There is nothing worse than noticing your roof is sagging. This is especially true if you are unsure of the cause. Luckily, there are a few common causes that are relatively easy to identify. Knowing these causes can help you address the issue more easily.
If your roof is sagging, you should first determine the cause of the sagging. Once you have done this, you should hire a professional to come to inspect your roof and begin the repair process. In the meantime, you should attempt to increase the structural integrity of the roof yourself. You can do this by reinforcing the framing, repairing the gussets, and repairing the roof decking.
The rest of this guide will focus on the different causes of roof sagging and the ways that you can address them.
What Causes A Roof To Sag?
First things first, we should talk about what causes a roof to sag. Knowing the common causes can make it way easier to tell what is causing your problem. There are all sorts of different things that could cause your roof to sag, including water damage, excessive weight, improper installation, or a roof that is too old.
We will go over all of these issues in this section of the guide. This is a big first step in working out your roof sagging issue.
Water Damage
Water damage is a big-time cause of a sagging roof and is your roof’s worst enemy. Any water that gets in under the roof into the wood can cause major problems, like rotting or sagging. The wood found under your roof is super sensitive to water damage. So, it is important to know how to inspect for damages on your roof.
Missing shingles or gaps in the flashing will make your roof way more vulnerable to water. It’s not uncommon to go outside after a storm to find some missing shingles. The same storm could have damaged your flashing and made a large gap that water can get into easier.
Water damage is not the only thing that can damage your roof’s integrity. If there hasn’t been a big storm in your area, and your shingles and flashing are in good shape, there could be some excess weight on the roof. We will discuss this possibility next.
Too Much Weight
Your roof can only handle so much weight. Roofs are strong, but too much weight can make it dangerous to be inside your house. First, rule out water damage, then consider the fact that your roof is simply buckling under too much weight.
You should think about who installed your roof and how long you’ve had it. These facts can influence how likely it is that your roof cant handle weight like it used to.
Bottom line, if your roof is old, it wont stand up to weight like it used to. There is also a chance that your roof was not installed right, making it more likely to fail under extreme weight. You are way more likely to notice weight problems with your roof if you live in a place where it snows a lot.
Its super important that you clear your roof of snow soon as you can. If not, the weight could bring down even a stable roof.
As I mentioned, a sagging roof buckling under heavy weight is dangerous. Once the frame of your roof gives in, it could easily cave in while you aren’t around or worse when you are.
The best thing you should do is hire a professional to come check your roof out. This will make sure that your roof is safe for you and your family. Like I said before, knowing who installed your roof is important. We will cover why in the next section.
Improper Installation
Nothing would be worse than having a roof installed improperly and not noticing till way later. A roof that wasn’t installed right will have way more issues over time, ones you may not notice till it’s too late. You should consider the fact that your sagging roof is caused by a botched installation job.
A ton of improperly installed roofs have major cracking issues that damage the structural integrity of the roof. Obviously, this is not good and will shorten your roof’s lifespan and make your home dangerous to live in. If you notice your roof is sagging and suspect that it was not installed correctly, you need to hire a new contractor and have them inspect it.
After you have a proper inspection, they will be able to tell whether your previous installation was done right or not. It’s a big deal when your roof is not installed correctly and may need to be replaced completely. This is a worst-case scenario so don’t worry too much.
Even if your roof was installed perfectly, an old roof is a worn roof. You should keep up with how many years your roof has been around. If it’s been too long, it may just be time for a full replacement or some big-time repairs.
It’s Just Old
Unfortunately for us all, a roof will eventually get worn out and need to be replaced. Luckily, its around 25 years before a roof will wear down enough to need serious repairs or replacements. If you are creeping toward the 25 year mark, it may be time to start thinking about a major replacement or repair for your sagging roof.
A roof that is healthy can sometimes last many years past this but if you notice sagging, it’s time to start looking into a replacement or repair. Unfortunately, the sagging will get way worse the longer you don’t take care of it.
Wrapping your head around a full repair or replacement will restore your roof to brand-new condition. Sure, you could ignore the issues, but a sagging roof is dangerous and can get your house completely condemned. Nothing would be worse than coming home one day and finding your roof collapsed except being inside the home yourself when it happens.
That’s it for the major causes of roof sagging. Now it’s time to dive into what you can do to help the problem. Don’t panic, the methods for fixing your sagging roof are pretty simple and can hold you over till you can get a full repair or replacement.
What Should You Do If Your Roof Is Sagging
I’m going to let you in on some things you can do to help make your roof more stable while you wait for a full repair or replacement. The process listed below can help you navigate this process and make it less stressful for you in the long run. This process includes determining the cause of the sag, reinforcing the framing, replacing any roof decking that is needed, or fixing damaged gusset plates.
