How to Fix a Leaking Roof (2024 Guide): Repair Tips, Costs, and Maintenance

Updated On 3 January 2024.

Maintenance of commercial roofs is critical for a business’s smooth operation as well as the protection of employees working inside. According to Architect Magazine, 40% of all structural problems arise due to water intrusion or leaks. Roof leaks are one of the biggest problems commercial building owners face when it comes to maintenance. That is because commercial roofs are more susceptible to leaks and require frequent roof repairs than residential ones, as they endure more foot traffic, equipment strain, and weathering.

If left unattended, a minor leak can damage the inside and outside of the building, risking electronics and equipment which can affect your business. Over time, roof leaks can lead to serious problems like mold, decayed framing, sheathing, and destroyed insulation and ceilings. In this blog, we will discuss how to repair a commercial roof leak and prevent future damage.

What is a Commercial Roof? 

A commercial roof provides protection against weather elements like snow, storms, and rain for the occupants of businesses, warehouses, and other types of commercial structures. These roofing systems are designed to meet the size, material, and structural considerations of commercial properties. 

Commercial roofing systems are generally made up of:

• Metal 
• Single-ply (TPO, PVC, EPDM)
• Concrete
• Modified bitumen
• Built-up roofing system
• Green roofing
• Spray-on silicon
• Shingle roofing
• Tar and gravel 

Commercial roofing types may include flat roofs, low-slope roofs, or pitched roofs, depending on the nature and requirements of the building. In 2022, the Commercial Roofing Market was valued at nearly $11.21 billion and is estimated to reach $17.08 billion by 2029.

How to Find a Roof Leak in Your Commercial Building?

As a property manager, watch out for these five warning signs that your commercial roof is leaking and needs immediate repair.

Sign No. 1 – Stained Walls or Ceilings

This is one of the obvious signs of commercial roof leaks visible to the naked eye. If you see dark-colored stains on the ceilings or flowing stripes across the walls of your facility, it’s a major indicator of a leaky roof.

Sign No. 2 – Blistered Roof Membrane

Over time, air and moisture can get trapped inside the roof membrane, causing blisters. Inspect signs of a blistered roof membrane in the form of bubbles, standing water, tears or holes, exposed seams, damaged flashing, or any similar symptoms.

Sign No. 3 – Dripping

Dripping of water droplets, rivulets, and puddling on the floor inside your commercial building are immediate calls for action to repair the leaky roof.

Sign No. 4 – Musty Odor

Moisture on the commercial roofing promotes mold growth and this can create a musty odor throughout the interior. If you come across any unexplained mold growth in the building, there is a high chance that a roof leak has gone undetected.

Sign No. 5 – Higher Energy Bills

A leaking roof saturates the insulation and because of this, it takes longer to retain warm air in the winter or cold air in the summer. Surprisingly, but true, higher energy bills indicate that your commercial building’s insulation is not working effectively.

What are the Major Causes of Commercial Roof Leaks?

A leaking roof has several different causes. Some possible reasons include:

• Poor-quality roof installation

Commercial roof installation requires the experience and expertise of a commercial roofing contractor. Mismatched shingles, missing drip edges, wall stains, uneven rooflines, and use of non-uniform roofing materials are key signs of poor-quality roof installation. Unprofessional commercial roof installation damages the structure and leads to expensive restoration for building owners.

• Cracked shingles

Even though asphalt shingles made with a fiberglass base provide great strength to the roofing system, they aren’t entirely leak-proof. When one shingle tears off the roof, it causes an exposed gap between the lower shingles. Water finds its way into such cracked shingles and you may spot an oddly placed leaky dark spot on the commercial roof.

• Damaged flashing

Flashing is a thin strip of metal that shields the inner edges of the shingles from water/rain and seals the joints between different parts of the roof. Frequent poor weather conditions and aging can cause cracks in these flashings. Eventually, this helps water to reach the ceiling and deck.

• Damaged roof valley

A roof valley is a V-shaped intersection between two sloping roof panels. Some commercial contractors use ineffective valley underlayment for shingles which start to corrode before their life expectancy, resulting in leaks. Other reasons such as the expansion of the commercial roof valley due to warm weather, overflowing of snow chunks, and incorrectly sealed valley edges may cause roof leaks.

• Accumulation of water or debris

A failure in your commercial roofing drainage system will allow water or snowmelt to accumulate on the roof and deteriorate its structure. If gutters and downspouts are clogged with debris, they will redirect water to the weak spots of the roof and begin seeping.

