Should you insulate internal ceilings? (2023)

Should you insulate interior ceilings?

In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, cathedral ceilings, floors over unheated garages or porches, knee walls, and in between interior walls—especially bathrooms—as well as ceilings and floors.

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.

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.

Without proper insulation, warm air from a home's heating system will flow directly to the house's colder areas, like attics, garages, mudrooms, and basements. In fact, nearly 40% of the heat in your home is lost through the attic.

5% of Your Home's Lost Heat is Through Ceilings

A small portion of your home's heat is lost through your ceiling. If you get a home energy audit and find that much of your heat is escaping through the ceiling and into the attic, it may be time to test and see how much insulation you have, and how much you need.

Roof and ceiling insulation. Installing roof and ceiling insulation can save up to 45% (or more) on heating and cooling costs.

The answer is, you should do both. The average home needs to be insulated high, middle, and low. All three areas are important. This means you need to have attic insulation, wall insulation, and basement or crawlspace insulation to produce the greatest level of comfort and energy.

Leave a minimum 20mm air gap between insulation and sarking membrane or roof material. Lay insulation between ceiling joists using the poker to push them into limited access areas. Do not leave any gaps between the insulation and ceiling joists.

As for attic vs. wall insulation, always go for the attic. The largest pay back will be seen here. You would stop heat loss from natural convection and block solar gain (an increase in heat) in the attic, which can result in energy savings of 30 to 50 percent.

Thicker is better

The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half.

How do I know if I have enough insulation in my walls?

The walls, floors and ceilings of your home should feel warm and dry to the touch. When drywall and panelling inside a home feels damp or cold, that's a clear sign there's not enough insulation. Alternatively, when touching an exterior wall, it should feel cold because insulation is keeping warm air inside a home.

Looking across your attic, if the insulation is level with or below the attic floor joists, you probably need to add more insulation. Assumes R-3/inch. If you cannot see any of the floor joists because the insulation is well above them, you probably have enough, and adding more insulation may not be cost-effective.

Insulation helps regulate the temperature in your home. When you don't have sufficient insulation, there's nothing to keep your heated or cooled air inside where it belongs. As a result, you and your family are always uncomfortable, either too cold in the winter or too hot in the summer.

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.

Walls, floors and ceilings should feel warm and dry to the touch in your home. An indication that there is not enough insulation can be drywall or paneling feeling damp or cold. Conversely, the walls outside of your home should feel cold because insulation stops the heat from escaping.

The biggest area for heat loss in most homes are drafts within in the walls, windows and doors. It's typical for these spots to be less noticeable than you'd think they would be. Just a single 1/8 inch gap under a standard 36-inch wide door will leak just as much cold heat out as an almost 2.5 inch hole through a wall.

If you are deciding between insulating the roof deck or the ceiling, Insulating your ceiling should be the priority. Not only is it easier but ceiling insulation is beneficial in a number of ways: Keeps the temperature in the building regulated. Saves on energy costs.

Spray foam insulation is the most effective type, with a maximum R-value of 6.5 per inch.

Fiberglass: Fiberglass is the most common insulation material. It's made from fine glass fibers and is most often used in batts, rolls and loose-fill insulation.

What is the most important place to insulate a house?

Attic. Arguably the most important space in the home to insulate is the attic. This is primarily because heat naturally rises, which means that the attic will hold a lot of the heat generated in the home. During the winter, having that heat escape through the attic will push up energy bills.

Insulating the right interior walls can regulate temperatures from room to room and between floors in your home. This is especially beneficial if your home has rooms used infrequently or closed off for parts of the year. Noise control. Soundproofing interior walls is an additional benefit of interior wall insulation.

An alternative way to insulate your loft is to fit rigid insulation boards between and over the rafters. Rafters are the sloping timbers that make up the roof itself. This isn't a DIY job, so you'll need a specialist professional to insulate your roof.

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.

