Being able to get into the roof space of your home is important, not just because of the extra storage capacity it offers but also to be able to deal with emergencies like leaking roofs and burst pipes. and also to be able to install extra light fittings to the rooms below.
Most houses already have some form of hatchway providing access to the attic but it may not always be in the most convenient place, and in some instances there may be no access to the attic at all. In both situations you can make a new opening with comparatively little trouble.
The usual position of an attic hatchway is in a hall or over a landing. but in the latter case make sure it is not over the staircase itself. Do not put it near an external wall either if this meets the eaves of the roof, as there will not be enough headroom above the opening.
Another important consideration when positioning an opening is the space needed in the roof and in the room below for any attic ladder you intend fitting.
Having decided on the approximate position. locate the adjacent joists by tapping the ceiling and probing with a bradawl. or mark through from the loft if you can reach it by some other route.
Break through the ceiling between a pair of joists and open up the hole until you can make a saw cut alongside one of them. Then mark out the opening on the ceiling from this baseline. Its size will be determined by the joist spacing and since this will be too close to make the opening between the pair, it will have to span three. This means cutting through the center joist and linking it to the joists on each side with short “trimmer” joists. The wood used must be the same size as that of the original joists.
Before you cut through the intermediate joists. support the ceiling on each side of the opening with stout planks and wood or adjustable metal props.
Line the opening with 1 in thick planed wood the same depth as the joists and nailed in place flush with the ceiling. The corners of this can be simply butted together.
Then make up a plywood trapdoor for the opening. hinging it to the bottom of the lining and either fitting a magnetic catch on the opposite side or an automatic catch such as that supplied with an attic ladder.
Finally, nail lengths of mitered molding around the opening, driving the nails into the joists so that the molding holds the edges of the ceiling firmly in place.