# What size should a loft hatch be? > No building regulation sets a loft hatch size. The common sizes, what the hole and the clear opening measure, and what each type of ladder needs. Source: https://completeloftservices.co.uk/advice/what-size-should-a-loft-hatch-be/ Generated: 2026-11-02 --- - [Home](/) - [Advice](/advice/) - Loft hatch size Advice # What size should a loft hatch be? No building regulation sets a size for a loft hatch in an existing home. It needs to be big enough for you, what you store and the ladder you want. The common drop down hatch fits a hole about 562 x 726mm, while a timber folding ladder with its own hatch needs an opening about 0.9 to 1.1m long. ## Is there a standard loft hatch size? Not one set by any rule. The size you see called standard is the size of a product. The size you will see called standard is a hole about 562mm wide and 726mm long. That is the size most drop down hatches are sold to fit, not a rule. One maker lists a fitting size of 726 x 562mm and an opening of 715 x 545mm once fitted. Another maker's datasheet gives a structural opening of 562 x 722mm. That is the hole in the timber. Once the hatch is in, the clear opening is 533 x 655mm. That smaller gap is the one you climb through, so two hatches for the same hole can leave you different room. Sources: [Manthorpe drop down loft hatch, product listing](https://www.toolstation.com/manthorpe-drop-down-loft-hatch/p20216), read 22 October 2026; [Easy-Trim, traditional loft hatch datasheet](https://easy-trim.co.uk/wp-content/uploads/2026/03/traditional-loft-hatch-datasheet.pdf), read 21 October 2026. ## What do the building regulations say about loft hatch size? Nothing on size. The Approved Documents for homes (B, C, K and L) give no width or length for a loft hatch. What the guidance asks for is a good seal. Approved Document L says: "Loft hatches: where the roof is insulated at ceiling level, hatches should be suitably designed and installed to ensure optimum airtightness." [Approved Document L](https://assets.publishing.service.gov.uk/media/662a2e3e55e1582b6ca7e592/Approved_Document_L__Conservation_of_fuel_and_power__Volume_1_Dwellings__2021_edition_incorporating_2023_amendments.pdf), volume 1. Approved Document C adds: "An effective draught seal should be provided to loft hatches to reduce inflow of warm air and moisture." [Why the seal matters](/advice/should-a-loft-hatch-be-insulated/). The one size rule is NHBC's, and it is for new homes. Its standard for homes begun from 1 January 2026 asks for "a minimum opening width of 520mm in each direction" (clause 7.2.12.1). That is a warranty standard, not a building regulation, and it does not apply to an existing home. Sources: [Approved Document L, volume 1](https://assets.publishing.service.gov.uk/media/662a2e3e55e1582b6ca7e592/Approved_Document_L__Conservation_of_fuel_and_power__Volume_1_Dwellings__2021_edition_incorporating_2023_amendments.pdf); [Approved Document C](https://assets.publishing.service.gov.uk/media/5a8192a0e5274a2e8ab54b5f/BR_PDF_AD_C_2013.pdf), both read 10 October 2026; NHBC Standards 2026, clause 7.2.12.1, read 11 October 2026. ## How do I measure a loft hatch? Measure the hole in the timber, not the lid or the trim around it. Take the structural opening both ways first. Then measure the clear gap inside any frame, since that is what a ladder has to fit. Note what sits at each end, such as a joist, a wall or the stairs. That tells you which way the hole could grow. ## What size hatch do I need for a loft ladder? A ladder that comes with its own hatch sets the hatch size. These are the smallest openings two makers list. TIMBER FOLDING From 113 x 55cm from one maker. Another lists 55 x 100cm, or 60 x 94cm for a four section model. SLIDING ALUMINIUM From 46 x 41cm for a two section ladder, and 51 x 43cm for a three section one. TELESCOPIC From 60 x 51cm. CONCERTINA A scissor ladder with its own hatch, from a 50 x 80cm opening. By these figures, the common 562 x 726mm hole is long enough for a sliding or telescopic ladder, but too short for any timber folding ladder they list. The loft above and the landing below matter too. [Which ladder fits a small hatch or a tight landing](/advice/loft-ladder-for-small-hatch/), and our [loft ladders](/loft-ladders/) page. Sources: [Youngman loft ladder brochure](https://www.roofgiant.com/resources/files/youngman-loft-ladder-brochure.pdf); [FAKRO loft ladder brochure](https://www.fakro.co.uk/att/FS_GB_E03A__2023-06-07.pdf). All read 21 October 2026. ## Want a ladder your hatch is too small for? Book a free survey and we will tell you which ladders fit. [Book a free survey](/contact/) ## Why are loft hatches so narrow? In a roof built from trusses, the hatch is meant to sit in the gap between two of them. The Trussed Rafter Association says: "Unless subject to special design, hatches and chimneys should be accommodated within the standard spacing between trussed rafters." It puts that spacing at "normally 600 mm". It also says truss members must never be cut or trimmed without special design arrangements with the trussed rafter designer. So a hatch can usually grow along the gap. Going wider means moving trusses to a designed layout, and the same sheet shows ways to do that without cutting any. We make [loft hatches](/loft-hatches/) bigger, and that costs extra. Source: [Trussed Rafter Association, Product Data Sheet 7, May 2007](https://www.tra.org.uk/download/2542/). Read 22 October 2026. ## Short answers **Is it easy to fit a new loft hatch?** Swapping a lid in the same hole is a small job. Cutting a new hole, or making one bigger, means working around the joists or trusses, so it needs planning first. We check the joists at the survey, and making a hatch bigger costs extra. Source: [Trussed Rafter Association, Product Data Sheet 7](https://www.tra.org.uk/download/2542/). Read 22 October 2026. ## More advice - [What loft ladder fits a small hatch? The makers' figures for the hatch, the loft above and the landing below.](/advice/loft-ladder-for-small-hatch/) - [Should a loft hatch be insulated? Yes, and sealed. What the guidance asks for, and why a draughty hatch lets in damp.](/advice/should-a-loft-hatch-be-insulated/) - [Is my loft strong enough for storage? What the joists were built for, and what to check.](/advice/is-my-loft-strong-enough-to-board/) [All loft advice](/advice/) ## Find out what your hatch will take The right size fits the ladder you want and the things you will carry up, and that is easier to judge with a tape in the loft. We measure the hatch at the survey and tell you which ladders fit. If it needs to be bigger, that costs extra, and it is in your written price. The survey is free and takes about twenty minutes. You get a written price before any work starts. New loft hatch, fitted: from £150 . [Book a free survey](/contact/) [Loft hatches](/loft-hatches/) Complete Loft Services boards and insulates lofts across Cambridgeshire and the surrounding counties, and fits loft ladders and hatches. Complete Loft Services sorts out loft boarding and insulation across Cambridgeshire and the surrounding counties. The survey is free, and you get a written price before any work starts. Written by Ben Criddle, who runs Complete Loft Services. Published 26 October 2026 . Facts checked on 10 October 2026 .