• Punctures

For proper installation of building systems like HVAC units, vents, drainage, and pipe systems, commercial roofing undergoes penetrations, leaving behind gaps and unfinished seals. Moreover, hail, falling tree branches, or other objects can puncture the roof’s membrane.

• Natural phenomena

One of the most common reasons for leakages in commercial roofing systems is harsh weather. Phenomena such as severe rain, storms, UV rays, and snowfall can damage roofs, creating crevices for water to seep in.

• An outdated roof

Typically, commercial roofing systems last between 20 to 30 years, and post a certain period, they require a roof replacement.

It is possible to repair minor commercial roof leaks by yourself however if the leak is significant, hire a professional roofing contractor with at least 5 years of experience before the damage worsens.

Top 10 Commercial Roof Repair Tips

Business owners spend more than $12 billion annually on roof repairs, restoration, and re-roofing. In case you hear a drip in the middle of a heavy downpour, arrive at your office to see a puddle, or notice damp stains on ceilings, here are the 10 expert tips on repairing a commercial roof leak by yourself:

Tip 1 – Finding The Leak Source

Think like water to find the source of a roof leak.

For repairing a leaking commercial roof, first, you need to find the leak source. Most water stains and spots are not exactly close to the roof leak source. In order to locate the source of the leak, you have to think like water and follow its path. Water travels downhill from the sheathing, rafters, or the top of the ceiling, so the actual leak could be several feet higher, left, or right on the plane of the roof. Another way is to remove the shingles which will reveal rotted wood or damp felt paper below the roof leak.

The intent is to search for any roof penetrations, which are the most common sources of leaks. These penetrations are mostly –

• Broken or missing shingles
• Poorly sealed or damaged flashing around chimneys
• Skylights
• Dormers
• Plumbing and roof vents
• The intersection of different planes
• Loose or missing nail spots

If you have access to the attic, go there and search for water stains, dark-colored marks, or mold. If you don’t have an attic or vaulted ceilings, you will have to examine the cause from the outside.

A commercial roofing company will identify the problems as quickly as possible and recommend solutions to help you get back to work.

Tip 2 – Fixing A Roof From The Inside

Seal the leaking spot by making a temporary patch.

During heavy rainfall, water will quickly seep into the drywall and soak the insulation. Follow the path of the dripping water to where it is coming from. Once you have found the roof leak source, circle the targeted areas with chalk. Wait until the rain subsides and the affected areas are sufficiently dried up. Here’s how to fix the roof from the inside with the help of a temporary patch:

• Make a temporary leak patch using some plywood or shingle along with roofing tar.
• Use a knife or tool with a flat surface to spread the material to the leaking holes on the inside of your roof.
• Place the shingle or plywood onto the tar and apply more around the edges of the patches.
• Press firmly to secure the circled areas with proper adherence.

You can also seal the whole area with caulking applied with a scraper. Finally, map out the leaking area using measurement tape. When the rain stops, wear rubber-soled shoes to repair the commercial roof leak from the outside.

Tip 3 – Fixing Shingle Roofs

Shingle roof repairs are relatively simpler than the other roof types.

Leaks usually occur due to cracked, curled, or missing shingles. Wherever two surfaces meet and around every vent or chimney, look for cracks in the flashing, caulking, or the lines of the roof cement.

Curled-back shingles can be repaired using asphalt cement or compound tubes applied with a caulking gun. In cold weather, make sure you soften the shingles with a propane torch before they are flattened out.

If shingles are torn, rotten, or missing, they need a replacement. Here is how to replace shingles:

• Lift the edges of the surrounding shingles and carefully pluck nails with a pry bar. Remove leftover cement and protruding nails.
• Slide the new shingle into the gap properly aligned and fasten it with nails.
• Cover with roof cement and smoothen the shingle edges.
• When you are replacing shingles, round the corners at the intersections of the top and bottom rows.
• Ridge shingles or tent-shaped shingles can be replaced the same way.

You can also replace the pulled or missing nails with rubber-washer screws and caulk the shingles down. This you can do without removing the shingles.

Tip 4 – Fixing Flat Roofs

Leaks in commercial flat roofs are caused by a blistered or cracked area.

The National Roofing Contractors Association estimates that up to 40% of flat roofs develop functional problems within 1 year of installation. ­Commercial flat roofs are built up of layered roofing felt and tar. Hence, such leaks occur at low spots or damaged areas. If there is water pooled in the leak area, dry it up and clean any gravel. Look for cracks or large blisters in the felt or where the top layer has parted.

