For 15 years, the GL250 has redefined airtight loft access. Discover why housebuilders still trust the original market‑leading design for outstanding performance.
Since its launch, the Manthorpe GL250 Loft Access Door has set the benchmark for airtightness and reliability. Traditional drop‑down loft doors struggled under negative pressure, bowing and lifting off their seals during air‑tightness tests. The GL250 was engineered to solve this problem completely.
By moving the hinge out into the frame edge, Manthorpe created a larger opening and a fully continuous air seal. This also enabled quick, single‑person installation and easy removal of the door without disturbing insulation.
The breakthrough feature is the sliding catch surround. Instead of one catch, the GL250 locks into twelve points around the perimeter, preventing bowing and eliminating secondary leakage paths. With all moving parts positioned outboard of the seal, insulation coverage is maximised and cold bridging is minimised.
Independent BRE testing confirmed exceptional air‑tightness performance, far exceeding both Part L and BS 5250 requirements. This proven reliability is why the GL250 remains the No.1 specified loft door for new‑build homes.
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