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How to Keep Your Roof Cool in Summer Naturally

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Keeping your roof cool during the summer is essential if you want the rest of your house to remain cool. Most of the sun’s heat is absorbed through the roof, which means you’ll need to somehow prevent that light from reaching the roof. And the best part is that many of the most effective sunlight-blocking methods are all-natural.

Here are 5 ways to keep your roof cool in summer naturally:

  • Install shingles with high solar reflectance.
  • Coat your shingles with tiles or aluminum.
  • Install a radiant barrier. 
  • Cover your roof in a thin layer of rocks. 
  • Create a rooftop garden. 

In this article, we will be looking into all of these solutions in great detail. By the end, you’ll have enough insight to decide which approach will work best for you.

Choose the right materials to keep your roof cool.

The first entry on your list is a no-brainer. One of the best and easiest ways to ensure your roof stays naturally cool in the summer is to make sure you’re using the right materials. It is currently estimated that as much as 90% of American houses have roofs that are designed in such a way that they trap a lot more heat than they should, and this usually makes these roofs a lot hotter than their general vicinity.

When selecting the material/coating for your roof, you need to be mindful of the material’s solar reflectivity and its thermal emittance.

  • Solar reflectance denotes how much of the sunlight is actually reflected back rather than being absorbed.
  • Thermal emittance refers to the roof’s ability to release the absorbed heat back into the environment, thus helping it cool faster.

Together, these two properties make up something called the Solar Reflectance Index. If you want a cool roof, you need to inquire about the Solar Reflectance Index (measured on a scale of 1 to 100) of the materials before you choose them.

Some materials like asphalt shingles have low solar reflectance (around 30%) and higher emittance, while others like metals have higher reflectance (over 70%) but lower emittance. Of course, asphalt roofs are a lot cheaper to install compared to metal roofs, but in the long run, the latter could end up saving you more money in electricity bills.

Choose the right coating for your roof.

Besides choosing the right material for your roof, you can also apply an extra layer of reflective coating that improves the overall solar reflectance Index of your roof. This option is particularly practical for people who don’t want to spend a lot of money re-doing their roofs altogether.

Tiles

One great and almost ubiquitous example of a great reflective coating are tiles.

Tiles are popular for multiple reasons. Not only do they add to the show of your house, but they also have a high solar reflectance index (more than 50%). They have a particularly high thermal emittance (more than 80%) and are also very durable and relatively cheap to install.

White Roof Coating

Another great reflective coating is a white roof coating. This is an opaque white coat of some polymeric materials that covers the top of your roof, adding to its reflectivity. The reflectivity improves as you make the coat thicker, and on average, a white roof coating is able to reflect over 70% of the sun’s heat!  

Aluminum Roof Coating

Another popular option is an aluminum roof coating. Not only do aluminum roof coatings help reflect back more than 50% of the sun’s heat, but they also serve a double purpose in preventing leakage from your roof.

Install a radiant barrier.

Another great way to keep your roof naturally cool in the summer involves the use of radiant barriers. Radiant barriers are basically aluminum foils wrapped around paper, and the best thing about them is that with a little bit of preparation, you can easily install them on your own.

Here’s the process:

  1. Go to your attic on a cool day (trust us, you don’t want to be working in the attic during a hot day). 
  2. Whatever your current roofing arrangement may be, tightly attach a layer of aluminum foil to the underside of your roof. Make sure you don’t leave any gaps. 
  3. Once you’re done attaching the aluminum foil, take a roll of paper and attach that over the aluminum foil. 
  4. The aluminum foil and the paper work together to prevent the heat from entering the house via the roof.

If installed correctly, a radiant barrier can help reduce the amount of heat that enters your house through the roof by up to 25 percent! So, this is definitely worth considering before you go out and invest in other more expensive options.

Cover your roof in a thin layer of rocks.

There is another rather intuitive way to keep your roof cool in the hotter seasons. You could add a thin layer of rocks and stones either on top or in between your roof membranes. 

What these rocks do is that they act as natural insulators, preventing the sun’s heat from penetrating into the house via the roof. They can achieve this owing to a property known as the heat capacity. The heat capacity of rocks and stones is high, which means they take a lot more time to heat up compared to other materials.

Also known as ballasted roofing systems, adding a layer of rocks or pebbles on your roof can greatly help reduce the amount of heat your roof traps. And if you’re feeling more adventurous, you could even combine this option with the next option on our list to get a rooftop that stays naturally super cool in the summer.

Marble chips and white gravel also work like magic, as they have high solar reflectance.

Create a rooftop garden.

This is perhaps the most interesting of all the solutions listed in this article. You can significantly reduce the amount of heat your roof traps during the summer by building a sort of a rooftop garden.

You can first cover the roof with a thin layer of sand and gravel and then plant some grass/plants on top of it. Once the plants are grown, they’ll act as natural coolers for your roof, owing to the properties of evaporation and transpiration.

Besides, your house is going to look a lot cooler with a garden growing on top of it. We recommend you make this a seasonal thing. In the colder seasons, you will, of course, want your roof to trap as much heat as it can. You can start building your rooftop garden in the spring so that the plants are fully grown by the summer. Likewise, you can remove the garden in the fall.

Conclusion

Houses can heat up a lot during the summer. A lot of this has to do with the heat absorbed by the roof of a house. Fortunately, there are plenty of ways you can keep them naturally cool. 

The first thing you need to consider is getting the right materials. Materials with higher solar reflectance and thermal emittance are preferred. Alternatively, you could also apply a special coating to your roof that can greatly improve its reflectivity. You can also bring down the temperature of your roof by adding a layer of rocks or stones or by building a rooftop garden.