Tents

With the first tour of the season coming up on May 1st, Chris and I thought it would be a good idea to check out some of our tents. We have a couple of new ones to look at and get used to setting up (The North Face Talus 3 and Talus 4) and one or two of the others that we haven't had out since last summer needed the cobwebs brushing off and to make sure everything was good to go. Hence we found ourselves in Meadow Park in Whistler on a partly sunny day putting some of our tents up by the side of the River of Golden Dreams.

Back row (l-r): MEC Wanderer 4, TNF Talus 4, TNF Talus 3; Front row (l-r): TNF Mica Fast and Light 1, TNF Rock 22

What makes a good tent? That all depends on your needs.

There are a number of factors that you should look at in choosing the right tent; size, weight, 'usable' space, size of vestibule(s), breathability, waterproofing and, of course, price.

Most decent tents will be rated according to the seasons they are designed to be used for, thus you might have 4 season (or winter) tents and 3 season tents. A 3 season tent will probably not have the waterproofing and structural strength that the 4 season tent will have but it will in all likelihood breathe better and be lighter. That's your trade off.

One question that is often asked in relation to tents (and outdoor clothing) is what exactly is meant by waterproof? Unfortunately getting an 'exact' answer for this is nigh on impossible. One way in which waterproofness is judged is by using the 'hydrostatic head' (HH) measurement. To measure the hydrostatic head of a material a piece of fabric is stretched over a frame in a laboratory and a column of water placed over it. The water level of that column is increased until pressure forces the water through the fabric. The amount of water in the column when this happens gives us the hydrostatic head of that material. For example if it took 2m (6' 6") of water for the fabric to be penetrated the hydrostatic head would be 2000mm. In Europe the standard for calling a material waterproof is 1000mm.

So a tent with a 1000mm hydrostatic head is waterproof? Simple huh? Not really. This is where it gets a little more nuanced. I would never consider 1000mm as waterproof in a jacket or pants where pressure is likely to be considerably higher if, for instance, you kneel on the fabric. Nor will 1000mm likely suffice for a tent if you were out in a gale with high winds for hour after hour where the speed at which the rain hits the fly increases the pressure. (Having said that the structure of the tent can make all the difference here. A good taut tent will repel water for longer than one that sags and pools water so it's not all down to the fabric. That also brings in how the tent has been set up by the user. Even a good tent will not function well if it has not been set up correctly.)

This tautness is why many tents that, to all intents and purposes, we would consider 'waterproof' may only have hydrostatic heads of 1000-1200mm. Personally I'm comfortable with that level of waterproofness even though we also own tents with 10000mm HH. The flipside to this added HH is that it adds weight to the material. Think of the coating (silicon or PVC maybe) required to stop a column of water 10m (33') high penetrating a fabric and then think of the amount of waterproof coating need to stop a 1m (3' 3") high column doing the same. This is one of the main ways in which a tent becomes heavier (though the poles and, obviously, size also matter) since the fabric weighs so much more.

Now we must also think of the floor of the tent. Although we have only discussed the fly material so far it was mentioned earlier how kneeling on a piece of clothing would require a greater HH due to the increased pressure. Obviously this is also the case with the floor of tents where much greater pressure is exerted than by rain pushed by wind. This is why good tents will have a higher HH for their floors than for their flys and will often be in the 2000mm to 5000mm range. 

Finally, it should also be noted that, materials aside, no tent will be 'waterproof' unless it has been seam-sealed i.e the holes that have been made where the pieces of material have been stitched together have been filled or covered over. There are two ways to do this. Firstly you can use seam sealer and do it yourself, this is basically a glue that plugs the holes. The second way is for the tent to have heat sealed tape fixed over the seams which will be done in the factory. This adds expense to the manufacturing process but works better (in our humble opinion) and is something we always look out for in a quality tent.

So there you have it, a 'waterproof' tent should be taut, well designed, have a good level of HH on the fly (1000mm minimum) and a a floor with an HH of a minimum 2000mm and be set up well. Achieve all that and you should be good for a night out in all weathers.