For the avid campers out there: have you ever been caught in a rainy situation while you are in your tent? We believe many of us have experienced something like that and when we see the shadow of the raindrops slowly cascading down the tent, we have this inscrutable urge to palm it.
Upon contact with the tent, you will notice a moist texture permeating through the surface which will probably make you question whether your tent is actually waterproof or not.
Here is where we can reassure you that you did not blow hundreds of dollars on good camping equipment.
This leakage can result from a combination of factors like hydrostatic head, capillary action, and surface tension, all of which will be explained.
For those of you who are unfamiliar with scientific terms, the hydrostatic head relates directly to water resistance. In simple terms, the hydrostatic head is the amount of water that the tent can resist. So, just imagine that water gathers in a cylindrical shape on your tent; the moment at which the height of the cylinder exerts the most pressure on the tent is what determines its hydrostatic head. When you see a label on the tent stating that it has a hydrostatic head of 5000, that means the tent can withstand a column of water that is 5000mm tall. However, the hydrostatic head does not play as much a significant role as the other factors. They simply determine how resistant your tent is to water.
Now we move on to one of the contributing factors that allow some water to seep through your tent into the inside. As we all know everything in nature is not gapless, if we took a microscope and zoomed into the fabric that makes up our tents, we will notice that it is porous in nature. These are what you would call capillaries. As for capillary action, the liquid can flow through tight spaces with little resistance. This phenomenon is similar to that of when you insert a straw into your drink. This is the reason why water can pass through the fabrics from the outside of your tent to the interior of your tent. However, with a higher hydrostatic head, the capillary action also becomes less which means less water will pass through the pores. So, while capillary action can explain how water passes through, it is not the most important factor.
Unlike the previous two factors which relate to the material of the tent itself, the surface tension comes from the water. When our eyes can see water droplets, it is the aftermath of the combination of millions of water molecules. At that point, each molecule is attracted to its neighbouring particle. When the water droplet becomes heavy enough, the bottom layer is where all the molecules gather together as a result of gravity. This creates a pressure difference between the top and bottom layer resulting in the surface tension. That tension is what keeps the water droplet from permeating through the fabric. However, when you run your hands through the inside of the tent, you end up breaking the surface tension, the main line of defence to prevent the water from pushing past the fabric.
Thus, if you are wondering what causes water to leak through our tents, it is not boiled down to just one factor. The driving reason is the surface tension but it can also be the result of a tent with an insufficient hydrostatic head.
How do I prevent water seepage?
Firstly, space is the number one reason why our hands can so easily brush across our tent which will cause a problem with surface tension. So, if you find yourself experiencing this, it might be time to consider whether your tent is too small or if there are too many items in the tent. If your sleeping area is taking up too much space and you can consider downsizing it, that would be a good solution. Otherwise, the best solution is to simply invest in a bigger tent.
Next, the main reason for water to seep through your tent when you touch it is because of the breaking of surface tension. If the hydrostatic head of your tent is high enough, it can repel some water even if the surface tension is broken. So, if you are intending to change your current tent, it might be good to look at tents with higher hydrostatic head values.
You might be wondering what exactly is a tent of sufficient hydrostatic head value. Normally, a tent that has a value between 3000 to 4000 would prove to be a good tent that can protect you from the elements.
Another thing that you can do to prevent such seepages is to check your surroundings before you pitch up a tent in the area. Removing any sharp rocks or sticks will prolong the lifespan of your camping gear and prevent cuts and tears. So, that is another extra precautionary step that you can take that costs nothing but can cut costs for you in the future.
Some additional alternatives that you can consider are also to make use of tarps as a shelter or mat for your tent. By suspending these tarps over your tent, you can decrease the amount of rain flow that comes into direct contact with your tent. Doubling up with a tarp under your tent can also protect the base of it in a similar manner.
Finally, if you have more budget for camping gear, you can even invest in a rainfly or waterproof silicone spray. Rain flies are designed precisely to keep out the rain which is why they would be the aptest gear. Otherwise, waterproof silicone spray can also protect your tent for a short amount of time.
Holing up in a tent when it rains is never fun, sure, but it doesn’t have to be a soggy and miserable experience. There are plenty of measures we can take to increase the waterproofing of our tents, and it is important that we look at not just our equipment, but our surroundings as well. Happy camping!