# How do I know if my basement is insulated?



## InTooDeep (Apr 21, 2014)

I bought a house with a finished basement. Its always cold there. And gets colder the further away from the furnace. Before I start any attempt to fix it I want to know if the problem is the low or lack of insulation. Is there a way to know this without ripping down the drywall?


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## Wuzzat? (Apr 21, 2014)

With a thermistor or thermocouple you'd first need to know the basement air temperature, the outside basement wall surface/ground temperature and the temperature of the inside basement wall surface.

http://www.webstaurantstore.com/tay...ogleShopping&gclid=CIWdssGE8r0CFYMcOgodWAkADA

I'd crumple up tin foil around the probe end to make better thermal contact with rough surfaces.
Then it's working backward from the thermal conductivity of your wall to what it might be made of, using formulas and tables.

If the air temperature says you should be warm but you're not, the walls may cold and so you lose body heat by radiation, the other two mechanisms of heat loss being conduction and convection.

You could spend a lump sum for insulation plus labor or 
pay a monthly charge for a room heater or 
use a fan or furnace plenum vent to put warm house air into the basement.


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## CallMeVilla (Apr 21, 2014)

Well, we all have ways of looking at problems.  I would rent a thermal imaging camera and check the walls for cold and hot spots.  You can "see" through the walls and detect the lack of insulation, particularly in corners and ceiling junctions.  Compare the readings against the upstairs walls to see if there is a big difference.

You will quickly determine exactly where your biggest problems are ... then map a strategy for fixing it.

http://www.amazon.com/dp/B0088EZZ78/?tag=skimlinks_replacement-20


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## nealtw (Apr 21, 2014)

Just cut a hole in the drywall carefully so it can be replaced and inspect what you have.


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## beachguy005 (Apr 21, 2014)

I'm with nealtw on this one.  Just punch a couple of holes .  It's easy and cheap to patch.


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## CallMeVilla (Apr 21, 2014)

Simple enough for us ... but In2Deep seems to be new to this and punching holes can be daunting.  I think a thermal scan is easier, faster, less intrusive, AND it can reveal a lot more information than a hole or two.


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## Wuzzat? (Apr 21, 2014)

CallMeVilla said:


> Simple enough for us ... but In2Deep seems to be new to this and punching holes can be daunting.  I think a thermal scan is easier, faster, less intrusive, AND it can reveal a lot more information than a hole or two.


In the image, is the insulation missing in the red zone because it's hot outside or the blue zone because it's cold?

Have you pointed this thing at women?


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## CallMeVilla (Apr 21, 2014)

This is STRICTLY in the interests of demonstrating the ability of the infrared camera to distinguish shades of temperature accuracy ... if you choose to see it as anything else, it will be between you and your spouse.


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## nealtw (Apr 22, 2014)

Any diyer either knows how to patch drywall or has to learn, what better place than in a closet or somesuch in a basement.
Villa: nice picture, now is she nude or wearing a silk shirt, there are just so many things that camara will tell you.  Everytime I have seen them used it is immediatly followed up with cutting holes in walls.


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## CallMeVilla (Apr 22, 2014)

Hole cutting after a thermal scan is the obvious next step.  What the scan tells you is WHERE to cut and also WHY to cut.

Sorry to disappoint you ... This is a pic of Wuzzat after a day at the beach.


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## bud16415 (Apr 22, 2014)

Reading this and eating breakfast at the same time and I just threw up in my mouth a little.


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## Wuzzat? (Apr 22, 2014)

CallMeVilla said:


> This is STRICTLY in the interests of demonstrating the ability of the infrared camera to distinguish shades of temperature accuracy ... if you choose to see it as anything else, it will be between you and your spouse.


Good disclaimer. . .


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## InTooDeep (May 8, 2014)

So to update the situation. I opened the wall. I have pink insulation in the walls with tar paper as the barrier. Problem is that the rim joists are not insulated. The basement is finished with drywall. I plan to have the basement as livable space all year round. Is it necessary to cut the ceiling to put insulation in them patch it back up? Or would I be fine with just the wall insulation?


