In the United States, most of the newer homes are designed with cavity walls. These walls are made of two parts that have a gap or are separated by a hollow space that needs insulation and the wall materials are commonly bricks and concrete blocks.
Cavity wall insulation is installed primarily for ventilation and heat loss reduction that can be brought by the cavity between the walls. It also preferred by homeowners because it can help reduce energy consumption as well as acts as a shield to prevent rain water from penetrating the outer wall and getting inside the home.
How Are Cavity Wall Insulations Installed?
To install insulation in the cavity wall, an insulating material known as polystyrene bead need to be injected. These small beads are inserted by drilling holes around 22-26 millimeters in diameter with a distance of one meter in the external wall. Afterwards, insulation materials are injected with the use of special equipment. To keep the beads from escaping, adhesive is used to pump these materials in. These materials are preferred than wool material because of its many advantages. Apart from size that makes beads easier to inject even in the narrowest cavities, they can easily fit in the cavity walls because they spread out.
How Will You Know If Your Home Needs Cavity Wall Insulation?
If the cavity has a gap of at least 50 millimeters, it is preferable to have cavity wall insulation to reduce the amount of heat loss. Also, if the home has been built 40 years ago or longer, chances are, it is not insulated sufficiently, thus installation is recommended.
Cavity wall insulation has benefits, making it popular among builders and homeowners. However, despite the good points attributed to this type of insulation, there is also a flipside to using this insulation type.
List of Advantages of Cavity Wall Insulation
1. Diameter Size Advantage
The insulation material used, polystyrene bead is so small that it can be pumped in easily even if the cavity is narrow. This is one interesting feature of this material that makes it more advantageous than other materials to be used. Additionally, with the smaller size, drill holes will also be small so they will not damage the walls and will be easy to cover as well.
2. Heat Loss Reduction
Another important advantage of cavity wall insulation is minimizing the amount of heat that escapes from the walls during winter months through convection, one of the three way that heat travels. By installing cavity wall insulation, it is like putting a lid on a cup of hot coffee. By doing so, it will take longer for the coffee to get cold because heat is trapped. This is also what this type of insulation does to the heat. It seals in the small amount of air that is between the walls made from masonry materials.
3. Cheaper in Expense
Cavity wall insulations are filled with materials that are heat insulators. Small polystyrene beads expand that once these materials are pumped inside, they will fill the cavity between the walls. Also, there are other cavity wall insulation materials that can be used which are inexpensive. These materials can be recycled paper that had been turned into shreds, treated glass fibers that are waterproof and vermiculites.
4. Mold Prevention
Molds result from condensation and this concern can be addressed by cavity wall insulation. This is because the insulation will restrict the moisture from passing through the wall. Water can pass or go through the outer wall because it is porous. With the cavity wall that is insulated, water will be trapped in between and will just run down the ground or above the windows instead of going through the inner wall and let moisture in. With lesser or no moisture, molds will not build up on the walls inside the home.
5. Lower Energy Bills
Homeowners with insulated homes save more in energy consumption because loss of heat is reduced. Consequently, the temperature inside is warmer and there will be no need for them to turn the heater on. Heaters use up more energy which can lead to higher energy bills.
List of Disadvantages of Cavity Wall Insulation
1. Insulation Cost
While materials can be cheaper especially if shredded recycled paper is used, critics of cavity wall insulation claim that the truth is, insulation costs are not cheap at all. This is because this is not a do-it-yourself home improvement project and needs experts to carry out the job. Moreover, a special equipment is used to inject the wall cavity with insulation materials and expertise and tools are needed that can be expensive.
2. Shoddy Work
Another disadvantage of cavity wall insulation is the risk of hiring inexperienced installers who will do substandard work and use lesser materials than what is really needed. If quality of work is poor, this can result to dampness and eventually mold build up.
3. Possible Insulation Restriction
Since the amount of insulation is dependent on the cavity or gap size between the external and the interior walls, there is a possibility of insufficient insulation if the width of the cavity is just small. If this is the case, the temperature in the house will not be balanced and there will still be a need to use the heater during cold months and the air conditioning system during warm months which can lead to higher energy consumption and consequently, costly energy bills.
4. Not Applicable to All Houses
Homes that have been constructed decades ago might have solid walls which make it impossible for cavity wall insulation. While newer houses can have this type of walls, homeowners with houses that do not have cavity walls will have to retrofit their homes. Apart from additional expense, it will also take time to do so. And if the owner has no budget for this or the house is too old to fix, cavity wall insulation is not possible.
Keeping the home warm inside I important not only for comfort but also for lower energy bills and cavity wall insulation is one of the ways to make this happen. And although there is a flipside to having this done, the advantages of this type of insulation are greater in number than the disadvantages. That said, homeowners should consider insulating their homes and determine if this is the option they prefer.
Natalie Regoli is a child of God, devoted wife, and mother of two boys. She has a Master's Degree in Law from The University of Texas. Natalie has been published in several national journals and has been practicing law for 18 years.