Vapour and CondensationWhy moisture moves through a wall, and the rule that keeps it from condensing inside.ArchitectureBuild tight to vapour on the warm side and open tovapour on the cold side, so moisture can dryoutward.resistance high inside, low outsideWarm humid insideVapour control layerinside the insulationCold wet outsideBreather membraneoutside the insulationAir leak through bothFar more moisturethan vapour diffusionTHE COMMON MISTAKEA sealed membrane on the outer faceA vapour open breather outsideA vapour-tight layer on the cold side traps moisture that got past the inner one.It cannot dry either way, so it builds up in the construction.Air leakage carries far more moisture into a construction than diffusiondoes. Fix the air barrier first.Vapour and Condensationlearnposters.com
Vapour and Condensation — printable design wall chart from LearnPosters. Free vector PDF, US Letter and A4.

What’s on the Vapour and Condensation poster

The rule, 3 worked examples, and the mistake everyone makes.

Air leakage carries far more moisture into a construction than diffusion does. Fix the air barrier first.

Questions about the Vapour and Condensation poster

What’s on the Vapour and Condensation poster?
The rule, 3 worked examples, and the mistake everyone makes. Build tight to vapour on the warm side and open to vapour on the cold side, so moistu…; resistance high inside, low outside; Warm humid inside = Vapour control layer; Cold wet outside = Breather membrane; Air leak through both = Far more moisture; Common mistake: A sealed membrane on the outer face → A vapour open breather outside. Air leakage carries far more moisture into a construction than diffusion does. Fix the air barrier first.
Who is the Vapour and Condensation poster for?
Vapour and Condensation belongs to the Architecture section rather than to a school year, because design is not something one grade owns. Anyone learning construction technology can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Vapour and Condensation poster?
Use it before you place the vapour control layer. The wrong side is a common error. A wall chart earns its place by being glanceable from where the work is happening, so Vapour and Condensation belongs on the wall where that design work actually happens, within glancing distance, rather than filed away.
What other posters go with Vapour and Condensation?
The Envelope, The Cavity Wall and Cladding Systems sit alongside Vapour and Condensation in the Architecture section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.The EnvelopeThe Cavity WallCladding Systems
Is the Vapour and Condensation poster free to download and print?
Yes. Vapour and Condensation downloads as a free PDF with no account, no email and no watermark, like everything else in the Architecture section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Vapour and Condensation poster print at?
Vapour and Condensation is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Vapour and Condensation loses nothing.Printing guide

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