Bivy and tarp
Leaving the tent behind means choosing between a bag that wraps you and a sheet that covers you. Each has its own specification sheet, and each has one figure that decides whether the night works — the breathability number on a bivy, the tie-out count on a tarp.
There are two ways to sleep out without a tent, and they fail differently.
A bivy bag puts a waterproof layer directly on your sleeping bag. It packs small, it needs no pitch, and every bit of moisture you produce has to leave through that layer or stay inside it. A tarp puts a sheet in the air above you. It is airy and versatile, it needs trees or poles and something to tie to, and it leaves your sides open to whatever the wind is doing.
Read the specification sheets and the difference is immediate: bivy listings publish waterproofing and breathability, tarp listings publish cut sizes and what is in the bag.
A water column is easy to publish and easy to understand. A breathability figure is neither, and it is the one that decides whether you wake up in a damp sleeping bag.
The MFH hooped bivy publishes both: a 10,000 mm (393.7 in) water column and 3,000 mvp, from a three-layer laminate whose face fabric is not named. It also publishes a pitched size of 235 x 70 tapering to 95 cm (37.4 in) with 45 cm (17.7 in) of height, six ground attachment loops, mat loops for mats up to 60 cm (23.6 in) wide, a side and head opening on a two-way zip, an integrated mosquito net, about 1.4 kg (3.1 lb) and a packed size of 35 x 13 x 13 cm (13.8 × 5.1 × 5.1 in). On this shelf that is close to a complete specification, and it is why it opens the list.
The normani cover publishes the same pair — 10,000 mm (393.7 in) and 3,000 MVP — on a Diamond Ripstop polyamide, with welded seams, a right-hand zip, a 230 x 90 cm (90.6 × 35.4 in) cut and a stated 397 g (14 oz). It is the light option here, and it is a cover for a sleeping bag rather than a shelter of its own: no pole, no hoop.
The Carinthia takes the other route. It names its material in full — three-layer Gore-Tex, polyamide face, PTFE membrane, polyamide lining — and publishes no water column and no breathability figure at all. What it does publish is size: 243 cm (95.7 in) long with a 98 cm (38.6 in) shoulder, which is a cut made for a bulky winter bag. The membrane name is what is being bought here, and the numbers are not on the page.
The GEERTOP is a different object again: a one-person shelter with two aluminum poles, a PU 5000 mm (196.9 in) flysheet, fully sealed and double-stitched seams, 215 x 75 cm (84.6 × 29.5 in) with 61 cm (24 in) of head room, 45 x 13 x 13 cm (17.7 × 5.1 × 5.1 in) packed, and approximately 1.3 kg (2.9 lb) stated for the complete set — labeled as the whole set rather than the canopy alone, which almost nothing else on this site troubles to say.
None of these bivies publishes a denier. The Carinthia and the GEERTOP publish no breathability figure. The Carinthia publishes no weight and no packed size, so the two questions a walker asks first cannot be answered before it arrives.
That is worth knowing rather than resenting. A listing that names a membrane and gives you a 243 cm (95.7 in) cut is telling you it expects the buyer to already know the model, and it is being straightforward about which half of the picture it offers.
A tarp is a simpler object and its listings are correspondingly more honest, because there is less to hide.
The Unigear is the one to read first, for a reason that has nothing to do with the fabric: it publishes a tie-out count, and it publishes it size by size. Eight loops on the 3 x 3 m (10 × 10 ft), eighteen on the 3 x 4 m (10 × 13 ft), nineteen on the 3 x 5 m (10 × 16 ft), sixteen on the 4.4 x 4.4 m (14 × 14 ft). Attachment points are what let one sheet become a lean-to, an A-frame, a flying diamond or a porch, and a tarp with eight of them and a tarp with nineteen are not the same tool. It also publishes a PU 3000 mm (118.1 in) water column, a 210D Oxford weave with a silver coating inside, and a bag containing six adjustable nylon guylines of 4 m (13 ft), six aluminum pegs and a separate pouch for them, packing to 30 x 17 x 10 cm (11.8 × 6.7 × 3.9 in).
