What is autoclaved aerated concrete? Autoclaved aerated concrete (AAC) is a lightweight, precast building product used around the world. Available in blocks and panels of various sizes, AAC is an ideal material for structural walls, firewalls, soundwalls, floor and roof systems. Check out our homepage for more information.

How is wiring installed in SafeCrete AAC walls? Easily. People often imagine that wiring will be a challenge due to the solid structure of AAC blocks. When they discover how versatile and workable AAC really is, they are pleasantly surprised. There are 3 standard methods for installing wiring in autoclaved aerated concrete walls. Many installers use a combination.
Routing: Build the walls first. The electrician draws directly on the block to indicate where the wires will go. The AAC installer uses a manual or electric router to cut channels on the inside of the walls. After the electrician installs the wiring, the wall is plastered or sheetrocked. Requires no pre-planning, and changes are easily made. Conduit usually required.
Behind Sheetrock: If sheetrock is being attached to the AAC wall with furring strips, then installing the wiring between the sheetrock and the block is a no-brainer. This method does not require conduit; however, wires and cables must be protected when crossing the furring.
Inside the Wall: With this method, the majority of the conduit is installed as the wall is built. For example, the installer may use a course of U-block at the height where the electrical receptacles will be, filling in the cavity with concrete after the conduit is installed. Wiring may also be run in the vertical cores. Pre-wired conduit is typically used to reduce the hassle of pulling wires. Wiring is deep in the wall and surrounded by a fire retardant material. Extra switches and receptacles can still be added by the routing method.

How can I find installers in my area? SafeCrete AAC may be installed by masons, carpenters or specialists. We provide free training for installers using SafeCrete materials at the SafeCrete marketing center. If there is an authorized SafeCrete dealer in your region, they will be happy to provide you with the installation information or even an installed bid.

How much does SafeCrete AAC cost? SafeCrete pricing is very competitive with other quality building materials. Unit costs may be found on our Products Page. Installed cost and operating cost must be considered as well. These costs are all affected by project size, location, labor market, current freight rates, building codes, and the particular application. Autoclaved aerated concrete typically pays for itself within 3-5 years.

Is SafeCrete AAC load-bearing? SafeCrete AAC blocks and panels with a minimum of 8" thickness are suitable for load-bearing applications, when used in accordance with our published design aids and allowable stress listings. 6'' blocks may be used for some interior loadbearing applications. Loadbearing applications require vertical cores reinforced with rebar and concrete. Code requires cores at corners, doors and windows. For design information, please consult our Technical Manual, or contact us to obtain one.

Can SafeCrete AAC be used in the construction of stem walls? Yes, AAC may be used for stem walls. Stem walls should be protected against permanent exposure to water by applying waterproofing material such as bitumen coating on any surface in contact with soil. For exposed surfaces (above grade) that will be finished, use a cementitious waterproofing to improve adhesion of the finish.

Can this product be used for basement walls? Yes. The walls must be designed correctly to account for axial loads when used as a basement retaining wall. Due to the extreme horizontal pressures exerted by backfilling, thicker walls with additional vertical conrete and rebar reinforcement should be used, as specified by a qualified structural engineer. All walls below grade should be waterproofed as discussed above.

Do AAC walls require insulation? Almost never. SafeCrete AAC walls are insulated by millions of tiny air cells which reduce thermal conductivity. The thick walls also benefit from high thermal mass, much like a log home. AAC block walls at least 8" thick typically provide sufficient insulation in southern climates. For more information, please see our Energy Efficient page.

What is the R-Value of a SafeCrete AAC wall? The thermal performance of AAC is equivalent to R-20 insulation. AAC combines the advantages of low thermal conductivity and low air-infiltration with high thermal mass. This product is used in every climatic region of the world, from humid South America, to the dry heat of the Middle East and the severe cold of Finland. Insulation is rarely added; the walls are simply thicker. For more information on thermal performance testing, please see our Energy Efficient page.

How durable is AAC in various climates? Autoclaved aerated concrete is extremely durable. It does not rot or decay like wood or other organic materials. It does not rust like metal. Termites and other pests do not eat it. AAC will not burn. The millions of tiny cells in AAC cushion buildings from major force, preventing progressive collapse. AAC has withstood earthquakes in Japan, the frigid temperatures of northern Europe, the harsh salt air of the French Riveria, and the hillside fires of San Fransisco.

Is a vapor barrier required in exterior applications? No. AAC construction provides a solid, monolithic wall system with an enclosed, non-connected cellular structure. Exterior finishes are designed to complement this structure, providing a healthy balance between moisture resistance and vapor diffusion. The positive pressure of the air conditioning system pushes water vapor out through the walls, while preventing moisture penetration from the outside.

