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Small Cabin Forum / Cabin Construction / I don't understand insulation
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Future Cabingirl
Member
# Posted: 17 Nov 2013 19:20
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I'm trying to get everything sorted for a cabin build starting next spring. I feel great about the building portion of the cabin, but figuring out how to keep it warm is a trip. I've read everything from don't worry about the insulation, to you need three foot thick or everyone will die. Whats the deal! We need the cabin to be comfortably livable year round. My gut says that people have build without insulation for a lot longer than they built with it. I want to forget it... that said, we have pretty solid winter here. What's the deal? Where can I got to get this figured out?

I would prefer not to use synthetic products, like tyvek, fiberglass, great stuff. The cabin is probably something like a 16x20 with a loft.

Martian
Member
# Posted: 17 Nov 2013 19:34
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Well, you can build 4' larger, in both dimensions, to maintain the interior space you want, and use small square bales of straw.

Tom

countryred
Member
# Posted: 17 Nov 2013 19:49
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Our future place will be in southern Missouri and we will get it as insulated as possible. Less energy to keep cool and warm.

If you have a big stove, lots of wood, then non insulating could work. It all depends on expense and how much you will use it.

MJW
Member
# Posted: 17 Nov 2013 20:04
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Quoting: countryred
If you have a big stove, lots of wood, then non insulating could work.


Until July and August...

I don't regret one bit going with 2 x 6 walls for the added insulation.

This past Summer it would stay cool in the house until well up in the afternoon. It was a relatively mild Summer (compared to 2012 anyway) but we didn't have to turn on the A/C but a handful of times.

Martian
Member
# Posted: 17 Nov 2013 20:05 - Edited by: Martian
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You can also put a reflective surface on the backside of your interior wall. It will reflect the heat in the direction from which it comes. Think, aluminum foil. If the stove is on, it'll reflect the heat back into the wall. In Summer, it works the other way.

Tom

MtnDon
Member
# Posted: 17 Nov 2013 20:12
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Quoting: Future Cabingirl
people have build without insulation for a lot longer than they built with it.


People have done a lot of things for a long time. Not all of them are actually good.

Question: Is where the cabin will be built required to meet building code? If so you will need insulation along with other things. In reality every location in every state is sunject to building and energy codes. It is the enforcement that is lacking in some locations. Some areas do have special reduced requirements for vacation properties. That can be worth looking into.

But even if one has a forever supply of firewood on their property an insulated building is much more comfortable in winter, not to mention summer. An insulated building also saves a lot of time, effort and expense in the cutting, hauling, splitting of firewood.

A starting point to see what levels of insulation are recommended for MI can be found online.

There are some "green" insulations made from recycled denim. If you don't like Tyvek use old fashioned tar paper, but that is a petroleum product as well. Just an old one. A weather resistant barrier is necessary.

silverwaterlady
Member
# Posted: 17 Nov 2013 20:29 - Edited by: silverwaterlady
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We have not insulated our cabin. When it's cold all the heat from our propane stove escapes through the roof. The only time you feel warm is if you are sitting directly next to the stove. This is in weather no colder than 42F. The end of September is the latest we can use the cabin.Or middle of May-Sept. One would freeze in the winter.

In the summer on a cloudy day when the sun comes through a cloud the metal roof makes loud popping sounds. It is so hot during the day in our loft it gets up to 100F.This is in Northern Ontario, Canada. It is to warm at night to sleep in the loft.

I don't have insulation yet because I want spray foam.. Due to my remote location and because its Canada it's going to be expensive. If I spent more time up there we would have cheaper insulation by now.

PatrickH
Member
# Posted: 17 Nov 2013 20:29
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you will never regret insulating ,we use as much as possible a well insulated building uses so much less energy to heat and cool and if building to code here if you heat it you must insulate it.

beachman
Member
# Posted: 17 Nov 2013 20:47
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You state that you want to live comfortably all year round and you have pretty strong winters. Definitely insulate! Our place is in Canada in the east and we can go on weekends in the Winter and get the place pretty comfortable with a wood fire. Temps get down below 0 f or less than-20 c. In summer, we can get 90 to 100 f. or 35+ c. We have 6" walls and double-pane windows with a really good seal. The roof has 8" of fibreglass insulation with venting above to keep the roofing cold so no condensation. Our old place does not have any insulation and it is not comfortable in May or September, and we would perish in Winter if we tried to stay there. The heat from the wood stove goes right up through the roof and melts the snow which turns to nasty ice when we leave. Unless you just want a Summer retreat, insulate.

MtnDon
Member
# Posted: 17 Nov 2013 22:30 - Edited by: MtnDon
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I see a trend here....

An excellent resource for how to do the best insulation is buildingscience.com . Along with doing insulation right they can tell you how to do the vapor barrier right. The two go hand in hand.