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## nealtw (May 8, 2014)

If you are renting the space you may want to insulate the ceiling. There are lots of houses that are missing that insulation. I guess it depends on how much heat you think you are loosing to it.
If you were going to do the whole ceiling, you just remove 1 ft strips every four feet and you can get it in there.


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## InTooDeep (May 8, 2014)

I do plan on renting it. But what's the advantage of insulating the ceiling when the plan is for me to pay for heating the whole house. Any heat lost in the basement would just go to heating the main floor. My main concern is losing heat to the outside.


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## nealtw (May 8, 2014)

Noise................


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## InTooDeep (May 9, 2014)

I may do that in the future if the noise transfer is exceptionally bad. But right now my concern is heating the basement. Can a basement be heated adequately in the winter without insulation in the rim joists?


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## bud16415 (May 9, 2014)

I think you will be ok if rim joists are sealed up good without insulation. I have seen construction where there are big gaps around the rim and air flow is the problem more than insulation. Don&#8217;t know if you can access that from outside or not or how house is sided. 

You said its always cold. What kind of heating is in there just a single duct or is it set up for heat?


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## oldognewtrick (May 9, 2014)

As Bud has mentioned, two areas that need to be addressed are air infiltration and thermal transfer. Merely adding insulation will do little if you have voids allowing movement of air into the basement. Weather sealing the house envelope is as important as adding insulation. Unfortunately, you have to have access to the framing to caulk and seal places where you can have air leaks.


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## nealtw (May 9, 2014)

Depending on where the house is, in a wet zone like where I am, air flow is stopped at the vapour barrier and we leave holes in the sheeting to allow the house to breath. Water is stopped on the outside with the house wrap. We treat the wall just like the ceiling/attic , air behind insulation.


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## bud16415 (May 9, 2014)

Last year I helped a friend with her basement rim joist problems. The basement was under insulated but cold and floor were always cold and robbing a lot of heat upstairs. When I pulled out the little bit of glass someone stuffed up in the rim joist area cold air just poured in. I foamed the big gap and let it to harden up and when I went back it was amazing how it had changed. We put the glass back in and added more but I don&#8217;t think it did much. Stopping the draft was 99% of it. 

If you have siding that snaps on its not that hard to take a couple rows down. It may be possible to do some good without taking the ceiling down. Most people dread opening the ceiling but that also isn&#8217;t that much to fix if you are careful how you open it up. 

Your question is hard to answer because we don&#8217;t know the whole picture. You can keep anything warm as toast if you pump enough heat to it. It&#8217;s hard to say.


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## Jungle (May 9, 2014)

It is like trying to keep warm by swallowing your sweater. Doesn't work you should wear you sweater instead. 

A basement should be insulated from the outside in. So you want to start there around your foundations with a strong vapor barrier such as blue skin, keeping the dampness out a couple inches of polystyrene at least.


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## nealtw (May 9, 2014)

Jungle said:


> It is like trying to keep warm by swallowing your sweater. Doesn't work you should wear you sweater instead.
> 
> A basement should be insulated from the outside in. So you want to start there around your foundations with a strong vapor barrier such as blue skin, keeping the dampness out a couple inches of polystyrene at least.



Over that sweater put on a rubber rain coat and get to work and see how that works. New rain gear can breath just like house wrap.


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## Wuzzat? (May 12, 2014)

Jungle said:


> A basement should be insulated from the outside in.


In principle and as to only heat loss or gain it should make no difference which side the insulation is on but there may be practical considerations that dictate one side or the other [beside the expense of excavation].

Can you post a link to a pdf file that supports your position/assertion/opinion/fact?  
TIA.


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## Jungle (May 16, 2014)

2" Of Styrofoam around the outside should make the concrete walls much warmer.

/watch?v=kwn0Vjw_ji0


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## InTooDeep (May 16, 2014)

Can you insulate the outside walls above grade? The rim joists are the problem.


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## nealtw (May 16, 2014)

I suppose you could, but it depends on what you have out there. you will want a flashing that goes behind the siding and house wrap above it and cover it so it looks nice.
Something like this just higher.


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## InTooDeep (May 16, 2014)

I have a brick exterior, can this still be done?