To repair a blister in the commercial flat roof:

• Use a sharp utility knife to cut the membrane open. Remember the cut should penetrate the membrane of the flat roof fully without reaching the roofing felt beneath it.
• When there is water inside the blister, press from the edge toward the center to squeeze it out. If the layers of the flat roof are completely saturated, use a propane torch with a flame-spreader nozzle to dry out the felt.
• Reapply a thick coating of roof cement on the bottom and firmly press down the edges of the blister. The new membrane should extend at least 6 inches around the blister edges to completely seal it.
• Nail the blister with a row of 6d galvanized roofing nails at each side of the cut, and then coat a layer of cement over the entire blister.

If water is coming from a large area, chances are it is flowing from an adjoining pitched roof surface. In this case, it is best to call a commercial roofing contractor to repair the commercial flat roof.

Tip 5 – Fixing A Wooden Shake Roof

As wood attracts water, it becomes highly vulnerable to cracks and leaks.

The constant cycle of swelling and shrinking of wood results in broken or split shakes. The sunlight invades the spaces between the shakes, called keyways, leaving the felt exposed.

A wood shake repair consists of replacing split shakes and installing wood segments in the keyways to block the exploded felt.

For wooden shake roof repair, follow these steps:

• Slant a sharp chisel up into the shake at the same angle as the pitch of the roof and split it carefully using a hammer. Remove pieces of damaged shake. Use a hacksaw to eliminate nail heads.
• Cut the new shake 3/8 inch smaller than the previous gap measurement (the shake swells the first time it rains), using a fine-tooth hacksaw.
• Install the new shake with its top edge placed on overlapping shingles. Nail down the shake with two roofing nails, one on each side.
• With a nail set, secure the nail heads and seal them with a caulking compound.

If you are not able to cut off old nails, you’ll have to carve the new shake to fit in the gap.

Tip 6 – Fixing An Open Roof Valley

Open valleys have exposed flashing that gathers rainwater and debris, leading to leaks.

Cracked commercial roof tiles, damaged flashing, and underlay allow water to enter roof valleys where the accumulation of debris and rainwater gives rise to leaks. As an emergency leak fix, you can locate the lroof eak source and apply a sealant to prevent any further leaking.

Here are the steps to repair an open roof valley: ­

• Check for small holes along the joint. Patch them with the same type of sheet metal from which the valley is made, otherwise, it will rust. Most valley metals are either aluminum or copper.
• Using a wire brush, clean the entire valley surface.
• Cut sheet metal patch about 2 inches larger than the hole.
• Apply a thick layer of cement on the targeted area and press the patch into the shape of a valley. Spread more cement to seal the edges of the patch.

Repairing an open roof valley means replacing roof tiles, flashing, membrane, or all three. You will need professional help in case of a full commercial roof repair or replacement of toxic lead flashing or roofing underlay.

Tip 7 – Fixing Metal Flashing

Detecting the metal flashing damage beforehand saves from expensive commercial roof leak repairs.

Roof flashing is thin galvanized steel used to secure joints of valleys, dormers, chimneys, vent pipes, and skylights, any area where the roof meets other structures. When flashing deteriorates, it succumbs to water leaks.

There are different ways to repair flashing, such as:

Patching Small Holes

If there are small holes due to corrosion, patch them using cement or a patch of the same material as the flashing. Cut the patch slightly larger than the hole to overlap its sides.

Replacing Corroded or Damaged Flashing

Highly corroded or damaged flashing needs replacement instead of repair. You will have to remove several rows of shingles to reach the base of the flashing. Hence, this work should be assigned to a commercial roofing company.

Cleaning Old Mortar and Caulk

Pull the cap lip flashing out of the mortar joint and clean the old mortar using a hammer and chisel. Brush off the debris and fill the cement mortar in the joint with a small trowel. Press the lip of the flashing into the mortar until dry. Finally, caulk around the joint with butyl rubber caulk. Use silicone caulking compound or urethane roofing cement to seal the seam between the cap and step flashing.

Tip 8 – Fixing A Vent Pipe

Vent pipes develop roof leaks when the metal flashing holding them together wears out.

Pitched roof vents are fittingly flashed with a metal sheet around the pipe and a protective collar that surrounds its base. For perfect replacement, the diameter of the replacement flashing must be the same as the old one.

The process of flashing around a vent pipe is as follows:

• Remove the old shingles along with the flashing. Clean the pipe from the outside and remove the old caulk.
• Install rubbery underlayments around the penetrations like nails to prevent water from seeping.
• Apply a layer of roof cement at the aluminum base and place the flashing on the pipe. Nail the flashing to secure them in place.
• Put the shingles back over the top of the flashing. Cut the shingles to leave half an inch around the base, meaning the flashing’s bottom must be left exposed.