The spray foam that silverwaterlady wants is one of the superior methods. I would have used it in our mountain cabin but ran into the same road block. The contractors who do that are not interested in doing remote sites, unless you pay the travel time and mileage. I don't blame them, they are in business to make a profit after all.

As for what is green, that's a place to find lots of differences of opinion. While foam does not meet some green manufacturing goals or definitions it is a superior insulation and to me at least, makes the use of fuels more green down the road for decades on end. The same might be said for PV and wind power which does seem to have a great number of worshipers.

Steve961
Member
# Posted: 17 Nov 2013 22:36
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While it's important to insulate, I do believe you can insulate too much. You need to look at a few different variables here.

First, what's the cost of your fuel source compared to the cost of extra insulation? For example, I can get a full cord of wood for about $50 where my cabin is. Considering the few times I'm at my cabin in the dead of winter, that $50 cord of wood is going to go a long way. On the other hand, if I was heating with electricity and kept my cabin heated while I was away, I would be better off insulating a lot.

Second, if you are going to heat with wood, too much insulation may make it hard to run your wood stove at an optimum temperature to prevent creosote buildup. I have the smallest stove that Jotul makes, and most of the time it makes my 450 sq ft cabin too hot. I only have 2" (R13) of closed cell spray foam and can't imagine needing any more than that. And by the way, I'm in northern Wisconsin.

silverwaterlady
Member
# Posted: 17 Nov 2013 22:40 - Edited by: silverwaterlady
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Hi MtnDon, You hit the nail on the head as to why we are so far behind in our cabin progress. I am not going to try and haggle a contractor into doing a job so cheaply that he or she does not make any money.

We were aware being remote would have its challenges. I'll take that over having neighbors that I can see and hear.

Edited to include: DH was a painting contractor for many years,he was also the owner. The cheapest people he had to deal with were the people with the most money, business owners worth tens of millions and even one guy worth billions. It was amazing how they would try to low ball a job.....So this is why I'm not going to expect people that I hire to work for wages that will only make them resent me. Word get's out and you will have a very hard time finding a honest contractor to work for you.

bldginsp
Member
# Posted: 18 Nov 2013 07:54
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CabinGirl- just to emphasize a point made many times above- it's all about your personal comfort. I don't care how big your woodstove is or how much wood you have, in an uninsulated building you will not be a happy camper in temps below 45F. When people do insulate they usually insulate the ceiling and walls first, but not the floor, thinking that heat goes up, so why insulate the floor. But, walking around on an uninsulated floor in freezing weather, even with wool socks and fuzzy slippers, will freeze your toes. Been there, done that.

Sure in the past buildings weren't insulated, that's because they didn't have insulation when Abe and Mary Lincoln built their dream home in Springfield. So in winter they lived near the fire. You don't have to do that.

RidgeRunner
Member
# Posted: 18 Nov 2013 08:29
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Another potential problem with an un-insulated roof (depending on the design and make-up of the cabin and roof) is damming (and all the bad things that go along with it) caused by melting and refreezing of snow!!!
The water from melted snow will flow to the edge and refreeze......that creates a dam that backs-up water.
That's something you definitely don't want!

RidgeRunner
Member
# Posted: 18 Nov 2013 08:34 - Edited by: RidgeRunner
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Condensation fueled by lack of insulation is another potential nightmare!

gersus
Member
# Posted: 18 Nov 2013 09:26
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Thanks for the link mtndon!

MtnDon
Member
# Posted: 18 Nov 2013 09:42
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Quoting: silverwaterlady
The cheapest people he had to deal with were the people with the most money


Oh does that ever bring back (unhappy) memories! Way back when I did finish carpentry for my bread and butter I ran into one of those. Guy had the largest house on the most exclusive street in our town, the most ostentatious grounds and all, and he was the cheapest sob I ever quoted for. I was between jobs and he knew it and figured I'd take his low ball offer. I did not. Of course he did not know I was welcoming the break between jobs.

TheCabinCalls
Member
# Posted: 18 Nov 2013 09:48
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- There are spray foams that use soy based foam and during warm parts of the year they can use compounds that are "green".

- There are batt insulation that claim to be made of all natural fibers. No more formaldehyde.

- Concrete and log walls are thermal masses to help store heat

- The direction you face walls and windows matter in relation to the sun

- Shade trees in the summer that lose leaves in the winter help

- thermal breaks in floor will keep heat from escaping and the floor feeling cold

- insulated and/or vented roof keeps that hot sun from entering and keeps roofing from wearing out.

We made our place almost air tight with insulation on all sides. We used mostly foam, but also some batt in attic space. We lost power for a week and the place never dropped below 50 degrees. So in a week at sub freezing temps we only lost 15 degrees. We can lose that much in hours at our poorly insulated house in the city.

MtnDon
Member
# Posted: 18 Nov 2013 14:30
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Quoting: TheCabinCalls
- Concrete and log walls are thermal masses to help store heat


Something to think about if the cabin is part time use only and is not heated while left vacant. The thermal mass can work against you if the structure has been sitting for a few weeks. It will be cold. You can warm the air but it will feel cold until the thermal mass temperature has been raised. That may take all weekend.