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## nealtw (May 19, 2014)

Brick absorbs water and releases it toward the inside, there is a space beteen the brick and wall to allow the water to run down and out wipe hole beween brick in the bottom row. The flashing in my photo would go behind the brick and house wrap. So in a word "no" I would sooner loose a little heat, than mess with the outside. You could be causing much bigger problems.


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## Wuzzat? (May 20, 2014)

Jungle said:


> 2" Of Styrofoam around the outside should make the concrete walls much warmer.
> 
> /watch?v=kwn0Vjw_ji0



Good link about heat transfer and vapor transfer.  I'll have take notes on this video, it goes fast.

Here are my unedited notes from the cold climate video which may serve as a checklist.
It seems that for existing construction, you'd need some way of measuring vapor and water transfer, relate that to basement comfort and decide what your comfort is worth in dollars.

Basement insulation

[ame]http://www.youtube.com/watch?v=kwn0Vjw_ji0[/ame]

Cold climate research

-below grade heat loss is outward, vapor pressure is inward.

-above grade, in winter vap out, in summer it's in.
-understand moisture flow, liquid and vapor
-capillary wicking water upward.  Need a capillary break between footing and foundation.
-vapor comes in two ways, by air and diffusion (pressure),  Soil is 100% RH.
-preferred is to put water membrane (spray on or roll on) and insulation outside so water & vapor does not saturate the walls.  Then the wall stays warm and if any moisture is in the wall it can rapidly be dried out by the basement air.
-basement wall moisture content strongly predicts joist moisture content by vapor transfer. Joist insulation makes it worse.  So extend the outside insulation over the rim joist.

-You can insulate from the inside but it has to be perfect because the wall moisture control has not been taken care of.  The cold basement wall will get condensation.  And if your basement floods the interior fiber insulation has to be removed.
-You could use styrofoam on the wall interior but basement wall surface has to be dry.  The bottom foam edge needs to be sealed.
-The slab has to stop water from underneath so use aggregate to allow drainage and prevent wicking.
-Seal the sump lid to prevent humid air coming into the basement.
-Use a thermal barrier under the slab because warmer is drier and the slab becomes part of the conditioned space.  
-Don't carpet the slab.

-The lump sum cost of exterior insulation may pay for itself over time.  This insulation needs to be protected from physical damage.  Interior insulation systems are risky but may be cheaper in the short run.
-Use paperless drywall for finishing, no insulation, use flat latex paint.

-The rim joist should also be part of the conditioned space.
-You could use spray foam inside but it may not bond properly.  The joist may absorb moisture.


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## Perry525 (May 23, 2014)

InTooDeep said:


> I bought a house with a finished basement. Its always cold there. And gets colder the further away from the furnace. Before I start any attempt to fix it I want to know if the problem is the low or lack of insulation. Is there a way to know this without ripping down the drywall?



You only mention the furnace, is there any other form of heating down there?
A room can feel cold, because you are too warm or because there is no heating or the heat is escaping.
How much heat are you putting into the rooms (same space) above? Are they warm? Are you putting the same amount of heat into the basement? Do you want to keep it at the same temperature? What temperature are the rooms above? What temperature is the basement?

For example, the palm of your hand is probably 30C, the walls of your living room are probably 20C, when you touch them they feel cold, the basement walls also feel cold to touch, they may be the same temperature, they may be colder.


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## Wuzzat? (May 24, 2014)

Heat is lost from your 37C core temperature by conduction, convection and radiation.  

A room with colder walls will feel colder even if the air temp is the same (radiation) but IIRC with a 50F or less air temp people feel cold no matter how hot the walls are.

Touching wood (a thermal insulator of sorts) at 72F will feel warmer than touching aluminum (a thermal conductor) at the same temp (conduction).

Moving dry air will feel cooler than moving still air (convection).

And women's comfort zone for temp and humidity is different than men's.


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## Perry525 (May 25, 2014)

Fascinating subject, it should be taught at school.
So many people have trouble understanding.
One thing that troubles me about the insulation industry and builders is, that a Polar bear has a two inch thick fur coat, yet with a body temperature of 37C it can play quite happily in temperatures of minus 30C, we on the other hand need insulation five or more times thicker.
Industry is missing something.......builders seem to just ignore radiation.


