What a 3,000mm rating means
The rating in millimetres, the hydrostatic head, is the height of a column of water the fabric holds back before water comes through, tested to BS EN ISO 811. A 3,000mm fabric holds back a column of water three metres tall. Tents in this range are filed by their flysheet's rating, from 2,500mm to 4,999mm. Where a maker gives only a groundsheet figure, as on a few tents here, that figure is used, so read every figure on the product page.
The tents in this range include:
- Backpacking tents such as the Naturehike Cloud Up, PU3000mm with taped seams, and the Naturehike Taga at PU4000mm. See backpacking and trekking tents.
- Hot tents such as the Coco Nest, with a 3000mm rainfly and floor. See hot tents with a stove jack.
- Family and inflatable tents, such as the BASTION 4-person tent at 3000mm, and an inflatable dome rated over 3000mm on both the outer tent and the groundsheet. See inflatable air tents.
- Roof and truck tents: hard shell roof tents at 3000mm, and a pickup truck bed tent rated over 4000mm. See roof tents.
Is 3,000mm enough for British rain?
For most camping in Britain, yes. Around 3,000mm on the flysheet is generally regarded as dependable for campsite weekends and holidays, heavy and long spells of rain included. Where it can fall short is high, open ground in a storm, where rain driven by the wind presses into the fabric harder than rain falling straight down, and long trips where the tent stays up in the wet for days. For those, look at waterproof 5,000mm and over. For dry summer weekends, waterproof to 2,000mm is enough.
Seams, groundsheets and the rest of the tent
The rating is for the fabric. Water also gets in at the stitching, so taped seams, where a strip is sealed over each seam inside, matter as much as the number. The groundsheet takes more pressure than the flysheet, because you kneel and lie on it, and that is why it is usually rated higher: the Widesea 2-person winter tent here has a PU3000mm flysheet and a PU5000mm floor, both seam taped. A footprint under the groundsheet protects it from stones and wear. Pitch the tent taut with its guy lines out, so the flysheet does not touch the inner tent: where they touch, water can wick through.
Questions people ask about waterproof ratings
Why does one tent have two or three ratings?
Because each part is a different fabric. The BLACKDOG Fantasy Maze dome tent here is rated 3000mm or more on its outer tent and 1000mm or less on its inner tent, which is not meant to take rain; the 2-person double-layer backpacking tent is PU 3000mm on its outer and PU 4000mm on its bottom.
What does PU mean before the number?
PU is polyurethane, the waterproof coating on the fabric. A silicone coating, used on many light nylon tents, does the same job.
How long does delivery take?
Delivery is included in every price and tracked to your door. Each product page says when that tent usually arrives, so check it before ordering for a set date.
More to look at