Part L 2026 Window U-Values: The Actual-Size Rule
Part L 2026 changes how window and door U-values are determined from 24 March 2027. Learn the permitted methods, limits and evidence to request.
Specification library
Aluminium technical guides
Spec-led answers on aluminium windows, doors and glazing: the performance figures, the standards behind them, and how the right product route is chosen per project. Written for installers, builders, architects and specifiers across North West England.
Aluminium U-Values Explained
What U-values mean for aluminium glazing, the figures to specify by system, and how whole-unit Uw is confirmed at quote. A trade guide from VitrineAlu.
Aluminium Fabricator or Installer: Which One Do You Actually Need?
A fabricator builds and glazes the units and picks the system; an installer surveys and fits them. Which one you need, and why it sets your spec.
How big can aluminium doors and windows go?
How big aluminium doors and windows really go: sliding sashes to 2.5 x 3.0m at 300kg on lift-and-slide, bifold leaves to 1.2 x 3.0m, up to 14 per run.
What is EN 13830 curtain walling?
What BS EN 13830 covers, stick versus unitised curtain walling, and the classes to specify. We fabricate to it on a 62mm frame system, Ucw confirmed at quote.
Aluminium window and door weather ratings explained
Air permeability (EN 12207), watertightness (EN 12208) and wind resistance (EN 12210) explained, and how to match each class to your site's exposure.
PAS 24 security explained for aluminium doors and windows
PAS 24 is the UK enhanced-security test for doors and windows. How aluminium meets it, the link to Approved Document Q, and how to specify a tested route.
Acoustic aluminium windows: how Rw ratings work
How Rw ratings work in acoustic aluminium windows: laminated panes, acoustic interlayers and asymmetric glazing, to Rw 46 dB where specified.
How an aluminium thermal break works
How a polyamide thermal break cuts conduction through aluminium frames, why frame Uf differs from whole-window Uw, and the U-values our units reach.
Aluminium glazing explained
The sealed glass unit does most of the work. How panes, low-e coatings, warm-edge spacers and argon fill set the whole-unit U-value and the acoustics.
Aluminium window and door finishes and colours
How aluminium finishes work: architectural powder coat in any RAL colour, matt to gloss, dual-colour inside and out, and anodised-style where specified.
Aluminium window styles explained
Casement, tilt-and-turn, heritage sash and fixed lights compared: how each opens, vents, cleans and meets egress, and where each style suits.
Advice for trade buyers
Roof lantern or flat rooflight?
The roof decides more than taste: pitch, kerb detail and build-up set which unit fits, and the U-value for either is confirmed at quote.
Door thresholds: level access or weathered upstand
A threshold choice is a drainage decision before it is an accessibility one. What each option asks of the build, and what to settle before quoting.
Steel-look internal doors: growing demand
Joiners and interior teams are using internal aluminium screens for light, zoning and glazed room division without making spaces feel closed down.