Free tool · Steel
Lintel and Padstone Helper
A steel beam over a new opening: the length to order, the span to check, the lightest UB and UC for your loads, and the end reactions for your engineer.
Quick answer
Enter the clear opening, the bearing at each end and the loads. The Koyda helper gives the lintel length (opening plus both bearings; Catnic gives a nominal minimum of 150 mm each end), checks the span between bearing centres with the same engine as the beam span checker (BS EN 1993-1-1, UK National Annex), lists the lightest UB and UC under 90% of capacity, and shows the end reactions your engineer needs to design the padstones. Guidance only.
Cite this: Koyda Ltd, “Lintel and Padstone Helper”, https://www.koyda.com/lintel-and-padstone-helper/, reviewed 10 October 2026.
Lintel helper
Guidance only. Starts with the top flange unrestrained and the load on top (the cautious choice). Padstones and the wall below are not checked. Not a substitute for a structural engineer. What is not checked
Enter a load
Enter the opening and the loads to see the lightest beam.
| Lightest under 90% | Utilisation | End reaction (each end) | Span checker |
|---|
Show the working
Send the engineer's design and Koyda will price the steel, fabrication and fitting.
Use the tables and calculator offline
Install the Koyda app: section tables, weight calculator, CSV and PDF downloads, even without signal on site.
How it works
What the helper does
- Lintel length = opening + 2 × bearing. Span checked = opening + 1 bearing (centre to centre of the bearings), which is longer than the opening and so more cautious.
- Wall weight = height × thickness × the density you enter from the product data (kg/m³ × 9.81 / 1000 = kN/m³). Added to the permanent load.
- Every UB and UC is run through the beam span checker's engine; the lightest of each under 90% is shown. Self-weight included, 1.35 × permanent + 1.5 × imposed.
- End reaction each end, unfactored and design, with the beam's own weight. Average bearing stress over the flange width × bearing length is shown for information only: it is not a masonry check.
Limits
What it does not check
- Padstones, the masonry under each end and the wall's own stability (BS EN 1996-1-1, clause 6.1.3 for concentrated loads).
- Web bearing and buckling at the supports.
- Proprietary steel lintels (pressed cavity lintels): use the manufacturer's load tables.
- Arching in the wall above, loads off-centre, two leaves on separate beams, or a beam carrying another beam's end.
- Temporary works and propping while the opening is formed.
Not a design
Guidance only. This sizes one simply supported steel beam used as a lintel for the loads you enter. It assumes the top flange is fully restrained unless you choose otherwise. It does not check connections, bearings, padstones, the walls or columns below, web bearing, fire, vibration or torsion, and it is not a substitute for a structural engineer. Building Regulations approval needs calculations from a competent engineer. Padstones and the masonry under each end are not checked: the end reactions are shown so your engineer can design them.
Questions
Frequently asked questions
How long should a steel lintel be?
Opening width plus the bearing at each end. Catnic says lintels generally need a nominal minimum end bearing of 150 mm at both ends, so a 1.2 m opening needs at least a 1.5 m lintel. For a steel beam on padstones, the engineer sets the bearing length: it is often more.
Which span does the helper check?
The distance between the centres of the two bearings, which is the opening plus one bearing length. That is longer than the clear opening, so the check is more cautious than using the opening width.
Do I need padstones?
Usually, for a steel beam bearing on brick or block. A padstone spreads the end reaction into the wall. Its size depends on the reaction, the masonry strength and the wall, under BS EN 1996-1-1 (concentrated loads, clause 6.1.3). Your engineer designs it: the helper gives the reactions to pass on.
How do I work out the weight of the wall above?
Enter the height of wall the lintel carries, its thickness, and the density from the block or brick manufacturer's data sheet. The helper multiplies them out. It takes the full height you enter: an engineer may allow for arching in some walls, but leave it as entered if unsure.
Should I tick 'unrestrained'?
Yes, unless something fixed to the top flange stops it moving sideways along its length. A lintel carrying a wall usually has nothing holding the top flange, so the helper starts unrestrained, with the load on the top flange. Both are the more cautious choices.
Related tools
Next steps
- Beam span and load checker
- Universal beam sizes and properties
- Steel Quote Builder: weights, cutting list and quote
- Delivery and lifting check
- All guides and tools
Enquiries