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Can you tell me what the level of 'waterproofness' these tents have?

Good day!

Could you help finding out the waterproofness (PU - mm/cm3) for these two:

I would like to understand whether one of these is a good choice for mountain hikes and I and my gear won't get wet during the rain.

Thank you in advance,



8 Replies

@GunaG thanks for reaching out! We will work on tracking down those specific numbers for you. In the meantime, we'd love to provide some suggestions on good tents for the activities you will be doing. What kind of mountain hikes are you considering, where and during what times of the year? Will you ever be on snow? 

Both tents you list above have fully waterproof rainflys and bases, and when staked out properly, each creates a vestibule in which you can have your gear fully covered. In addition, proper ventilation during set-up and proper maintenance over time are critical to ensuring your rainfly successfully and continually keeps your tent and gear dry.

At REI, we believe time outside is fundamental to a life well lived.

Hi @GunaG , I could be wrong, but I think PU is associated with breath-ability. 

All of REI tent's (and probably everyone else), have rain flys which are WATERPROOF, not breathable.

I would be more concerned about the tents seam-sealing, which also has to be done to make them watertight, it's a matter if it's done at the factory or if you have to do it when you get the tent.

also, you're pack is going to get soaked in a rain, even a pack rain cover is no guarantee of keeping the pack 100% dry.  Make sure you keep your stuff in the pack in some sort of waterproof bags.  I use an industrial strength black plastic garbage bag from lowes to line the inside of my pack and keep everything bone dry.

Another thing to think about is how you're going to put up your tent in a driving rain so the inside stays dry and is still dry, at least up to the time you get into it, while you are soaked and dripping all over the inside.  This is important because you don't want the floor of you tent soaked while unloading your pack.  At least you can keep you bag dry by keeping it on your air mattress.

This is a thought-process you want to work out before doing it in real time.

REI Member Since 1979

Hi guys!

This is, what I am looking for:

“Tent fabric ratings - Most tents are made using polyester fabric which is not waterproof. So a PU (Polyurethane) coating(s) is applied to provide ‘waterproofness’. The hydrostatic head is a measurement of how waterproof the fabric is, and is measured in mm, usually ranging from 800mm up to 10,000mm. There’s no internationally recognised standard of what specific rating ‘waterproof’ is, but 1500mm is widely accepted as being the minimum to be deemed waterproof and able to handle most rain conditions. A tent with a 1500mm rated fly means a 1500mm high column of water can be held up against the fabric for one minute before a drop of water seeps through.”   


@GunaG Thanks for the clarification!

We've reached out to the engineer who designs our tents. They were out of the office today so we'll circle back here as soon as we get the information you are looking for. Thanks for your patience!

At REI, we believe time outside is fundamental to a life well lived.

my friend, you're going down the wrong rat-hole here, they sell what they sell. 

Trust me, if you get wet, it won't be because one rain fly had a different PU rating from another.

REI Member Since 1979

@GunaG Both tents will be waterproof enough as far as the fabric. 

According to the Product Listing Questions section...

The QD SL2 uses 1200mm hydrostatic rating PU coated 15-denier ripstop nylon for both the rainfly and tent floor.

The Flash Air 2 fly uses a silicon based durable water repellent finish (DWR) on the outside and  polyurethane waterproof coating on the inside of 15-denier nylon. The hydrostatic rating is 1,200mm.  The floor is also 15 denier.

According to me...

The mostly single wall Flash Air 2 will be probably be more prone to condensation problems.  It has a continuous wall front and back with no built in gutter like other single wall trekking pole designs...probably better than the flash air 1 which has a continuous side wall in addition with fairly minimal ventilation on that side.   The Flash Air 1 test I saw also showed some water intrusion in the roof where it folds back.   I don't know if that is common or a problem on the Air 2.   Extra seam sealing might help.  Being single wall it intrinsically allows fly first pitching so you might be able to get your gear out of the rain quicker if you are well practiced at pitching it but it will take some practice since there is no framework of poles to provide intrinsic have to guy it out which can be troublesome in some terrain.  

The Quarter Dome SL 2 is probably the more certain design.  It is semi freestanding so it has to be  guyed out but less so.   If it has fixed guys you may want to modify them to be adjustable which is what I did on my similar Big Agnes TW2.   I don't think the QD SL2 has a fly first feature but I don't have one so I can't be sure.   You can set it up fly only with the optional footprint which is nice if you know there will be no bugs.  




Thanks for your patience as we tracked down the answers to your question. We spoke with our materials and design team and both of these tents have a minimum 1800mm PU coating. We're not sure why the questions were answered incorrectly on the product page, but we'll get that taken care of right away. Thanks to @OldGuyot for tracking down that info!

Hope this helps!

At REI, we believe time outside is fundamental to a life well lived.

Thanks a lot!