Attic Door Insulation: How to Install The Five Best Options
Attic doors, covers, and hatches need insulation. They should have a weather strip to prevent air leakage and latches to give a positive seal. Any amount of insulation is good, but ideally, the hatch should have the same R-value as the attic insulation.
Why Insulate the Attic Door
Attic door insulation prevents heat loss in the winter, cuts down on energy bills, and helps to keep the attic dry.
- Increased Comfort. Hot air rises and escapes through uninsulated attic doors. Cool air flows along the floor to replace it, creating drafty floors.
- Lower Utility Costs. Insulating the attic and attic hatch can save up to 15% in heating and cooling costs.
- Indoor Air Quality. If enough moisture gets into the attic, it can promote mold and mildew growth, leading to roofing damage. Insulating the attic door prevents moisture from seeping in.
How to Insulate an Attic Door: Five Best Methods
Insulating attic trap doors, hatches, or attic pull-down doors is a DIY-friendly project. Whether insulating an existing cover, adding a tent, or installing a kit, the time and effort are well worth the results. Hiring a contractor is an option for more complicated applications.
For effective insulating and sealing, attic doors or covers should have a minimum 12” high framed box around them that extends into the attic. If one exists or you are adding a new one, seal all the wood-on-wood connections with acoustic caulking. Construct boxes out of ¾” plywood–if possible.
Install a 1 x 3 around the interior of the box flush with the ceiling drywall for the cover to rest on. Use a wide casing to finish the door opening and install eye hook latches to provide a positive seal.
1. Rigid Foam Board Insulation
Rigid foam board installation is one of the top products for the attic door. You must install rigid foam board insulation on the attic side of the attic door. Use expanded polystyrene (XPS) like Styrofoam SM. XPS is rigid, easy to cut and fit, and R-5 per inch. Eight to ten inches thick is ideal, and two or four-inch thick material requires fewer pieces.
To install rigid foam board insulation, cut the pieces ¼” smaller than the attic cover and glue them on in a stack. Leave ⅛ “ of cover exposed on all four sides. Use foamboard adhesive to attach them.
2. Fiberglass Batt Insulation
Cut fiberglass batts slightly smaller than the attic door to prevent the fiberglass from pulling off or being curled up when the door is closed. Two layers of R-30 batts are perfect. Glue the first layer to the door and glue or duct tape–gently– a second layer on top.
Another option is to build a box on the attic cover that’s at least 12” high and ⅛” smaller than the framing. Fill the box with fiberglass batts, loose-fill fiberglass insulation, or loose-fill cellulose insulation. To make removal or replacement easier, spray the outside of the box and the framing hole with dry silicone lubricant.
3. Thermal Tent Covers
Premade tent-shaped attic door covers are available from home improvement outlets and online. They are a reflective insulation sandwich with a polyester filling. (Some claim an R-value of R-15.)
Most thermal tent covers measure around 25” wide x 54” long and fit standard pull-down attic doors. They come with detailed installation instructions and are fairly easy to install.
Thermal attic door covers can reflect up to 97% of the heat away from the access. They prevent air and humidity from entering the attic. Many of them are equipped with a zippered door, like a tent, to allow easy access into the attic without removing them.
4. Attic Door Insulation Kits
Attic door insulation kits are extruded polystyrene that fit both pull-down attic doors and standard attic hatches. They’re available up to a standard R-38 rating and provide upgrades to R-49. They are the most expensive option but provide the best and simplest solution.
You can install attic door insulation kits between and on top of trusses. The kits come with all the necessary hardware, adhesive, and handles.
5. Air Sealing
Regardless of the style or size of attic doors, you must seal them against air leaks. Warm air rises and escapes into the attic through any gap or crack. The thermal tents and insulation kits are self-sealing, but the original door below them should be weather-stripped too.
The best options are compression bulb-type products that are self-adhesive. Install them on the doorstop where the attic door rests, and then install four eye hooks on the underside of the door. When the door is closed, the eye hooks will create a positive seal against the weatherstrip–eliminating air leaks.