Metal Stud Wall Systems
On the following pages, details are shown using the standards in anchoring of Cast Stone with metal stud wall systems. A metal stud wall system consists of exterior veneer masonry, isolated from the metal stud backup by a minimum 1″ airspace and attached to the backup with corrosion – resistant metal ties.
Details of anchoring, as applied to this method of construction, can usually be derived from the conventional masonry details shown on the preceding pages. Joints between stones are 3/8″ wide across the face.
Axial loads – Masonry veneer should not be subjected to any axial loading other that its own weight. The weight of the Cast Stone is carried by the veneer to be self-supporting for its full height, support the veneer at each floor with relieving angles as shown. Click here for relieving angles.
Lateral loads – The masonry veneer is separated from the metal stud system with a 1″ minimum – 2″ maximum air space. The wall system must be designed and detailed so that lateral loads are shared by both the veneer and the backup.
Anchoring – Anchors tie the veneer to the backup; they must be stiff enough to resist tension and compression, but flexible enough to not resist shear. This flexibility permits in-plane differential movements between the backup and veneer. Continuous anchor slots running the entire length of the stone are used in lieu of anchor pockets to facilitate alignment with studs. There should be a minimum of two anchor straps per stone and one brick tie for each 2-2/3 sq. foot of wall area. Corrugated metal brick ties should never be used in connecting veneer to metal studs.
Deflection – A maximum allowable metal stud deflection of L/600 is recommended, with an L/720 to L/900 preferred. Consult your engineer.
Sheathing – Sheathing must be securely attached to both sides of the studs. Sheathing must be rigid and properly attached for it to be effective.
Masonry Openings – Studs should be doubled at the jambs of all windows, doors and other openings.
Windows – The window can be attached to the Cast Stone or to the backup system, but should not be attached rigidly to both.
Mortar – Type S mortar is recommended for use in veneer walls at locations where loads are expected to exceed 25 psf.
Projecting Profiles – Maintain projecting profiles at less that 30% of the total cross sectional area of the stone an uses horizontal cross bracing as shown on pages 63 and 65; or use adequate structural tie back as required to provide proper counter-balance for larger projections. The design of the structural member should include torsional effects created by the stone.
For certain areas of the building, the designer may wish to consider changing the backup system from metal studs to masonry. It may be more advantageous to use cavity wall or insulated cavity wall design instead of veneer design.
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