Home Improvements

How Stuff Works: What is Waterproofing?

Most of us know waterproofing is important. And we get the concept well enough – waterproofing keeps water out. 

But what is waterproofing exactly? How does it work? What happens without it? Keep reading to learn more. 

What is waterproofing? Image description: close up of water on brown bricks.

What is Waterproofing?

Waterproofing is essentially filling all the gaps where water could get into your home. This is an important task because, without it, you’ll have all sorts of problems. 

Moisture in your home leads to mold and bug infestations. These can have serious consequences on your health and safety. 

Too much water can also lead to structural damage in your home. Wood is particularly easy to waterlog, meaning water gets trapped in the material and it swells and rots. 

Waterproofing can also help decrease the humidity in your home. Since humidity is often due to a high moisture concentration in the air, making it more difficult for water to get in helps reduce this. 

lots of rain, heavy stream of water running off the roof of a house

What Areas are Most Important for Waterproofing?

Your roof and ceiling get a lot of focus. This is because the roof gets the most exposure to rain, so it’s got the biggest chance of collecting water and bringing it into the rest of the house. 

The seams between the walls and roof also get a lot of focus for waterproofing. Window frames are installed in a way that seals them so water can’t get in. 

How Does It Work?

There are a few ways of waterproofing an area. You can do indoor and outdoor waterproofing. The most effective method of waterproofing is when you can build the membrane between the layers you’re sealing. 

What is waterproofing? You can see the reinforced metal around window frames and skylights. Image description: orange tiled roof with windows that jut out, with thick dark metal frames surrounding them.

Torch On 

The torch on method involves a plastic membrane that comes in sheets. The sheets are rolled out across an area. Using a blowtorch, the sheets are melted onto the area. 

Once the sheet is applied, you can apply a finish to it that makes it look more aesthetically pleasing. The membrane is impenetrable, so it’s perfect for roofing. And since you’ve got lots of options when it comes to the mineral finish, it means it works for lots of different types of roofing styles. 


This method is also a popular choice for roofs. Flashing uses small pieces of metal and applies them to the joints and seams on roofs, like chimneys, vents, and skylights. There are flashing metal slabs designed specifically for roofs, windows, and walls. 

This process is ideal when you are wanting to reinforce the seam in an area, or are sealing up a problem area that had started leaking. 

White wall with a window with a wooden frame set into it. Thick black metal is set around the wooden window frame. This is an example of flashing waterproofing.

Image from Flickr.


Sealants are great for smaller areas like windows. There are sealants you can buy in stores and apply yourself. These solutions are soft and plastic based. 

Using an applicator, you pump the sealant into the identified gaps (e.g., around the window frame). The plastic substance fills the gap completely. Once it’s dry, it hardens and is impervious to water or moisture penetration. 

wooden window frame having sealant applied to it by a gloved hand

Waterproofing Your Home

Now that you know the answer to ‘what is waterproofing?’ you know how important it is. To keep your home safe and sturdy, you’ve got to put in the steps to keep water out of the building. 

Make sure your waterproofing is up to date. Contact an expert waterproofer to do an inspection or redo your waterproofing now!

You’re in good company