How to Fix a Roof Leak

woman trying to catch water in a pan from a leaking roof

If you have water stains across your ceilings or walls, the cause could be a roof leak. Even over a short time, a leaky roof can cause big problems for homeowners, such as mold, rotted framing, waterlogged insulation, and ruined floors. Maintaining your roof is important to protecting your home. So, how do you fix a roof leak?

Roof leak repair is a labor-intensive project, but it’s relatively inexpensive. Locating the source of the leak is the tricky part, but the repair is fairly simple.

Signs You Have a Roof Leak

A homeowner’s worst nightmare is to discover they have a leaky roof. It can happen with stormy weather, heavy downpours, or if you have a roof that is reaching its lifespan. Before it gets worse and you have to replace your roof and everything inside your home, you need to repair it quickly.

Other than obvious roof damage, here are some signs you are dealing with a roof leak:

  • Water spots and stains on the walls or ceiling
  • Shingles are warped, cracked, or missing
  • Missing or damaged flashing or boot covers
  • Water spots or wet roof decking can be seen through the attic
  • Musty or moldy smells
  • Bulging sections on interior walls
  • Water-damaged exterior siding 
  • Rusting on metal roofing

Once you determine you have a leak, the next step is to track it down.

How to Find a Roof Leak

You would think a roof would leak right above a water spot on your ceiling, but that’s not always the case.

Look for the Signs

Knowing how to detect roof leaks starts by recognizing the signs of a roof leak. Water may drip inside during a rainstorm, but there are several other signs to look out for, such as water spots on the ceiling, warped walls, or damaged siding.

Rule Out Interior Leaks

Just because you’ve found water damage inside your home doesn’t necessarily mean you should conclude there’s a roof leak. Check for any faulty piping in bathrooms, laundry rooms, or kitchen sinks, and make sure your HVAC unit and water heater are working properly to rule out any other types of leaks.

Once you’ve ruled out all the possible interior leaks, you can start looking for roof leaks.

Inspect the Attic

When checking for a leak, it’s important to investigate your attic for all the signs of water damage. Bring a flashlight and look for mold or water stains around the rafters and roof sheathing.

Examine the Surface of the Roof

Since getting on a roof is dangerous, we recommend you hire a roofing professional to inspect it. 

Check around any and all vents, chimneys, skylights, and seams for water damage or water collection. Look for loose or damaged shingles, missing nails, cracks, or staining. Since debris can trap moisture along the surface of the roof, examine any areas where leaves collect.

Hose Down Your Roof

If you haven’t found the source of your leak, you can test your roof by having someone stay inside to observe the area of the roof leak while you (or a roofing professional) slowly spray your roof with a garden hose, one section at a time. Spend a couple of minutes in each area and have your helper call you when any dripping starts.

Before Fixing a Roof Leak

A room with roof leaking in the ceiling
Photo Credit: 400tmax / Canva Pro / License

Roof repair is a risky business that requires someone with experience and expertise, as well as confidence with heights. You need to work in ideal weather conditions as well, so don’t ever attempt to fix your own roof in wet, snowy, or icy conditions, or you will risk falling and injuring yourself. The best time for roof repairs is late spring and summer.

Be sure the surface of your roof is clear of leaves, twigs, moss, and other debris. We cannot stress how invaluable a roofing professional can be, and it’s better to let an experienced, licensed pro handle your roof repair for you.

That said, you should at least know the process so you know exactly what goes into fixing your roof.

Supplies You Need to Fix a Roof Leak

All of these supplies can be easily found at your local hardware store.

  • Ladder
  • Flashlight
  • Tape measure
  • Pencil
  • Flat pry bar
  • Utility knife
  • Caulking gun
  • Chalk line
  • Circular saw
  • Hook blade shingle cutter
  • Hammer
  • Roofing nails
  • 8d common nails
  • Asphalt shingles 
  • Roofing paper or synthetic underlayment
  • Roofing cement or exterior sealant
  • Roof vent (if replacing a damaged vent)
  • 7/16-inch exterior-grade plywood or OSB board (if fixing a damaged roof deck)

9 Steps to Fix a Roof Leak

Step 1: Find the Source of the Roof Leak

Follow the roof leak inside the lowest point of the house where the signs of a leak are still visible, and work upward toward the attic.

If your attic doesn’t have a hatch, you can access it with a ladder, and if your attic doesn’t have a light source you should bring a flashlight to closely examine the walls and roofline for signs of a leak. Leaks can start a few feet higher than the roofline and their location might have black or white stains with mildew and mold.

Step 2: Inspect the Roof Vents

If your roof vents are leaking, use a ladder to climb onto your roof and check if the vents are dislodged or if the boots are cracked. Make sure the nails attaching the vents to the roof are securely in place.

A major source of roof leaks is roof vents, which include attic fans, turbines, or metal flashing raised higher than the roofline.

Remove and Replace Damaged Roof Vents:

  • With the pry bar, pull out the nails holding the shingles to the vent
  • Do not remove the shingles. Use a pry bar to pull back the shingles over the base of the vent.
  • Remove the nails holding the vent to the roof. 
  • Remove the damaged vent from the roof.
  • Apply exterior sealant or roofing cement to the bottom of the vent’s flashing. 
  • Carefully separate and roll back the shingles as you slide in the vent. The vent flashing’s lower section should be over the shingles to prevent any further leaking. 
  • Nail down the vent every 4 inches and at all corners. 
  • Cover the nails with sealant or roofing cement.

Step 3: Remove the Old Shingles

Removing the shingles is the only way you’ll be able to access the damage to start your repair. Start removing shingles at about two rows above the section in need of repair and work downward through the rows.

Slide the pry bar under the bottom of the shingles and push upward, prying the nails loose and pulling the shingles away. Break up any of the old caulk that has been holding the shingles together while prying up the roofing nails.

Step 4: Remove the Old Underlayment

Shingles are kept separate from the roofing deck with roofing paper or synthetic underlayment. Inspect the underlayment for damage, and if you notice any rot, then it will need to be replaced. Use a utility knife to slice off the paper or underlayment while keeping it as undamaged as possible.

Step 5: Mark the Area You Plan to Cut 

Using existing nails as a guide to the center, snap a chalk line down on the right and left sides of the roof deck’s damaged section. Then, snap a chalk line both above and below the damaged section crossways to the rafters.

Step 6: Cut Away the Damaged Roof Deck

Set the depth of the circular saw blade to 1/16 of an inch more than the thickness of the roofing deck. Follow the chalk lines with the circular saw, cutting away the damaged section of the roof deck while making sure to keep your body outside of the marked-off section to avoid injury. Pry out any nails from the section that you cut out, then pry off the damaged plywood.

Step 7: Attach the Roof Deck Patch

Use the section you just cut out from the roof deck as a template for the new patch. Make sure to cut your new patch on the ground to avoid injuring yourself. Set the new roof deck patch into the hole and hammer it into place using 8d common nails.

Step 8: Replace Underlayment

Nail down the roofing paper or underlayment with roofing nails, working from the bottom up. Overlap each row by at least 4 inches.

Step 9: Lay Your New Shingles

Lay the first row of new shingles, starting at the bottom-most row. Hammer down the shingles along the top with roofing nails in a perfectly straight line at equal distances apart, and apply roofing cement along the bottom of the shingles.

Work your way up to the top row. Slide the new shingles under the top row to mesh with the existing shingles. Be sure to line these up exactly.

DIY or Hire a Pro to Fix a Roof Leak?

picture of roof leaking and damaged ceiling
Photo Credit: victorass88 / Canva Pro / License

When to Do DIY Roof Leak Repair

While not recommended, there are times when you can handle minor roof leaks on your own without a roofing professional:

Cracked Caulk

If the roof caulk was cracked or in poor condition, you can replace the damaged caulk beading. You can fully remove the caulk by loosening it with a putty knife and pulling it off in strips before applying a fresh bead of roofing caulk.

Clogged Water on the Roof

Locating and removing whatever object is causing standing water to accumulate on your roof doesn’t require a pro. Water on your roof should be able to move freely to reduce the chances of creating rot, resulting in a leaky roof. You should clear out your gutters regularly to avoid any standing water.

Reattach Shingles

You don’t need to spend money on a pro just to nail down a few shingles. If you have missing shingles or the shingles have cracks, the best thing to do is replace them.

However, if the shingles are still in good shape, you can reattach them with a hammer and some roofing nails. You also can use an adhesive, but be sure to use a material that is made for roofing. Make sure you correctly insert the shingles into their assigned slots.

When to Hire a Pro for Roof Leak Repair

While home improvements like gardening and gutter cleaning can be DIY, it’s wiser to trust roofing maintenance, roofing repairs, and roof replacements to professionals. If you are not experienced with using a ladder and working up high or have any misgivings about your ability to effectively repair a leak, we recommend you leave the job to an expert.

Roofing companies and contractors are more equipped to inspect and assess the damage. Even something that looks like a small leak can cause extensive damage to your home. What you might think is a minor roof repair might actually end up being a full roof replacement.

If something goes wrong, a small DIY project can turn into a bigger roof repair. When you hire a professional roofer, you ensure that it will be fixed right the first time. Also, a DIY project could void a warranty.

Cost to Fix a Roof Leak 

The typical roof repair cost runs between $348 and $1,186 on average. Depending on the size of the roof and the extent of damage, most homeowners spend about $767.

FAQ About How to Fix a Roof Leak

What is the most common reason for roof leaks?

The primary cause of a leaking roof is age. The roofing materials simply reached the end of their lifespan, and, eventually, will be more vulnerable to leaks.

How long does a roof last?

Depending on the material, how well it’s been maintained, and the weather conditions in your area, the average life expectancy of a roof is anywhere between 15-25 years.

What size hail is damaging to roofs?

While pea-sized and marble-sized hail does not usually damage roofs, golf-ball-, baseball-, and softball-sized stones have been known to cause damage to asphalt shingles.

When to Hire a Roofing Pro 

Don’t spend your free time climbing ladders and nailing shingles when you can hire an experienced and reliable local roofing pro instead. 

Main Image Credit: PixelsEffect / Canva Pro / License

Lydian Pine

Lydian Pine is a creative writer and studio artist whose work first debuted in a short story anthology. She graduated from the University of North Texas in 2020 and enjoys video games, theatre, and swimming. Lately, she has started to study entomology as a hobby.