What is a Foundation Bolt?


A foundation bolt is a structural bolt used in construction. It comprises three parts: the foundation bolt, a square washer plate and a waxed cardboard cone.


Also known as


Square square holding down bolts, construction bolts, or anchor bolts.


Why use Foundation Bolts or Holding Down Bolts?


Foundation bolts are essential for building solid foundations, particularly in steel fabrication and industrial or agricultural building projects.


Unlike drilling, which can put stress on the concrete, foundation bolts are cast into the concrete at the foundation stage, so everything is secure before construction begins.


This way, when your contractors arrive on site, they can immediately start work with the foundations already set.


Foundation Bolts: How they work


First, you excavate the site, mark out the footing, position the bolts and pour the concrete around them. You then bolt down steel uprights with usually four foundation bolts, creating a template that matches the baseplate.


The bolt’s square head and neck securely hold the washer plate in place.


The washer plate helps to anchor the plate in the concrete due to it’s wide diameter.


The waxed carboard cone creates a void in the concrete, allowing for alignment of the bolt with the steel stanchion.


Foundation Bolts: Features and specifications



  • Bolt diameters range from M16 to M30

  • Lengths: 300mm to 600mm

  • Sold individually but always with the square washer plate and waxed cardboard cone for complete installation.


Buy your Foundation Bolts at Fastco


We stock foundation bolts with free delivery on orders over £30*. Order now through our website, email us at sales@fastco.co.uk or call us on 01270 252326.


*Restrictions apply; please see our delivery page for details.