insulation of foam mattress
Submitted: Saturday, Jul 29, 2006 at 15:02
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loughma
I have a 75mm think foam mattress in my swag. I am going to add a 'closed cell foam sleeping mat' (20mm) to insulate me from the cold ground.
My question is, should I position the closed cell foam under the mattress (against the ground) or on top of the mattress ( against me)? What will keep me warmer?
Your thoughts please.
Reply By: The Explorer - Saturday, Jul 29, 2006 at 15:13
Saturday, Jul 29, 2006 at 15:13
Hello
I would have the closed cell sleeping mat on top on the assumption that it is a better insulator than the thicker foam mattress.
Cheers
Greg
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Follow Up By: The Explorer - Saturday, Jul 29, 2006 at 19:41
Saturday, Jul 29, 2006 at 19:41
To further elaborate I would assume the thick foam mattress will absorb your heat. Having the best insulator closest to you reduces area into which all your precious heat can go. Having the closed cell sleeping mat between the ground and main mattress would mean your heat would be lost to the 7.5cm of foam. Keep as much body heat as you can closest to you. Probably all theoretical really - get a good sleeping bag and thermals and you’ll be sweating.
Cheers
Greg
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Reply By: Member - Phil G (SA) - Saturday, Jul 29, 2006 at 15:42
Saturday, Jul 29, 2006 at 15:42
I'd have it closest to the ground. Are you sure you need it with a 75mm foam mattress??
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Reply By: Member - Mike DID - Saturday, Jul 29, 2006 at 16:11
Saturday, Jul 29, 2006 at 16:11
I don't believe this "Heat Loss to the Ground " theory.
At
Easter we camped on the Turon River where it got close to zero at night. It was in a deep valley where the sun set at 3pm so there wasn't much heating of the ground.
I slept on a Air Mattress which lay directly on the floor of the tent which went directly on the ground.
In June I slept on a 32mm self-inflating mattress which lay on the tent floor.
I felt no cold at either time coming up through the mattresses.
My secret - I have the entire TOP of the mattress covered in quilt to prevent cooling of the warm air in the mattress. Any warm air rise to the top of the mattress, so it doesn't get cooled by the ground - it only gets cooled by any uncovered TOP part of the mattress.
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Follow Up By: Bros 1 - Saturday, Jul 29, 2006 at 18:08
Saturday, Jul 29, 2006 at 18:08
Sounds good mike. In the early days of our
camping we slept in the back of my old cruiser on a steel plate floor. No one said any thing about air bed straight on steel with the result that we froze. LOL.
Cheers,
Bros.
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Follow Up By: Footloose - Saturday, Jul 29, 2006 at 22:31
Saturday, Jul 29, 2006 at 22:31
Interesting. I sleep the same way without the quilt. Maybe I should have an air bag sleeping bag made up :))
One thing I did notice was it getting colder just after the sun rose. If anyone can tell me why (or give me a reason why it ain't so) I'd appreciate it.
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Follow Up By: disco1942 - Saturday, Jul 29, 2006 at 23:47
Saturday, Jul 29, 2006 at 23:47
Footloose
The Earth and its surrounding atmosphere will loose its heat while the sun is not warming it. Have not you noticed that there is not much warmth coming from the sun until it gets up a bit.
PeterD
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Reply By: Member - John (Vic) - Saturday, Jul 29, 2006 at 16:49
Saturday, Jul 29, 2006 at 16:49
I use those Blue (Other colors available) foam mats that lock together under my swag to both act as protection for the bottom of the swag from sharp rocks etc and to add 12 mm of high density closed cell insulation under my 50 mm mattress.
They stack easy and work
well.
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Follow Up By: bucky - Sunday, Jul 30, 2006 at 06:44
Sunday, Jul 30, 2006 at 06:44
I agree with you John
But I have a roll of the same stuff, I got from Clark Rubber, Its a bit bulkier than those mats, but it fits snug under my swag and makes a huge difference..
Some of my mates are actually using those aluminium fold
camp stretchers, and chuck thier swags on them ,, those who do this swear by it,,
I'm for my ground sheet roll
Cheers Bucky
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Reply By: Mike Harding - Sunday, Jul 30, 2006 at 08:33
Sunday, Jul 30, 2006 at 08:33
I'd suggest you forget the extra mat and buy a decent sleeping instead.
A few weeks ago I camped in the High Country for a few days and every night went down to minus 5C. I have a -5C bag on a 70mm foam mattress (which is probably closer to 60mm these days) in a swag and the swag cover is normally about 25% undone (so I can see the stars :) On the first night I was a little cool, so on subsequent nights I put a car rug on top of the sleeping bag and was as warm as toast. One night I remembered to put my beanie on and was too hot.
Mike Harding
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Reply By: Member - Mike DID - Sunday, Jul 30, 2006 at 10:44
Sunday, Jul 30, 2006 at 10:44
When I first went bushwalking none of this fancy technology had been invented so we just slept in a sleeping bag on a groundsheet. For a bit more comfort and warmth you would gather up leaf litter or dead fern fronds.
Then in the eighties Karrimor came out with the yellow closed-cell 12mm foam mats - never had problems with a cold underside after that.
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