Q. How much does it
A. The most popular products weigh 32 pounds per cubic foot. This
is about 1/5 the weight of concrete. Thermacrete AAC reinforced panels
have a mass density of 37 pounds per cubic foot.
Q.What is the
compressive strength of AAC?
A. 580 psi (lb/in2)
Q. Can AAC products be
made at the construction site?
A. No. AAC products are manufactured in a factory employing a
carefully controlled process. The key to AAC's strength and durability
is steam curing in an autoclave, which cannot be readily accomplished at
a construction site.
Q. How do you
build with AAC?
A. AAC products can be used for walls,
floors and roof decks of buildings. There are two types of products for
walls: blocks and panels. AAC blocks are used much like regular concrete
blocks. Panels are two feet wide, up to 20' long and from 2" to
12" thick depending on the needs of the building. Special panels
for floor and roof decks are available as well as panels to build
interior partitions. Panels are set in place with thin-set mortar.
Q. Will an AAC
building last as long as other buildings?
A. Yes. The
durability of AAC has been proven in every type of climate in the world
-from Northern Finland to the deserts of the Mid-East for over 80
Q. How are AAC
A. A mixture of cement, lime, water and
quartz (sand or ash) is mixed and placed in a steel mold that is 20'
long, 4' wide and 2' high. A tiny amount of aluminum powder is injected
into the mixture and millions of tiny bubbles are formed causing the
mixture to rise in a manner similar to bread rising. After the casting
is set, it is cut into the panel or block dimensions by pulling it
through wires strung on a loom. The casting is then fully cured in a
large steam chamber called an autoclave.
Q. What are
the main advantages of AAC over other building materials?
AAC is highly fire resistant, has excellent thermal insulation value, is
decay and rot proof, has good sound reduction properties and is cost
effective. AAC performs well in seismic situations and high wind areas.
Building with AAC can reduce the quantity of materials used and labor
needed to build a building.
Q. How is AAC
A. Standard elastomeric paint, traditional or
synthetic stucco, thin brick facing, tile, siding materials or any other
building finish can be used on the outside of AAC walls. Inside, AAC
walls can be finished with textured paint, plaster, gypsum drywall or
any other interior finish. AAC floors can be carpeted, tiled or finished
with wood flooring.
Q. How do you hang
heavy items like cabinets or shelves on AAC walls?
Fasteners are available that easily drive into AAC walls and are capable
of securing heavy items. These fasteners are similar to standard
concrete "spread-fast" anchors. Since AAC is less dense than
standard concrete, fasteners can be driven in with a hammer. Specialty
drills are not required. Unlike stud walls, fasteners can be placed
anywhere in AAC walls. No need to explore to find studs for hanging
Q. Why is AAC a new
product in the USA?
A. AAC manufacturing plants are more
expensive to build than manufacturing plants for concrete block,
dimension lumber or steel buildings. This does not mean
the products are more expensive. AAC plants will produce very large
quantities of products so unit pricing is competitive with other
building materials. To be competitive, however, a large plant - and a
large capital investment - is needed. This fact, along with the ever
increasing costs of field labor compared to factory labor, make AAC more
attractive now than it has been in the past.
Q. Where is AAC
A. There are over 350 AAC factories world
wide, mostly in Europe and Asia. In North America, there are factories
operating in Mexico, Florida, New Jersey, and Arizona.
Q. How safe is AAC?
A. AAC is probably the safest building product available.
Tests conducted by independent laboratories show that AAC is not
hazardous or toxic. It does not emit fumes or emit radiation above that
of familiar foods. There is no waste produced during manufacturing.
Q. Is AAC
A. Yes. AAC is a non-toxic product
which does not pollute the air, land or water. During the manufacturing
process, waste from the cutting process is recycled back with raw
materials and used again. During construction, there is virtually no
waste generated. AAC products were designed to respond to the urgent
need to conserve and protect the earth's precious natural resources.
Q. Is AAC
cladding like EIFS?
A. 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, no mesh, employs natural,
mineral-based products, is termite resistant, water resistant,
breathable and prevents moisture build-up. There is no peeling or
rotting. and it does not burn, melt, or off-gas AAC is virtually
maintenance-free and typically less costly than EIFS systems.
Q. Is a vapor
barrier required in exterior applications?
A. 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.
Q. How is
wiring installed in AAC walls?
A. Easily. 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 requires no 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.
Q. Why is AAC
considered a "green" building product?
A. Non-polluting Manufacture-
Autoclaved aerated concrete manufacturers use a closed-loop
manufacturing process, so that nothing is ever released other than clean
steam. Product trimmings, slurry and water are reprocessed, and steam is
reused whenever possible. Resource Efficiency- The end
product is approximately 80% entrained air and 20% mass. Thus 5 parts
AAC are produced from just 1 part raw materials. Low Energy
Consumption throughout Lifecycle- The total energy consumption
to produce AAC is 1/3 to 1/2 that of comparable building materials. When
installed, AAC results in tremendous energy savings for heating and
cooling the building. Healthier Indoor Air Quality- AAC
products are an excellent choice for the chemically sensitive because
autoclaved aerated concrete does not offgas. AAC does not promote the
growth of mildew and mold, and cannot be infested by termites. Rats and
other pests find no home, since there is no cavity in an AAC wall.
Pestacides can be reduced, and the occupants can breathe
Q. Are vertical
A. Yes, vertical cores are an integral part of the AAC
block system and are required. Cored blocks may be used for this
purpose, or installers may core standard blocks using a 3” or 4” drill
bit kit or core drill. Rebar is inserted into these cores and is tied to
both the foundation and the rebar in the bond beam. Cores are then
filled with conventional concrete grout. Vertical reinforcement cores
lend additional strength to the AAC structure, and are required in all
regions. Minimum code requirement is one reinforcement core on either
side of each opening, in each corner, and wall intersections. For more
information see ICC code for AAC construction.
AAC construction qualify for LEED certification?
A. AAC materials are environmentally-friendly,
and LEED does recognize this. Please note however, that LEED
certification is based on the construction project, not a single
material. LEED recognizes autoclaved aerated concrete products in the
following manner: Recycled content (applicable to AAC blocks containing
fly ash and copper mine tailings); Reduced energy consumption; locally
sourced products (if applicable to project), and locally sourced raw
is the lead-time for my Thermacrete order?
A. The lead time for standard products is
typically one to two weeks. Lead time for custom products such as
special length panels may require additional time for manufacturing. In
either case, we encourage you to contact us with enough advance notice
to provide ample time for your required delivery date. We will be
pleased to assist you with estimating, design recommendations, choosing
appropriate products, and locating additional resources for your
type of surface treatment is required for AAC floor panels?
A. All autoclaved aerated concrete floor systems
should be finished. Common commercially-available products such as
carpet and pad, ceramic tile, wood flooring, marble, and industrial
surface treatment may be used.
type of roofing material can be used over AAC roof panels?
A. 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.
gypsum board or sheetrock be used on AAC walls?
A. Yes.Gypsum board or sheetrock may be
attached directly to AAC walls with construction adhesive and screws, or
it can be attached to furring strips. The AAC should be dry before the
sheetrock is applied.
type of mortar is used with AAC?
A. Thin-bed mortar designed especially
for AAC is used to install Thermacrete AAC blocks and lintels. It is
sold in ready-to-mix powder form. Thin-bed mortar is polymer modified
Portland cement specifically designed to bond AAC blocks or panels 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 a notched trowel. For AAC block installation, choose a trowel the
same width as the block.