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.
The general recommendation is a minimum R13 in a 2x4 wall. If you're going to go with batts I would recommend looking into mineral wool instead of fiberglass. It provides a lot of benefits including a higher R-value per inch.
Excellent Thermal Performance Owens Corning™ R-15 EcoTouch® insulation is specifically engineered to solve the efficiency problems of exterior 2x4 walls. “High density” means more fibers per square inch. It delivers a higher R-value per square inch in less space than standard insulation products.
no, R19 will not provide better sound attenuation than R-13. In fact, just like thermal properties, it will actually provide less. What you're trying to block are airborne noises. An R11 sound batt will provide the best attenuation in a 2x4 wall compared to any of the fiberglass insulation products.
In terms of R-value, exterior walls typically require higher insulation values than interior walls. The recommended minimum R-value for exterior walls in Canadian building codes is R-22, while R-20 is suggested for basement walls.
Insulation to Use
For 2x4 walls, use R-13 or R-15 insulation. For 2x6 walls, use R-19 or R-21 insulation. With either type of wall, use kraft-faced fiberglass or mineral wool insulation.
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 Bottom Line About How Much Insulation You Really Need
Many online experts claim that two inches of closed cell spray foam is enough for any project. These experts present data and charts to demonstrate the efficiency of insulation reaching a reasonable high at two inches.
Energy Efficiency
These pockets create substantial resistance to heat flow, dramatically reducing heat loss in winter and heat gains in summer. Attic insulation thickness directly enhances efficiency. With an R-value of 3.6 per inch, rockwool exceeds fiberglass. For cold climates, recommend R-38 to R-60 rockwool.
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.
You can use both in similar places and climates. R15 insulation offers slightly more thermal resistance than R13 insulation, but it also costs more. Ultimately, it's difficult to justify paying a significantly higher price for R15 when R13's insulative properties are only slightly lower than R15.
Installing a vapour barrier is optional when utilising ROCKWOOL solutions, as stone wool insulation is water repellent. However, adding a vapour barrier can help to prevent additional moisture coming through the ceiling space.
Spray foam insulation is a top choice for Canadian homes due to its superior air-sealing properties and high R-value. It expands to fill gaps and cracks, providing both insulation and an airtight seal that reduces energy loss. R-Value: Around R-6 to R-7 per inch.
One effective option for soundproof insulation for stud walls is to use an acoustic insulation roll. These rolls are made from materials such as fibreglass, rockwool, or recycled materials, and are designed to absorb sound waves and reduce the transmission of noise.
Mineral wool batts are a great choice when it comes to thermal performance. They beat the fiberglass batts with a 22–37% higher R-value per inch.
A vapour barrier is not necessary with closed-cell foam but with open-cell spray foam such as Icynene®, it is sometimes required. Any air that migrates though a building envelope will carry water vapour. As Icynene® spray foam creates a seamless air-seal, it controls air leakage and the moisture in the air.
Generally, 9-10 inches is ideal for most sleepers, while heavier individuals or side sleepers may benefit from a 12–14-inch mattress. Is a thicker memory foam mattress always better? Not necessarily. While thicker mattresses provide more cushioning, they may not suit everyone.
The recommended thickness for attics is typically 12-16 inches. Spray foam insulation: As discussed earlier, the recommended spray foam insulation thickness can vary depending on factors like climate and location. For attics, a thickness of 2-4 inches is usually sufficient.
Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers.
For example, if you need extra soundproofing or don't want to spend time installing a separate vapor barrier, then face may be the best option for you. However, if cost savings are more important than convenience, then unfaced may be the better choice in this case.
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.
R-13 insulation offers a balanced blend of cost-effectiveness and thermal resistance, making it ideal for standard 2x4 wall cavities, floors over unheated spaces, and crawl spaces.
After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.
2×6 construction creates more room for wall insulation, which can help enhance home efficiency and reduce cooling and heating bills throughout the warmest and coldest months of the year.