How To Insulate A Garage Roof (Explained!)

Garage roof insulation may seem like a simple matter, and sometimes it can be; however, before you begin insulating your garage roof, there are a few things you ought to consider. In this article, we explore these considerations and provide sound advice on insulating your garage roof. Read on to learn more.

What Kind Of Garage Roof Do You Have?

What Kind Of Garage Roof Do You Have

There are lots of ways to build a garage roof. In hot, dry areas, you’ll tend to find flat or gently sloping roofs. In areas where extreme cold and snow are problematic, garage roofs are often quite steep (pitched).

Take Care Of Garage Roof Damage

If your garage has a fairly flat roof (ten degrees pitch or less) you’ll need to take great care to be certain the roof is undamaged and water tight before installing insulation.

If the roof is very steep or pitched, you’ll naturally want to be sure it’s in good shape and won’t let water in, but this is not as imperative as with a flat roof because water is more likely to shed off a steep roof and is less likely to pool and leak in.

Of course, whether you have a flat roof or a pitched roof, if you find damage, you’ll want to repair it before you begin installing insulation. Damage, no matter how small, will only worsen with the passage of time.

Choose Safe Equipment

Another difference between insulating a flat roof and insulating a pitched roof is the type of equipment you’ll need. For a flat roof, you can probably complete the whole job using an A-frame ladder and/or a step ladder.

If you have a steeply pitched roof, you’ll need to build some scaffolding to access the high parts safely.

Work Efficiently

Your work method will also differ between a pitched roof and a flat roof. When you install your fiberglass bats in a pitched roof, you’ll work from top to bottom, and you should be able to do this entirely while standing on the scaffolding you have erected.

When you install your fiberglass bats in a flat roof, you’ll work entirely from below using a ladder. This will mean quite a bit of climbing up and down, and you may find it a lot more efficient to have a helper when working this way.

The type of fiberglass bats you use will also differ, depending upon whether you have a flat or pitched roof and whether or not your roof has frames or wooden trusses.

If it does, you should buy fiberglass bats that will fit very snugly between these structures. This is called friction fitting, and it makes installation very easy.

The gentleman in the video below uses a friction fitting method, although not with fiberglass batting, and not in a very effective way. Even so, you can see the concept.

Incidentally, the method shown in this video might be alright for the short term, but in the long term this method isn’t very effective and will cause condensation problems.

How to insulate your garage rafters storage area the fast and easy way

Another difference between insulating a steeply peaked roof and a flat roof involves venting. If your roof is steeply peaked, you should also install channel vents (aka: attic baffles or vent chutes).

These will help provide space between the insulation and the wood interior of the roof to enable good air flow in your attic space.

How Do You Plan To Use The Space?

Another consideration with a steep roof is whether or not you may want to use the attic space as a living space in future. If so, your choices in materials and methods of installation will differ from those used for a simple storage space.

If you’ll be using it as a living space, make sure all of your materials are safe for people to be around on an extended basis.

Is Your Roof Warm Or Cold?

In a warm climate, you can get away with putting insulation above the rafters or above and between the rafters to prevent energy transfer and loss of heat. In this sort of situation, you are unlikely to get a lot of potentially damaging condensed moisture between the insulation and the roof.

In colder climates, it’s better to put the insulation between the rafters or between and under the rafters at the level of the ceiling joist. This will ensure good ventilation between the insulation and the roof, thus preventing condensed moisture.

TIP: Before you install any insulation, install a vapor retarder. This plastic sheet will keep condensation from your garage floor from gathering on the wood trusses and the sheathing. It will prevent mold and mildew from growing in your insulation.

Is This A DIY Project You Can Do Safely?

Working on the underside of your garage roof has a lot of potential for danger. Follow these nine tips to work safely and efficiently.

  1. Plan your job carefully. Assemble all your materials and tools so that you won’t have to stop for trips to the home improvement center or searches around your shop.
  2. Always choose materials that comply with fire codes, as well as local ordinances, codes, rules and regulations.
  3. Read the instructions that come with the materials you choose. Follow them carefully for the best and safest results.
  4. Be sure to measure twice and cut once. Doing so will save you time, money, materials and frayed nerves.
  5. Remember to use protective gear. Wear goggles, a face mask and gloves to prevent injury.
  6. Set up scaffolding before you begin working. This will make it quicker, safer and easier to get the job done.
  7. Have an A-frame ladder and a step ladder on hand for access to hard to reach areas.
  8. Examine the entire underside of the roof before you begin. Make sure you won’t be dangerously covering electrical outlets and lines. Doing so could cause a fire hazard, so you’ll need to be sure to leave space for 3” of ventilation around wiring, lights, outlets and the like.
  9. Set aside a block of time. If you are well organized, you should be able to complete your garage roof insulation project in two or three days.

Garage Roof Insulation Is A Good Investment

A well insulated garage increases your ability to use your space and increases your property value. Properly installed roof insulation saves you money by keeping punishing temperatures out while keeping the desired temperature in.

Insulating your garage roof can be quite challenging, but if you take care and follow the steps and tips suggested here, you’ll have a garage that provides a lot more protection for stored items and for you when you are working or relaxing in your garage space.

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