CAVITY WALL: BRICK VENEER/WOOD STUD

Often used in residential design, this classic wall system pairs a beautiful, long lasting brick exterior with a wood structure.

  

RECOMMENDED BUILDING TYPES

• Single-family and multi-family residential, shopping centers and restaurants, low-rise construction
• Use where budgets are more important than longevity
• Choosing the Right Masonry System for your Budget

BENEFITS

• Looks like a solid masonry building but a wood stud backup system costs less
• Many of the benefits of a masonry façade: durability, low maintenance, high fire rating, and numerous design choices
• Drainage cavity keeps building interiors dry

SPECIAL CONSIDERATIONS

• wood stud construction flexes more than the masonry veneer – this can lead to cracks developing in the masonry unless the studs are designed to strict deflection tolerances
• Volatility of wood prices makes it difficult to predict final project costs
• Multiple trades are involved, which makes jobsite coordination more difficult
• Carpentry tolerances are looser than those for masonry – which can lead to conflicts during veneer construction
• Wood rots if water penetrates past the drainage cavity. If the wood studs rot, the structure is compromised
• Interior surfaces (drywall) are prone to vandalism and damage in heavy traffic areas
• There is a potential for mold growth on sheathing unless mold-resistant sheathing is used

DEFINITION AND ASSUMPTIONS

Backup: 2" x 4" studs @ 16" on center. Fiber batt insulation between studs.

Sheathing: 5/8” oriented strand board, nailed into studs.Weather resistive barrier over sheathing.

Veneer: Cored modular clay brick 4" x 2-1/3" x 8" (nom.)

Cavity: 1 inch air space

flashing: Base flashing and weeps.

Veneer ties: Adjustable galvanized ties anchored to studs. Spacing: 16" vertical x 16" horizontal

mortar: Type N, Portland cement/lime, plain gray

Joints: Concave tooled

REGIONAL VARIATIONS

• When masonry veneer is used in areas of high seismic risk, veneer ties are required to attach to wire reinforcement embedded in mortar bed joints in the veneer. Check your local requirements – and save money by using normal veneer ties in areas of low seismic risk.

FIRE RATING (HOURS)

2 hours (with 2 layers Type X gypsum board)

• Fire Resistance of Brick Masonry
• Fire Rated Assemblies (BXUV)
• Fire Endurance Ratings of Clay Brick Masonry

SOUND TRANSMISSION CLASS (DB)

STC 56

• Architectural Graphic Standards

WALL WEIGHT (LB/SQ. FT.)

47 lb/sq. ft.

ENERGY RATING

R-value: 16.2 with 6” fiber batt insulation

Calculation:

• R-Value Calculations and Wall Sections
• Thermal Mass Advantages of Masonry Walls

GREEN/LEED RATING

• Energy efficiency, thermal comfort and energy analysis – up to 10 pts
• Innovation and design – 1 pt
• Recycled content – 2 pts
• Regional material (where applicable) 2 pts
• Renewable energy and thermal mass – up to 10 pts
• Sustainablility / Green Building Design

DESIGN TIPS

• Use insulation that is installed in the cavity whenever possible: it is nearly continuous and is much more effective than insulation installed between the studs. Studs provide a direct thermal path through the wall and reduce insulating efficiency. Studs are denser than the insulation and the cold travels through the studs and ignores the insulation. This phenomenon can reduce the insulating capacity of a wood stud wall by 40% and by 60% when Steel studs are used.
• New requirements in energy codes may require that you use rigid insulation in the veneer drainage cavity when the structural backup is built of wood stud or steel stud. If your construction project is subject to the International Energy Conservation Code (IECC) or the requirements of ASHRAE-2004 or ASHRAE-2007, you might be required to also install a continuous layer of insulation to this wall. IECC requirements vary by climate, so make sure you understand local conditions and what energy code is relevant in your area.
• Use galvanized hardware (including screws) for masonry veneer ties to minimize corrosion potential.
• Design the wood stud backup to a deflection limit of L/720 to minimize veneer cracking.
• Tighten up the tolerances for wood construction to match those for the masonry veneer. Some of the difference can be taken up in the drainage cavity but there can also be significant conflicts between the wood erection and masonry trades.
• Attach windows and doors to the wood studs, not the masonry veneer.
• Make sure you have at least ¾" overlap of the door and window jambs onto the brick veneer. Install backer rod and sealant around all openings.
• You must use sheathing to face the stud wall at the drainage cavity.
• Use building paper to cover the sheathing,or use a water resistant sheathing with taped joints.
• Be careful supporting brick on wood stud construction. Currently the Building Code limits these applications to situations where no more than 12 vertical feet of masonry are being supported.
• Carefully detail movement joints in the brick veneer – you will need extra joints to separate brick supported by wood construction from brick supported off the foundation.
• Provide extra clearance between brick sills and windows for 2 and 3 story construction. Wood shrinkage combined with brick expansion can lead to serious movement issues on multi-story buildings.

CONSTRUCTION TIPS

• Meet with the general contractor early in the project to make sure the carpenter understands masonry construction tolerances.
• Anchor veneer ties into the studs using screws or nails to meet Building Code requirements. Anchorage into sheathing alone is not permitted.
• Construct wall openings oversized to accommodate a sealant joint around doors and windows. Provide extra clearance between brick sills and windows for 2 and 3 story construction. Wood shrinkage combined with brick expansion can lead to serious movement issues on multi-story buildings