Concrete fasteners
for concrete, brick and block are found around the home for various
purposes. There are different basic constructions of homes including
those being built on a concrete slab and those that are built over a
basement that is made from concrete or block. The exterior may be a wood
frame or be made from brick, aluminum, vinyl or even block or concrete.
Many of the fastenings that are done during construction of the home
will not be repeated. For example, the stud walls are fastened once to
the concrete when homes are built on a concrete slab. Other home
improvements, such as adding a deck, may also require the use of
concrete anchors. Anytime that something will be attached to the base
material of a home, the procedure will require the use of some type of
fastener that is designed for the base material.
Fastening to concrete,
brick or block is different than fastening to wood or sheet metal.
Screws are used when fastening to wood or holding two pieces of metal
together. Nut and bolt can also be used for these purposes. Concrete,
brick or block are basically solid material that is very hard because
only one surface is available- it is not 3-dimensional for fastener use.
Fastening to concrete, brick or block must be done to the surface and
the holding values are wholly dependent on the base material. Mnay
different fasteners are available and are designed for fastening to
concrete, brick or block. It is very important to remember that the
holding values of the anchor chosen is entirely derived from the
strength of the base material.If the anchor is installed correctly, the
base material will fail first- not the anchor. The choice of concrete
fastener to use is dependent on the specific application and personal
perference. Several concrete fasteners are designed to use only in
concrete while others can be used in all 3 base materials (concrete,
brick and block).
Choosing the fastener is
dependent on the base material, the weight of the object to be
fastened, the head style required and whether the anchor will be indoors
or outdoors. Concrete fasteners can be categorized into three
categories: light duty (smaller diameter, shallow embedment), medium
duty (deeper embedment) and heavy duty (larger diameter with deep
embedment into base material). All concrete fasteners have a minimum
embedment depth at which they must be inserted into the base material in
order to achieve holding values. This minimum embedment is dependent on
the type of anchor being used and the anchor's diameter. Fasteners for
concrete must also be spaced at least 10 anchor diameters from each
other and no closer than 6 anchor diameters from an unsupported edge.
Concrete fasteners are available in two basic types (male and female)
and their uses are dependent upon the specific application at hand.
Wedge anchors are male
type anchors for use in concrete only. They should no be used in brick
or block. The loading capacity of wedge anchors range from light to
heavy duty due to the large range of diameters that are available. Wedge anchors are available in zinc plating for indoor use and hot dipped galvanized and stainless steel for outdoor applications.
Strike anchors are only
available in a male version and can only be used in solid concrete.
Diameters range from 1/4" to 3/4" with lengths up to 6" for use in light
to heavy duty applications. Strike anchors should not be used outdoors since they are only available with yellow zinc plating.
Drop in anchors
are female concrete anchors that are designed to accept machine
threaded bolts or a threaded rod. These can only be used in concrete.
Loading capacity of these anchors range from light to heavy duty and are
available in a wide range of diameters. Each diameter is only available
in one length. Stainless steel drop in anchors can be used outdoors or
indoors.
Tapcon® concrete screws
are male anchors designed to tape threads into concrete, brick or block.
The standard blue concrete screw would be considered a light duty
anchor in diameters or 3/16" and 1/4" in lengths up to 6". The large
diameter Tapcons can be used in medium duty applications. Both have a
special coating that provides excellent rust resistance. These screws
can be used outdoors where the anchor will be submerged in water. The
stainless steel Tapcons can be used outdoors while the zinc plated screws should be used in indoor applications.
Sleeve anchors
are male type anchors that can be used in concrete, brick or block. The
loading capacity of this anchor ranges from light to heavy duty. These
anchors can be used in both indoor and outdoor applications since they
are available zinc plated and in stainless steel.
Metal hit or hammer drive anchors
are male type anchors that are suitable for use in concrete, brick or
block. They are not recommended for overhead use. Metal hit anchors are
light duty anchors available in two diameters- 3/16" and 1/4". The body
of the anchor is made from rust resistant materical called zamac. The
nail comes in zinc plating and are suitable for indoor use and should
not be used outdoors.
Machine screw anchors
are female anchors that can be used in concrete, brick or block. They
are available in a range of diameters from 1/4" to 3/4" and should only
be used in light to medium duty fastening applications since they don't
allow for deep embedment into the base material. Machine screw anchors should only be used indoors.
Lag shields
can be used in concrete, brick or block. They are also excellent for
use in suspect base material. They are available for light to medium
duty with anchor diameters ranging from 1/4" to 3/4". Two lengths are
available in each diameter- a short and long length. These anchors are
made from rust resistant material and are suitable for indoor and
outdoor use. They should not be submerged in water and should be used in
conjunction with a stainless steel lag screw.
When using concrete anchors in your home and
for home improvement projects, it is imperative that the correct
fastener for the specific application be chosen to ensure that the
project goes smoothly. If the application is outdoors, then it is
necessary to purchase concrete anchors that can be used outdoors in
terms of material and rust resistance. All of these considerations can
make using concrete fasteners faster and easier.
Please remember with all fastening jobs to keep safety in mind. Always follow safety instructions on all tools, and refer to manufacturer's installation instructions when available and always remember to wear safety goggles!
Article written by: Michael Pistorino, Concrete Fastener Specialist