How to Make a Flat Roof Watertight?

Once a flat roof starts to leak it, patching rarely stops the leaks for long. Finding and fixing leaks be a costly and frustrating endeavor. But it doesn't have to be. ArmorGarage Flat Roof Coating is specifically made to stop all leaks on all rubber or tar based roofs. In this article we'll go through what to do and what not to do. Such as applying all sorts of black roof cements, fillers, aluminum fibered coatings all over the place. This leads to all sorts of bigger problems down the road. You can even spray parts of your roof with stuff out of a can you bought on TV but then you'll have to replace your roof shortly thereafter because it will last a few weeks and start peeling but not peeling all the way off. Getting the rest of it off is very difficult and nothing else can stick to it. So you can see the problem.

Flat roofs are a popular choice for both residential and commercial buildings. However, they require the right attention when it comes to keeping them watertight. Unlike sloped roofs that allow for natural water runoff, flat roofs are prone to water pooling, leaks, and moisture-related damage. Getting and keeping a flat roof watertight isn't just smart, it's essential for maintaining long-term durability and avoiding damage to your roof, building structure and the assets inside your building.

With the right materials, waterproofing your flat roof can be an easy and successful DIY project. This guide will walk you through effective application methods and how to use ArmorGarage's high-performance products to protect your investment. Most importantly, it will help you avoid an astronomically expensive roof replacement.

Prevent Water Damage

Water that sits on the surface can penetrate even small cracks in your roof, damaging insulation, drywall, and even the structural integrity of the building. It will also destroy most roof coatings and roof patch products. You must use a Ponding Water Proof Roof Coating in those areas. How do you if you have ponding water? Any area of the roof that still has water sitting on it after 48 hrs is a ponding water spot. Left untreated it will eventually decompose your roof material in that area. In those areas you will notice that after the water evaporates there will be a layer or layers of soot and silt. 

Extend Roof Lifespan

A quality roof coating protects the roof from weathering, helping it resist breakdown over time. A high quality durable material like ArmorGarage’s Roof Coating can dramatically increase the life of your flat roof by decades.

Boost Energy Efficiency

ArmorGarage roof coatings reflect heat and sunlight, improving the insulation factor of your roof, lowering internal room temperatures, and reducing the load on your HVAC system. A sealed, reflective roof will contribute to lower utility costs year-round.

Preserve Functionality and Appearance

Many flat roofs double as functional outdoor spaces. Our roof coating can protect these areas from damage while maintaining a clean, usable surface. ArmorGarage roof coatings are tough enough to handle high foot traffic. We have a version of our coating with rubber granules embedded into it for heaviy traffic areas. Be cautious with silicone coatings that are vey soft and are easily damaged.

Why You Don’t Need to Hire a Contractor

Coating your roof doesn't require a professional crew or industrial equipment. With the right product and preparation, you can do it yourself and often get better long-term performance by using systems made for long term wear resistance. If you can use a roller you can apply a roof coating to your roof. ArmorGarage experts can help guide you through the straight forward process. Our Flat Roof Coating Product Page has step by step instructions on how to prep your seams and flshings and how to easily apply the coating at the correct thickness.

ArmorGarage Makes Coating Your Roof Simple

ArmorGarage offers high-performance products specifically designed for user-friendly application, like the:

• ArmorGarage Roof Coating System: A heavy-duty rubber-based epoxy coating designed to seal flat roofs and stop leaks fast.
• ArmorGarage Metal Roof Coating: Made specifically to handle large expansion and contractions, lower room temperatures and stop leaks.
• ArmorGarage Ponding Water Roof coating for roofs that hold water due to low spots.
• ArmorGarage Seam Mastic: For sealing items such as seams, screws and flashing, for a more comprehensive solution.

These products are engineered for first-time users and seasoned DIYers alike, eliminating the need to outsource the job. If you need to outsource the job, any handyman or painter can do the job very easily. We work with on roof projects all the time.

