Insulating An Attic Staircase
Insulating walk-up attics is one of the hardest and most tedious tasks there are in home improvement. But when done correctly, this improvement will save you up to 20% on your energy bills.
Walls Around The Attic Staircase
Insulating these wall is challenging because they are typically finished surfaces. The walls will need to have holes drilled in them in a line. Then they will be filled with dense pack cellulose insulation for maximum R-value and air sealing. Don't forget about closet walls and walls but up to the staircase that are not exterior walls. Exterior walls should be insulated already. If they are not, you shouldn't be worrying about this project. Sidewall insulation is more important.
There are a few options on insulating the door depending on how wide the door is. If the door is standard size (standard exterior door sizes are 2' 6", 2' 8", and 3' 0"), then you could just go to your local mill works store and buy a pre-hung insulated exterior door. The reason for the exterior door is because it is made to withstand extreme temperature and being pre-hung, has all of the seals and air sealing products already part of the door and door frame. You simply have to remove the old door frame as carefully as possible as not to damage the door casing (trim). This job should be performed by a professional if you have not installed a door before.
If an exterior door cannot be used, you will have to glue 2 layers of 2" polyicynene foam board insulation to the interior of the door. make sure the door can close properly. Then compression seals will have to be added and tacked in with a hammer to make sure the door seals properly. A door sweep (seal on the bottom of the door) should also be added.
The Bottom of the Staircase
If the bottom of the stair case is finished with drywall, then holes should be drilled under every step and dense pack cellulose should be used to insulate and air seal the steps. If the method is used, it is important to make sure that all gaps and crevices are filled and/or caulked to prevent a mess.
If the staircase is unfinished, spray foam insulation should be used to seal and insulate the steps. This will ensure that there is no air movement and the steps are completely insulated and sealed. No other method will work as well as spray foam insulation.
The Attic Floor
It is important to check the attic floor around the stairwell opening as insulation usually is low in this area because of people moving things around and storing objects near the stair well. If insulation needs to be added, it is recommended that blown in cellulose insulation be used at a minimum depth of 12 inches. If there is a floor surface to walk on, simply drill holes in the floor and dense pack cellulose insulation in the areas needed. Hopefully, that does not include the whole attic.
This entire project should cost between $800 and $1,500. The spray foam kit is the most expensive at $300-$400 for a 200 board foot kit. The rest is the other materials that are needed.
Please keep in mind that this project is messy. Use drop cloths and tarps to protect flooring. If you are uncomfortable with a project like this, hire a contractor to perform the work. This may cost around $2,000-$2,500. Always get work references. Quality and craftsmanship is ALWAYS more important than price.