In fact, adding too much insulation to your walls can lead to problems such as poor ventilation, mould growth, and condensation. This is because thicker insulation can block airflow and trap moisture, leading to indoor air quality issues and even structural damage.
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.
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.
Many of us know what causes mould; when moisture is trapped in the rooms of you home. Sometimes, there is insufficient insulation in the walls, so mould grows. However, not many people realise that additional insulation isn't always the answer. In fact, too much insulation can be the secret cause of mould.
As a general guideline, it's advisable to install double layers of thermal insulation throughout your house. Nevertheless, this may not be feasible in all areas due to space limitations. Typically, it's not practical to add two layers of insulation within the walls of your home.
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.
R19 Insulation offers superior thermal insulation compared to R13. With a typical thickness of 6.25 inches, R19 fiberglass is designed for use in 2x6 wall cavities, making them suitable for colder climates where higher thermal resistance is necessary.
In fact, adding too much insulation to your walls can lead to problems such as poor ventilation, mould growth, and condensation. This is because thicker insulation can block airflow and trap moisture, leading to indoor air quality issues and even structural damage.
Once the project is complete, if there is still leftover insulation, place it in a durable trash bag and drop it off at a specialized waste facility, like a building materials disposal site.
Mold does not grow directly on insulation because the insulation is not its food source. However, when your attic or crawl space is attacked, then it will spread to the insulation. And as such, it will start to grow on the insulation.
For standard 2x4 walls, which are common in older homes, an R-value of R-15 is considered good, while R-21 is excellent. This can be achieved with high-performance fiberglass batts, dense-packed cellulose, or a combination of cavity insulation and continuous insulation.
If we wish to label the strength of the association, for absolute values of r, 0-0.19 is regarded as very weak, 0.2-0.39 as weak, 0.40-0.59 as moderate, 0.6-0.79 as strong and 0.8-1 as very strong correlation, but these are rather arbitrary limits, and the context of the results should be considered.
Unless your home was specially constructed for energy efficiency, you can probably reduce your energy bills by adding more insulation. Many older homes have less insulation than homes built today, but even adding insulation to a newer home can pay for itself within a few years.
Now, to answer whether R-Value can be too high, the answer is technically no. The higher the R-Value, the better the insulation will reduce heat transfer. However, a few things to remember when choosing an insulation R-Value.
One sign of good insulation is having even temperatures throughout your home. If different rooms have different temperatures – say, you freeze in the kitchen but feel too warm in your living room – that's a clear sign your house is under-insulated.
Exposure to some insulation products can cause certain health effects if the product is mis- handled, mis-applied, or if the wrong product is used in certain environments. Common symptoms may include irritated, itchy, watery, or burning sensation of the eyes, nose, or throat, or itchy skin or skin rashes.
The Short Answer
If your house has too much insulation, it becomes too tightly sealed, and moisture becomes trapped inside. If there isn't proper ventilation, especially in the attic where the warm air travels when it rises, mold will grow, and your home's air quality can decline.
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.
If your old insulation is made of mineral wool or natural fibers, you can take it a recycling center. Fiberglass insulation can also be recycled, but it requires more specialized facilities, so you can call the center beforehand and inquire about the kind of insulation materials they readily accept.
Lifespan of cavity wall insulation materials
Polystyrene beads can last up to 100 years due to their resistance to moisture and decay. Polyurethane foam and mineral wool are durable, typically lasting over 50 years. Extruded polystyrene (XPS) has a 20—to 30-year lifespan, and fibreglass can last 80—to 100 years.
If the existing attic insulation is an R-19, you may choose to add another layer of R-19. Two layers of R-19 at 6¼ ” thick will achieve a total R-value of 38. So adding an R-19 batt to an existing R-19 batt will give you a total insulation value of R-38.
As a general rule, insulation should be replaced or retrofitted every 15 to 20 years. However, it may need replacing or retrofitting sooner depending on the type of insulation installed, the R rating of the original insulation, compression and movement over time, and whether any damage has occurred.
The DOE Insulation Fact Sheet (DOE/CE-0180) can be ordered from the Energy Efficiency and Renewable Energy Clearinghouse or accessed from the Internet at www.ornl.gov/ roofs+walls. Fiberglass and rock wool batts—2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products.
The dip from R10 to R4 seems odd, as one would expect more R as you travel further north through the zones. Thicker is not better! Doubling the amount of insulation will double the R-Value, but so what? Doubling the insulation from R-19 to R-38 does NOT cut the heat loss in half (50%) it cuts it by around 3%!
A well-built staggered stud wall increases the sound damping of a wall. Basically, this involves staggering 2x4 boards along alternate edges of the top and bottom frame. In existing walls, this includes the addition of furring strips to bring the outside frame to 2x6.