Roof Coating Application

It's applied with rollers, brushes or sprayers and cures into a flexible membrane that expands and contracts with temperature changes.

Seam Reinforcement

Use ArmorGarage Seam Mastic to reinforce critical areas before applying the coating. These materials add strength to joints, penetrations, and edges, ensuring water doesn't find a way in.

Multi-Layer Systems for Extra Protection

ArmorGarage falt and metal roof coatings are applied in two coats with no primer required unless you’re coating over a painted metal roof. Then we recommend a Bonding Primer to ensure the coating bonds to the paint on your roof. Two coats provide the proper thickness for durability and 100% water tightness. The Ponding water Roof Coating gets applied in one thicker coat.

Signs Your Roof Needs Attention

Even if your flat roof appears fine, these signs may indicate it’s time to apply a waterproof coating:

• Water pooling that doesn’t evaporate after 48 hours
• Mold, mildew, or water stains inside the building
• Blistering, bubbling, or cracking on the roof surface
• Exposed seams or peeling paint/coating
• High energy bills due to poor roof insulation

Catching these early and using a reliable roof coating product like ArmorGarage’s can prevent much bigger repairs down the road.

What Not To Do:

Once your roof starts to leak it can a long, costly and futile effort to stop it if you try the putting a band-aid on it by patching wherever you think the leak is coming from. Almost always the leak is not where the water is coming into the building. Depending on the roof size it can be a long way away from the actual leak source. The water gets past the roofing material and then runs under it causing damage to your insulation, roof boards or sheathing until it finds the first opening, which is where it makes itself visible via drips inside your building. 

Then what happens is you go to your locl home improvement store and purchase black roof cement and start patching. This may stop the leaks but they always come back. Why? because the cement ages quickly, gets brittle, and starts alligatoring. In short the patching materials fail. Then you try a different product and that fails. Before you know it, you have a bunch of different and most likely incompatible products on your roof, creating a mess, and your roof is still leaking. What's worse is that many times you can go too far and actually ruin your roof to the point it needs to be replaced. We get pictures from customers of their roofs and sometimes we can't tell if its a roof. There are so many patches, spliced in materials, dirt, and soot from ponding water, and the roof material is so deteriorated that no coating can save it, not even ours. We then have to give them the bad news, and if you've seen the prices roofers are getting for new commercial roofs, you know it's really bad news.

The best thing to do is at a minimum, patch with our Epoxy Roof Mastic. It's far superior than roofing cement. It's made to be a permanent fix. If you haven't stopped the leaking with seam mastic then you need to apply the roof coating to avoid damage from water under the roof and water damage inside your building, not to mention the damage you will do with improper patching with inferior products.

How to Apply ArmorGarage Waterproof Coatings

1. Clean the Roof – Remove all dirt, grease, and debris. A clean surface ensures maximum adhesion.
2. Repair Damage – Patch any cracks or holes using ArmorGarage repair materials.
3. Reinforce Seams – Apply seam mastic over vulnerable areas, flashings and roof penetrations.
4. Apply Base Coat – Roll or brush on the first coat. Let it cure per product instructions.
5. Apply Topcoat – Once the base  coat cures, apply the second coat for extra durability and leak protection.
6. Inspect and Maintain – Periodic checks  to keep roof drains clear of debris help extend roof life even further.

Full instructions are included along with unlimited support before, during and after the job is done.

Final Thoughts

Waterproofing a flat or metal roof doesn’t have to be complex or expensive. With the right products and a DIY approach, you can protect your roof against leaks, extend its lifespan, and enhance its performance and lowering energy bills without calling in a crew.

ArmorGarage provides everything you need to get the job done right the first time. From heavy-duty waterproof roof coatings to reinforced seam materials, our coatings are built for roof protection that lasts. Once fully coated with an ArmorGarage roof coating it’s impossible for water to leak through! Whether you're dealing with an old roof or preventing future damage, ArmorGarage gives you the confidence and materials to seal your roof like a pro, without hiring one.