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Roof Leaking where Porch Meets Roof

Roof Leaking where Porch Meets Roof

Roof leaking where porch meets roof? Not a fun situation to be in for any homeowner because the area where the porch meets the roof is a sensitive joint that is likely to leak if not protected properly. 

Roof Leak Suspects to Check

  1. Prime suspects to check are roof protrusions which are anything sticking out of the roof (chimney, air vents, plumbing, etc.), and any sensitive joints between house walls and the roof (includes the porch) or between two connecting roof planes;
  2. Other sneaky suspects are gutters overflowing due to heavy rainfall, causing a leak at one point of the roof (usually the weaker fascia behind it), and attic condensation causing a dripping leak due to extreme cold or hot outside temperatures and the attic not being well ventilated.

As roofers, we realize that finding a leak isn’t as easy as we say it is. To help the homeowner we’ve created a set of steps to find where the leak is without a professional, if you're planning to make the roof repair yourself. 

Otherwise, it's important to consult a professional immediately if the roof has two or more layers and is leaking, as this indicates major repairs are required. Here are some reasons not to put shingles on top of shingles, or layer shingles, for further information on the subject.

In an emergency leak situation, for example during rainfall, it’s recommended to keep the area clear for safety; Use tarpaulins to keep leaking areas dry and seal the joints as soon as possible before installing new shingles or other roofing materials over the area; It will help to avoid water damage during a roof replacement.   

General Guidelines to Follow

  1. If the water can pool anywhere on the roof, then it can leak just as easily; 
  2. Always track a leak downhill from the area and trace it back to find all of the water damaged areas; 

Knowing where the leak actually is, is only half of the battle. While repairing it in a way that makes the most sense for your home will make it last way longer than you would first expect. 

Without further ado, let's get right into it.

A Simple Approach to Roof Repairs

Repairing Sensitive Joints

Sensitive joints like where the porch meets the roof are areas that have gaps for water to enter through and are at risk of ice dams forcing this water through in colder climates. That’s why as the repair person, the goal is to redirect the water away from these areas and replace any damaged boards in these areas to prevent further damage to the home. 

There are two approaches to repair this area are either to:

  1. apply caulking, or
  2. install flashing 

Firstly, applying caulking to the leaking area is a short-term fix because the waterproofing lasts until the caulking dries up and comes at the cost of slowing water damage while allowing it to continue spreading. Repairing this further damage can become quite costly, an easier but not recommended fix for this reason.

Secondly, installing flashing is a long-term fix because flashing is waterproof sheet metal (aluminum, copper, steel, etc. - steel is the most common) that lasts as long as it remains secure to the area of the installation and the installation requires the installer to replace any damaged boards in the process. Properly installed flashing easily outlasts an average roof’s lifespan of 20 years, preventing the need for costly repairs in the future. A little more costly on the homeowner to install but is the recommended fix.

Steps to (Re-) Install Flashing

To install flashing where the porch meets the roof is as follows:

  1. Uninstall siding in the order they were removed for easy reinstallation later, uninstall any roof rafters, and uninstall any roof shingles in the area (4 to 6 feet radius to get the entire affected area); 
  2. Inspect the underlying boards for signs of water damage (rot, mold, dark streaks of algae, etc.) that has made the boards soft, these soft boards need replacing while those still intact can be cleaned with denatured alcohol spray and a rag;
  3. Replace any wall siding, roof fascia and roof shingles that have signs of damage;
  4. Clean the surface where the flashing will be installed;
  5. Apply silicone caulking to the sensitive joint where the porch meets the roof;
  6. Install flashing to the roof deck, fastened with stainless steel roofing nails every 12 inches, and depending on the length of each flashing, overlapping flashing sheets every 4 inches with caulking between overlapping surfaces; Repeat until the entire area is covered.
  7. Reinstall roof shingles and wall siding on top of flashing and reinstall roof rafters to the area 

During the repair, it’s worth considering what else could affect the longevity of a repair to the area where the roof meets the porch. Which we’ll go over in the next section.

Homeowner Repair Considerations

Depending on the home’s location, type of porch, its surrounding landscaping and weather conditions, it may be vulnerable to leaks because a home can only handle so much water and wind at the end of the day. 

Meaning homeowners should consider wind-driven rain and falling branches to be a concern for their home because even the smallest hole from a missing nail could result in a leak. 

Protecting a porch from the elements involves protecting it internally and externally:

Check the Internal Wood Framing

Internal wood framing; Every home’s porch should have wood sealer applied to prevent water, cleaning products and chemicals from entering into the wood causing damage and making it unsafe by retaining moisture. Installed quickly with a garden sprayer and a quick mist over the porch’s surface is enough to provide this protection, especially for an exposed porch.  

Inspect Any External Barriers

External barriers, depending on a home’s rain and wind conditions being: 

  • Lighter conditions; Consider planting trees and rain screens or window shades to cover large areas of the porch.
  • Heavier conditions;  Consider weighted water-resistant curtains and not planting trees close to the porch or roof (risk of falling branches). If budget permits, upgrade to a porch enclosure with glass walls and glass doors which protects it from the elements and allows natural light to enter.     

For those fringe cases where the homeowners living in stormy areas want to be extra sure the area where the roof meets the porch is protected, they should install ice and water shielding under the flashing and/or roof fascia; Upgrading roof fascia to metal instead of wood is another inexpensive option worth considering. 

Cautions About Exposing Water Shielding

A word of caution, ice and water shielding should never be permanently exposed to weather and rain, instead it should always remain covered by other materials. It is a backup solution to prevent water or leakage from coming through the primary roofing material (shingles, tiles, panels, etc.) or any other home covering.

