Tar and Gravel Flat Roofing Guide
You don’t have to be a construction expert to notice that there are a lot of different styles of buildings. The preferred styles of homes and business change from decade to decade and vary by region. For one, tar and gravel flat roofs gained popularity in the 50’s and 60’s, especially in commercial building roofs.
Flat roofs are ideal for factories, malls, schools, and other large buildings because they are simple to build and they allow for roof decks or patios and extra storage. Tar and gravel was the preferred roofing material for flat roofs and remains an excellent option to this day.
Chris Fraser, the owner of Crest Roofing, is a tar and gravel expert. He has over 30 years of experience installing and maintaining these special roofs. With all this experience, he confidently says that tar and gravel flat roofs can last 35 or 40 years!
They may seem like the “old school” option, but we want to see tar and gravel roofs make a comeback. It’s a specialized system with lots of great features with manufacturers who continue to make improvements in the quality of the materials used to make tar and gravel roofs.
At Crest Roofing, we’re serious about tar and gravel roofs. They require their own special equipment and insurance. Recently we bought a gravel hopper and roof bocker specifically for our tar and gravel projects!
Pros and Cons of Tar and Gravel Roofs
There are lots of different roofing materials you can use on a flat roof and each comes with their pros and cons. What you decide on is always going to be based on what meets your unique needs because every roof is different.
Here are a few things to consider about tar and gravel roofs:
Disadvantages of tar and gravel roofs:
Mold: In general, flat roofs are more susceptible to mold. It can be found in the walls or insulation. Flat roof mold usually happens when the roofs don’t have proper ventilation. Trapped moisture in the wooden structure or insulation will make mold grow.
We find that roofs that haven’t been maintained well (or they’ve been completely ignored) tend to be the ones that have mold.
The weight on your roof: Compared to lightweight systems like SBS or EPDM, tar and gravel roofs are very heavy. With SBS there are usually a couple layers of a synthetic rubber product, but with tar and gravel, there are three or more layers of tar, felt or fibreglass layers, and small rocks.
Tar and gravel roofs need to have proper support structures that won’t be stressed by the weight.
The tar smell during installation: Yes, it smells. The pungent smell of bitumen boiling in a kettle for the duration of the project. It’s the same smell you get when you’re driving through a construction zone as they’re laying new road.
It’s definitely not the best smell in the world, but your air will go back to normal when the project is finished.
Finding leaks in a tar and gravel roof can be tough: To be fair, it can be hard to find leaks in just about any type of roof. With membrane roofing like EPDM, finding a leak is like finding a needle in a haystack. We are experienced roofing pros, so we know what signs to look for and have special equipment to help us.
Fire risk: Every year there are roofs that go up in flames because of careless roofers. With tar and gravel application, there is a giant kettle full of molten tar. If the kettle is too hot or the materials are too low, a fire can break out. Read more about kettle fire causes here.
At Crest Roofing, we are experienced and trained to deal with our equipment, and if a fire ever broke out, we are prepared.
Advantages of tar and gravel roofs:
Quick Installation: We find that it’s quicker to install than other types of roof systems.
Proven to last: There are roofs from the 70’s are still around. Roofs don’t last forever, and it’s a testament to their durability that they can still offer protection after almost 50 years.
Protection from UV rays: The gravel coating protects your roof from harmful UV rays, making your roof last a long time. The many surfaces on gravel also scatter light instead of absorbing it, which can keep your roof cooler in the summer.
Usually one of the least expensive flat roofing materials: This is one of the biggest draws of tar and gravel roofs. You get the most bang for your buck. It’s a durable, long-lasting roof system that costs less than synthetic membranes.
Extremely rugged: SBS systems are delicate compared to tar and gravel roofs. Wearing the wrong footwear causes wear, and if you’re not careful, you could end up putting holes in it! Tar and gravel is tough. It has multiple layers of rocks and bitumen, so it can stand up to foot traffic.
