Insultex Underquilt

Insultex is an incredibly thin, micro-porous, closed cell foam. While it does not compress, it is so thin and light that the pack size is only slightly larger than down (when comparing for the same temperature rating).

This three layer design will get most users to 35-40° F when wearing warm sleeping clothes.

For most people, each additional layer of Insultex will give another 10-13degF of comfort.

Another great use for Insultex is as an outer shell for a lofted insulation (like PrimaLoft or Down). As a closed-cell foam, Insultex will cut heat loss significantly that the wind would normally steal from lofted insulations. Just a layer or two will drastically boost the temperature rating of your current insulation system.

Top Quilt

The Top Quilt is a very simple design, and very effective. Works great with PrimaLoft or Climashield synthetic insulation. The Top Quilt could also be built with Insultex to give your current quilt an amazing heat boost - as an overquilt or quilt liner, depending on how you want to use it. I have one with two layers of Insultex that I use with my 3oz Climashield Top Quilt to extend the range from the high 40's down into the high 20's.

45 thoughts on “Insulation

  1. Scott, I am thinking about the climashield build as I am just getting into hammock and really don’t want to spend $200 for a UQ. I am good with a sewing machine and understand your parents for the Insultex quilt. If I do the single layer climashield with 1.1 ripstop should I dart both sides the same? If I do an Insultex as a separate layer, like you have mentioned, do you cover both sides with nylon? Thanks for any advice, winter is coming in the Midwest, so seems like a great time for a project..

    1. Hey Jerud,
      This is a great project, definitely saves a lot of $$ doing it yourself. I usually put a nylon ripstop shell on both sides of all my insulation projects – but if you’re looking to save weight, I’d only do it on the outside of the Insultex layer. For darts on the shell, you dart the shell fabric the same as the layer of insulation it is going to go up against. So if you use one layer of climashield and you dart that, then yes, dart both layers of nylon the same.

      Hope that makes sense. Enjoy!

    1. Hey Todd. I didn’t notice if you’re referring to a top quilt or underquilt – but either way, make it either the same as the largest layer, or just a couple inches larger.

  2. Hello, wanting to build your under quilt. Do you have a kit like the hammock or do i order individual materials? Also what ripstop do I get?
    Thanks Andy

    1. Hi Andy. We do not have quilt kits available yet, so you’ll need to add the materials to your cart. For the shell, 1.1oz Ripstop Nylon is a great choice.

  3. Thanks Scott for the professional service. I am 100 percent happy with my 3.6 Apex. I calculated that 3.6 oz should be .86″ thick, and I made a camping quilt with two layers, and it measured 1.63 to 1.75″ thick. I recycled 1.1 nylon from an old sleeping bag for the cover, and my finished quilt weighs 2 1/8 lbs. I ordered 3 yards of Apex, ($40 delivered) and had to fit pieces into the foot area, but had no extra insulation. Next time I am ordering 1.1 nylon from you, I see it would have only been about $20, and it took me hours to take apart that old bag for the cover. Note that I did not use your quilt pattern. My pattern was a lot shorter, with more foot taper. I am 5’8″ tall and my finished quilt is 50″ wide x 70″ long. Terry

  4. Hello again!

    I am getting ready to bribe the wife to sew me a climashield top quilt. Looking for comfort range down into the mid 20’s. How many layers ofclimashield insulation is needed? Or, should I consider less layers of climashield and use a couple layers of insultex? I need it to compress well as I’ll be packing my clothes, food, hammock, tarp, under quilt, bino’s, water filtration, and other hunting gear etc.. in a 3000 ci bag for two night stays while spike camping. Your suggestions would be appreciated. God Bless.

    1. Hi Justin. Most people find one layer of 3.6oz Climashield Apex to be good to around 40dF. For the 20dF range you’ll want two layers for sure. You could boost one layer with a few layers of Insultex, but unless you’re sure you want to go that route, I’d go with the purely Climashield build. The combo system works well, and gives you the option of taking just the one-layer Climashield piece for warmer weather, but on a top quilt Insultex breathes so little that you can end up with condensation issues. That can be managed, and I haven’t had issues with that in my combo system, but it would be wise to look into VBL (Vapor Barrier Layers) systems before going that route.

      Hope that helps.

      1. Thanks for the info Scott. I’m going to follow your advice and stick with a pure Climashield build. Just awaiting all the supplies to be in stock. I really like the pic of the top quilt on your home page. I’m going to copy it. :^) God Bless

  5. Hey Scott, I’ve made the Climashield top quilt and can’t wait to try it out. For later, when it’s colder, I’d like to consider making an extra IX top quilt, like you mention above. Do you try to attach the insulation quilt to the vapor barrier quilt in any way? I’m thinking of sewing ties into them to keep the outer layer from sliding around too much.

