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Building components · Frame Members

Sole Plate

Explains the sole plate as the framed wall's base member and its point of connection to the structure beneath.

Form:Linear memberRoles:SupportAttachment

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 sole plate is

A sole plate runs along the bottom of a framed wall. The studs stand on it and are fixed to it, and it in turn is fixed down to the floor or foundation beneath, which is how the whole wall is held in position.

It is therefore the transition between a framed element and whatever it stands on, and it deals with the tolerances and the moisture conditions of that transition.

Boundaries

How it differs from nearby elements

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

  • It is not a wall plate. A wall plate is at the top of a wall receiving what spans onto it; a sole plate is at the bottom of a framed wall transferring into what it stands on.
  • It is not a column base plate, which is a fixing detail for a single vertical member rather than a continuous member under a wall.
  • It is not a floor member. It runs along the base of the wall rather than spanning as part of the floor structure.

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.

  • sole plates
  • bottom plate
  • base plate of a framed wall
  • sill plate

Dependencies

What it depends on

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

  • How it is fixed down, since that fixing is what secures the wall against sliding and uplift.
  • The levelness and regularity of what it sits on, because the whole framed wall inherits it.
  • Separation from moisture where it sits on concrete or masonry.
  • Whether it is packed or bedded where the surface beneath is not true.

Considerations

Topics that genuinely apply here

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

Moisture

Timber sitting on concrete or masonry near floor level is in one of the positions where moisture separation is routinely specified.

Tolerance & fit

A framed wall inherits the level and line of the plate it stands on, and correcting it later means correcting the whole wall.

Structural transfer

The fixing of the plate to what is beneath is the load path for horizontal forces on the wall, not merely a means of holding it in place while it is built.

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 softwood →Softwood is the usual form in timber-framed construction.Materials LibraryPreservative-treated timber →Treatment is commonly specified given the plate's position at floor level.Materials LibraryLight gauge steel framing →In cold-formed steel construction the equivalent member is a steel track.

Materials

Commonly incorporates

Materials this element commonly contains as a distinct constituent part, rather than being made of.

Materials LibraryDamp-proof course →A separating layer beneath the plate is a distinct constituent of the arrangement.

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 supportTimber Platform Frame →The base member of each framed wall, fixed down to the platform beneath.Primary supportCold-Formed Steel Frame →The base track the studs locate into and through which the wall is fixed down.Primary supportFramed Partition →The base member the partition studs stand on and are fixed to.Primary supportTimber Frame Wall →Transfers the framed wall's loads and restraint into the structure beneath.

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.

  • Building Interior
  • Internal Partition
  • Superstructure

Clarifications

Commonly misunderstood

  • That the sole plate is a setting-out convenience. It carries the wall's connection to the structure beneath, including against wind uplift and sliding.
  • That packing under a plate is a workmanship shortcut. Where a surface is not true, how the plate is bedded or packed is a design consideration.

Conversations

Questions for qualified professionals

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

  • How is the sole plate fixed down, and what forces is that fixing designed for?
  • What separation from moisture applies where the plate sits on concrete or masonry?
  • How is the plate bedded or packed where the base is not level?
  • Does the fixing arrangement change at corners and openings?

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 fixing type, spacing, section or bedding arrangement is stated here.
  • Fixing framed walls down is structural design work, particularly where wind uplift is a consideration.

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 →