The loft hatch size guide.

There is no single standard loft hatch size in the UK. Most domestic openings are around 560mm wide by 640–760mm long, because joists are usually set at 600mm centres. Compact openings in older houses could fit a 536 x 536mm or 550 x 550mm. Larger openings for boarding and storage go up to 600 x 900mm. Anything outside those is made to measure.

To work out which size you need measure the structural opening of your loft — joist to joist, trimmer to trimmer — not the old frame.

The hole you can post things through is smaller than the hole in your ceiling. The frame takes up space on every side, and the insulated lid takes up more. The figure that matters when you are working out whether something will fit is the clear opening once installed, not the structural opening.

On a hinged hatch you lose roughly 60–105mm of length. On a push-up you lose 16–24mm. Every product page gives its own figure.

Hinged, almost always. The lid swings down and hangs neatly out of the way, and it is far easier and safer to use with a retractable loft ladder — you are not holding a lid while you find your footing.

A push-up lid gives a bigger clear opening, but you have to do something with it: lift it up into the loft and put it down somewhere, or angle it and squeeze it back through the opening, overhead, on a ladder. Worth it if you are regularly passing large items up and you have somewhere to put the lid. Not otherwise.

Does better insulation cost you access? A little, and less than you would think, because the lid hinges down out of the way rather than sitting in the opening. The product code tells you where you are: the number is the U-value, and a lower number means a thicker lid. AT35 to AT25 costs 22mm of length. AT25 to AT15 costs nothing — same clear opening, better U-value.

Then we make one to fit it. Non-standard openings are normal — older properties, refurbishments, anything where the joists were set out before 600mm centres became the convention.

Made-to-measure hatches are hand-made in North Yorkshire from 1mm powder-coated Zintec steel, white as standard, to the size you give us. They keep the insulation and the draught seal, and a hatch that actually fits loses less heat than a stock hatch wedged into an awkward opening.

The biggest we make is 950mm wide by 1100mm long, or 900 x 900mm fire rated. Past that the lid is too heavy to handle safely over your head. The smallest is 400 x 400mm — though a hatch has to be big enough to get you and whatever you are carrying through it.

Browse made-to-measure loft hatches

Part B — fire. A hatch into an empty roof void in an ordinary two storey house needs no fire rating. It matters when the ceiling itself is doing a job: a compartment floor or ceiling (Three Storey houses, HMOs, flats, maisonettes, commercial), a hatch opening off a protected stairway or escape corridor, or the common areas of a block of flats.

There, the hatch has to hold the fire resistance of the ceiling it sits in. That means integrity tested as a horizontal element to BS 476-22 or BS EN 1364-2.

Two things to check before you buy, from us or anyone. Is it tested as a ceiling? A hatch tested in a wall is no evidence of anything in a ceiling — different orientation, different test. Ask for the test certificate; ours are linked on the product pages. Fire rated loft hatches

Part L — heat and air. Two separate requirements, routinely muddled.

Continuity of insulation. The hatch is part of the roof's thermal envelope, so it is assessed as part of the roof and must not be a disproportionate cold bridge. Part L publishes no hatch-specific U-value, so judge a hatch on its own tested U-value against the roof it interrupts. Every hatch here lists one. 

Air permeability. ADL1 2021 requires a continuous air barrier and caps a dwelling at 8 m³/(h·m²), against 5 for the notional building. A loft hatch is one of the best-known leakage paths in a house, and it is the one that shows up when an air test fails. What stops it is a compression perimeter seal — the door pulling tight onto the seal as it locks, rather than resting against it.