    1. Hey Jimmy. I actually do not attach them together at all, works fine for me – but if you wanted them to stick together better then something like side ties is a great solution!

      1. Thanks, Scott. Will keep that in mind. Tried out the Climashield top quilt the other night. It got down to 40, but I was perfectly comfortable with just a T-shirt. I’m really impressed. Thanks for selling the good stuff! 🙂

        (also had an IX UQ and a poncho liner UQ set up)

  6. Same question as Matthew back in 2014, I don’t see an answer.

    I’m making the Underquilt. Do the ripstop layers get the V’s in them?

    And on the topic if the V’s, aren’t they essentially just darts? Can’t you just bind the edge instead of cutting and then throw a quick row in there? I understand if you put them into the ripstop, you’d want them to be hidden, but it seems like the same purpose is being accomplished?

    1. Hi Matt. Yes. The outside shell (ripstop) should have the same shape as the closest insulation layer. Same with the inside shell side (inside shell same as closest insulation layer). And yes, you can just sew them as darts, really not much difference unless you’re really interested in saving every ounce and gram in your pack weight. No matter how you do it, or what you call it, the key is that the short side is the same length on all layers after your adjustments, even though the actual width per layer is different. Hopefully that makes sense. Good question. Thank.

  7. How does the underquilt attach to the hammock? This is my first DIY project so I want to make sure I have all the materials.

    1. Shock cord. We run shock cord through the channels along the long edges in one continuous loop. That loop end gets connected to the suspension line of your hammock so when you tighten the shock cord up properly it holds snugly against the bottom of your hammock. Hope that makes sense.

  8. On the underquilt pattern, how deep are the V cuts (edge to center of layer)?

    I’m assuming the 2″, 3″, 4″ annotations are the length of the V cut along the edge.

    1. Hi Greg. Yes, you are correct – the 2″, 3″, 4″ are the width of the V-cuts.
      It’s not too terribly important for the V-Cut height, but 12″ tall does a good job. Anything close to that will work fine, go taller if you make the quilt longer, and maybe a few inches shorter if you go shorter.

  9. I am about to sew up the underquilt for my husband. I am a visual-kind of seamstress. I’d like to see what the finished steps should look like (for real, not in a sketch) before I proceed because I don’t want to have to take a ripper to this fabric!!!!
    Does anyone have links to photos(or video) of each step and of what the corners are supposed to look like? I am having trouble imagining what the end product should look like!
    Thank you!!!

  10. I have a Hennessy Hammock Explorer Ultralight bottom entry and I want to adapt your design to work with am asym hammock. Do you have any suggestions on how to do this?

    Thank you,

    1. Hi Chuck. There are a couple solutions (well, probably a lot more than that – but at least a couple easy ones). First, if you take the pattern I have, and just shift it from a Rectangle shape into a Rhombus / Parallelogram shape, that might help things align well. The other solution is to do nearly nothing to the design – just add asym ties to attach to the netting tie-out points on the asym hammock. The actually Hennessy hammock body is a rectangle, it is only the netting and tie-out points that force it into that asym shape – so a rectangle underquilt should work fine if you design it to sync up with the tie-outs on the hammock.

  11. Okay. i just bought another Hennessy the other day. its the newer jungle explorer with the double bottom so you can slip in the bubble insulation. Not sure how i want to arrange this one since i am eager to make an UQ. Probably don’t need the UQ and the bubble pad together right? If not then i would rather go with the UQ since that pad makes some noise when moving around.

    I’m 6′-4″ and want to make an full UQ using IX. if going with 3 layers of IX i was thinking of going with 7 yards to cover the 3 layer @ 6ft + 1ft = 7ft per layer.
    Is this an overkill with the layers since i live in Houston and the temps are not as severe as most? It can get into the low 60 during most of my trips in the spring and fall and i have a nice 30F bag if it gets down in the 35F-40F range. Although it’s not too cold but the humidity makes it feel much colder
    compressible: 3layer vs 2layer doesn’t seem like it would make a difference right?



    1. Hi Jason. I think you could get away with two layers. That would pack 1/3 smaller, and if the weather report shows a lot colder than you find you’re comfortable in the two-layer quilt, then you can always bring the pad as well. I bet they’d work great together.

  12. Quick question. I just ordered the fabric for a couple of underquilts, but I’m curious about how small these underquilts pack down and what size of a stuff sack you recommend making.


    1. Hi Chip. We moved recently and I couldn’t find my IX quilt to measure, sorry. I’ll put pictures up with packability when I finally find it. I know it weighs exactly 16oz (mine has 30d ripstop on both sides as a shell), and it packs just a hair larger than my down quilt of similar temp range. Your best bet is to make the quilt, fold/roll it up and then determine how large to make your stuff sack.