Regardless of whether fiberglass insulation is installed in a wall, attic, or crawlspace; the paper facing should always face toward the inside of the home. That's because the paper contains a layer of asphalt adhesive which prevents water vapor from passing through it.

The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams, and the material will block that flow. For the same reason, insulation shouldn't touch the roof's underside.

You should only install cold insulation if you have an unfinished attic and plan on keeping it that way. Warm insulation is installed on the underside of the roof deck at the top of the attic, just below the roof decking.

That's because walls, like attics, are major components in regulating heat flow in your home. For the most cost-efficient, comfortable living environment, it's best to insulate both your attic and your walls.

Gaps in insulation are known to have a major impact on heat loss and thermal bypass. It also can result in risks of condensation and mould; two things you want to avoid at all cost with a new dwelling. For that reason, a keen eye for detail at both the design and construction stages is essential.

The attic is arguably the most important area in your home to insulate. This is because air rises when heated. So, if you don't have proper attic insulation, all your heated or conditioned air rises to the attic and gets out during colder months.

What is the R-value for ceiling?

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.

If you have an Energy Performance Certificate (EPC), you can check to see what type of walls you have. If they are cavity walls, the EPC can tell you if they have been previously filled. You can also see whether your property has a loft and whether it has been insulated.

On the insulation manufacturers label on every bag you'll find that for an R-25 you'll need 28 bags per 1000 sq ft. So if you have 2100 sq ft, take 28 x 2 = 56 bags for 2000 sq ft.

On average, a home loses 20-30% of its heat through its roof, if it is not properly insulated. This loss of heat not only costs you money in the form of higher heating bills, but it also harms the environment by increasing greenhouse gas emissions.

Don't allow gaps in your attic. If you do find small gaps, use spray foam or seal with caulk. Often, attic doors are not insulated. If yours is not, place insulation against the attic door and then add weather stripping around the edges of the door.

If your attic is too cold, it probably lacks sufficient protection from outside temperatures. According to the U.S. Department of Energy (DOE), the average unimproved attic has just R-19 insulation – the insulation value of a five and a half inch thick fiberglass batt.

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.

Generally speaking, you only need to insulate the ground floor. If you're on an upper floor, you don't usually need to insulate your floor space. However, you should consider insulating any floors that are above unheated spaces such as garages, as you could be losing a lot of heat through those.

Heat rises to the ceiling. Because a large volume of indoor heat is lost through the ceiling, the attic floor above is considered the most important area in the house to insulate for winter comfort and efficiency.

Which part of the house needs most insulation?

The key areas of your home that need insulation are the attic, roof and exterior walls. Additionally, up to 10% of heat can be lost through the floor of a home with no underfloor insulation. Attic or roof insulation can save you the most in energy bills and is a key area to insulate.

Give or take, about 25% of the heat produced by your boiler will escape through the roof of your home. About 35% of the heat will escape through the walls and through gaps, in and around windows and doors, and about 10% of heat will disappear through the floor.

If the air distribution system is not within the conditioned space but within the attic, insulating the rafters will enclose the distribution system. Finally, if you live in a hot or warm climate, consider installing a radiant barrier in your attic rafters to reduce summer heat gain.

If you want to use your loft as a living space, or it is already being used as a living space, then you need to make sure that all the walls and ceilings between a heated room and an unheated space are insulated.

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.

Typically we suggest you have an air gap between 1/2″ and 3/4″ for the radiant barrier to work. Air gaps larger than this work well too – they promote ventilation on the foil and help keep the air dry and the air temps lower. Insulation is technically a solid with a lot of air in it therefore, it is NOT an air gap.

The main reason why you do not need insulation on the floors is simple. The floor does not belong in the building envelope. Sometimes, adding insulation to the floor can cause problems for your home. Floor insulation can hamper the dynamic of vapour barriers and thermal resistance.

Here's where you should insulate in your garage: Your garage ceiling—if it's attached to a room in the house or an attic that extends to other parts of your house. Any garage walls attached to interior rooms in your house—other than the ceiling, this is where you get the most improvement in cutting energy waste.