What is the purpose of holding down bolts
You may be wondering what is the purpose of holding down bolts? Holding down bolts, also known as foundation bolts, are most commonly used in construction. Holding down bolts are used to fasten steel frames to concrete pads or column base plates to concrete flooring.
At Speedy Fixings we offer a wide range of holding down bolts. Read on to find out more.
How are holding down bolts used?
Holding down bolts are assembled with square/square bolts, nuts, round washers, square plate washers and waxed cardboard cones (see image below). This group of components are then cast into the concrete pad. The square hole plate washers prevent rotation and pulling out of the holding down bolt when being tightened.
Four foundation bolts are commonly used in each baseplate. Concrete is then poured around the waxed cardboard cones to allow lateral movement of the bolts. This then makes the lining up of the above ground structure much easier. Once the steel frame is set in place, the foundation bolts will be grouted in. If needed, vertical adjustments can be made by using packers and shims between the baseplate and the concrete.
Different types of holding down bolts and accessories
Assembled package of holding down bolts
To simplify the buying process and reduce the price, we have put together an assembled package of holding down bolts containing the most popular sizes of Holding Down Bolts.
Our standard holding down bolts are supplied in grade 8.8, high tensile steel and conform to BS 7419. We can also supply galvanised steel and stainless steel in sizes up to M72. Bespoke bolt cluster ‘cages’ can be manufactured to our customers’ specification. For further information please contact us.
Square Hole Plate Washers
Square hole plate washers are used to prevent rotation and pulling out of the holding down bolt when tightening. We stock a variety of sizes of mild steel square hole plate washers, including M20 100×100×10mm square hole plate washers, M24 150×150×10 mm square hole plate washers and M30 150×150×10 mm square hole plate washers.
Our square hole plate washers are 10mm thick. We can manufacture bespoke “specials” in our own factory.
Tapered waxed cones
Tapered waxed cones are suitable to be used with holding down bolts. The waxed cardboard void former is placed over the bolt, standing on the plate washer. The cone is left in place whilst the concrete sets, allowing for lateral, circular movement of the bolt. This makes lining up of the above ground structure much easier. The void can then be filled with grout.
Our range of tapered cones comes in various sizes, including 305mm tapered waxed cones and 535mm tapered waxed cones. These can be easily cut down if necessary.
Made to order, we also supply Parallel Bolt Tubes in solid steel and expanded mesh steel.
Square/Square holding down bolts
Our square/square holding down bolts come with nuts in various sizes, including M16, M20, M24 and M30. Special sizes, galvanised and stainless steel finishes are also available. Please contact us for details.
We hope you have found this blog post useful. If you have any more questions or to request bespoke holding down bolts, please contact our team today by calling us on 01206 793100