Building components · Terminations
Upstand
Explains the upstand as the vertical extension of a horizontal waterproofing plane, and why its termination is the vulnerable point.
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 upstand is
An upstand is where a waterproofing layer stops being horizontal and runs up a vertical face — a parapet, a wall, a kerb. It exists so that the waterproofing continues above any level water could reach before it terminates.
The termination at the top is the critical point. Water is kept out by the waterproofing being continuous up to a level above where water can rise, and by the top edge being closed so water cannot get behind 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 parapet or a kerb. Those are the constructions the upstand runs up; the upstand is the waterproofing itself.
- It is not a flashing. A flashing covers and closes the top of an upstand from above; the upstand is the layer being closed.
- It is not a tilting fillet, which sits at the bottom of an upstand to ease the angle into it.
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.
- upstands
- membrane upstand
- turn-up
Dependencies
What it depends on
What has to be right elsewhere for this element to do its job.
- The height it reaches relative to where water can stand or be driven, which is a design determination rather than a fixed value.
- How its top edge is terminated and closed so water cannot enter behind it.
- The angle at its base, since a sharp internal angle stresses the material.
- Whether anything above — a coping, a flashing, a cladding edge — protects the termination.
Considerations
Topics that genuinely apply here
Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.
Water entering behind the top of an upstand is behind the waterproofing entirely, which is why the termination matters more than the upstand's height alone.
The junction between a horizontal deck and a vertical wall is a position where differential movement occurs, and the upstand has to accommodate it.
Upstands are formed early and then built against, so damage during subsequent work is a recognised risk.
Upstand terminations are frequently concealed by later construction, which makes their condition hard to assess.
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.
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.
Junctions
Interfaces this element takes part in
Junctions where the condition between this element and another governs how the construction behaves. These name the junction and the subjects it raises; they are not details, arrangements or approved ways of building.
Parapet Base to Roof Upstand
Where a flat roof meets the wall continuing above it, and where three exposed surfaces converge on one waterproofed corner.
Raises: Moisture · Thermal continuity · Movement · Weathering
Tilting Fillet at Upstand Base
Where a horizontal waterproofing plane turns up a vertical one, and where a sharp angle is deliberately softened.
Raises: Moisture · Movement · Buildability · Weathering
Upstand to Flashing Termination
Where waterproofing turned up a vertical face stops, and where a flashing above closes that stop.
Raises: Moisture · Weathering · Movement · Buildability
Wet Area Floor to Wall Tanking
Where a wet area's floor waterproofing turns up the wall, forming the corner water finds first.
Raises: Moisture · Movement · Buildability · Structural transfer
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.
- Basement
- Building Envelope
- Deck & Terrace
- Flat Roof
- Wet Area
Clarifications
Commonly misunderstood
- That a higher upstand is always better. Height matters, but an unclosed termination at any height lets water behind the waterproofing.
- That the upstand and its flashing are one element. They are separate layers doing complementary jobs, and either can fail alone.
Conversations
Questions for qualified professionals
Questions worth asking someone with the project in front of them. This page cannot answer them.
- What height does the upstand reach, and what determined it?
- How is the top edge terminated and protected from water getting behind it?
- How is the angle at the base of the upstand formed?
- How is differential movement between deck and wall accommodated here?
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 height, termination arrangement, lap or fixing is stated here.
- Waterproofing manufacturers specify their own upstand and termination requirements, and those govern rather than any general description.
Terminations & Weathering
The elements where a plane stops, turns up, sheds water or is deliberately interrupted — parapets, upstands, flashings, drips, weeps and movement joints.
Browse all terminations entries →