Old houses often have wonderful usable attic space. Sadly, access is often limited. When appropriate, installing a good pull-down attic stair case can be a boon for storage and mechanical space. We use our conditioned attic for our return air duct work, energy recovery ventilator, and dry storage. As a net zero energy expert I have to first caution you about poking holes in your ceiling. Pull down stairs make the most sense for attics or rooms that have conditioned space and are well insulated.
The ceiling of my attic is encapsulated with spray foam insulation, so there's no risk of losing conditioned air into the attic space. If the space you're cutting into is connected to the outdoors, then you must read these Energy Star tips on how to install an insulated attic hatch. http://www.energystar.gov/index.cfm?c=diy.diy_sealing_attic_door
Here's some of my tips on how I installed attic pull down stairs in my Victorian through a fragile 112-year-old plaster and lathe ceiling. Simply taking a Sawzall to it can create more repair work than retrofit work.
1. Prep the room: Plaster dust can be a nightmare. To prevent dust from getting everywhere I taped the entire room with plastic.
I placed a box fan in one window facing out and turned it on full blast. This sucks the dusty air from the room.
Then I made a double layer plastic door over the bedroom door, leaving a slit in the center for access. With the fan sucking out, air from the hallway was forced into the room. This forces all the dust out through the fan in the window and prevents dust from blowing into the hall and rest of the house.
Finally, I taped plastic over the smoke alarm to prevent it from clogging.
2. Measure and tape hatch:
Using the instructions from my pull down stairs I measured the space between the attic floor joists, drilled pilot holes from inside the attic, and taped the area to be cut. This allowed me to make sure I was positioning the stairs properly and gave me a surface to cut through and hold the plaster in place. Then I measured and penciled my cut lines along the painters tape.
3. Cutting plaster with multi-tool:
Using a multi-tool I plunged through the plaster and lathe along the taped line. I did this in four smaller rectangles rather than attempting to cut the entire opening and having hundreds of pounds of plaster land on my head. The multi-tool creates a nice clean line.
4. Add a mini-skylight:
Since my attic has two gable windows that allow lots of sunlight, I cut a rectangle through the face of the pull down stairs. Then I added a piece of translucent white plastic. This hides the attic and will blend in with the face once it's painted. But, it will allow sunlight from the attic to enter the bedroom and act like a mini-skylight. Free sunlight during the day minimizes the need for artificial light. Again, you can only do this trick if the space above is a conditioned space and is insulated to the outside.
If you've got any questions about this or anything else, send me a Tweet https://twitter.com/mattgrocoff