What are Holding Down Bolts?
Holding down bolts, which are also known as anchor bolts, foundation bolts and ground bolts, are used in construction to hold steel frames to concrete pads, or column base plates to concrete flooring.
Holding down bolts comprise of a holding down nut bolt and nut, and round washer, a square plate washer and a waxed cardboard cone. There are usually four foundation bolts to one baseplate, but the number can vary depending on the design and connection required.
How to use them
The waxed cardboard is placed over the bolt, standing on the plate washer. The square hole in the plate washer locates over the square section of the Holding Down Bolt. This ensures that the bolt cannot turn when tightening the nut. Concrete is then poured around the cone. Once set the space within the cone allows for horizontal adjustments of the bolts. This makes it easier to line up the above-ground structure. Vertical adjustments can be made by using packers and shims between the baseplate and the concrete. When tightening the holding down bolt, the square hole plate washer keeps it from rotating and pulling out. Once the concrete sets, the pocket can then be filled with grout.
What we offer
Here at Speedy fixings, we have identified the most popular sizes of holding down bolts (or foundation bolts) and created a pre-assembled package, in order to cut out the hassle and save you money. The package includes an 8.8 high tensile steel bolt, a nut and round washer, a square plate washer and a waxed cardboard cone.