How to Repair a Leaking Porch Roof

Roof Care & Maintenance
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How to Repair a Leaking Porch Roof

Porches are fantastic structures. They add to the square footage of your home, offering extra storage space, protect you from the elements, and add another layer of security to your front door. But what if you notice your porch roof is leaking? There are many reasons why your porch may be suffering from a roof leak, from damaged flashings to worn roofing materials. In this guide, we’re going to talk about the causes, potential warning signs, and ways to fix a leaking porch roof.

Causes of a Porch Roof Leak

Porch roofs can spring a leak for a number of reasons, but the most likely is age-related wear-and-tear to the materials that make up your porch’s roof. Here’s a list of the most common causes of roof leaks in porches:

Mono-Pitch or Lean-To Roof Porches:

Mono-pitch porches, which feature a single sloped roof similar to a lean-to, most often leak due to damage over time from rainwater falling from your house roof onto the porch. Eventually, this will compromise elements such as the flashing or tiles.

Gable-End or Double-Hipped Roof Porches

These more complex pitched roof porch designs can often fail for the same reason as single sloped porches. Wear-and-tear from falling rainwater or debris can take its toll, eventually causing leaks, particularly on more vulnerable parts of the porch roof such as the ridge.

Flat Roof Porches

Choosing a flat roof for your porch is a great way to minimise project costs, and take up less space. However, flat roofs are highly prone to leaks, particularly if the flashing has been damaged, or if water has been able to work its way between the layers in your flat roofing system.

How to Fix a Porch Roof Leak

Step 1: Find Out Where And Why Your Porch Roof Is Leaking

The first step in repairing a leaky porch roof is identifying the source of the problem.

From the Inside

If your porch roof features a wooden ceiling, you may be able to find and fix your leak from the inside. Remove any boards around where the leak is coming from, and take a look underneath your porch roof. Are there any damp patches, or brown stains? If so, that might just be where the leak is coming from. However, if you can’t pinpoint the source of the leak, you may have to look outside.

From the Outside

It’s time to crack the stepladder out and take a closer look at your porch’s roof. Things to look out for include a build-up of moss, dirt, or other debris, split or raised lead flashing against the wall, as well as damage to the roofing materials. If you spot any of these issues, the offending material will need to be replaced to prevent water from leaking through to your porch in future.

Step 2: Repairing or Replacing Damaged Flashings

Depending on your style of porch roof, it will more than likely feature lead flashing. The flashing is an integral part of any roofing system, providing a watertight seal along vulnerable edges and details. Small holes can be filled using a small amount of silicone sealant. However, if your flashing is badly damaged, it will need to be replaced. If any lead flashing needs removing and replacing, this should be done by a qualified professional. This is because lead is toxic, and properly dressing lead flashing requires an experienced hand.

Step 3: Repairing or Replacing Damaged Roofing Material

For flat porch roofs covered with EPDM membranes or roofing felt, a coat of Cromapol waterproofing paint will be enough for minor repairs. Due to the size of the average porch roof, it’s not worth performing more than a low-level repair. If your flat porch roof is badly damaged, we recommend replacing it with a new layer of flat roofing material.

If your porch features a pitched roof covered with tiles, slates, or shingles, these can be sealed if the damage isn’t severe. However, any badly damaged or missing tiles should be replaced ASAP. Pry up damaged tiles using a pry bar or claw hammer, then slide and fix new tiles back in their place. This is a good opportunity to check the condition of your roofing underlay, as this can also cause leaks.

Learn more about how to replace roof tiles.

Step 4: Install Gutters (Optional)

If you’re looking to improve the way your porch roof handles wet weather, we’d recommend installing guttering. The great thing about modern guttering systems is they’re made from UPVC, which is inexpensive, yet long-lasting and easy to install. Adding gutters to your porch roof will prevent any rainwater or debris from splashing your door, windows, or the sides of your property, which can be unsightly and cause damage over time.

Cost to Repair a Leaking Porch Roof

Depending on what you need to do to fix the leak in your porch roof, you should expect to pay between £30 and £300. Silicone sealant, or acrylic-based waterproofing paint used to fix minor porch roof leaks will cost around £30-50 at most. However, if you need to replace any roofing materials, this could cost up to £300 accounting for materials and labour.


We hope this guide has been helpful to anyone dealing with a leaky porch roof. If you’ve got any more questions, please get in touch with our award-winning customer service team. They’ll be able to answer any queries you may have. Call them on 01295 565 565, email [email protected], or use the handy livechat below.

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