Ok, thanks for the info. I was just going to use one as extra protection for the tent floor and to have the porch dry if the ground was wet.
Still, it adds 100gr so maybe not:)

I use a silver heat-reflecting sheet instead of the double glazing film.
The material is just as flimsy - but much warmer to sit on.

There are Tyvek products that are less flimsy, but I have yet to try them out.

How heavy is underlay? It is a slippery slope, the next step you'll be lining the tent with Axminster carpet ...

I take a Sol Emergency Blanket with me on the Challenge as it serves several purposes.

1) Obviously if required it will serve as intended.

2) I can lay it on the tent floor (Stratospire 1)and it serves as a heat reflector back into my mat

3) As it is 211x141mm on very cold nights I can fold it back over my quilt to keep the warmth close to me

4) Despite it being very thin it is made of a very tough vacuum-metalized polyethylene which will resist tears and punctures, so on rough ground I lay it under the tent to act as a footprint.

All this for less than £6 and it only weighs 71g

Simples

Okay. I'll bite.
I have previously carried a thin, lightweight foiled mat to put underneath my mat. It served to protect my mat from puncture and reflected warmth back up into my mat. However, I slid all over the tent. You simply can't find a level, even ground in the wilds of the highlands! So I felt it was counter-productive as I spent so much time caterpillering around my tent in my sleeping bag at night! So...
I use a footprint for my Laser Comp.
a) It adds that little bit extra insulation.
b) It's thicker/tougher than the floor of my inner and gives protection from punctures to my tent floor and my Synmat UL7, which I feel is not as robust as my Thermarest Prolite.
c) It provides a groundsheet and therefore a dry/mud free porch area for entry/exit and storage.
d) I am a lazy toad at heart, pegged out neatly the groundsheet protector helps my pitch my Lovely Laser properly, less flapping = better sleep! It also keep mud off the bottom (and worse) off my tent and is easier to clean.
e) It's my choice and peace of mind (the puncture risk really bothers me)

Hi All,

I've been using double glazing film for the last few years - mine came from Wickes. It's surprisingly very strong and it weighs next to nothing.

It's long-lasting, I'm still using the original piece I cut for my Akto - I cut another one for my HexPeak. I would guess the Akto one has so far lasted 40-45 nights and the HexPeak one about 10 nights.

When you consider the very low price I'm surprised that more folk don't use the stuff - so much more cost effective than commercially available footprints.

For those who like to use reflective / foil stuff, have a look at mylar foil - available from shops that sell stuff for propogating, er, interesting plants. Although it's heavier than double glazing film it has the advertised advantage of reflecting radiated heat.

Hope this helps.

I think it's doubtful that a reflective thin foil membrane will stop any heat loss at all if it's beneath your ground sheet, as the heat loss will be from conduction.

Thin reflective foils work by reflecting radiant heat, which means that they require an air gap to work. This is why they are placed in the centre of Thermarest NeoAirs. If you place them directly under your mattress they could add to the insulation value as there will be the air gap of the mattress but as Louise has already pointed out you'll be in for a lively ride at night.

I'm not at all convinced that the thin films are likely to offer any significant protection to your groundsheet from punctures caused by sharp things beneath your groundsheet either - a thistle spine will just laugh at it!

As far as I can see, all a thin film - reflective or non-reflective - will offer is additional water protection from the ground, which is useful if your groundsheet is old and knackered and has a reduced hydro-static head. It will of course keep the underside of your tent a little cleaner, but you will still be faced with a muddy film to deal with each morning, which is probably harder to deal with than sponging mud off your groundsheet.

Spot on Alan - exactly why I pointed out that the stuff was 'advertised' as reflecting radiant heat.

However, if you check out the stuff I sourced you'll see that it's not smooth but finely dimpled. This has the effect of offering the *teensiest* bit of conductive insulation and a bit of radiation reflection by way of the dimples creating a slight gap between your mat (and cold bum). The benefit is certainly very obvious when camping on snow.

It's also *very* tough, thorns and other ******* things will ultimately puncture it - but it's another layer of protection.

The finish of the sheet is such that you don't slip and slide about....too much.

Louise

I carry a roll of this stuff at the bottom of my bag

http://www.lakeland.co.uk/8297/Slip-a-Grip-Non-Slip-Fabric-Shelf-%26-Surface-Liner---3m-Roll

A 180 x 30 cm length only weighs 125 gm and is very effective at stopping the overnight face plant into the wall of your tent.

If you take a roll with you but reduce the amount of chocolate you carry by just 5% there would be no increase in the overall weight of your pack.....

"If you take a roll with you but reduce the amount of chocolate you carry by just 5% there would be no increase in the overall weight of your pack....."

...cheeky!! :smile:

Hi
I use a piece of the material used to make sails for racing yachts. Very light and tough. It goes between the tent and Scotland with the hope it will protect my cheap tent. It also provides a table cloth to cook & eat on. So far it has worked. Also it is Bright Orange so I can use it to attract attention if needed - which I hope I never will. Cost was Zero as it was an off cut from the sail makers.
William

Bought a Sol - Survive outdoors longer - last week to try as an alternative to my silver reflective foil blanket. I like it. Certainly it is stronger, and feels more substantial. It’s 20g heavier than my foil sheet, but on first impressions 20 g is worth it.
The size at roughly 5 ft x 8 ft is ideal for the porch of the trookstar. Let’s see how it lasts over two weeks in Scotland acting also as a rain kilt and picnic mat.

I've bought a Tyvek sheet that I will cut to size as soon as I put up my tent and I can measure properly. So not sure yet how much it weighs.

Well, for what it's worth, in quite a few crossings I have never used anything under the tent inner. Actually, never ever on any tent. And never needed.
If on the other hand it is to use in a porch area, then that it totally different with a larger porch. And the double glazing film is super light and more than adequate.
If you are worried about a puncture leak, take some TENACIOUS TAPE. It is mighty stuff, and actually sticks to sil Nylon, unlike Duck Tape that is useless.

I use a ground sheet from Home bargains, £1,99 well worth the weight which is not much,👍