“For Rain is always prepared to do mischief, and wherever there is the least crack never fails to get in and do some hurt or other…”

Leon Alberti, 1485

Course Description

This two-part lecture takes a practical, first-principles look at how water gets into metal cladding façades — and how to stop it.

Part 1: Water Management opens with the six physical forces that drive water through a façade (gravity, kinetic energy, surface tension, capillary action, pressure difference, and air movement) and the only three strategies available to counter them: Deflect, Drain, and Dry. It traces how the industry moved from thick mass walls with ornamental water-shedding features to the flat modernist box — and why the box failed at every interface. The lecture then covers the two-stage drainage principle common to all façade types (rainscreen, curtain wall, precast, and insulated render), the real reasons behind UK cavity sizing requirements, and the implications of cavity depth for fire performance post-Grenfell. It closes on the five interfaces where leaks actually occur, with detailed examination of coping geometry and sill end-cap details.

Part 2: Cold Smoke Propagation addresses a live regulatory issue: Gateway 2 submissions being rejected over open-state horizontal cavity barriers. The lecture explains the building safety regulator's concern about cold smoke travelling through façade cavities before intumescent barriers activate, demonstrates why the proposed fix — closing all horizontal barriers — traps water and fails Approved Document C, and works through the practical limitations of sloped closed-state barriers across a range of real façade configurations. It concludes with the NHBC-based resolution: vertical closed-state barriers at no more than 6-metre centres and at corners, with horizontal barriers left open — limiting smoke propagation to narrow vertical lanes while keeping the drainage function intact.

Together, the two parts equip façade professionals with a coherent framework for detailing against water ingress and for navigating the tension between fire compliance and moisture resistance in ventilated rainscreen systems.

Interactive 3D details

are based on case studies from the Facade Intelligence platform. These models showcase how the concepts of deflection and drainage manifest in modern facade assemblies—including masonry veneers, insulated render systems, precast concrete, and curtain wall facades.

Multiple-choice tests

for this course were carefully selected from other courses offered by IAST and provide additional insights on the topic. We design our questions not just to test knowledge but to introduce new material—so don't skip them!

Lecture

In this full conference session recorded at the MCRMA Conference on 10 June 2026, the Institute for Architectural Science and Technology — delivers a masterclass on the single thing metal cladding façades are asked to do most, and fail at most often: keeping water out. Drawing on decades of research, real-world case studies, and detailed 3D façade models from the Façade Intelligence platform, the session brings together the physics of water movement, the history of how the industry got to where it is today, and the practical detailing knowledge that separates façades that perform from façades that leak. Whether you are a façade engineer, cladding contractor, architect, or building control professional, this session offers a rigorous yet accessible guide to understanding why water gets in — and exactly what to do about it.

Certificate

Successfully complete the multiple-choice test and you’ll receive a Certificate of Completion, officially recognising your achievement. This course also qualifies for Continuous Professional Development (CPD) hours, helping you stay on track with your annual professional requirements.

Course Schedule

    1. Course Overview

    2. Course Objectives

    3. How to Navigate the Learning Materials

    1. Presentation Recording MCRMA Conference

    1. Traditional Brick Masonry - Interactive 3D detail

    2. Precast Concrete Facade - Interactive 3D detail

    3. Precast Concrete Panels Joint Drainage - Interactive 3D detail

    4. Stick Curtain Wall Facade - Interactive 3D detail

    5. Unitised Curtain Wall Facade - Interactive 3D detail

    6. Insulated Render Facade - Interactive 3D Detail

    1. Test - Part 1

    2. Test - Part 2

    3. Test - Part 3

    4. Test - Part 4

    1. Further Reading Recommendations

    1. Certificate: Download & Share

About this course

  • Free
  • CPD Certificate: 2 hrs
  • Interactive 3D models

Course Highlights

  • The six forces that drive water in — and how to beat them
    A clear, memorable framework covering gravity, kinetic energy, surface tension, capillary action, pressure difference, and air movement — each paired with a real failure mode and a practical design fix.

  • Why all façade systems drain — even the "sealed" ones
    An eye-opening look at how rainscreen, curtain wall, precast, and insulated render systems all rely on the same two-stage drainage principle, and what that means for how you detail every junction.

  • The truth behind UK cavity sizes
    A evidence-based breakdown of where the 38 mm and 50 mm figures actually come from — spoiler: it's not drainage — and the dimensions that genuinely do the work: the 6 mm weep hole and the 10 mm open joint.

  • Where façades really leak: the five critical interfaces
    A detailed walkthrough of copings, sills, head reveals, jamb reveals, and bases — the interfaces where drained systems fail — with correct detailing for coping drip geometry and sill end caps in insulated render.

  • Cavity size, fire performance, and the lessons of Grenfell
    A frank examination of how cavity width affects fire behaviour, drawing on the original NRC Canada research, and why the post-Grenfell response in the UK created a new tension between water management and fire compliance.

  • Resolving the cold smoke conflict: a practical, compliant barrier strategy
    A step-by-step explanation of why closing horizontal cavity barriers traps water and fails Approved Document C — and how the NHBC approach (vertical closed-state barriers at ≤6 m centres, horizontals left open) resolves the Gateway 2 rejection problem without compromising drainage.

The course is free and available to all

Join IAST on this journey into water management in building envelopes

Join the Facade Intelligence Professional Membership (FI PRO)

Membership fees start from £320 per year

Gain access to all upcoming seminars and a wide range of the most sought-after short courses. Corporate discounts are available for teams of 10 or more.
For a bespoke quote, please contact our team at [email protected].
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Collaborate With Us

We believe the most effective way to raise industry standards is through collaboration. If you are a practicing specialist with expertise in a particular area of façade engineering, or an academic interested in sharing knowledge with a wider audience, we welcome the opportunity to co-develop high-quality short courses and CPD content. Email us on [email protected] or use the contact button below to start the conversation.
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