Whether you need faced or unfaced insulation depends on how you use your garage and local climate rules.
The majority seem to agree that insulated, unheated garages, should be allowed to breathe. If the garage is heated, you will need a vapor barrier, otherwise you will get frost and mold.
Faced or unfaced insulation in basement walls is a common question we get. Use faced insulation in basement walls when insulating between studs, with the facing toward the interior. However, if you're adding insulation over existing insulation, choose unfaced to avoid creating a double vapor barrier.
Insulating a 24x24 two-car garage typically costs between $𝟗𝟎𝟎 and $𝟓,𝟔𝟎𝟎, with the national average sitting around $𝟒,𝟕𝟎𝟎. This cost varies primarily by whether you choose budget-friendly fiberglass batts or premium spray foam, and whether you also need to insulate the ceiling or the garage door.
We recommend using fiberglass insulation, since this type is easier to handle and can be used throughout the entire garage, including the walls, floors and ceiling. If you plan to use a different type of insulation, we suggest hiring a professional, since other materials can require more experience.
Insulating an unheated garage is generally worthwhile if you plan to spend time there (e.g., as a workshop) or if it shares walls with living spaces. It moderates temperature extremes, dampens noise, and protects stored items, though it will not keep the space perfectly room-temperature without an active heat source.
The ideal R-value for garage insulation depends on how you use the space and your local climate. For walls, an R-13 to R-21 is recommended. Ceilings should have R-30 to R-40, while garage doors typically use R-6 to R-12 for standard protection or R-13+ for climate-controlled spaces.
What time of year is Insulation cheapest?
Yes, you can absolutely insulate your garage yourself. It is a highly approachable DIY project. Tackling the walls, garage door, and ceiling with materials like fiberglass batts or rigid foam boards can typically be completed over a single weekend depending on the size of your space.
Mice are curious and always searching for safe, snug, and warm nesting sites. Attics filled with blown-in insulation provide an excellent option–from the mice's point of view. As long as there is a ready food source. Mice are omnivorous and will eat and chew on almost anything including wood and electrical wires.
Installing insulation without a vapor barrier in an exterior wall can cause condensation inside the wall cavity. In cold climates, this moisture buildup leads to mold, mildew, and wood rot. Use faced insulation or vapor control to prevent structural and health issues.
Yes, homeowners can add new insulation over existing insulation in most cases. This approach works well for attics, walls, and floors where the current layer remains intact and undisturbed. Building codes and energy experts often support this method to boost thermal performance without full removal.
Moisture Issues
In some cases, improper insulation installation can trap moisture within the walls, leading to potential mold or mildew problems. It's crucial to choose insulation materials with moisture-resistant properties and ensure proper ventilation.
Drywall is inexpensive compared to other materials, but you may have to patch or replace it often due to wear and tear. Shiplap. Shiplap is a popular wall material to match a farmhouse aesthetic; plus, it is very durable and can be affordable for your budget.
Yes, mold can absolutely grow under a vapor barrier. While vapor barriers are designed to block moisture, any moisture that gets trapped beneath the barrier—due to a plumbing leak, groundwater seepage, or poor installation—will create a prime environment for mold to grow, out of sight.
Insulating a 20x20 (400 sq. ft.) garage typically costs between $800 and $4,000, depending on whether you DIY with fiberglass batts or hire a pro for spray foam. This usually covers the walls, ceiling, and garage door.
An uninsulated garage door is perhaps the biggest culprit for heat loss in your garage, as there is no barrier to slow the heat transfer out of your garage. In order to protect your garage from heat loss, you need a door with insulation.
It's not recommended that you apply fiberglass insulation directly to a concrete wall. If you must use fiberglass, there needs to be a space between the insulation and the wall. If not, the place where the insulation touches the concrete will be overtaken by mold and mildew.
Foam insulation is a common target because it's easy for them to chew through. The material offers little resistance, allowing mice to create tunnels or nests within the insulation. But mice aren't just interested in chewing for the sake of it—they're also drawn to the warmth and shelter insulation provides.
When balancing upfront cost and overall thermal efficiency, the cheapest and most effective standard insulation is fiberglass batt insulation. However, if you are looking for long-term savings through superior air sealing, dense-pack cellulose often provides the best overall value.
Because spray foam can trap moisture, hide the condition of the roof, make it difficult for surveyors to inspect, which means risks like timber decay, dry rot, and not forgetting increased fire risk. If you've got it or you're buying a property that does, this is something you need to know upfront.
Yes, mice can chew through rockwool. While the dense, spun-stone fibers are not edible and are much harder to burrow into than soft fiberglass, a determined mouse will chew through rockwool to build nests or create pathways through walls.
Generally, if possible, insulating concrete below the concrete floor is the best form of installation. This is because the concrete helps to absorb the heat much better, whilst also preventing the room from overheating.