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.
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.
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 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.
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.
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.
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.
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.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
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.
In fact, cellulose has the highest rate of settling rates, ranging from 13 to 20% after installation. This settling continues for weeks, months, and years after installation, and if not addressed properly during the insulation, it can cause serious energy efficiency issues.
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.
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.
Too much of anything is bad, including too much insulation in an attic. Over insulating your house and tightly sealing it too much creates a vapor barrier and forces moisture to settle on fixtures inside your home (hello, water damage!).
Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.
Moisture damage
This can occur due to leaks in the roof or foundation, inadequate ventilation, or high humidity levels inside a building. Moisture can cause the insulation material to become compressed and lose its effectiveness, leading to increased energy consumption and potential mold growth.
Based on new research, the North American Insulation Manufacturers Association (NAIMA) estimates that roughly 90% of existing U.S. homes are under-insulated. That means that the occupants are less comfortable, and both energy and money are being wasted.
Unlike exterior walls, which must meet local and state codes for insulation, interior wall insulation is rarely required. This is because interior insulation has much less impact on your home's energy efficiency – but it can still play a role.
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.
Attic mold often appears as a thin grey or black layer on the very top of the insulation. The dimensionality of the growth is difficult to determine, as the underlying insulation presents a rough and uneven surface.
To put simply, the cause any mould growth on interior walls & ceilings is excess levels of moisture. Black mould requires this moisture in order grow, meaning high levels of humidity can create the ideal conditions for the mould to bloom and eventually multiply.
R-value is used to judge thermal insulation performance and the higher the number, the better the product's insulating ability. So R19 has better insulating ability than R13. Now R-Value ranges widely across products and home applications.
Besides safety concerns, installation inexperience can result in insulation mistakes that can affect both the quality of your insulation and installation. Improper placement can leave gaps and cause energy loss, lessening the insulation's lifespan.