7 Things to Know About an Expansion Bolt

An expansion bolt is designed to expand after it has been installed. Expansion bolts are made from a bolt and a nut inside a sleeve which is usually made of lead. They are usually used to install items into masonry, brick or concrete or other materials where threaded screws or bolts aren't suitable. 

Fact 1 - Usage of and Expansion Bolt 

Expansion bolts are very good for filling any gaps or cracks in masonry.  This makes them a popular choice for construction work in areas where there is heavy vibrations, such as football stadiums or near train lines. They are also used commonly in areas that are susceptible to earthquakes. 

Fact 2 - How Expansion Bolts Work

They are generally used for installing heavy-duty items into masonry, brick and concrete, as the friction created between the bolt and the concrete is enough to secure weighty items with little force. You will need a specialist tool for removing an expansion bolt called an extracting gun.

Fact 3 - How to Install an Expansion Bolt

Using an expansion bolt is a simple process. First, you must drill a hole for the bolt. After the hole has been drilled, clean all the dust out of the hole with a blower or similar tool. Hammer the expansion bolt into the hole, then tighten the nut. you need to make sure the nut hasn't been over tightened, however, otherwise you can cause unnecessary stress on the bolt and cause it to break.  

Fact 4 - The Lead Sleeve of an Expansion Bolt

One of the reasons that expansion bolts are so effective for filling any gaps in masonry is that generally the sleeve is made of lead. Lead is a soft metal that is very pliable and will mold easily when pressure is applied to it. This means that it will fill the cracks and also create more than one anchor point with the concrete giving stability. 

Fact 5 - Expansion Bolt Materials

The bolts and nuts of expansion bolts are generally made from steel alloys containing zinc and cadmium plating. This gives the bolt a coating that will not easily corrode, making it perfect to use in areas that are exposed to the weather and water. 

Fact 6 - Types of Expansion Bolt

There are several different types of expansion bolt, all with slightly different purposes. Here are some of the common types:

  • Anti-tamper expansion bolts. These bolts need a specialist tool for both insertion and removal with an anti-tamper fixing. They are made from steel
  • Permafix security expansion bolt. These bolts are designed for fixing bars and grilles into place. 
  • Lifetime expansion bolt. These bolts are designed so that they can never be removed. They have a steel cone which fits over the head of the bolt, preventing it from being removed. 

Fact 7 - Standards of an Expansion Bolt

Expansion bolts have standards and specifications that they must meet. These are set and tested by The American Society for Testing and Materials. They must also meet the standards and sizes specified by the American National Standards Institute.