  13. Hi,
    Planning to make a top Quilt and using your pattern. Everything is very clear, but the velcro part. The directions say, “insert at the foot end.” Where? At the end of the stitching on the foot end? On the sides near the foot end? What is the velcro used for? That might help me figure out where it goes. Maybe you could add arrows to the pattern to show where it goes.
    When will you be getting the Climashield insulation?

    1. Hi Carol. In the Illustration, at the upper right side there is a diagram showing the layers at the foot end. See how the sides angle down toward the bottom, that is showing the angle from the full size where it angles at the foot end. The Velcro parts are the Black sections in that diagram, and I’ve shown how the Velcro needs to be facing opposite directions (if down on the left, then up on the right, or vise versa). I hope that helps a bit. I’ll get pictures of the real thing up when I find it (we moved recently, lots still packed away).

  14. It appears that you add gross grain to the diagonal corners in step three, however, in step four it appears that that gross grain is on the long and short edges but not on the corners. Is gross grain added to the corners?

    1. Hi Ric,
      Yes, I do bind the corners at 45deg. with gross grain in Step 3. When the 1-1/2″ gross grain is used along the long and short sides in Step 4 it mostly covers up that corner. It gets a little too busy in Step 4 trying to show ever bit, so I just illustrate the part that is being done.

      Thanks, and enjoy your projects!

  15. Could you simply add additional layers to the UQ to boost lower temp range? If so, how would you cut? Also, how’s packability on this (for packing)?

  16. In making the top quilt, I am going to use 2.5 oz Climashield Apex Insulation. I was wondering if I could get away with using just one linear yard of this material (60″ wide), for a summer quilt for use in my hammock? It only needs to work down to about 60* at the absolute coolest. Most nights will be around 70*. I am a pretty warm sleeper and I will be using this quilt with the Sea to Summit Coolmax sleeping bag liner if that is relevant.

  17. Bought everything from DIY Gear Supply to make a top quilt and under quilt. They turned out awesome! I have used down to 38 degrees F with no problem at all.

    The only mod that I made was using layered Insultex for the top quilt since I couldn’t find the recommended Climashield (I didn’t look very hard) and I used polar fleece on one side of the top quilt. This kept me very warm (almost too warm), but it doesn’t pack very well. I am going to make another following the instructions verbatim this time.

    Any idea where I can find the Climashield fabric?

    1. We will be carrying Climashield sometime this Winter. I’m really looking forward to having that here in the shop, it’s such a great synthetic insulation.

  18. Was considering using this uq plan using polar fleece instead of the insultex. Any idea how a single layer of 200 weight fleece wrapped in a nylon shell would coare to the insultex in therms of insulating quality? I’m guessing I need to stay warm to 40-50f or warmer most of the time. Do you think you’ll be getting any more insultex anytime soon?

    1. Hi Andy,
      I’m afraid I don’t know much about the thermal properties of thermal fleece. Sorry. I do know that I have a new shipment of Insultex coming on a truck now, should be here tomorrow (5/27/14), if not the next day.

    1. Hi Scott,
      Yes, coated should be fine, for at least two reasons. 1. Because Insultex is very minimally breathable, and 2. Because you’ll be using it in an underquilt – heat rises and the moisture your body gives off overnight will naturally want to go up rather than down (which is why I do not recommend Insultex as a top quilt, except in very specific applications).

  19. The Insultex Underquilt with three layers is designed to be used no lower than 35 degF. Comfort levels are very subjective, some people are warm sleepers, others cold. It’s hard to determine, so always test your DIY gear before taking it out into the field.

    I have used this quilt in the mid 20’s and been warm, but I had supplemented it with a windshield reflector pad and was wearing warm fleece to sleep in.

    Generally speaking, each layer of Insultex gives you another 10-13 degF of comfort. So if you’re comfortable sleeping at 70 with nothing covering you, then 3 layers could get you to around 35-40deg.

    Hope that helps. Also, this thread at regarding this exact quilt may be very useful – lots of field testing and peoples results:

  20. Yes, the Bottom Shell layer should match the bottom layer of Insultex, and the Top Shell layer should match the top layer of Insultex.

    And yes, I went with 60″ long to maximize the use of the Insultex. If you end up with 57″ useable, just make it 57″ long. Either that, or you’ll need more Insultex (5yds total for the project instead of a little less than 4yds).

  21. For the Insultex Underquilt, do the top and bottom ripstop nylon cover layers need to have the V shapes cut into them like the Insultex? Or should they be left as perfect squares, matching the dimensions? I just want to double check before cutting the material.

    Also, for the Insultex, is the 60″ supposed to reflect the horizontal roll length of the material? When I laid it out, the material is ~60″ wide, but some layers are shorter than others, so I would have to sew around 57″ to secure every layer of the material. Is that correct?

Leave a Reply

Your email address will not be published. Required fields are marked *