Why Do Garage Ceilings Sag And What To Do About It? (How to Fix Sagging)

why do garage ceiling sag

We experienced some heavy storms this summer, and as a result, I noticed that my garage ceilings were sagging. It appears as though it was from rain, but I could not see any water damage on the ceiling, which made me wonder: Why do garage ceilings sag, and what can be done about it?

Garage ceilings sag because of water damage, poor installation, wrong ceiling material, or even when the fasteners or the spaces between them are unsuitable. The remedy for a sagging ceiling is to redo it completely, although sometimes less complicated methods also work like replacing fasteners.

Before I could start thinking about what needed to be done about the sagging ceiling in my garage, I needed to research and consult experts. In this article, I will share the advice that I got from the experts, and hopefully, it will help others with similar problems.

Establish Why The Garage Ceiling Is Sagging

There is a whole range of reasons why ceilings in a garage will start to sag. In this section of the article, I will briefly discuss these; I will go into detail later on when I discuss how to fix these ceiling problems. The reasons why ceilings sag are:

  • Poor installation standards; ceilings start to sag when they are installed by people or contractors that do not possess the right skills or adequate experience.
  • Using the wrong thickness ceiling material; ceilings start to sag when the material is too thin; people tend to always go for the cheapest option, which is sometimes not the best option.
  • Using wrong fasteners for ceilings; in some cases, the wrong fasteners are used when ceiling boards are being installed. Using screws or nails that are too short will cause the ceiling boards to come loose and start sagging.
  • Spacing issues between fasteners, timber is used with fasteners to secure ceiling boards, and when the timber supports are spaced too far from each other, the ceilings will start to sag.
  • Water damage as a result of roof leaks or water pipe leaks will result in the weakening of the ceiling board, and that will cause the garage ceiling to sag.

In the next section of this post, I will explain these garage ceiling sagging reasons in more detail, as well as explain what to do about it.

Ceilings Sagged Because Of Poor Installation, What To Do?

Through my research, I have found out poor installation standards are one of the biggest causes why garage ceilings will start to sag. People tend to use the cheapest contractor to install their ceilings, but sometimes that means shoddy workmanship.

Sometimes choosing the best contractor to do ceilings can be hard, but that is why I normally ask for references, and I also look at reviews from websites to make sure that I get a qualified contractor to do the work. The signs that the ceiling was installed badly will be:

  • The whole ceiling appears to run wavy, and the joists do not line up.
  • There will not be enough fasteners holding the ceiling board in place.
  • The fasteners are spaced far from each other in length and width; this happens because the timber is not spaced correctly.

Ceilings Sagged Because Of Poor Installation- How To Fix It

The chance is that when the ceiling in the garage is sagging because of poor installation by a shoddy installer, then the timber framework is probably also a mess. If this is the case, the best and only solution is to rip everything out and start again.

Why Do Ceiling Boards Sag When Using The Wrong Thickness?

When installing ceiling boards, it is important to look a the timber framework you will use to attach the ceiling boards; the farther the timber supports are spaced, the thicker the ceiling board material should be.

Used The Wrong Material Thickness- How To Fix It?

The advice that ceiling experts gave me was to replace the thin ceiling board with thicker material, which obviously means ripping the garage ceiling out again and putting in a thicker board.

Suppose it is only a small portion, though, and because of the wrong spacing of timber supports, the ceiling is sagging. In that case, it is a great idea to install extra timber supports above the ceiling board in the roof, which should fix the problem when the board is fastened to the additional supports.

You can use small L-shaped brackets to mount the extra timber supports in place with wood screws. These brackets work well because there are holes inside the bracket already for the screws. If this does not work, then there is no other option than to replace the board with the thicker material.

Fixing A Sagging Ceiling Caused By Using Wrong Fasteners

insulated garage ceiling

If unsuitable fasteners cause a sagging garage ceiling, it will start to sag, and the fasteners will fall out of the ceiling board. When this happens, the easiest and best way to fix it would be to use longer or thicker fasteners; sometimes, it helps to use screws instead of nails.

Fixing A Sagging Ceiling Caused By Water Damage

A sagging garage ceiling caused by water is a serious problem if the leak’s origin is not properly fixed. Portions of the ceiling can be fixed by removing and replacing sections between the joists.

I saw a brilliant idea where some people cut the water-damaged section out to install a trap door, so that is also an option.


When I first noticed the sagged ceiling in my garage, I thought that I would have to replace the entire ceiling. Luckily for me, it was not the case. It only happened because the contractor used the wrong sized fastener. When the contractor installed the ceiling, he used really short nails.

It was easy to fix because the only thing I had to do was to replace the short nails that he used to secure the ceiling boards with long screws. I prefer using screws because they do not come loose so easily. I hope you found this post or at least some sections informative and helpful in sorting out the sagging ceiling in your garage.

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Barry Gray

Hi, I’m Barry. I’ve loved woodworking and bringing things back to life for more years than I care to remember. I hope my passion for tools comes across loud and clear in everything you read here on The Tool Square.