Insulating your attic will never be a bad idea, but whether it's a DIY project or time to call in a professional is another matter. You'll have to be honest with your own abilities and expectations for the space. Do you eventually want to finish it? Does the roof need work? Is cold air escaping into your living space? We'll go over some options for how to move forward on sealing up one of your home's most potentially drafty areas.
Get to Know Your Space
Attics are notoriously difficult to insulate properly because any air leakage makes your efforts null and void. They also come in various shapes and sizes. Some have only exposed joists to walk on, while others are without a lot of headroom to stand up in. Some have hatches and others are walk-up. If you have an open floor, you may be able to fill in between the joists with batt insulation or have cellulose blown in. If your attic has a floor already installed, then you may have to insulate the walls or rafters leading to the roof.
What's the Temperature?
Another thing to consider is your particular climate. Houses in warm climates or rainy seasons are going to need different applications than homes that see a lot of snow or freezing temperatures. Get to know your regional climate guides and recommendations for your home. Proper ventilation is also a factor depending on the type of weather coming inside. Even in winter months, having proper air flow will prevent unwanted condensation or mold problems.
Check for Moisture or Cold Air
If you can feel a draft coming through the door leading up to the attic or around the hatch, then insulating is going to save you money on your heating bills. Before you do anything, however, moisture problems or major air leaks will have to be dealt with first. Any water or moisture will ruin your efforts and it might be better to fix a leaky roof rather than spend money on insulation. Also, any windows or vents that lead to the outside will have to be properly caulked or sealed.
If you don't have a large budget, a cheaper solution could be to seal the area leading to the attic. An attic door can be weather-stripped and a draft snake can go on the bottom of the door. An attic hatch can have foam board applied to the back side as well as weatherstripping along the area where it meets the ceiling. Sometimes installing trim around the square opening can prevent drafts coming in through the drywall.
Blown-In or Batt?
Batt insulation is long rectangular pieces made of fiberglass, wool, or sometimes cotton. They're DIY-friendly, however, the fibers can be itchy and irritating to eyes and skin, so cover up! They are made to fit differently sized spaces and have various "R" values, which refer to how well they will resist heat flow. The higher the R value, the better it will insulate.
These insulators are only functional when they fit snugly into place. If there are wires, vents, or other obstructions between the joists or rafters they will prevent the batts from doing their job. You want to be able to put a full batt into place without having to modify it too much. Cutting it in half or taking out large chunks with a utility knife is fine as long as there are no gaps for air to escape. Never rip batt insulation or stuff the off-cuts into the space.
Blown-in insulation is usually made of cellulose and is a good option because it fills in the nooks and crannies where batts may not reach. It's an especially good product if you're filling in the exposed area over a floor that may have some insulation already. Sealing up the floor above the ceiling of your living space is going to be the easiest and cheapest way to insulate the whole house below, but may mean that you won't be able to finish the space or use it for storage.
Professional spray foam will most likely do the best job at insulating your attic space, but the cost is substantially higher than the other two options. If you have a healthy budget for this job or a small area, it might be a cost worth incurring since spray foam will find its way into even the smallest of areas. In some regions, there are even grants or government funds for custom spray foam.
Your Future Plans
Though functional, using the attic for storage is not very good for your home. Boxes and stuff piled up can be detrimental to proper venting and lead to stagnant air. They will also increase dust and mold potential, and will mean that any repairs or installation will require a possibly arduous clean-up of your stuff. Clearing the area and providing better access to walk or move around will be better for your home and perhaps earn you a few dollars if a yard sale is in order!
If you do want to finish the space with drywall and new flooring, remember that the material will take way from how much space you have. Fire-rated drywall is usually thicker than regular drywall and an extra inch in flooring can really diminish the spacious feeling you imagined. Be real with how much extra square footage you are going to obtain by finishing the attic and whether the cost involved will bring you usable living space.
The attic is an essential part of your home and shouldn't be ignored. Whether it needs to be insulated, cleaned out, or properly vented will depend on your particular space. Get to know your attic and think seriously about what kind of maintenance is in your best interest. Your home, and those who live in it, will benefit.