Always wear gloves while working with metal flashing as they have sharp edges.

Tip 9 – Maintaining And Fixing Gutters

A well-maintained drainage system is an important component of a building’s structure.

Due to bad drainage, blocked gutters, downspouts, and scuppers, commercial roofs tend to accumulate leaves, debris, and bits of detritus from shingles. Excessive debris can lead to ponding of water, damaging the building’s infrastructure through roof leaks, mold, and insects. That is why conducting regular inspections and maintenance of the gutters is necessary.

• Regularly cleaning gutters to identify any roofing problems and to ensure that they can transport water flow properly.
• Check if there are any corrosion, stains, loose fittings, or separations along the seams. Separations can be fixed by resealing, but corrosion will need replacement.
• Trim the trees away from the commercial roofing by at least 3 feet to prevent natural debris.
• The gutters and downspouts should be securely fastened to the building. In high-wind areas, employ hurricane straps to secure them.
• If the drainage system is frequently clogged, inspect commercial gutter guards that act as a shield against debris.

Clogged gutters should be immediately cleared, as they put considerable strain on other roofing components.

Tip 10 – Applying A Waterproof Paint

Waterproof paints are a protective barrier against harsh weather and other damage.

Last but not least, to maintain your commercial roof’s integrity, invest in high-quality waterproof paint for your commercial building. Advanced, durable paints work as a protective layer and are more resistant to harsh chemical and environmental factors.

It prevents damage from external elements like thunder, rain, scorching heat, and radiation that can cause roof leakages for a long period. Masonry paint, a waterproofing paint made from ceramic and latex paints is one of the most preferred options for concrete roofs.

Epoxy and acrylic waterproofing paints are some other reliable paints.

Commercial Roof Repair Safety Precautions:

The do-it-yourself commercial roof repair can be dangerous for someone who’s not professionally trained. Make sure to take the following necessary precautions to avoid injuries or accidents.

1. Wear Protective Equipment

Roofers must wear eye protection goggles or glasses to keep off debris or dust. A hard hat, a pair of non-slip boots made with proper tread and rubber soles as well as rubber gloves will protect you while working with electrical equipment.

2. Secure Ladders

Before commencing the commercial roof repair work, ensure that your ladder is placed on even ground and is firmly secured. OSHA recommends using ladders or stairways whenever there is a ‘break in elevation’ of 19 inches or more.

3. Safety Harness

When your building has sharply pitched roofs, it’s safer to invest in a high-quality safety harness. Tie the harness to the roof to hold your weight and prevent any risk of falls and slips.

4. Act According to Weather

Strictly avoid working on the roof leak in case of heavy precipitation and strong wind. Also, extreme heat can lead to dehydration and loss of balance.

5. Keep an Assistant

Instead of handling commercial roof leak repairs single-handedly, ask someone to assist you, organize the space, bring additional equipment, and ensure your safety.

Now that you have understood how to fix a leaking roof, let’s find out the roof leak repair cost.

How Much Do Commercial Roof Repairs Cost?

Generally, the roof restoration costs range from $3 to $7 per square foot. Firstly, the costs depend on the scope of the commercial roof leak repair; minor repairs like patching leaks or replacing damaged shingles will be less expensive than a roof replacement. 

Secondly, commercial roof repair cost depends on the roof material. According to the Architectural Digest, costs of asphalt shingles range between $5 to $9 per square foot whereas barrel tile costs from $8 to $25 per square foot. For commercial business owners looking for a full roof replacement, the costs range anywhere from $7 to $8 per square foot.

Thirdly, the cost of repairing steeper commercial roofs will be higher than flat roofs. Lastly, other aspects such as labor cost, time of the year, location, permits, and inspections are contributing factors to roof leak repair costs. 

Commercial roofing contractors will provide you with a free repair quote for the work that is required, the timeline, and the cost needed to complete it. If your facility has suffered internal or external damage, make sure your insurance claim covers the commercial roof repair costs.

Commercial Roof Repair Services:

If you are not able to locate the source of the leak or don’t have the necessary skills, time, or tools to fix your commercial roof, it’s time to seek professional help. Commercial roofing contractors carry the expertise and equipment to repair most types of roof leaks quickly and efficiently. They conduct a professional roof survey to determine the requirements of your commercial roof repair or replacement. Additionally, expert commercial roofers will advise you on quality materials for roof installation, maintenance practices, and applications.

How to Find the Best Commercial Roofing Contractor?

When you need professional roofing services, you can either hire a commercial roofer or a general contractor. Below are some helpful tips for selecting a quality commercial roofing contractor. 

