The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space.
Yes, it is possible to put too much insulation in a loft or attic.
The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.
However, it is possible to have too much insulation. If there is too much insulation, and it comes in contact with the roof sheeting, it can block air circulation, which can lead to condensation, mould and mildew.
Your walls or floors are always cold. Your home is drafty, especially in certain areas. You notice water leaks or moldy insulation, especially in attic spaces.
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. That's when mold starts to grow.
Conclusion. Attic insulation can last 80 to 100 years, though it loses its energy efficiency benefits with time.
The short answer, yes, insulating the attic is an effective way to keep your home cooler during the summer months. While it's a given that the insulation in your attic will keep the home warmer during the winter, it isn't immediately obvious that insulation can also help to keep the home comfortable during the summer.
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.
Signs It's Time to Replace Insulation
Age 👴🏼 – Insulation is typically pretty hearty. For most homes, it can last for 20-80 years! That being said, like all things, insulation tends to wear down over time.
The bottom line is the old insulation needs to be removed because it hinders the airflow into the attic, it can promote mold growth, and it is dirty.
If your home, or upper floor, is too hot in the summer and too cold in the winter it is likely that you have insufficient attic insulation. If a visual inspection of your attic identifies that the insulation is level with or below the attic joists – you need more insulation.
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).
If you live in the Southern part of the U.S., the recommended insulation level is a minimum of R-38 or about 13-14 inches of insulation. If you live in the Northern part of the U.S., the recommended insulation level is a minimum of R-49 or about 16-18 inches of insulation.
New build home roof trusses are designed and built to support the weight of the roof structure, storage items and an individual accessing and moving around in the loft. It is recommended that no more than 25Kg per square metre is stored in the loft to avoid over loading the structure.
In colder climates, where the home's heating system sees more use, the vapor barrier should typically be installed on the insulation's interior side. In warmer climates, where the home is often kept cooler, the vapor barrier should usually be installed on the exterior side.
In hot, humid locations, it may also be advisable to construct unvented rather than vented attics to help reduce the entry of moisture-laden air into the attic. In hot, humid locations, the outside air is likely to be more humid than the inside air.
In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below.
About the Insulation Tax Credit
The credit is effective for products purchased and installed after January 1, 2023. U.S. residential homeowners can claim 30% of product costs, with a maximum credit amount of $1,200. This must be an existing home & your principal residence. New constructions and rentals do not qualify.
Does insulation make your house hotter? "Insulating homes has very little, if any, impact on the risk of overheating," said Professor Kevin Lomas from Loughborough University, who led the largest national study so far into overheating in homes.
At first it may seem odd to add insulation for warmth and then purposely allow cold air to enter the attic through vents, but this combination is the key to a durable and energy-efficient home.
In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.
Fiberglass insulation typically needs to be replaced 15-20 years into it's life, as it can easily become dirty, wet, moldy, and ineffective if there's a roof leak or water damage of any kind.
In most cases, it will be a single-day project, though you may need to stay out of your house for 24 hours to let certain forms of insulation dry safely due to fumes they might release.