TheWildMan
Member
# Posted: 18 Nov 2013 15:50
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how far north are you? insulation is measured in R value (or resistance). it determines how fast heat can move through the walls. an R value of 1 or 2 is all you get with uninsulated walls and heat will move very fast out of the cabin, the structure will also heat up very quick in direct sun. R 11 to R 13 is average for 2x4 walls and will work if you don't have too extreme temperatures (mild winters where the coldest it gets is 10 degrees). if you live in the far north you want as much as you can get and an R value of 30 or more is prefered, it slows the rate at which the cabin will cool down. if its very cold out such as 40 below and you have no insulation you will need to constantly run the heat to replace the heat that is lost. the better your insulation, the less often you have to fire up the stove.

not all insulation is equal in R Value. wood is roughly 1 R for every inch of thickness so cabin walls made of 6" wide square logs will have an R value of 6. 4 inch fiberglass insulation will be R11 or R13. spray foam 4 inches thick will be R30. so 4 inches of spray foam will provide as much insulation as 3 feet of solid wood.

rockies
Member
# Posted: 18 Nov 2013 18:56
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You can go to the buildingscience.com website http://www.buildingscience.com/index_html and search for articles about how to insulate and vapour barrier correctly for every type of climate

Borrego
Member
# Posted: 18 Nov 2013 22:16
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Insulation, insulation, insulation! I'm in the desert so it's kinda backwards, but still - there are no downsides, it's relatively inexpensive, and the upside is huge! If you want to go 'green', there are plenty of options, including recycled denim! I would pack in as much as you can, and don't forget the floor (if you are on a raised foundation, or even not) You will never regret what ever you put into this area of your build, and you can't do it again, so do it right.......

Smawgunner
Member
# Posted: 18 Nov 2013 22:25
Reply 


If you're going to insulate anything at all, do the ceiling or attic. Heat rises and tries to escape upward. If you can do the walls great...but definitely do above to keep the heat in.

Truecabin
Member
# Posted: 19 Nov 2013 01:28
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funny this post

yes in the past they didnt insulate the house because they didnt have insulation so they had to wear a warm coat and stay by the fire

and nobodys house was warm they were used to the cold but people nowdays cant live in the cold they wont come to your house maybe thats what you want

Future Cabingirl
Member
# Posted: 19 Nov 2013 11:55
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hmm... I guess I may look at log infill walls and that building science website for the proper cathedral ceiling insulation.

It's hard to find the right mix between over thinking and poor planning. I just want to make real steps toward moving (permanently) up to our property, but its hard to get any work done with no place to stay!

Malamute
Member
# Posted: 21 Nov 2013 11:03 - Edited by: Malamute
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I used to dislike fiberglass for several reasons, but have come to appreciate it very much. If you decide to use another material, that's alright, but the cost of fiberglass is one of the smaller costs associated with building and is a very good insulating material. I just do it (with proper masks and covering), clean up and vacuum afterwards, and get on with the project. At this point, I feel the green impact of fiberglass, a one time use for the building, is minimal compared to needing far more energy to heat and cool to be comfortable. Regardless of how cheap wood may be. The cost difference over time will pay for the insulation many many times over. I'm also a big believer in tyvek. When done well, it also will save quite a lot of energy over time by keeping air from coming into the walls from outside. If you use it, buy the real tyvek tape for the joints and whatever holes you make make. It works very well.

For a cathedral ceiling, they make "C" type fiberglass batts. It's the same R value as a standard batt, but is slightly compressed so you get the air space for proper circulation above it.

There's different opinions, but I've gone to unfaced batts. The paper of a faced batt is supposed to be the vapor barrier, but its hard to keep it perfectly intact, and totally sealed compared to unfaced batts and a plastic covering. Unfaced batts covered with heavy mil plastic sheeting is far easier to keep the house airtight if you tape all the edges and openings when building.

BTW, my experience with log and its thermal mass is that its not an issue, the first fire is made warm enough to be comfortable, and I haven't noticed any issue with the building radiating cold inward to any great degree. I've lived in log for most of the past 25 years.

Borrego
Member
# Posted: 21 Nov 2013 15:43
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fiberglass is now being considered 'green', because such a large percentage is made from recycled product....

rayyy
Member
# Posted: 23 Nov 2013 17:10
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I know that nasty old itchy pink stuff is no fun to put in but once done,,,oh so nice and toasty warm.My recommendation for your cabin is to insulate on all 6 sides!The thicker the better.

Malamute
Member
# Posted: 26 Nov 2013 11:07
Reply 


Actually, some of the newer stuff isn't as itchy. You still need to wear a good mask to keep from breathing the particles when working with it. I also clean the area up really well before doing anything else.

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