The Big Garage Question: To Insulate or Not?

Most of us agree that in Minnesota you need a garage. But does that garage need to be insulated?

I’ve built and designed numerous garages and I’ve found that the answer depends on your expected end user experience. What are you going to be doing out there?

If all you are going to do is park your one car in the garage, it may not be worth the time, money and effort to insulate.

If, however you are going to store personal items in the garage, do wood working or other tasks, or you like your cars to be cool in the summer and not too cold in the winter, consider insulating. In these cases insulating is most often worth the extra few hundred dollars and couple weeks of waiting.

Estimating the cost

The added cost to insulate is not that much: most likely a few hundred dollars depending on the size of your garage. An R-13 batt will work for the walls. The tricky part is insulating and sheet rocking the ceiling. To insulate the ceiling you may use batt insulation or you will need to install plastic sheeting and then rent a blower. At the high end, blown insulation runs over $500 (for example low-dust cellulose). At the cheap end for it runs about $150 (fiberglass expanding blown-in insulation).

Hanging the sheetrock

You can hang the sheet rock vertically or if you have a 9′ wall you can hang it horizontally and use a 1-foot belly band when you mud. 1/2” thickness is fine unless you are creating a fire wall. In St. Paul firewalls are required for walls within 5’ of a neighboring property line. Here you will need 5/8” type X on both sides of the studs.

You may also need to rent a drywall lift to for the ceiling. Pro tip: If you are doing more than one drywall project you may just want to buy the drywall lift.

Estimating the time

For the average garage it will take one person a day or two of labor to insulate. A team of professionals can insulate an entire garage in a day or less. It will then take another day or two for a team to sheetrock, again this is size-dependent and type-dependent.

One Caveat: Inspections

One thing that can hold up your project is getting it inspected. If the city inspectors are busy they may make you wait a week or longer to get your concrete work, framing and drywall inspected. The electrical needs to be inspected as well. As much as you plan for this you are at the mercy of the inspector’s office as far as timing goes. Once the garage is framed and sheathed and inspected you can move forward and insulate.

There are many uses for a garage beyond parking a car. An architect can advise you on what your garage can be: a yoga studio, artist quarter, storage center, home office or other dynamic space.