In some extreme cases, you may find that you need to replace the entire roof. This is a worst-case scenario so don’t worry, hopefully, it will not come to that. We will discuss all of these fixes in the sections below.
Determine What Caused The Sag
First things first, you are going to need to find out what is causing your sagging. This will include using the sections listed above to determine the most likely cause of your issue. It’s usually way easier to have a professional do this, so I really recommend this.
This is a safer and more practical option to consider, as many people do not have the knowledge needed to accurately and safely identify the exact cause of roof sagging. Once a professional has come an inspected your roof, they can tell you the next best steps to address your issue.
Reinforce The Framing
To start, reinforce the framing of your roof to hold you over till you can get a professional repair or replacement. To do this, I suggest adding some reinforcement to your trusses and rafters.
I know some of you are handier and can probably do this yourself but if you don’t feel confident, hire a professional to do it for you. If you do feel pretty confident handling this part of the repairs by yourself, then the steps below will walk you through the process.
- Gather a steel L channel that will be used to get your rafters or trusses back in the right shape.
- Once you have done this, drill four holes into the sides of the L channel.
- Then, remove any rotted or damaged wood from the roof using a chisel.
- Begin with the end that is most difficult to get to and mount the L channel onto the rafter or truss.
- Next, secure the end of the L channel to the rafter or truss using washers and bolts into the holes that you have drilled previously.
- After you have done this, move the broken piece into the correct position once the end is in the proper place.
- Measure the gap carefully between the L channel and the rafter or truss. Once you have done this, gather bolts that are 1.5 to 2 inches longer than this gap.
- Insert the bottom bolts and tighten them securely. After that, tighten the bolts that are farthest from the break until the bolt head is around ¼ inches from the channel.
- Continue to tighten the front and back bolts till the rafter or truss is secure against the channel.
- Insert the rest of the bolts and tighten them securely.
- Keep in mind that eventually, you may want to add extra support to this area.
Now that this has been completed, you can move on to repairing the roof decking. This is not as complicated as reinforcing the framing. We will discuss this in the section below.
Replace The Roof Decking
If your roof decking is damaged, you may be better off hiring a professional to do the job. A temporary fix till you can do this can be achieved using the process below:
- Measure the damaged area between the roof trusses or rafters. Then, cut a piece of ½ inch plywood to cover this area.
- Using glue, attach a 1-inch rigid piece of Styrofoam to the plywood. It is important to not use nails, as this can make the issue worse.
- Next, place the plywood and Styrofoam against the damaged roof decking.
- Push the plywood up till the foam touches the decking on the roof’s underside.
- Keep the plywood in place by using a piece of lumbar strapping till you are able to get a professional out to look at your roof.
Now that we have covered the roof decking, any damaged gusset plates will need to be repaired. We will cover this in the next section of this guide.
Fix The Gusset Plates
Fixing the gusset plates is the next thing that you should do. This is not a very complicated process and can help keep your roof secure till you can have it inspected by a professional. The process to do this has been detailed below:
- First, remove any gusset plates that are damaged or have been pulled away from the wood underneath the roof.
- It will be incredibly difficult to reinstall, so instead, replace it with a ½ inch of plywood.
- Using a nail gun, attach the gusset on both sides of the wood pieces.
- Once you have done this, this should be sufficient for replacing the gusset plate’s original strengths.
Unfortunately, there are some cases where the entire roof will need to be replaced. We will cover this in the section below.
Replace The Entire Roof
If your roof is damaged substantially, then you may need to consider replacing the whole roof. This is a worst-case scenario situation but one that may be necessary depending on the damage. If this is the cause, you will need to hire a professional to take care of this for you.
The cost associated with fixing a sagging roof will be detailed in the final section of this guide.
How Much Does It Cost To Repair A Sagging Roof?
It can cost between $750 to $2000 to fix a sagging roof, depending on the severity of the damage. A full roof replacement will likely exceed these costs but will vary depending on the contractor and the extent of the damage to your roof.
Final Thoughts
A sagging roof can be a dangerous situation for your home. If you notice your roof is sagging, then you will need to determine the cause of the issue as soon as possible. Once you have done this, you should hire a professional to come to inspect it and begin the repair process. In the meantime, there are a few things you can do to improve the structural integrity while you wait.
Ruben has a diverse background in the home services industry, with experience running a construction company, a kitchen and bath showroom, and a moving and relocation company. This breadth of experience has provided him with a wealth of knowledge and expertise in various areas of home improvement in general and specifically in the heating and plumbing niche.