Jan 21, 2016
Choosing the right construction anchors and fastening systems for the job at hand is essential to completing the task on time and within your budget. It is also essential to ensuring that the project is completed to the best possible standards.
Anchors differ from other types of fasteners in that they are used to secure something to a solid base material; in most cases materials such as concrete or brick. As a general rule construction anchors fall into two categories:
- Mechanical Anchor Fasteners
Anchors must be able to withstand the forces working on it in two directions -- forces acting in the same direction as the axis of the fastener (pullout forces) and those acting at right angles to the fastener (shear forces). Weakness in either direction can cause the anchor to fail. Mechanical anchors use friction to withstand these opposing forces. Once embedded, the anchor expands, gripping the base material and wedging firmly in place. The process works similar to that of a raw plug or dowel when items are attached to walls.
- Chemical Anchor Fasteners
These types of construction anchors require the addition of an adhesive to get them in place. A hole, slightly bigger than the anchor, is created in the based material. Then, the hole is cleared of all dust, debris and anything else that may affect the bonding process. Next, the hole is completely filled with adhesive so that no air pockets or gaps remain. Then, the bolt can then be inserted, and the adhesive left to dry. Depending on the type of chemical adhesive used, drying time can range from 1 hour to 24 hours.
Which To Choose
The type of anchor you choose will depend on a number of factors, including speed and waterproofing. Chemical fasteners need to dry before the load can be applied so where speed is an issue they are not always suitable. Mechanical fasteners, by their very design always leave a small gap between themselves and the base material. So, if they are being used externally, it could potentially cause water leakage into the structure.
When it comes to load, both types of anchor fasteners are suitable for construction jobs and available for a range of load requirements. Ultimately your choice will depend on the specifics of the project at hand.