Overcome the Challenges of Fastening to Block

Block can be a poor base material for fastening because it is lightweight, porous and has large hollow cores. There may be inconsistencies from block to block, and a block anchor may work well in one block and not as well in another within close proximity. Drilling into the hollow section of the block can cause the interior of the block to spill out, leaving very little material to fasten to.

The quality of fastening into a mortar joint depends on the quality and quantity of mortar. The mortar joint may be an excellent base material if enough mortar is in place and the mortar is of high quality. Small quantities and a poor mortar mix will most likely result in a poor base material for any type of block anchor to work well.

Bolting Through the Block
Bolting is the process of inserting a piece of threaded rod completely through the block wall and then placing a large plate washer and nut on each end. Access to both sides of the block wall is a necessary condition for this method, which will provide consistent holding values for the application.

Sleeve Anchors for Block

A sleeve anchor is the most popular anchor for fastening to block because of its variable expansion.
The sleeve anchor is designed to expand over a wide area allowing the sleeve anchor to grab, and then expand once solid block is reached.
The sleeve anchor comes assembled with a nut and washer.
Hole size is anchor size.
They are available in stainless steel.
A wide range of sleeve anchors are available for fastening to block from 1/4” to 3/4” and lengths ranging from 5/8” to 6-1/4”.
The sleeve anchor also has a number of different head styles to choose from depending on the specific applications: acorn head, hex head, flat or round head.
Sleeve anchors can be used in block or the mortar joint and they are simple to use and cost effective.

Tapcon Concrete Screws for Block

Concrete screws used in block will tap threads into the block.
The concrete screw requires a predrilled hole and, as it is inserted into the hole, taps threads into the block to give excellent holding values.
Tapcons can be used in both the block and mortar joint.
They are available in two diameters and lengths ranging from 1-1/4” to 6”.
Tapcons come in coated carbon steel for use in indoor block applications and a 410 stainless steel for use in moist or outdoor block applications.
The two head styles that are used include the hex slotted washer head and the flat countersunk Phillips.
They are packaged 100 pieces per box with the one proper sized bit in each box.

Other Block Anchors

Other block anchors are available and all work well in block base material.

They are all female type concrete anchors and require a bolt and washer.

They require spotting of the hole since the diameter of the hole that needs to be drilled is much larger than the diameter of the bolt inserted into them.

Below is a list of other block anchors: