Fix a Leaking Roof From the Inside (Simple Steps)

You’ve got water dripping into your attic or down your walls, and climbing up on the roof during a storm isn’t an option. Here’s a clear, realistic, human-written guide on how to fix a leaking roof from the inside — temporarily. It won’t last forever, but it’ll buy you time until you can get professional help. We’ll walk through what to do, step-by-step, using real tools and methods that work in Toronto or anywhere else you’re stuck indoors with a leaky ceiling.

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How to fix a leaking roof from the inside

A roof leak isn’t always a massive hole — sometimes it’s just a slow, frustrating drip that won’t quit. You hear it in the middle of the night or see it as a stain growing across the ceiling. And when it’s pouring outside, getting up on the roof isn’t safe. So you start inside.

This is not a permanent repair. But it’s a realistic, useful patch for anyone dealing with an active leak inside their home.

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First — figure out where the water is coming in

Follow the drip

• Go to the attic, if possible. Bring a flashlight.

• Look for dark, wet spots on the rafters or insulation.

• Use your hand to feel for moisture if it’s hard to see.

• Sometimes the water enters in one place and travels along a beam before it drips down — this throws people off.

Don’t assume the wet ceiling spot in your living room is right under the hole. Roof leaks are sneaky like that.

Mark the spot

Once you find where the leak is dripping from:

• Use chalk or a marker to circle the area

• Put a bucket or pan underneath it to catch the water

• If insulation is soaked, pull it away and let the area breathe

You want everything around the leak to be as dry as possible before you patch it.

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Supplies you’ll need

• Utility knife

• Roofing tape or tar

• Plastic sheeting or heavy-duty garbage bags

• Staple gun or tacks

• Plywood scrap (optional)

• Bucket or container

• Towels or rags

• Spray bottle with bleach solution (to clean mold)

If you don’t have these already, you’ll find most of them at a hardware store. The goal is to temporarily stop water from coming in and spreading.

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Temporary roof leak fix from the inside — step-by-step

Step 1: Catch the leak

This sounds obvious, but contain the drip first.

• Place buckets or pans under the leak

• Line the area with towels to stop water from spreading

• Change out full buckets as needed

Water pooling inside your attic or ceiling can cause mold fast. This is damage control.

Step 2: Clear the area around the leak

• Pull back insulation

• Wipe down the surface

• Get rid of any mold with a diluted bleach solution (1 part bleach to 3 parts water)

• Let it air dry if possible

If the area is soaked, aim a fan at it or use a hair dryer on low heat. You want the surface to be dry before sealing.

Step 3: Apply roofing tape or tar

This is your temporary patch.

• Cut a piece of roofing tape slightly larger than the hole or crack

• Press it firmly over the leak

• Smooth the edges out to prevent peeling

If you’re using roofing tar:

• Apply a thick coat directly to the crack with a putty knife

• Press a small piece of plywood or plastic into the tar to reinforce the patch

• Add a second layer of tar over the top

Let it cure for a few hours if you can. The seal needs time to harden and block the water.

Step 4: Cover with plastic sheeting

If the leak is larger or persistent:

• Cut a piece of plastic to fully cover the leak area

• Staple or tack it into surrounding rafters or framing

• Tape the edges tightly so water doesn’t sneak in

You’re building a barrier here. It won’t be pretty, but it should stop the drip.

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Optional: reinforce with plywood

If the roof is sagging or damaged, a small piece of plywood adds support.

• Place it over the patched area

• Nail or screw it into the rafters (not the roof deck)

• Add plastic over the top to prevent water seeping around it

This works best if the leak is part of a larger structural issue.

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Monitor the leak during the storm

Leaks change fast. What starts as a drip can become a stream if more shingles tear or water pools on the roof.

• Check your patch every hour or so

• Replace full buckets

• Keep an ear out for new drips

• Watch for sagging drywall or ceiling cracks

If water starts pouring or your ceiling bulges, poke a small hole in the lowest point and drain it into a bucket. Sounds backward, but it stops water from pooling and collapsing the ceiling.

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After the storm — get professional help

This fix is temporary.

Roofing tape and tar won’t last long. Once the weather clears up, call a roofing company to do a proper exterior inspection and repair. Especially in Toronto, where snow and ice can reopen patched leaks during freeze-thaw cycles.

Don’t let this wait. The longer water gets in, the more expensive the repairs.

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Warning signs you need outside help now

• Multiple leaks at once

• Large stains forming on ceilings or walls

• Moldy smell in attic or living spaces

• Roof deck sagging or soft spots underfoot

• Electrical issues near the leak

If you’re in Toronto and this sounds like your house, reach out to Toronto Roofer. We fix emergency roof leaks, even in bad weather, and do full inspections once things dry out.

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FAQs

Can you seal a roof leak from the inside?

Yes — but only temporarily. You can slow or stop a leak using roofing tape, tar, and plastic sheeting from inside the attic. Permanent fixes require exterior work.

What’s the best product to patch a roof from inside?

Roofing tape like Gorilla Waterproof Patch or Flex Tape works well for small leaks. For larger ones, use roofing tar or sealant.

Is it safe to go in the attic during a leak?

Usually, yes. But if the attic floor is soaked or sagging, stay out. The ceiling below could collapse. If you smell gas or hear electrical buzzing, leave immediately.

Will a tarp inside the attic help?

Yes, plastic tarps or heavy-duty sheeting can redirect water and protect insulation or ceilings. Secure it tightly above the leak and direct water into buckets.

How long will an inside roof patch last?

Maybe a few days to a couple weeks. Rain, snow, and temperature swings will break it down fast. Don’t rely on it longer than necessary.

What if I can’t find where the leak is?

Water often travels before it drips. Look for damp beams, insulation discoloration, or mold. If you can’t find it, wait for rain and follow the drip.

Should I remove wet insulation?

Yes. Wet insulation loses its effectiveness and can grow mold fast. Remove it, let the area dry, and replace it once the roof is repaired.

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Summary

Fixing a roof leak from the inside is a temporary move. It buys you time — nothing more. It stops water from wrecking your ceilings, flooring, and wiring until the rain ends.

Use roofing tape or tar to plug the leak. Cover it with plastic. Catch every drop. Then call a roofer. The real fix starts outside.