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Building components · Facade Support

Subframe

Explains the subframe as the assembled system, distinct from the individual brackets and rails within it.

Form:Connector or supportRoles:SupportAttachmentStructure

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 subframe is

A subframe is the whole framework a facade is carried on: brackets, rails, and whatever else connects them, considered as one system. It takes the loads from the cladding and delivers them into the backing structure, and it establishes the plane the cladding sits in.

That second job matters more than it sounds. Backing walls are built to construction tolerances; facades are made to manufacturing ones. The subframe is where the difference is absorbed, which is why adjustability is designed into it.

Boundaries

How it differs from nearby elements

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

  • It is not a bracket or a rail. Those are components; the subframe is the assembled system they form.
  • It is not a backing wall. The backing wall is what the subframe is fixed to.
  • It is not a frame in the structural sense. It carries the facade, not the building.

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.

  • sub-frame
  • carrier frame
  • secondary framing

Dependencies

What it depends on

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

  • What the backing structure can hold, which constrains the whole arrangement.
  • The adjustability designed into it, since it has to absorb the tolerance difference between wall and cladding.
  • How it crosses the insulation, which is where its thermal consequences are.
  • Metal compatibility throughout, since the whole assembly sits in a cavity that can become damp.

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

The subframe is where a wall built to one tolerance meets a facade made to another, and adjustability is what makes that possible.

Thermal

The subframe crosses the insulation line, and its bridging effect is a facade-wide consideration rather than a per-bracket one.

Structural transfer

All facade loads pass through the subframe into the backing structure, in both directions under wind.

Durability

A subframe in a ventilated cavity is subject to wetting; dissimilar metals throughout the assembly are a corrosion risk.

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 LibraryCladding support systems →The proprietary bracket-and-rail assemblies covered by this published material entry.Materials LibraryAluminium →Aluminium is the most common subframe material in rainscreen systems.Materials LibraryGalvanised steel →Steel subframes are used where loads or spans govern.Materials LibraryPreservative-treated timber →Timber batten subframes are met behind timber and lightweight claddings.

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.

Primary supportAttachmentRainscreen Facade →The assembled support carrying the cladding and setting out its plane.Primary supportAttachmentBrick Slip Facade →Carries the slip system clear of the backing wall.Primary supportVegetated Facade →Supports the planting system and keeps it clear of the wall.Primary supportExternal Shading →The framework carrying shading elements off the facade.

Where it is met

Application contexts

Building contexts where this element is commonly encountered. Association is not recommendation: appearing here does not mean the component suits every instance of that context, or any particular one.

  • Facade

Clarifications

Commonly misunderstood

  • That the subframe is a fixing detail. It is a designed load-bearing and geometry-setting system.
  • That its parts are interchangeable between one proprietary system and another. Bracket, rail and panel components are commonly designed to work together and tested as complete assemblies.

Conversations

Questions for qualified professionals

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

  • What is the subframe fixed to, and can that backing take the loads?
  • How much adjustment does the subframe provide, and does it cover the expected tolerances?
  • How is the thermal bridging through the subframe assessed?
  • Are all metals in the assembly compatible in a cavity that can get damp?

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

  • No arrangement, spacing, adjustment range or capacity is stated here.
  • Facade support systems are engineered and commonly tested as complete assemblies; component substitution is a design matter.

Facade Support & Panels

The brackets, rails, subframes and framing members that hold a facade off a backing structure, and the panels they carry.

Browse all facade support entries →