Camping

[nick crisp]

Bought a new tent from Go outdoors for Scotland this summer , on the bag it says Hydrostatic head with the number 4000 above it , anyone knows what this means .

I'm glad you asked that  :lol

HH is a measure of how waterproof a fabric is.
It's tested by taking a tube of water and fixing the material over the bottom. If it resists leaking up to 2m (2000mm) of water in the tube, then it's rating will be 2000mm HH. For a tent groundsheet, you ideally want 5000mm HH or more, as your weight is pushing the material down, effectively trying to force water through.

4000mm will most likely be fine in the summer, as long as you don't pitch on particularly wet/boggy ground. In fact, for most commercial campsites, where drainage is usually quite good, you won't have to worry about it.