The FREE SOLDIER publishes the other half of the argument: a 300 x 300 cm (118.1 × 118.1 in) square in 150T ripstop polyester, seam-sealed, with every load point reinforced with multiply-stitched nylon webbing stated to spread the load across the strap. Reinforcement is where a tarp tears, and a listing that describes the stitching at the load points is describing the failure it has thought about. It states 1 kg (2.2 lb), and does not say whether the four ropes and four pegs are inside that figure. Its water resistance is published as a 3000 PU coating, with the figure given without a unit.
A tarp does not have a floor, so its cut size is doing the work of both a footprint and a roof. Square sheets — the 300 x 300 cm (118.1 × 118.1 in) on both tarps here — pitch in the most configurations. Rectangles favor one long axis, which suits a hammock or a two-person lean-to.
Fabric is published unevenly. The Unigear gives a denier — 210D Oxford — while the FREE SOLDIER gives 150T, which is a thread count and not the same measurement at all. Reading one against the other is reading two different quantities.
Take the bivy if the pitch is unknown, the trees are absent, and the priority is packing small and lying down anywhere. Then buy on the breathability figure, and if there is not one, buy knowing there is not one.
Take the tarp if there are trees or poles, if you want to cook and sit under cover, and if you would rather have air moving than fabric on your bag. Then buy on the tie-out count and on what is in the bag, because a canopy without lines and pegs is a half-purchase.
And take both if the trip is long: a tarp overhead and a light cover on the sleeping bag is the combination that handles a night of rain and a night of dew without carrying a tent for either.
A water column describes a fabric. A seam is where that fabric ends, and it is where water gets in first — so the seam line deserves the same reading as the millimeters. The GEERTOP states fully sealed seams with double stitching, the normani states welded seams, and the FREE SOLDIER states waterproof treatment at the seams. The MFH and the Carinthia publish a fabric and say nothing about what holds it together.
A bivy bag fits in a pocket and changes everything when night falls too early.
Bivy bag and tarp replace the tent for a fraction of the stated weight.
A pitched tarp serves as much for cooking in the rain as for sleeping.
| The shelter | Its advantage | Its limit |
|---|---|---|
| Bivy bag alone | Minimal weight | Condensation |
| Tarp alone | Space and airflow | Insects |
| Bivy bag and tarp | The compromise | Two things to pitch |
| Tent | Comfort | The stated weight |
A bivy bag and a tarp age through their coating and their tension points. A seam that has worked in wind gives way before the fabric itself.
This site publishes stated specifications and describes no shelter pitching.
Hooped bivy · poles supplied · 3-layer laminate · 10,000 mm (393.7 in) water column · 3,000 mvp · mosquito net · 1.4 kg (3.1 lb) and 35 × 13 × 13 cm (13.8 × 5.1 × 5.1 in) packed, stated
The one hooped bivy here with poles in the box — it publishes a water column, a breathability number and six ground loops, and names no test for the number.
Best for: A one-person pitch where the head space of a hoop is wanted and a tent is not.
Sleeping-bag cover · Diamond Ripstop polyamide · 10,000 mm (393.7 in) water column · 3,000 MVP · welded seams · right-hand zip · 397 g (14 oz) stated
The listing in this hub that publishes both numbers: a 10,000 mm (393.7 in) water column and a 3,000 MVP breathability figure — with no test named for the second.
Best for: A sleeping bag that needs a light, fully specified waterproof cover rather than a shelter of its own.
One-person bivy shelter · two aluminum poles · PU 5000 mm (196.9 in) flysheet · sealed and double-stitched seams · 215 × 75 × 61 cm (84.6 × 29.5 × 24 in) · 1.3 kg complete, stated
A poled one-person shelter sold as a bivy, publishing a flysheet water column, sealed seams and a complete-set weight — with no fabric named and no breathability figure.
Best for: A solo pitch where head room and a sealed floor matter more than packing small.
Sleeping-bag cover · 3-layer Gore-Tex · polyamide face and lining, PTFE membrane · 243 cm (95.7 in) long, 98 cm (38.6 in) shoulder · central zip · no weight or packed size
A 3-layer Gore-Tex cover that names every layer of its construction and publishes neither a waterproof figure, a breathability figure, a weight nor a packed size.
Best for: A winter sleeping bag that needs a long, wide cover and where the membrane name is the specification being bought.