What type of mortar is used with SafeCrete? Thin-bed mortar designed especially for AAC is used to install SafeCrete blocks and lintels. It is sold in ready-to-mix powder form. Thin-Bed Mortar is polymer modified Portland cement specifically designed to bond our blocks for interior and exterior wall construction. Just 1/8 inch mortar bed is needed to adhere the products. This extremely thin joint prevents heat loss and speeds installation. For best results, apply Thin-Bed Mortar with our notched trowel. Choose a trowel the same width as the block.

What type of finishes are available for autoclaved aerated concrete blocks? SafeCrete AAC can be finished with stucco, acrylic finishes, brick, stone, siding, or approved paints. On the inside of the building, AAC may be finished with sheetrock, plaster, stucco, wood panel or tile. Free consultation, color matching, and installer recommendations available.

Is SafeCrete AAC like EIFS? No. Autoclaved aerated concrete is the European construction method that EIFS imitates; however, construction and performance are entirely different. EIFS consists of layers of polysterene insulation board, mesh, and base coats followed by an acrylic top coat. AAC is more practical, efficient and durable than EIFS:
- AAC requires no surface preparation. - AAC requires no mesh. - AAC employs natural, mineral-based products. - AAC is termite resistant. - AAC is breathable. - AAC prevents moisture build-up, thus there is no peeling or rotting. - AAC is virtually maintenance-free. - AAC is water resistant. - AAC does not burn, melt, or off-gas - AAC is typically less costly than EIFS systems.

Can gypsum board or sheetrock be used on SafeCrete AAC walls? Absolutely. Gypsum board or sheetrock may be attached directly to AAC walls with construction adhesive and screws, or it can be attached to furring strips. Please note that AAC should be dry before the sheetrock is applied. Customers who prefer not to use sheetrock can purchase a mineral based finish from SafeCrete.

What type of roofing material can be used over SafeCrete roof panels? Any commercially-available roofing system may be used. When AAC roof panels are installed flat or near flat, they are typically covered with a membrane system such as built-up or EPDM. On a pitch, the panels are often covered with shingles, tile or concealed fastener metal roofs.

What type of surface treatment is required for SafeCrete floor panels? All autoclaved aerated concrete floor systems should be finished. Common commercially-available products such as carpet and pad, marble, ceramic tile, wood flooring, and industrial surface treatment may be used. SafeCrete supplies self-leveling toppings and other products to be used indoors and out.

What are the guidelines for AAC installation in severe heat or cold temperatures? The following chart addresses temperature guidlines. Please note that these limitations are related to the thinbed mortar, not AAC itself. Thus the requirements are not applicable when installing AAC panels without mortared joints.
Provisions for work in progress
Condition Requirement: Ambient temperature above 40° F (4.5° C) --> Normal construction practice. Cover stored materials.
Ambient temperature below 40° F (4.5° C) or temperature of units below 40° F (4.5° C) --> Heat mortar materials to produce mortar temperatures between 40°F (4.5° C) and 105° F (40° C) at time of mixing. Maintain mortar above freezing until used in masonry. If units have a temperature below 20° F (-7° C), heat to above 20° F (-7° C). Remove visible ice from units.
Ambient temperature is between 25° F (-4° C) and 20° F (-7°C) --> Heat masonry under construction from both sides. Install wind breaks when wind velocities reach 15 mph (24 km/h).
Ambient temperature is below 20° F (-7° C) --> Provide heated enclosure for masonry under construction and maintain temperature above 32° F (0° C) within that enclosure.

Is fly ash used in SafeCrete AAC production? Sometimes. The primary ingredient in the chemical reaction needed for autoclaved aerated concrete production is silica. The silica and other raw materials combine to form Tobermorite, a manmade version of a naturally occurring mineral. This gives AAC its unique strength-producing crystalline structure. Silica is found in many sources, such as sand, copper mine tailings, volcanic ash, and fly ash. SafeCrete products are made with locally sourced materials and may contain sand, fly ash, copper mine tailings, or some combination.
Fly ash blocks are light gray in color, whereas sand-only blocks are white or tan. Autoclaved aerated concrete made from copper mine tailings is pink. Since AAC is nearly always finished with stucco or some other exterior application, color of the product is irrelevant. The color that matters is "green."

Fly ash makes a "green" product "greener."
- Fly ash is reclaimed from coal combustion. We prefer to see a product re-used rather than sand mined.
- Fly ash saves electricity during AAC production. Fly ash particles are tiny and round, with the consistency of talcum powder. Thus, fly ash does not require the 1000 kw ball mill that must be used to grind sand to the proper consistency.
Please note that all SafeCrete Manufacturers must comply with the same standards (ASTM, NER, UL), so the end products perform the same in regard to strength, fire resistance, sound absorption, and other design considerations.