• Prefer working with a local commercial roofer as they are knowledgeable about local weather, building codes, and regulations which is extremely important for roof installation. 
• To find a qualified roofer in your area, search online for “commercial roof repair near me” or “commercial roofing services”.
• Request at least three to four itemized quotes from different roofing contractors to evaluate your best bet. 
• Perform due diligence by checking their licenses and certifications. In California, commercial roofers must have a C-39 roofing contractor license for projects over $500. Additionally, ensure they have NRCA Certifications. 
• While evaluating different bids, check if the commercial roofing contractor has experience in similar roof installation, roof replacement, or repair projects to yours. Ask for client referrals. 
• Double-check if the commercial roofers have these insurances: workers’ compensation, general liability, and a surety bond. Compare their workmanship warranty and manufacturer’s warranty (often lasting 10, 20, or 25 years) before making your final decision. 

5 Best Practices for Your Commercial Roof Maintenance 

Regularly maintaining your commercial roof significantly prolongs its life expectancy. Commercial roof maintenance prevents costly repairs, improves energy efficiency, and protects your building from water damage. Here are the best practices to include in your commercial roof maintenance plan and avoid future roof leaks. 

1. Conduct Regular Inspections 

The standard rule of thumb in the roofing industry is that you should inspect a commercial-grade roof twice a year. You can also hire professional roofers for inspections and maintenance who will identify cracks, leaks, or other damages. Scheduling routine inspections helps solve problems before they occur and avoid expensive roof repairs. 

2. Keep the Roof Clean 

Keep your commercial roofing system free of debris, leaves, dirt, sticks, or ice dams that can obstruct water from draining off the roof. If left unattended, pooled water results in mold and mildew, which can weaken the roof and cause leaks or other serious damages. Cleaning gutters, drains, scuppers, and leader boxes frequently is essential for proper commercial roof maintenance. 

3. Invest in Roof Coatings 

Roof coatings are liquid solutions applied to commercial roofing by spraying or rolling, adding a protective layer. For example, acrylics, asphalt, polyurethanes, and silicones. Applying roof coatings is viewed as a best practice in maintaining commercial roofs because they form a waterproof barrier, reflect UV radiation, and help in temperature regulation. Using reflective roof coatings can minimize temperatures by up to 50°F, lowering energy costs. 

4. Maintain Your Roof Documentation 

As a best practice for commercial roof maintenance, building owners and facility managers should preserve all roof information. Keeping detailed reports helps one track the history of a commercial roof’s condition. Your documentation file must include: 

• Records of roof inspections, maintenance, repairs, replacements, guarantees and warranties.
• Your commercial roof’s design and dimensions 
• Drainage system details 
• Placement and size of mechanical equipment 
• Information about thermal insulation 

5. Immediately Repair Damages 

Late commercial roof repairs can promote more complicated and expensive issues. Hence, immediately addressing damages as soon as you identify them prolongs roof maintenance. If required, seek professional help from a commercial roofer or inspector to find and repair roof damages expertly. 

Conclusion:

Commercial roofs are an important element of any building’s infrastructure. Regular inspection, estimates, and small commercial roof repairs or replacements can minimize your expenses, enhance your roof’s condition, and maximize its longevity. As soon as you spot leaks, you should deal with them right away. Always wear rubber gloves and shoes while working on commercial roof repairs.

It’s important to know when to seek professional help as repair works include several safety concerns. A commercial roofing contractor carries the proper tools and experience to conduct assessments, repairs, and replacements.

At Constructive Solutions, Inc. our skilled specialists will check for leaks or other roofing problems and provide longer-lasting solutions.

If you want to schedule a commercial repair or replacement, contact us today.

FAQs:

What services are provided by a commercial roofing contractor?

Commercial roofers conduct inspection and damage assessment surveys, installation and repair of commercial roofs. They also provide various maintenance packages and specialty commercial roofing services.

Should I temporarily shut down my business during the roof repair? 

Roofing works often generate dust, noise, and vibrations. If the roof repairs are minor and your employees can adjust to slight traffic disruptions, then continue with your operations. If not, then it’s better to shut down the business till the roof repair is done. 

How can I determine whether my commercial roof needs a roof replacement or a roof repair? 

While commercial roof repair is an affordable method for repairing localized damages, some roof repairs are not feasible and cost-effective. If your commercial roofing has suffered substantial damage, is nearing the end of its life, and leading to high energy costs, then a commercial roof replacement is the best long-term investment.

Relevant Resources:

10 Green Flags To Look For in a Reliable Commercial Contractor

Building a Greener Future: Techniques for Energy-Efficient Construction