Camping tarp · 210D Oxford, silver-coated inside · PU 3000 mm (118.1 in) · tie-out count published per size · six guylines and six alloy pegs supplied · 30 × 17 × 10 cm (11.8 × 6.7 × 3.9 in) packed
The only tarp here to publish a denier, a hydrostatic head and a tie-out count for every size it sells — and it never says which size the listing is showing.
Best for: A first tarp bought complete, where lines and pegs in the box matter as much as the canopy.
≈ $25
Camping tarp · 300 × 300 cm (118.1 × 118.1 in) · 150T ripstop polyester, 3000 PU coating · seam-sealed · webbing-reinforced load points · 1 kg (2.2 lb) stated · four ropes and four pegs supplied
A 3 × 3 m (10 × 10 ft) tarp with a coating figure, sealed seams, webbing at every load point and a stated 1 kg (2.2 lb) — and no count for the load points it reinforces.
Best for: A square tarp bought complete, where sealed seams and reinforced load points matter more than pack weight.
Because the fabric is against your sleeping bag rather than an arm’s length away, so moisture that cannot get out condenses where it does the most harm. The MFH publishes 3,000 mvp and the normani publishes 3,000 MVP; the Carinthia names Gore-Tex without a figure, and several bivy listings make no breathability claim at all.
It is the number of attachment points, and it sets how many pitches the sheet can take. The Unigear publishes it size by size: 8 loops on the 3 x 3 m (10 × 10 ft), 18 on the 3 x 4 m (10 × 13 ft), 19 on the 3 x 5 m (10 × 16 ft) and 16 on the 4.4 x 4.4 m (14 × 14 ft). Most tarp listings publish none.
No. A bivy bag is a shell over a sleeping bag; the ground insulation still comes from a mat underneath, and the MFH is explicit about it with mat loops for mats up to 60 cm (23.6 in) wide.
The GEERTOP comes with its own two-pole frame. The Unigear ships with six 4 m (13 ft) guylines and six aluminum pegs, and the FREE SOLDIER with four ropes and four pegs. The flat covers and the plain bivy sacks come with nothing.
For walks that: A one-person pitch where the head space of a hoop is wanted and a tent is not.
Its best point: A hoop and poles are supplied, and the pitched dimensions are published as 235 × 70/95 × 45 cm (17.7 in)
Its worst point: The breathability figure names no test, so it can only be compared with a figure quoted the same way
For walks that: A sleeping bag that needs a light, fully specified waterproof cover rather than a shelter of its own.
Its best point: Publishes a hydrostatic head and a breathability figure together, which is what makes a bivy comparable at all
Its worst point: The breathability figure names no test, so it cannot be set against a figure quoted on any other scale
For walks that: A solo pitch where head room and a sealed floor matter more than packing small.
Its best point: The weight is labeled — approximately 1.3 kg (2.9 lb) for the complete set — which almost nothing else in this hub does
Its worst point: Names no fabric and no denier, so the coating figure has no material behind it
For walks that: A winter sleeping bag that needs a long, wide cover and where the membrane name is the specification being bought.
Its best point: Names all three layers separately — polyamide face, PTFE membrane, polyamide lining — which nothing else here does
Its worst point: No hydrostatic head and no breathability figure, on the most expensive cover in the hub
For walks that: A first tarp bought complete, where lines and pegs in the box matter as much as the canopy.
Its best point: Publishes a denier and a hydrostatic head together, which is what makes a tarp comparable at all
Its worst point: Never states which size the listing itself is, so the tie-out count cannot be attached to the price
For walks that: A square tarp bought complete, where sealed seams and reinforced load points matter more than pack weight.
Its best point: Publishes a coating figure and states that the seams are waterproof-treated, which is two thirds of what keeps rain out
Its worst point: The 3000 figure is published without a unit, so it is a coating grade rather than a stated millimeter rating
Two items compared directly, where that page is already published.
The gear here comes from the catalog of this site. Specifications are those the maker and the Amazon listing publish; prices are what Keepa recorded on the date below, and both move. The order rests on declared specifications, on stated strengths weighed against stated limits, and on price. None of it has been carried on a walk by us, and nothing here suggests it has.
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Prices in these summaries were read on the dates each review gives. The live figure sits beside every product.
