If you’re looking to buy a waterproof tent that uses a polyester-based material, then you’ll likely come across the term Waterhead Rating. But what does it mean?
Waterhead Rating, also called Water Column (WC) rating is the measure of how water resistant your tent material is. It measures how tall a column of water the fabric can hold before water starts to seep through the weave.
A rating of 3000mm means that a tent fabric could hold a column of water that is 3000mm tall. 3000mm of water exerts more pressure on the fabric than 2000mm of water. A more accurate description of Waterhead rating is the measure of water pressure equivalent to a column of water that is 3000mm tall. The higher the rating, the more water resistant a fabric is, and the more water pressure it can withstand before it leaks.
WHAT’S A GOOD WATERHEAD RATING FOR MY TENT?
Obviously the larger the number the better – but that’s not the whole story when it comes to how dry your waterproof tents will be. A tent made from 2000mm Waterhead rating can keep you perfectly dry for most camping in Australia. You could also buy a tent that has a 3,000mm rating but still get wet.
That’s because Waterhead rating is only one part in a waterproof tent’s design.
The seams where the fabric of the waterproof tents has been stitched together have to be good. That means double stitching for strength, and taped over and sealed so that no water can enter via the stitching holes or between the two sheets of fabric.
Zips should also have protection. A good tent will often cover over the zips so that water keeps away from them. Some waterproof tents even come with a few zip covers, and you can also get tents where the doors are protected with a small porch or ‘storm entrance’ as it is sometimes called.
Any entry point to the tent is a weak point in the waterproofing, but a good design around the doors can really help with keeping the tent interior dry.
Tents may come with a waterproof and UV coating, in addition to the Waterhead rating of the material.
Additional waterproof coating will help water bead off your tent. The UV coating will protect the polyester based fabric from degrading in the sun, reducing both the loss of colour and degradation of the waterproofing. UV and waterproof coatings can deteriorate over time and get damaged. Oils and even simple washing up liquid could damage the coating.
You can get waterproofing sprays as well as seam sealers to repair patches yourself.
CAN YOU IMPROVE THE WATERHEAD RATING OF YOUR TENT?
No, but you can improve the water resistance.
Additional waterproofing sprays and seam sealers can improve the water resistance. However, the Waterhead rating (how much water pressure the fabric can hold), is related to the physical properties of the fabric, such as how small the holes are between the weave.
If you are stuck with a very strong downpour or heavy wind-driven rain, then an additional tarp over the tent may help. You may only need to cover one area of the tent, such as the side most exposed to the oncoming wind and rain.
We always recommend that you take at least one tarp when camping.
It’s not hard to stay dry but choosing the right equipment is important.