Are you wondering about the pros and cons of other flat roofing materials? Check out our article: Which is the Best Roofing Material for my Flat Roof.
Tips for Flat Roof Maintenance
Tar and gravel roofs are easy to maintain, you just need to know what you’re doing. Here are a few easy tips that will help you get the most out of your tar and gravel flat roof.
1. Get your roof inspected yearly
A lot can happen in a year. That’s why it’s smart to have your roof inspected each year, especially if there has been extreme weather like high winds, heavy snow, or rainstorms.
2. Make repairs immediately
Roof leaks, rot, blistering, ponding, cracking, and bubbling are all problems that can show up on a flat roof. The problem might be small, but with roofing, it’s only a matter of time before it gets worse.
You could end up with structural problems, rotting that spreads like cancer or leaks that flood the entire building. Stay on top of your inspection and maintenance and fix problems as soon as you spot them.
3. Clear off the roof
Some winters are worse than others, but Edmonton tends to get a lot of snow. Sometimes the skies open up and we get two feet in a day. This can be a huge problem for tar and gravel roofs because they are already heavy to begin with. Be sure to clear off ice and snow in the winter.
4. Clean the roof
When you’re cleaning your roof, make sure to check the drains for debris. You should also take a close look at the gravel to see if things are growing. It’s not unusual to have trees or grass take root on your roof. If you see things growing, have a roofing professional inspect and clean your roof.
5. Trim trees
They’re lovely, they provide shade, and they can add value to your property, but trees can be terrible for your roof! Make sure to keep the trees near your roof trimmed. With flat roofs, make sure to check that the drains and gutters are clear of leaves, seeds/pollen, and branches.
6. Get the right roofing company
You should always do your homework when hiring a company to do your roofing work because there are lots of fly-by-night roofing contracts out there. Beware of low quotes because lower quotes mean they’re cutting corners by using low quality materials or not having insurance.
For details and explanations about residential flat roof maintenance, check out the full article: Our Beginner’s Guide to Maintaining Your Residential Flat Roof.
Here are a few of the most common questions we get about tar and gravel roofs
1. I can see blisters or bubbles poking through the gravel, but my roof isn’t leaking. Can these be fixed?
Yes, we can fix blisters and bubbles. These can be caused by moisture trapped between the layers of tar and gravel. Rain during installation is a common cause of blistering and bubbling.
We scrape away about a foot of gravel from the blisters, cut them out and add two layers to the existing membrane. Don’t put off having them fixed because foot traffic from shoveling snow, checking the drains, or other maintenance can make the problem worse.
2. How much does a tar and gravel roof cost?
Each roof is unique and there are a lot of things that go into your roof quote besides just the roofing material. That can include things like
- Complexity of the project,
- Removal of the old roof,
- Size of the job,
- Roof additions: chimneys, vents, skylights, hatches,
- Parapet walls,
- Roof deck repairs, and
- Repairs to the curb and flashing.
Flat roof replacement is a very labour-intensive job. It might seem that your quote is high, but scrimping on price by going with an inexperienced contractor or using lower quality materials will lead to trouble sooner than later.
Crest Roofing is a leading roofing company in Edmonton and we will look at your roof and recommend the best roofing system to meet your needs. Feel free to shop around, google information, and consult with an accredited roofing inspector. You’ll find that we know what we’re talking about and we’ll treat you like respected friends.
3. What brands do we use for tar and gravel roofs?
Call Crest Roofing for an Expert Installation or Repair of Your Tar and Gravel Roof
At Crest Roofing, we are the flat roofing experts, so if you’re thinking about installing tar and gravel or any other roofing system, give us a call.
We will do a roofing inspection and give you recommendations on the best type of system for your unique needs.
We do installations, repairs, and replacements. If you need snow removal during the winter or repairs or upgrades to your ventilation or drainage systems, we can help you with that too.
Give us a call at (780) 466-1601 or send us a message to find out more about your tar & gravel roof!
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