Installation Requirements

Installation requirements in the BOQ should specify how beams are to be mounted, what substrate preparation is required, and what quality standards the finished installation must meet.

Mounting Method: Beams shall be mounted using [SPECIFY: wooden ledger boards / steel angle brackets / proprietary mounting system as supplied by beam manufacturer]. Mounting hardware shall be hot-dip galvanized or manufactured from Type 304 stainless steel for all exterior applications. Fasteners shall penetrate a minimum of 50 millimeters into structural substrate or designated blocking.

Substrate Preparation: The contractor shall verify that all mounting surfaces are clean, dry, and free from loose material, grease, or contamination before installing mounting hardware. Any substrate that does not meet this requirement shall be prepared accordingly and brought to the attention of the architect before proceeding.

Sealant and Joint Treatment: All joints between beam sections and between beams and adjacent building surfaces shall be sealed with a paintable exterior-grade polyurethane sealant. Joint width shall not exceed 5 millimeters. Sealant shall be applied in accordance with the sealant manufacturer's written instructions and tooled to a smooth, concave profile.

Tolerances: Installed beams shall be level to within 2 millimeters over any 3-meter span and aligned to within 3 millimeters of the specified centerline. Spacing between parallel beams shall not vary from the specified dimension by more than 5 millimeters at any point.

BOQ Line Items and Quantities

The following table provides a sample structure for the quantity schedule. Actual quantities should be taken from the project drawings and specifications.

A complete and detailed BOQ specification ensures that all parties—architect, client, contractor, and supplier—share the same understanding of what is required. When discrepancies arise, a well-written specification provides the reference point for resolving them fairly and efficiently.