Which materials to choose for a hammock underquilt??

Hammock underquilt – choosing the materials

Anyone who has slept in a hammock using only a sleeping bag knows how important insulation from underneath is. On cooler nights, an extra mat is not enough, and even the best down sleeping bag will not provide adequate insulation.

It is therefore worth considering additional padding, which will keep you warmer than in a tent with conventional gear. Why is this certain? Heat always comes from our own body, and the type of insulation only ensures that this heat doesn’t escape. When we lie in a sleeping bag, we compress the down beneath us and reduce its insulating capabilities. That’s why a hammock underquilt is such a revolutionary solution. The insulating layer is not compressed, and the down warms us during sleep like no other sleeping bag can. On the market, this type of solution goes by many names:

Hammock underquilt
Underblanket
Underquilt
Hammock wrap
Insulator
Hammock blanket
Hammock duvet

It seems we still haven’t decided on the exact name for a product whose purpose is to keep us warm on a cold night while sleeping in a hammock. Underquilts, underblankets, blankets, or insulators—sometimes you’ll also see borrowed terms like underblanket or underquilt. All of these names refer to a lightweight quilted material with insulation that is attached beneath a hanging hammock. The naming confusion comes from the multifunctionality of this gear. With the right design, an insulated hammock underquilt can also function as a sleeping bag (quilt), an outdoor blanket, or a duvet for hostel stays.

If you are already convinced of the value of such a gadget as an underquilt, and the only thing holding you back is the price, below are some tips on how to easily make one at home. It’s immensely satisfying, and its performance won’t fall short of the top products on the market.

Types of Filling for a hammock underquilt

Filling is the first and most important choice when deciding to sew your own underquilt. It will determine the choice of materials, sewing method, and the amount of time and effort you’ll put into it. 😉 There are two basic types of filling: natural—such as down, a down-and-feather mix, or feathers alone—and synthetic, like polyester batting (rolled wadding) or granulated synthetic down from a bag.

Underquilts with natural filling are more difficult to make and more expensive. In return, you get a product that is much more compressible while providing significantly greater sleeping comfort in low temperatures (see article: down vs. synthetic insulation). The best choice for fast & light enthusiasts is always pure down, which is highly resilient and, consequently, offers greater thermal insulation even with a small amount of down.

To help you decide how much down you’ll need for your underquilt, we provide measurements for 700FP down available on our website. Keep in mind, however, that the data refers to down that may differ from yours. Comfort is also a subjective matter. 🙂 The information should be taken as approximate.

Estimated study by Ripstop.pl

The second group, i.e., linings made of synthetic insulation, is a much cheaper and structurally simpler solution. However, when packed, they take up significantly more space, and their comfort level is noticeably lower. The synthetic filling offered on our website is a 2 cm thick batting. With a double layer of such filling, we can achieve comfort equivalent to +5 degrees.

Type of outer material of the hammock lining

The decision on material selection largely depends on the type of filling. If choosing down or a down-feather mix, a much stronger and heavier material will be required compared to using pure down. A sharp feather, especially a cut one, can easily damage or pierce delicate fabric.

In the case of down, a much thinner and lighter material can be selected, but still with a dense enough weave to prevent down from escaping—around 10–20 denier. Lightweight material also allows the down to expand more, resulting in higher thermal performance.

For our project, we used Ultra Light Marine Blue Ripstop polyester, weighing 35 g/m². Our lining required 3 meters. For making linings, we also recommend breathable, down-proof nylons: calendared ripstop nylon and 10D nylon. During calendaring, the fabric is passed through heavy, heated rollers or drums, which flatten the fabric and effectively “seal” the weave, making the material down-proof.

For linings with synthetic filling, we would recommend diamond ripstop nylon (40 g/m²) or ripstop nylon (65 g/m²). This gives the lining a pleasant-to-touch feel. For comparison purposes, we will definitely make ours using Ripstop Ultra Light (polyester) Marine Blue to compare the packability of down versus the lining.

Quilting

There are two basic technologies for attaching down to fabric: quilting or box baffles. The difference between them is the shape of the compartments in which the down is filled. In quilting, we create compartments by stitching the fabric with a straight seam. A so-called cold spot then forms along the seam. Here you can find instructions for a DIY version without compartments.

If, instead of a seam, we sew a panel connecting both materials, we will create a three-dimensional box, providing a sealed insulating layer without so-called cold spots at the seams. If you decide to use boxes, you can use the 55g/m² nylon mesh available on our website to create them. Here you will find instructions for a underquilt with boxes and the quilt option.