18″ (457mm) waxed cardboard cone / conical bolt box. For deep foundations on larger portal frame and industrial buildings. Creates a void for bolt adjustment and alignment.
What Is a Wax Cone?
A wax cone (also called a conical bolt box or void former) is a waxed cardboard cone used when setting holding down bolts into concrete foundations. It creates a conical void around the bolt, giving you the lateral adjustment needed to line up your steelwork accurately when the columns are erected.
Without a wax cone, the concrete would set tight around the bolt with no room for movement. That makes it almost impossible to get your base plates and columns to line up — even a few millimetres out and the bolt holes won’t match. The cone gives you the tolerance to nudge each bolt into the exact position before grouting.
Which Size Do I Need?
The wax cone depth should match your foundation depth and bolt projection. As a general guide:
- 9″ (229mm) — shallow pad foundations, lighter structures
- 12″ (305mm) — standard pad foundations for agricultural portal frames — most common size
- 15″ (380mm) — deeper foundations or where more bolt adjustment is needed
- 18″ (457mm) — deep foundations, industrial buildings
- 21″ (564mm) — very deep foundations, heavy-duty structures
- 24″ (610mm) — the deepest foundations, large industrial or commercial buildings
Your engineer’s foundation drawing will show the pad depth and bolt projection — choose a cone that covers the full threaded length above the bend in the bolt.
How Many Do I Need?
One wax cone per holding down bolt. A typical base plate has 4 holding down bolts, so you need 4 wax cones per base. For a 6-bay building with 7 frames, that’s 28 wax cones minimum, plus extras for gable post bases.
What Else Do I Need?
Each base connection needs: holding down bolt sets, square plate washers, wax cones, and the base plate itself. We sell all of these — check our full holding down bolt range.
Why Buy From Us?
- Sold individually — order exactly what you need, no box quantities
- Full size range — 9″ to 24″ to suit any foundation depth
- Next-day dispatch — order before 12pm for same-day dispatch
Delivery Information
Estimated Dispatch: 4–7 Working Days
These items are supplied to order. Please allow 4–7 working days for dispatch from order confirmation. This ensures we maintain consistent quality and availability while keeping pricing competitive.
Standard Delivery Cost
Shipping is calculated at checkout based on weight and order size. Depending on the quantity ordered, items may be shipped in boxes or via pallet delivery.
Packaging
All components are securely packaged and clearly labelled to ensure safe and tidy arrival on site.
Order Tracking
You’ll receive an email with tracking information once your order has been dispatched.
Returns
We supply components to specification. If you’ve ordered the wrong item or something arrives damaged, please let us know within 5 working days and we’ll get it sorted.
For full details, see our Returns Policy.
