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How to Fasten Anything to Concrete or Masonry

Sooner or later we all come across the need to firmly attach something to concrete, brick or masonry. Ground and wall anchors, for example, need to be firmly attached to something immovable like a wall or concrete floor. Even installing a simple washing line might mean attaching a pully to a property wall. In this post we cover the various options to consider when attaching something to concrete or masonry.

What is Masonry?

Before we take a look at fastening options it’s worthwhile clarifying what’s meant by the term ‘masonry’. Masonry is a broad term that encompasses everything from brickwork and building blockwork to various types of stone. Blockwork structures most commonly use what are often incorrectly called ‘breeze blocks’. But the original form of breeze block has been superceded by a whole range of versatile building block materials including thermalite blocks, concrete blocks, aerated concrete blocks (called aircrete), dense masonry aggregate blocks, lightweight masonry aggregate blocks along with hemp masonry blocks. There are also a number of clay based building blocks along with specialised insulated concrete form (ICF) masonry blocks.

The fundamental principles involved in establishing a firm fixing to all of these substrates is basically the same.

Removable and Permanent Fastenings

When researching which type of fastening is best for a particular job one of the main things to consider is whether the fixing will ever need to be removed. If it’s anticipated that, at some point in time, the fastening will need to be undone then a removable fastener is the sensible choice. In any security related application non-removable, permanent fastenings are by far the most secure and robust option to choose. But there are many non-security related masonry fastening tasks for which removable fasteners would be most appropriate - such as attaching a washing line to a wall.

Concrete Fastening Options

There are fundamentally 3 main types of concrete or masonry fastening.

1. Expansion bolts and fasteners
2. Self tapping concrete screws
3. Chemical resin anchors.

Expansion Fasteners

Expansion based fastenings, as the name indicates, use various expansion techniques to expand and press firmly against the sides of a drilled hole. The high level of friction between the fastening and the hole wall is what holds the fastener firmly in place. But this expansion is also one of the weaknesses of this type of fastener as it places significant stresses on the substrate. This makes them entirely unsuitable for use near the edge of the substrate material as it could be caused to fracture due to pressure from the fastening expansion. Expansion based fastenings are also unsuitable for any weaker substrates including brickwork, masonry, stonework and blockwork.

Self Tapping Fasteners

Self tapping masonry screws are tough and highly versatile. Importantly they require pilot holes to be drilled to the correct diameter and depth. It’s also useful to note that it can be very difficult to screw in masonry or concrete screws by hand so an electric driver is what’s needed. Removable fastenings will often be of the self tapping variety. These can generally be made non-removable by hammering a ball bearing into the head socket. Important advantages provided by self-tapping concrete screws and fastenings are:

• They are simple to install.
• Once installed the fastening is immediately ready to take a full load.
• They are cheaper than other forms of concrete and masonry fastening.

Chemical Resin Anchors

Expanding and self tapping fasteners are widely used to create firm attachments to concrete and masonry. But, as noted, one of their main drawbacks is the possibility of causing splitting or cracking, especially when used close the edge of the substrate material.

Chemical resin anchors or fastenings overcome this inherent weakness. Instead of the mechanical expansion or threaded fastening being secured in place due to friction a chemical resin is allowed to cure and set around the fastening in the hole that’s been prepared for it. This naturally provides a strong bond with the substrate material as the resin flows into the rough surface of the prepared hole and around the fastening to establish a robust attachment without putting the substrate under stress.

The main drawbacks associated with resin based fasteners is that, unlike expansion or self tapping fasteners, the prepared hole must be thoroughly cleaned of dust and debris and time is required for the resin to fully cure and harden before they can be subjected to load.

High Quality Concrete Screws

An important factor to consider when buying concrete screws and fastenings is quality. There are an abundance of low quality, cheap concrete fastenings on the market today. These are often manufactured from low quality, weak steel and offer very poor corrosion resistance.

Quality is what counts. This is why we promote the use of high quality Atlas Bolts and screws.

These versatile fasteners are widely used for both indoor and outdoor applications by many people and professions including builders, kitchen installers, roofing contractors and fencing installers. Atlas bolts are simple to use, reliable and long lasting.

If you have any questions or would like to know more about concrete fasteners and Atlas bolts remember that we are here to help. Give us a call on 01273 475500 and we’ll provide you with free, expert advice and guidance.

This message was added on Thursday 22nd April 2021