What seals does a uPVC window have, and what do they each do? Here's a plain guide.
A uPVC window seals in layers — gaskets between sash and frame block air and water, glazing seals hold the glass, and the perimeter seal between frame and wall keeps weather out of the structure. All three matter.
People focus on the glass and miss that the sealing does at least as much work. A window is only as weathertight as its worst seal — which is why fitting matters as much as manufacturing.
Gaskets between sash and frame (blocking air and water), glazing seals around the glass, and the perimeter seal between frame and wall. All three matter.
Poor-quality gaskets harden and lose flexibility over time. Quality gaskets stay flexible for years.
They work together — but a window is only as weathertight as its worst seal, which is why fitting matters as much as manufacturing.
Related guides covering this topic from other angles — different products, applications, or contexts.
Tell us your openings and we'll measure on site, advise, and give you a real quote — factory-direct from our Pannimadai works in Coimbatore.