Which is 56.2cm x 72.6cm. Or 22″ x 30″ in inches. Standard loft hatch sizes can only really be used with a traditional extension ladder, that is placed inside the framework of the loft hatch to allow you to climb in and out of the loft.Click to see full answer. Furthermore, how Big Should loft hatch be? 562 x 726 mm Beside above, how wide should a loft ladder be? They are manufactured such that the tread width is maximised to suit your ceiling opening width. Our range of Supreme loft ladders (pictured here) offer the greatest range of widths – with steps up to 580mm wide. They also benefit from tread depths of 140mm (or 160mm for larger step widths of 430mm to 580mm). Herein, how do you measure a loft hatch? To work out the correct height of loft ladder you will require, measure from the floor of your landing to the top of your roof joints, to the floor of your loft. Most loft ladders will reach up to 3m. Don’t forget to measure the dimensions of your loft hatch too, as you’ll need this information too.Do I need a loft hatch?It’s a legal requirement that there is roof access to any loft space in a building. In a building of three or more stories, there is also a legal requirement for the access hatch to be fire resistant for at least 30 minutes.