Finally, small visible holes where the porch meets the roof can be filled with caulking because it will prevent any sneaky leaks from happening right under a homeowner’s nose. Caulking is acceptable here because it is able to fill the hole’s shape and it will retain its waterproofing longer like this as well. 

Otherwise, any homeowner with a new roof that experiences this particular situation can contact their roofer to repair it on their behalf or pay another roofer to repair it correctly.

Homeowners with more unique porch and roof joint configurations may need an equally unique solution.  Which is covered in the next section.

Variations of Porch and Roof Joint Configuration & Their Repairs

Where the porch meets the roof is a sensitive joint, which can vary based on the vertical elevation between the roof and porch and the steepness of the roof. These variations cause water to run-off into different areas and would cause the homeowner to consider how they can redirect this water away from this sensitive joint.

The key to redirecting this water is to trace where the water is currently traveling downhill on the roof and porch’s surface.  

To make it easier for the homeowner, use our considerations and joint configurations to make the best decisions for your unique home’s situation.

Considerations When Repairing a Sensitive Roof Joint

There are a few considerations to help judge the situation:

  • Elevation differences between the roof and porch normally results in up to a 3 feet water run-off splash range depending on the gutter installation in place
  • Beware of water backing up against the house, roof fascia and house siding. Normally caused by a porch being within the splash range specified above or being right against the house’s wall, and/or the porch’s roof slope is redirecting water back to the house. If possible, a porch with a flat roof is best to reduce the effect of water back up.
  • Replacing roof fascia wood boards is a nightmare that is completely avoidable; Major repairs include removing the gutters to replace the roof fascia boards, roof framing, roof deck, etc. and then reinstalling the gutters.  
  • Recommended to keep water run-off a minimum of 6 inches to 1 foot in front of the house, always away from the house’s roof fascia. The further away the better.  

Porch and Roof Joint Configurations:

  • Roof and porch have less than 3 feet vertical elevation between them; Causes water splash from the roof and water to back-up to saturate the roof fascia, so the easiest solution is to install metal roof fascia boards. 
  • Porch is within 1 foot or against the vertical (90 degree) house wall horizontally; Not ideal, water will splash both from the roof and the porch’s roof back onto the house and porch drip can quickly become a big issue if not dealt with. So the homeowner should install a porch roof overhang with metal drip edge to drop any remaining water away from the house, the vertical house wall and roof fascia/soffits require ice and water shielding installed (3 to 9 feet depending on the porch and roof slope), and continuous roof flashing against the vertical house wall and porch’s roof. 
  • Roof and porch sloped in opposite directions like a valley; This will cause water to run-off into the valley, a sensitive joint, so it’s recommended to install ice and water shielding under metal flashing and roofing material to offer the most protection possible. When the roof and porch slope the same way, this becomes less of an issue.   

For whatever reason the homeowner is feeling unsure, install ice and water shielding and flashing within 3 to 9 feet of the joint to be extra sure the area is protected. If the roof fascia and soffit is within that range, install metal fascia to prevent the prospect of a future major repair situation. Always replace any damaged siding, roof shingles, roof fascia, roof framing, etc. to keep all roofing materials installed on top secure for the long-term.      

As a final note, a porch is different from a veranda and a gazebo. Where a porch is a covered shelter supported with columns or screens for the house’s main entrance, a veranda is an open-air porch that wraps the front and sides of the house and a gazebo is a domed structure supported with columns or screens that is not connected to the house. 

Suggestions provided above apply to homes with porches and verandas specifically. Although, adding an overhang on a gazebo never hurt either, if there are issues with water leakage.   


A homeowner should not leave this issue unaddressed because the water damage to the porch and more importantly the home can become significant really quickly. It is recommended a homeowner repairs the area within 3 to 9 feet of the joint with ice and water shielding and flashing if they’re ever unsure, this will protect the area. Always replace any damaged boards and shingles in this area to avoid water damage from making its way into the home.

The homeowner should never attempt the repair themselves if it means putting themselves in an unsafe position, instead consult a professional with all of the necessary safety equipment. Risking avoidable injuries are never worth the risk. 

If there is water damage in the area and it doesn’t look sturdy enough to hold weight, don’t risk doing the repair yourself. 

By all means, at the first signs of the sensitive joint between the roof and porch looking water damaged get the minor repairs done earlier than later, to avoid costly major repairs in the future.


What is a common issue with roofs where porches meet the main structure?

Roof leaks often occur where porches meet the main roof due to poor flashing installation, allowing water to seep in and cause damage.

How does improper flashing contribute to leaks at the porch-roof junction?

Inadequate flashing or gaps in sealing create vulnerabilities, enabling rainwater to penetrate and lead to leaks along the intersection.

What are the consequences of ignoring a leaking roof at the porch connection?

Ignoring leaks can result in water damage, rotting wood, compromised structural integrity, and potential interior damage.

How can homeowners prevent leaks at the junction of a porch and the main roof?

Proper installation of flashing, regular inspections, prompt repairs, and sealing gaps with appropriate materials can prevent leaks.

Why is it important to address porch-roof leaks promptly?

Timely repairs prevent escalating damage, minimize repair costs, and extend the overall lifespan of both the porch and the main roof.

BulletpRoof Roof Systems is family operated roofing contractor with over 15 years of experience. We have been helping families throughout Mission, BC and neighbouring areas resolve issues with their residential sloped roofs for many years now. We pride ourselves on providing genuine professional roofing services and are dedicated to helping our clients resolve issues with their roof systems as efficiently as possible.
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