My attic is well-insulated with fiberglass insulation strips laid between the joists, silver thermal wrap stretched across the joists, and 18-20 inches of blown insulation on top.
But as I conclusively demonstrated yesterday, there is no flooring to prevent me from plunging through the ceiling and into the room below.
What is the best way add flooring to the attic without compromising the insulation factor? There is too much blown insulation for me to simply compress it all under plywood. Should I add plywood to the existing joists and leave the blown insulation on top?
Two slight complicating factors: my only attic access is through a standard pull-down ladder, so I can't fit whole sheets of plywood. Also, I have an A/C unit (no heat) in the attic that sprawls extensively across the floor. I can work around that, but it makes access more difficult.
Best Answer
The alternative to Eric Simpson's simple solution is a product like the following. (This particular one is from Amazon, but searching for "loft flooring legs" will find many like it.)
Plywood/chipboard is often sold in 2400x600mm (8'x2') sheets precisely for fitting through a hatch to floor a loft.
Also, beware! Roof trusses are usually designed down to a price, which means using the thinnest pieces of wood which can take the load of the roof. They are usually not designed to carry substantial loads like a standard floor and a massive pile of junk on top of it. If you want to put in a pathway and store empty suitcases and spare duvets/sleeping bags that should be fine; a complete floor + piles of old books - not so much. (Thanks to isherwood for the comment.)