Approx. 21". If there is space for it, consider the size of a drop down ladder unit, which is more useful than an opening that requires a ladder.
30" x 22"
4 by 4 ft
Minimum attic access opening
depends on the size of your attic
If you are tired of crawling through the small space in your closet to access your attic, you should consider installing an attic ladder. An attic ladder can be installed in your garage or breezeway and will give you better access to your attic than a small crawl space. Most attic ladders come completely assembled, so installing an attic ladder is easy and only takes a few hours. It is much safer to use an attic ladder too, as it offers more stability than a traditional ladder or step stool.
Wasted Spaces - 2006 Attic Access and Flooring 1-2 was released on: USA: 27 December 2006
Supported minimum size
Minimum size is 36
My home needs ventilation. What size attic fan would I need for a 1200 square foot house?
The minimum size of an Excel workbook is 1 spreadsheet.
you put a trap in the attic and leave awindow or ddoor open for it to have access to enter and then set soome bait for it and hopefully this will lure in the opossum and this is how you catch and opossum.
There is no physical minimum door size - custom doors can be made to any size. There might be building codes for your area specifying what the minimum door size is for a commercial or residential structure, though...
The minimum size of a standard South African bedroom is 4000x2500
give more details like the area etc