This dark and oily substance can repair leaks on your flat roof and protect against outside elements. A by-product of petroleum and coal tar, this thick black residue hardens over your roof to create a waterproof seal against the elements.
We’ve got everything you need to know about roofing tar, from price to pros and cons, below.
What Is Roofing Tar and What Do You Use It For?
Sticky, dark, viscous. Roofing tar is a waterproofing barrier designed for low-slope or flat roofs. This sealant fills gaps and cracks to stop rain and snow from finding their way inside.
What’s it for? This watertight coating is used to patch holes or new cracks in your roof to prevent damage worsening. It’s a key part of the ‘tar and gravel’ roof system, where gravel and tar layer up to create a durable waterproof barrier.
Apply it hot or cold – roofing tar can be done DIY and is quick to apply. Curing will take a couple of days though.
Different Types of Roofing Tar
- Coal tar is the traditional kind of tar, made from distilled coal. This one is exceptionally water-resistant.
- Asphalt-based tar is made from petroleum byproducts and is the most common roofing tar used today.
- Modified roofing tar bitumen is asphalt tar enhanced with polymers or rubbers. This one has added flexibility and durability.
How Much Does Roofing Tar Cost?
You can expect to pay somewhere between $0.15 and $2.75 per square foot for your tar roof materials. When you consider the labour and installation costs, prices could rise to around $1-4. Overall, you might pay as little as $500 for your whole roof, or as much as £2,000.
Why the big variation in numbers? Well, different types of sealants have different costs. Higher quality products inevitably come with a higher price tag – but then again, they should last longer, making them more cost-effective in the long run.
The existing material already on your roof will affect the cost too, as this can change the amount of preparation needed and the number of layers for an effective seal.
Finally, an experienced roofing expert will cost more than doing the job yourself. But with a pro, you can rest assured that the job is done well.
Consider what works best for you and what you can afford – DIY or pro? Quality material or something slightly cheaper?
How to Apply Roofing Tar?
Ready to get going? Here’s your step-by-step to applying tar to your roof.
1. Measure How Much Tar You Need
First things first, how much tar do you need? You’ll need to climb up to your roof with your measuring tape and calculate the dimensions manually to find out.
Asphalt tar is usually your best option for flat roofing surfaces. Pitched roofs with a steep slope might need coal tar bitumen. Not sure? Snap a picture of your roof and show the pros at the roofing supply store.
2. Put Down a Base Layer
Now you’re ready to begin the work. Create a base layer by nailing elastomeric, asphalt, or aluminised underlay to your roof – this will protect the building from the hot temperatures of the sizzling tar you’re about to pour on it. A gravel-embedded layer will strengthen and thicken your roof structure, better protecting your home from extreme weather.
3. Transport the Tar
Right, so you’ve got the base layer down and the recently-purchased tar ready and waiting. Have you thought about how you’re going to get that boiling hot tar from the safety of the ground to the top of your roof? This is an important consideration.
For smaller projects, you might be able to carry bucket-sized amounts up a ladder. Don’t overfill your bucket – you don’t want to spill anything. Bigger roofing jobs might require you to pour the tar directly from the pipes of a truck.
4. Apply the Tar
Start in the corner of your roof and pour the tar out. Use a fiberglass mop to spread, focusing on smooth movements to create a thin layer across the whole of your roof – you don’t want any lumps or clumps. It’s a good idea to work in a straight line.
Done? Now spread tar paper across the top. Use your mop again to go over it. Overlap the tar paper to create a seal.
Pros of Roofing Tar
No one likes a damp home. Mould and mildew ensue, and it’s all-around bad for you and your home’s structural integrity. A little thing like roofing tar can go a long way to reducing the humidity inside your home. Here are the pros of roofing tar:
- It creates a watertight seal that reduces the moisture inside your home
- It protects your roof materials from extreme weather, like rain causing ponding water, wind, or strong UV rays
- It’s efficient and low-cost
Cons of Roofing Tar
The downsides of roofing tar tend to lie in the safety considerations.
- The asphalt can give toxic fumes during application, so it’s important to wear protective masks
- Hot tar can be dangerous to handle – especially on sloped roofs
- If installed improperly, it can trap moisture which exacerbates damage
Final Thoughts on Roofing Tar
Good for waterproofing flat roofs, but might require a pro’s touch if you’re attempting anything else – roofing tar is a cost-effective and durable sealant. It’s a quick job and can be left to cure on its own. This oily mixture of coal tar roof cement will help keep your home dry from the elements.
FAQs
Will Roofing Tar Stop a Leak?
Certainly! Roofing tar is a quick, temporary solution to prevent water seeping through cracks in your home. It’s inexpensive and highly waterproof. If you’ve noticed water damage, it’s best to consult a professional to find a lasting solution.
How Long Does Roofing Tar Last?
A quick patch job might last anywhere from three to five years. A full hot tar and gravel roofing layer might survive for 20-30 years with regular TLC. Quality of the roofing material, installation, climate, UV exposure, and maintenance practices all play a part in how long your roofing tar lives for.