Roof tents for UK weather: the specs that matter
Compared on published specs, not tested. We haven't tested these products. Figures come from makers' and retailers' published specs, linked in the sources. How we compare.
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A roof tent spends its nights high on the car and exposed to whatever blows through, so in the UK the specs to look at are the ones about rain, wind and damp. This guide explains what each one means and how to read it on a maker's spec sheet. It doesn't rank tents: to put models side by side, see roof tents compared on published specs.
What UK weather asks of a tent
Three things, mostly: keeping rain out, standing up to wind on an exposed roof, and dealing with the damp that builds up inside overnight. A UK outdoor retailer, Highlander Outdoor, describes a fabric rating of about 3,000 mm as typical for UK campsite and weekend camping, with higher ratings for exposed or persistently wet conditions.
Damp inside isn't always a leak. Thule explains that moisture from your breath, wet clothes and kit, and humid air condenses when it meets cold tent walls and the floor, and can collect under the mattress.
Specs that matter
Fabric and waterproof ratings
Waterproof ratings are given in millimetres as a hydrostatic head. Highlander explains the test: a fabric sample sits under a tube that's slowly filled with water, and the height of the water column when water first comes through is the rating. A 3,000 mm fabric resists a three-metre column.
Higher numbers mean more resistance, but the figure is for the fabric in a lab, not the whole tent. Highlander points out that stitched seams make small holes (which taped seams cover), and that dirt, sunlight and repeated use reduce waterproofing over time. Groundsheets are often rated higher than flysheets, because your weight presses moisture against the floor.
As an example, TentBox lists a 3000 mm rating for the fabric on both its Classic 2.0 and Lite 2.0 roof tents.
Ventilation
Ventilation is the main way to deal with condensation. Some makers sell a mat that goes under the mattress for the same reason: Thule's anti-condensation mat is spacer mesh that lets moisture escape from under the mattress, and TentBox says its ventilation mat improves airflow under the mattress to help reduce condensation in cold weather. When you compare tents, check whether one is included or sold separately.
More on keeping a tent dry is in condensation, drying and storage.
Wind
Some makers publish a wind rating. TentBox gives the Classic 2.0 a rating of up to 50 mph and calls it Gale force 9. That fits the Met Office's Beaufort scale, where Force 9 (strong gale) is 41 to 47 knots, about 47 to 54 mph (the Met Office converts knots to mph by multiplying by 1.15).
Two things to bear in mind. The Met Office says the Beaufort speeds are mean speeds, so gusts can be stronger. And not every maker publishes a wind rating, or says how it was measured, so ask.
Insulation
Few makers publish an insulation figure for the tent itself. Check the maker's spec sheet, and ask the retailer if it isn't listed.
Reading a maker's spec sheet
Take TentBox's page for the Classic 2.0 as an example. It lists:
- Weight: 67 kg. Check this against your roof load before anything else.
- Fabric rating: 3000 mm. That's the hydrostatic head of the fabric, not a guarantee for the seams or zips.
- Wind rating: up to 50 mph. Check the mph figure, not just the force label.
- Closed and open sizes: 128 × 218 × 35 cm closed, 100 cm high open.
If a figure isn't listed, treat it as not published rather than assuming. For how shell type changes these numbers, see hardshell vs softshell.
Questions for a retailer
- What's the hydrostatic head of the flysheet and of the floor, in mm?
- Are the seams taped?
- Does the tent have a wind rating, in mph, and how was it measured?
- Is an anti-condensation or ventilation mat included, or sold separately?
- Is there any insulation, and where (floor, walls or roof)?
- What's the weight, and which roof bars does the maker recommend?
Check current price with the retailer.
More in Roof tents
Sources
- Met Office Beaufort scale: Force 8 gale 34–40 knots, Force 9 strong gale 41–47 knots; mean speeds; knots × 1.15 = mph (checked )
- Highlander Outdoor, Scottish retailer: how hydrostatic head is measured; about 3,000 mm typical for UK campsite use; groundsheets rated higher; seams, wear and condensation aren't covered by the figure (checked )
- Thule anti-condensation mat: spacer mesh under the mattress lets moisture escape; moisture from breath, wet kit and humidity condenses on cold walls and floor (checked )
- TentBox ventilation mat: improves airflow under the mattress to reduce condensation in cold weather; fits Lite, Lite XL and Classic (checked )
- example spec sheet: 3000 mm fabric, wind rating up to 50 mph (Gale force 9), 67 kg (checked )
- TentBox Lite 2.0: 3000 mm fabric rating (checked )