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Building components · Frame Members

Cleat

Explains the cleat as the intermediate piece that makes a connection possible where two members meet, and as the piece that fixes what kind of connection it is.

Form:Connector or supportRoles:AttachmentSupportStructure

Educational reference entry. What this element has to do, and whether any particular arrangement of it is adequate, depends on the whole assembly, the loading, the exposure, local requirements, the manufacturer's instructions and qualified professional design.

Overview

What a cleat is

Two members meeting at an angle rarely have anything to fasten through. A cleat is the intermediate piece — most often a short length of angle, sometimes a flat plate — fixed to the supporting member so that the supported member can be bolted to it. It is commonly welded or bolted on in the fabrication shop and the remaining bolts made on site, which is what allows a frame to be assembled from pieces.

The arrangement also decides what the connection is. A joint made through a pair of thin angles that can flex is behaving differently from one made through a stiff plate, and whether the frame above assumes the joint turns freely or resists turning follows from that. The cleat is therefore not only how the members are held together but part of how the frame behaves.

Boundaries

How it differs from nearby elements

The distinctions that keep this entry from being a restatement of its neighbours.

  • It is not a structural bearing. A bearing is a condition that exists wherever one member happens to sit on another, whether anyone designed it or not; a cleat is a piece that had to be made and fixed before any connection was possible at all, which is why its presence, its position and its fastenings are all recorded decisions rather than consequences of how two members met.
  • It is not a gusset connection. A gusset gathers several members converging at a node and turns their forces between each other; a cleat serves one member meeting another, and its job is to provide the fastening interface rather than to collect forces arriving from several directions.
  • It is not a support bracket. A bracket carries a facade panel, a rail or a service back into the structure it is fixed to; a cleat is a connection piece within the frame, joining one structural member to another.

Terminology

Common names and aliases

These names describe the same element. The library keeps one entry per component so that a trade term or a regional name never becomes a second, thinner page.

  • angle cleat
  • clip angle
  • connection angle

Dependencies

What it depends on

What has to be right elsewhere for this element to do its job.

  • What the connection is designed to do, since a joint arranged to pass a reaction only and one arranged to resist turning are different arrangements even where they look alike.
  • The bolts and the holes they pass through, because the play between them is part of what a cleated connection exists to absorb.
  • Access to make and to tighten the connection, which is what commonly decides which fastenings are made in the shop and which on site.
  • The member it is fixed to, since the force arriving through the cleat has to be accepted by that member at that position.

Considerations

Topics that genuinely apply here

Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.

Tolerance & fit

Cleated connections are one of the places where fabrication accuracy and erection accuracy are reconciled, and the clearance that allows a frame to be assembled is a deliberate part of the arrangement.

Structural transfer

Everything the supported member carries at that end passes through the cleat and its fastenings, so the connection carries the same significance as the member.

Buildability

What is shop-fixed and what is site-fixed determines how a frame goes together, and a cleat is commonly the piece that makes that split possible.

Durability

Clamped faces hold moisture where it cannot dry, which is why the condition of a connection is assessed by inspection rather than from the appearance of the members either side of it.

Materials

Commonly formed from

Material families this element is commonly realised in. This states common practice only — it is not a statement that any of these materials suits this component in a particular building, which depends on the whole assembly and on qualified review.

Materials LibraryStructural steel →A short length of rolled angle or a cut plate is the form most commonly met in steelwork.Materials LibraryGalvanised steel →Protective treatment is common where the connection is exposed or sits in a demanding internal environment.Materials LibraryLight gauge steel framing →Cold-formed clips and angles fill the position in light steel framing, where members are too thin for the connections used in heavier steelwork.

Assemblies

Building systems this element is met in

The role this component fills inside each assembly. A role describes what the element does there — it is not a statement that this component suits that system in any particular building.

AttachmentPrimary supportSteel Frame →The connection position at which a beam is joined to a column or to another beam.AttachmentPrimary supportMezzanine Structure →Joins the members of a mezzanine frame, commonly with the split between shop and site fastening chosen to suit assembly inside an existing building.AttachmentPrimary supportCold-Formed Steel Frame →Clips and angles join light steel members where the sections themselves are too thin to be connected directly.AttachmentPortal Frame →Connects secondary members such as purlins and side rails to the frames, distinct from the moment connection at the knee.

Clarifications

Commonly misunderstood

  • That a cleat is a minor fitting holding members in place. It is the connection, and everything the member carries at that end passes through it and its bolts.
  • That a bolted connection through angles is necessarily a pin. Whether a joint is treated as turning freely or as resisting turning is a design decision, and the frame above depends on which was assumed.

Conversations

Questions for qualified professionals

Questions worth asking someone with the project in front of them. This page cannot answer them.

  • Is this connection designed to pass a reaction only, or to resist turning as well?
  • What fastenings were made in the shop and what on site, and were they completed as drawn?
  • Can the member the cleat is fixed to accept the force arriving at that position?
  • What corrosion protection applies at this connection, and is it intact?

Go deeper

Related Build Design Hub guides

Planning guidance behind the decisions this element involves.

Preparation

Related planning checklists

Owner-side preparation before the conversation where this element comes up.

What this entry does not do

  • This entry describes a connection position. It states no bolt arrangement, plate or angle size, weld specification, capacity or fire rating, and none can be inferred from it.
  • Whether a cleated joint is treated as turning freely or as resisting turning is fixed by qualified design, and altering the cleat, its fastenings or the member it is fixed to changes which of those the frame above was relying on.

Structural Frame Members

The columns, beams, joists, rafters, plates and bracing that make up a load-carrying frame, identified by the position each occupies.

Browse all frame members entries →