Design a lintel over an opening in loadbearing masonry and check the walls either side. Set the opening, pick the masonry, add floors and point loads, choose a lintel, and every check updates as you go.
Drag point loads and floors on the drawingScroll to zoom, drag empty space to panF fits the viewEsc closes dialogs
Examples gallery
Worked examples
Each preview is calculated live with the current method. Load one to start from it; it replaces the design on screen.
About
Lintel Loaderv1.2 “Report”
A single-page design aid for masonry lintels and the piers either side, in the style of Frame Pusher. Everything runs in your browser; your design is kept in this browser only.
What it does
It finds the load on the lintel from the masonry above, using either a 60° or 45° arching triangle or the full masonry height, together with floors and dispersed point loads. It then checks steel, reinforced-concrete or proprietary lintels. For the walls either side it checks bearing, axial capacity, arch thrust and the Approved Document A pier rules. See Method for the full set of assumptions.
Changelog
v1.2 “Report”November 2026
⎙ Report opens a full-screen report dialog with options on the left and a live A4 preview on the right, built the same way as Frame Pusher’s.
Calculation-sheet title block: company, address, project, subject, job no., revision, calc by / checked with dates, and automatic sheet numbering (“3 of 8”) with a first number and prefix.
Ref. / Calculations / Output columns, with code clause references (EC6, EC3, EC2, BS 5977-1, ADA) and key results in the Output column.
Contents you can choose: design summary, geometry and elevation, masonry properties with the fk working, loading and arching (with the thrust working), lintel design with diagrams, pier checks, Approved Document A, method, and your own notes.
Drawing options: colour or black and white, compact/standard/large, 1–3 decimals, peak labels, load triangle and zone, dimensions and masonry courses.
Vector PDF in standard Helvetica, exactly as previewed, so the text can be selected and searched. Report settings are remembered.
v1.1 “Gallery”November 2026
Examples moved to the left panel, with a Gallery button.
New examples gallery with live previews, pass/fail tags, category filters and search; two new examples (basement engineering brick, aircrete with proprietary lintel).
Welcome guide on opening (can be turned off), reopened from the top bar.
About & changelog page.
PDF report: an A4 calculation sheet with elevation, diagrams, inputs, loads and every check, built in the page with no external libraries.
Save design now downloads a .json file; Open reads one back.
Fix: in the light theme, the text on selected buttons (lintel type) was white on a transparent background.
v1.0 “Lintel”November 2026
Opening, masonry library (10 types) with EC6 fk, fd and fvk0; floors and point loads, dragged on the elevation.
Arching check with load triangle and 1.1L zone; 60° point-load dispersal that sends any spill past a jamb into the pier.
Steel (UB/UC/PFC, LTB option, lightest-section picker), RC and proprietary lintel checks; load, shear, moment and deflection diagrams.
Pier checks: EC6 bearing, axial at bearing level and mid-height, arch thrust, and the Approved Document A Diagram 14 rules.
Disclaimer
This is a design aid. Results should be verified by a competent engineer, and library properties replaced with the manufacturer's declared values.
Lintel Loader · method
A design aid for a lintel over an opening in a single leaf of loadbearing masonry, and for the masonry piers either side. Units: kN, m (inputs in mm). Run each leaf of a cavity wall separately with the loads that leaf carries.
Loads on the lintel
Arching. Where the masonry above can arch, the lintel carries only the masonry inside a load triangle (60° to the horizontal by default, as BS 5977-1) plus loads applied within a loading zone of height 1.1 × clear span. Loads above the zone are carried by the arch to the piers. In Auto mode arching is taken only when: the masonry above is at least the triangle height + 150 mm, there are no openings or movement joints in the zone, neither side is a free wall end, and both piers resist the arch thrust.
No arching. All masonry up to the height entered and every floor are carried over the full clear span.
Floors are line loads (kN/m² × tributary width). Within the zone they act over the full span; optionally, those inside the triangle can act only over the triangle chord at floor level.
Point loads spread at 60° to the horizontal through the masonry (EC6 6.1.3) onto the lintel. The part of the spread that falls beyond a jamb goes into that pier.
Lintel span = clear span + one bearing length (centre to centre of bearings). Self-weight is included.
Lintel checks
Steel (EN 1993-1-1): section classification, Mc,Rd (Wpl or Wel), Vpl,Rd, and SLS deflection under G + Q. If the flange is not restrained, LTB uses Mcr with C1 = 1.13 and rolled-section curves b/c. Properties come from the nominal dimensions with root radii ignored, which is slightly conservative.
Reinforced concrete (EN 1992-1-1): rectangular stress block bending, VRd,c without links, span/effective-depth (7.4.2) and minimum steel. The deflection diagram uses a rough long-term cracked stiffness (Ecm/3, 0.5 Ig) and is indicative only.
Proprietary lintels: the equivalent UDL, max(8M/L, 2Rmax) under unfactored loads, is compared with the maker's safe working load. Use the maker's table for the actual length, leaf ratio and load case.
Walls either side (piers)
Bearing (EC6 6.1.3): NEd ≤ β Ab fd, with a1 = 0 at the jamb. The effective length lefm spreads at 60° into the pier only, so it is capped by the pier width. Ab/Aef ≤ 0.45, and β = 1 for units that are not Group 1.
Axial (EC6 6.1.2 / Annex G): the pier is a column b × t with hef = ρn h. It carries the lintel reaction, the masonry and floors over the pier, the share of arched loads, and any point-load spread beyond the jamb. The check is made at bearing level (Φi) and at mid-height (Φm, with em ≈ einit + 0.6 etop). The small-area factor (0.7 + 3A) applies when A < 0.1 m².
Arch thrust: T = WarchL/(8z), with z = 0.8 × min(triangle height, masonry height). It is resisted by bed-joint shear in the pier, fvk = fvk0 + 0.4σd ≤ 0.065fb, with σd from permanent load only.
Approved Document A (England, Diagram 14, advisory): no opening wider than 3 m, total openings ≤ 2L/3, a return pier of at least max(665 mm, W/X), and a pier between openings of at least the larger opening / X. A free wall end falls outside the guidance.
Masonry properties
fk = K fb0.7 fm0.3, with fm ≤ min(20, 2fb). fvk0 comes from EC6 Table 3.4. The library values are typical and indicative; replace them with the manufacturer's declared normalised strength and density.
Limits
This is a design aid, not a substitute for engineering judgement. It does not check lateral (wind) loading on the piers, concentrated loads on the lintel's bottom flange or toe, cavity-tray or thermal details, or construction-stage (green masonry) loading, except through the LTB option. All results should be verified by a competent engineer.