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Alternative Stucco Lath

Non-metallic, fiberglass product for exterior wall reinforcement of stucco and mortar for lightweight veneer

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New lathe products are poised to save the hands of stucco and other cementitious exterior wall coating applicators. An alternative to metal lathing and stucco netting, a mesh lathing made from fiberglass can be used for applying stucco and plaster to exterior walls. Alternative stucco material.  Photo courtesy of BASF It comes in rolls, is lighter than traditional products such as metal lathe, and can be applied either vertically or horizontally, making it suitable for use in a variety of vertical wall applications with solid backing.

Currently one manufacturer offers two varieties of fiberglass lathe. The original product, Permalath, is suitable for wall coating applications from 3/8” to ½” thick. Another product, Permalath 1000, is suitable for stucco applications between ½” and 7/8” thick, and mortar for lightweight stone veneer with a maximum weight of 15 pounds per square foot. Both products can be placed over steel stud walls, gypsum sheathing, cement board, concrete, and masonry walls.

Both Permalath products are non-metallic so they do not rust, and are lighter than metal products, making them easier to handle. The manufacturer claims that there is a savings in labor costs because of the relative ease of handling the material. It can be easily cut with a utility knife or scissors into varying shapes as needed.

Safety and Disaster Mitigation

Easier to handle product with fewer sharp edges, which reduces the installer’s risk of injury.


Using this product is relatively easy, and no addition skill is necessary over traditional materials. Fiberglass lathe is pliable and can be cut easily with a utility knife or scissors. Once cut, it does not have the sharp edges common to metal products, which reduces the risk of installer injury. Also, the rolls are lighter than traditional metal lathe making the product easier to manage at the jobsite.

Fiberglass lathe products must be used on solid vertical surfaces, and cannot be used over open framing or on soffits. Except for unit masonry and non-insulated concrete substrates, applications using Permalath require the use of a polymer weather-resistant barrier (WRB); one example is DuPont™ Tyvek® StuccoWrap®. In most applications, when using Permalath 1000 the exterior walls must include two layers of grade D building paper. However, many construction applications already have a solid subsurface so it should not be difficult to install the WRB or building paper. Also, depending on the application, different fasteners than those used with metal lathe may be required, but the methods to install them are essentially the same. Follow manufacturers’ instructions regarding the proper fasteners for the substrate.

Per square foot, fiberglass lathe is more expensive than traditional metal products. Average prices range from 23 - .26 per sq. ft. for PermaLath and .32-.35 per sq. ft for PermaLath 1000, however pricing varies by region.

Not Applicable

Permalath has been approved by ICC Evaluation Services for use in residential construction as specified in the manufacturer’s instructions and the ESR report. Permalath 1000, is awaiting ICC-ES approval.

None available

Fiberglass lathe products can be installed over cement board, gypsum sheathing, plywood, OSB, poured concrete, or unit masonry exterior walls. The product must be applied with a minimum 3-inch overlap at vertical and horizontal edges and overlap on the flange of trim accessories. Fastener and fastener scheduling is determined by the substrate; the manufacturer provides installation instructions for each including masonry, steel framing, and wood framing.

Not applicable, though manufacturers and installers may provide a warranty on the entire cladding system.

Fiberglass stucco lathe is a safer, easier to handle material suitable for reinforcing stucco and mortar for lightweight veneer on exterior walls. The cost of fiberglass lathe is comparable to or slightly higher than metal lathe products, but the manufacturer claims reduced labor times (and associated costs) can be achieved.

The material can only be used on vertical exterior walls with a hard substrate, and builders must be sure to install the necessary layer of WRB or building paper.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.