Although ICF exterior walls can accommodate nearly any exterior finish, until recently interior wall finish options were limited primarily to gypsum board. Due to national fire code requirements, gypsum board is the most common interior finish over all exposed EPS. Abuse-resistant gypsum board that offers resistance to indentation, breaking, and puncturing is available from several gypsum manufacturers as an alternative to regular gypsum for high-traffic areas. However, gypsum board is fragile, ceiling installation is labor intensive and time-consuming and, paper-lined drywall can support growth of mold and mildew.

However, in the past few years, several companies have developed products that make finishing ICF interior walls easier, faster, and more cost effective than ever before – and these options are often healthier and more durable.


The primary purpose of this hard finish is to increase durability in abuse-prone areas. These products can be sprayed or troweled over EPS with one or two-coat installation without mesh or gypsum board. Applied directly over ICFs, the product is ten times stronger than gypsum drywall, and is available in a range of colors and textures. It also creates a barrier that protects the EPS from melting despite intense heat. It has zero-VOC, does not off-gas, and is composed of non-combustible recycled materials.


Like the hard veneer plastic products, clay plasters can be applied over drywall with one coat or directly to the foam applying using a two-coat application and does not require sanding. This is a natural organic product composed of marble dust, clays, and mineral pigments and has zero VOCs. Since most marble dust is recycled from other industries the product is typically 72% post-industrial content by weight.


Another option is to use acrylic stucco – commonly used as an exterior finish – inside the building. Like most acrylic stuccos, it is applied directly to the foam and no drywall is needed but is typically reinforced using fiberglass mesh. It is a cement-based product that can be troweled or sprayed on and requires two coats to finish the wall. It also provides a fire barrier without the use of drywall.