Purchase Anchors

There are a number of considerations when fastening to different types of masonry material, such as solid concrete, brick or block. 

Base Material

Different types of base material require a different type of masonry fastener. 

• The holding value of any masonry fastener is directly related to the strength and holding values of the base material that will be placed. If the base material is soft and sandy then the likelihood of the fastener obtaining adequate holding values is remote.

• Some masonry fasteners are designed for use in solid concrete while others can be used in brick, block or concrete.  Fasteners designed for specific base materials provide the best holding values in the material they are designed for.  Masonry fasteners with more versatility will have less holding values.  For example, a fastener designed for use in brick, block or concrete will have less holding values in concrete than an anchor designed specifically for concrete.

• The fastener may be inserted into the block, brick or the mortar joints when fastening into a brick or block wall.  Sometimes the fastener will be inserted into the hollow spot of the block or brick.  All of these different factors help to determine the holding values that a masonry fastener might obtain.

  1. Concrete – a solid base material that is made from cement, sand, gravel and water.  The strength of concrete is measured in pounds-per-square-inch; minimum strength concrete is about 2000 psi and high strength concrete is rated at 5000 to 6000 psi.   Most masonry fasteners work well in concrete because it is consistent, solid and strong.

  1. Block – sometimes called cinder blocks or CMU, blocks are very lightweight, porous and brittle with large hollow sections.  Drilling into the solid section of the block provides the greatest opportunity for a quality fastening.  Drilling into the hollow section will spall the block on the inside when the drill hammers through the last portion of the hole.  This will decrease the amount of base material and lessen the opportunity for achieving a quality fastening. 

  2. Brick – can be solid or can have hollow sections.  Brick is a very hard abrasive base material and, once a hole is drilled, it can provide excellent holding values for a masonry fastener.  Each brick may provide different holding value results because each brick may be different in its exact makeup and hardness.

  3. Mortar – holding values of any masonry fasteners in mortar are totally dependent on the quality of the mortar and the quantity of mortar in the joint. 

Item Being Fastened

The item being fastened may determine the type of masonry fastener required. 

• If the material requires a countersunk headed fastener, then a masonry fastener with a countersunk head must be used.  If the head of the fastener can protrude above the surface of the item being fastened, then a round or hex headed fastener may be used.

• The weight of the item will impact the application. The heavier the item then the larger the diameter required and the longer the length of the fastener in order to allow deeper penetration for adequate holding values.

•  A specific anchor may be recommended by an engineer or the manufacturer of the product to be fastened. It is important that the exact fastener specified is used to fasten the item down and a substitute is not used.

Holding Values Required

Type of Load

Expansion or mechanical type masonry anchors should only be used in dead load applications, which are loads that do not move or vibrate.  Expansion type masonry anchors get their holding values from friction.  Movement and vibration reduce the friction and will decrease the holding values or make it nonexistent. Some examples of dead loads and vibratory loads are described below:

•  Dead Loads – electrical plug, light fixture on a wall indoors, 2x4 stud for a wall, firing strips, picture frame

• Vibratory or Shock Load – curtain rod, sign on a wall outdoors in the wind, flagpole, basketball hoop and punching bag

Special Requirements

Location
The location of the application is important in determining the type of material that the masonry anchor is made from.  To avoid rust, the material used to make the masonry fastener becomes an important consideration. Rusting will decrease the holding values to the point where the fastener has no holding values at all.

• Dry Environment – if the application is in a dry environment then the standard zinc plated fastener will work well without any concern of rusting 

• Moist Environments  - if moisture is present then the hot-dipped galvanized or stainless steel should be considered.  Only wedge anchors come in a hot-dipped galvanized.  Hot-dipped galvanizing is a coating that may be chipped or scraped off during installation and can, over time, allow the wedge anchor to rust. The best rust resistant fastener to use would be stainless steel to ensure rust resistance.

• Wet – if the masonry fastener is submerged in water then a stainless steel masonry fastener must be used.  The 304 stainless steel works well in these types of applications.

• Submerged in water/chemicals – masonry fasteners that will be subjected to certain chemicals, as well as water, should be manufactured from 316 stainless steel.  This type of steel is formulated not to rust in these types of applications.  Examples of this type of applications would be a swimming pool with chlorine, in salt water, or near a beach or the ocean.

Types of Masonry Fasteners

There is not one best type of masonry anchor because each application is different and each masonry fastener has its pros and cons.
Listed below is a description of each masonry fastener in accordance with the above requirements:

	Wedge	Sleeve	Tapcon	Drop-In
Type of Material
Concrete	X	X	X	X
Block		X	X
Brick		X	X
Head Style
Countersunk		X	X	X
Hex	X	X	X	X
Location
Dry	X	X	X	X

Purchase Anchors