Before you insulate, air seal the attic. WAY easier to do before adding insulation, and just as important as insulation. Go around and find all the places the attic is penetrated and seal those openings.
Before Installing Insulation
Check your local building code for R-value (insulation level) recommendations and any vapor barrier requirements that apply to your area. Seal gaps that allow unconditioned air into the space you're insulating. Pay attention to areas where plumbing, ductwork or wiring enter the space.
Insulation is graded by its R-value—the higher the R-value, the greater the insulating power. If you live in a mild climate, your attic should have a minimum grade of R-38, or about 13–14 inches of insulation. If you live in a colder climate, R-49 is the minimum recommendation, or about 16–18 inches of insulation.
This rule means, at least half of your attic space must be 7 feet high by 7 feet wide, with a total of 70 square feet. Keep in mind, codes vary from place to place, but for using the attic as an actual room, this rule typically applies.
It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers.
Leaving Too Many Gaps
One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.
Before insulating, seal any air leaks and make roof and other necessary repairs. If it is located in a conditioned part of the house, also remember to insulate and air seal your attic access. Insulate and air seal any knee walls -- vertical walls with attic space directly behind them -- in your home as well.
If you consider to insulate your attic or crawlspace it will be hard to beat the quality of spray foam because it outperforms other insulation materials in terms of R-value, resistance to mold and moisture damage, durability, air sealing, and versatility.
Best Time of Year to Buy Insulation
In this case, the spring is the best time, because you will also start to see savings in the summer months. The same is true for warmer climates, just different times of year because you'll want the job finished before the heat sets in.
Removing old insulation is generally recommended if it's damaged, contaminated with mold, or infested with pests. However, if the insulation is in decent shape and just needs a boost, adding a new layer on top can be a cost-effective option.
The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.
Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).
Overall, the second layer of insulation plays a crucial role in improving insulation performance, reducing heat loss, and maintaining a comfortable and energy-efficient living space.
With certain types of insulation materials, installing your own insulation is definitely doable—and you can save money not hiring a professional. Installing fiberglass or mineral wool insulation are simple DIY projects. Other insulation types, such as spray foam insulation, require the use of a professional.
Before installing insulation, first seal any cracks that allow air to flow from the living area into the attic. This prevents moisture-laden air from reaching the attic where it can condense, leading to mold, wet insulation, and possible damage to building components.
Spray foam insulation is installed in new construction after the windows and roof are installed and electrical, framing, and plumbing inspections are complete — and after any other electrical or mechanical system located behind the drywall is installed.
Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.
Long-sleeved shirts and long-legged pants, gloves, and head coverings are generally recommended to protect against skin irritation when working with fiberglass insulation. In some cases, eye protection and respiratory protection may also be necessary.
Irritation to skin and respiratory system
Wall insulation solutions like Rockwool are made of ultra-fine fibres. While thermally efficient, they can cause skin and respiratory irritation.
Below are some additional considerations for insulating around a few common objects in the home. Wiring – When wiring exists in the cavities that are being insulated, simply split the insulation so that it is placed around the wire on both sides, allowing the wire to be comfortably nested inside the insulation.
If your attic has little or no existing insulation, you'll want to install an R-38 rated material. If your attic has 2-3″ of existing insulation, you'll want to install an R-30 to achieve a total of R-38. If your attic has 5-6″ of existing insulation, you'll want to install an R-19 to achieve a total of R-38.
Can I put plywood over insulation in the attic? Yes you can install plywood subflooring directly over the floor joists and insulation on your floor. You need to install rigid insulation boards on top of the attic flooring joists and then install plywood over the top.
Conclusion. Attic insulation can last 80 to 100 years, though it loses its energy efficiency benefits with time. Certified attic specialists' professional advice is to upgrade it every 15 years to ensure that it is still performing the job.