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EXTERIOR FINISH MATERIALS
The exterior, both above and below grade, of SmartBlock insulating forms must be covered with a protective and waterproof finish after the reinforcing steel and concrete have been placed. This chapter describes exterior finishes that may be applied to SmartBlock insulating forms.
6.1 Below Grade Waterproofing
SmartBlock insulating forms must be waterproofed in below grade applications. Section 6.1.4 contains an approved list of waterproofing products for SmartBlock insulating forms.
SmartBlock insulating forms absorb only 2% by volume in water. In addition, water vapor transmission allows water to flow through the block. In a below grade structure, water vapor transmission will damage the interior drywall, causing it to warp and discolor. In the case of a retaining wall, water vapor transmission caused by inadequate waterproofing will cause the stucco on the exterior to discolor and possibly to spall off the wall.
EPS is a petroleum by-product that will dissolve when placed in contact with solvents, keytones, esters, and pitches. It is very important when selecting a waterproofing product that it is checked for compatibility with EPS. If you are concerned with the compatibility of a waterproofing product with EPS, call your material distributor or take a small portion of the product and apply it to a section of a SmartBlock insulating form. If you notice any disfigurement of the EPS (shrinkage, warping, etc.) within 24 hours, select a different waterproofing product.
There are many waterproofing products that work well with SmartBlock insulating forms. Most waterproofing failures are due to improper application, so waterproofing should be applied according to the manufacturers' instructions.
Waterproofing must be applied thoroughly to cover the SmartBlock insulating form wall leaving no holes or voids. Any pinholes or voids will permit moisture to infiltrate the wall. Particular attention should be given to assure that the joints and seams of the forms are sealed.
There are three common types of waterproofing used on EPS: Liquid emulsified products, sheet goods (membranes) and acrylic based cementations products.
6.1.1 Liquid Emulsified Products
Liquid emulsified products work well in confined work spaces. The surface of the SmartBlock insulating forms must be clean and thoroughly dry before the waterproofing is applied. To test for dryness, tape a 4" square of aluminum foil to the EPS surface of the form being sure to tape the perimeter edges completely to prevent moisture escape. Allow the foil to remain undisturbed for 24 hours. Remove the tape carefully, and turn over the aluminum foil. If moisture is present on the foil then the surface requires additional drying. After thorough application of waterproofing (this may require 2 coats), protection board, usually 1/4" extruded polystyrene, must be applied over the waterproofing. This is required to prevent damage to the waterproofing material during backfilling. Waterproofing should be applied to a minimum of 6" above the planned finish grade in all applications.
6.1.2 Sheet Goods
Sheets goods also provide an effective method of waterproofing. The EPS exterior of the SmartBlock insulating forms must be clean and thoroughly dry, as required for liquid emulsified waterproofing. Sheet goods are placed on the wall, then the seams must be sealed with an adhesive strip. Do not use a system that requires the seams to be torch sealed as this may cause the SmartBlock insulating forms to melt. The same use and application of protection board is required as with the emulsified materials.
6.1.3 Acrylic Based Cements
Cement products that contain acrylic bases are also commonly used for waterproofing. The application is the same as for emulsified materials except that this material may be colored and may be applied to the entire wall both above grade and below grade. The main benefit to this particular type of application is in its aesthetic appearance. However, because it is a cement product it does not have the same expansion and contraction and freeze thaw durability as the other methods.
6.1.4 Compatible Waterproofing Products
NOTE: Any product that is certified by its manufacturer to be compatible with EPS, such as the products listed below, may be used with SmartBlock forms. American ConForm Industries makes no endorsement or guarantee for such products, or for the product listed below.
You will need Adobe PDF software to see the list of Compatible Waterproofing Products. Download the list here.
6.2 Above Grade Exterior Finishes
This section describes recommended stucco finishes and coatings for use with the SmartBlock insulating forms. See Section 6.2.4 for approved stucco list (download the list here.
6.2.1 Exterior Insulation Finish Systems
The first group of coatings are generically known as Exterior Insulation Finish Systems (EIFS). These systems are designed specifically for exterior EPS construction. The installation sequence for all EIFS coatings is as follows:
1) Liquid acrylic is mixed with common cement and applied to the EPS surface as a base coat.
2) Fiberglass mesh with 1/4" grid is embedded into the base coat.
3) Colored liquid acrylic of varying textures is applied as a finish coat.
The average thickness of EIFS coatings is 1/8". These systems have color fastness for up to ten years and are highly resistant to freeze-thaw conditions. In addition they provide a waterproof coating due to the acrylic additives. The main disadvantage of these systems is their low impact resistance to puncture. As a result, these coatings are often installed away from high traffic areas. EIFS coatings also tend to be more expensive than other finishes.
6.2.2 One Coat Stucco
"One coat stucco" is designed for use on exterior EPS construction. The installation sequence for one coat stucco finishes is typically as follows:
1) Apply pre-mixed base (cement, sand, and cut (approx. 3/8") acrylic fibers) to the EPS surface with either a trowel or plaster application gun.
2) Fiberglass mesh, with a 1/4" wide grid may be imbedded in the base in areas of high traffic (below 6').
3) Apply desired pigment box, also known as color packs, over the base to achieve desired color finish.
The average thickness of these systems is 3/8" to 1/2". These finishes have high impact resistance, are very easy to apply and allow for many texture variations.
6.2.3 Polymer Based Stuccos
Direct liquid or polymer type additives are poured directly into a cement, sand and lime brown coat mixture. The installation procedure is as follows:
1) Combine cement, sand and lime per manufacturer's specification in standard cement mixer or plaster application gun.
2) Add specified amount of liquid polymer per manufacturer's specification in order to insure proper chemical bonding of cement base coat to EPS surface.
3) Fiberglass mesh, with 1/4" wide grid may be applied in areas of high traffic (below 6').
4) Finish in stucco-like textures, as required.
5) Apply finish coat of color integral stucco or paint with acrylic exterior paint.
The average thickness of this system is 3/8" to 1/2". These products are very easy to apply, have very high impact resistance, especially with applied mesh, and provide a solid waterproof coating due to the polymer additives.
6.2.4 Compatible Exterior Stuccos - updated June 1999
NOTE: Any product that is certified by its manufacturer to be compatible with EPS, such as the products listed below, may be used with SmartBlock forms. American ConForm Industries makes no endorsement or guarantee for such products, or for the product listed below. E.I.F.S. are Exterior Insulated Finishing Systems.
You will need Adobe PDF software to see the list of Compatible Exterior Stuccos. Download the list here.
6.3 Compatible Adhesive List
NOTE: Any product that is certified by its manufacturer to be compatible with EPS, such as the products listed below, may be used with SmartBlock forms. American ConForm Industries makes no endorsement or guarantee for such products, or for the product listed below.
You will need Adobe PDF software to see the list of Compatible Adhesive List. Download the list here.
This list is only a portion of the products you could use. If the material is not listed, check with the manufacturer for compatibility and installation instructions.