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## Wuzzat? (May 25, 2014)

Perry525 said:


> Fascinating subject, it should be taught at school.
> So many people have trouble understanding.
> One thing that troubles me about the insulation industry and builders is, that a Polar bear has a two inch thick fur coat, yet with a body temperature of 37C it can play quite happily in temperatures of minus 30C, we on the other hand need insulation five or more times thicker.
> Industry is missing something.......builders seem to just ignore radiation.


They used to have a resi HVAC system with an outside temp sensor that boosted the inside temp a bit depending on how cold the outside got.  Maybe that somehow didn't work out but the principle is sound.

Apparently humans gave up fur, claws, fangs, speed, strength and night vision for increased brain capacity.  
Fair trade?


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## slownsteady (May 28, 2014)

> One thing that troubles me about the insulation industry and builders is, that a Polar bear has a two inch thick fur coat, yet with a body temperature of 37C it can play quite happily in temperatures of minus 30C, we on the other hand need insulation five or more times thicker.



That's why I insulated my basement with bear fat. Acquiring the fat was nothing compared to the installation

(no bears were actually hurt in the making of this post)


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## InTooDeep (Jun 18, 2014)

Thanks for all the replies. Follow up question. I ended up opening some more walls only to find that there was pink insulation but no vapor barrier (no plastic film or tar paper). Is a vapor barrier needed in a basement against the exterior walls?


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## nealtw (Jun 18, 2014)

The vapour barrier should be next to the drywall, the idea is to keep warm moist air from the house from getting into the framing in the wall, if you are not finding any problem with rotting wood I would not worry to much about it.


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## InTooDeep (Jun 19, 2014)

I found a bit of black wood along the floor. Everywhere else seems fine. I do plan to have the basement as a living space. So I'm worried that I won't be able to keep it warm in the winter. I live in Canada.


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## nealtw (Jun 19, 2014)

With a screwdriver poke at the black wood to see how solid it is, compare it to clean wood higher in the wall. If it is soft and mushy you have a problem.
Any wood that is in contact with concrete will draw moisture from the concrete.
In the wood structure upstairs there are holes and gaps in trhe sheeting that allow moisture to get out of the wall if it gets in there. the vapour barier stop house air from entering the wall. In the basement there is less chance of moisture getting out because it is a more sealed unit. so with the black wood you know you have some moisture at the floor prehaps not having a barrier is a better bet. Experts have fought about this for years.
Your biggest heat loss will be the windows and doors and the biggest problem is to get enough heat into the basement (HVAC design)
I live near the coast in BC and live in a basement suite. We have 4 inches of fg in the walls, to stop noise transfer and add fire stopping we closed off the heat and added electric baseboad heat
We also added a 4" air intake to provide air for the kitchen and bathroom fan. The only thing I would change now is something on the floor, the concrete is cold.

What you want to be sure about is the water isn't leaking thru the concrete wall, the age and condition of the weeping drain on the outside, to keep it dry


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## Wuzzat? (Jun 19, 2014)

The black wood is kind of a go/no-go, binary, test.  A moisture meter with needle probes may allow you to map out the intensity of moisture problems in your wood at several locations.  
You might as well know the full extent of any problems.

I'm surprised at how warm the ground temps are for Canada, Fig. 2 of this link
http://archive.nrc-cnrc.gc.ca/eng/ibp/irc/cbd/building-digest-180.html


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## InTooDeep (Jun 20, 2014)

So I've decided I'm going to rip down the walls and insulate the rimjoists and put up a vapour barrier. The basement is going to a living area and it's important that it stays warm during the winter. I was thinking for the rim joists to install 2in extruded foam board and seal it with expanding foam. Then reuse the pink batts and run the plastic vapor barrier from the bottom of the foam boards to the ground. Stapling it to the studs. Is this the best method?


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## nealtw (Jun 20, 2014)

The insulators do use the foam board in the rim but they seal it in with some chaulking made just for that.
 Our code calls for the exterior wall to be built 1" away from the concrete wall and that gap behind the wall at the top must be firestoped so fire in that wall can't get to the floor above. Depending on what you have for a sill on top of the concrete we intall either a 2x4 or a 2x6 against the sill and then the top plate of the wall goes against that and the space behind the wall is really close to that inch that is needed and the room comes up just as square as the room upstairs. The vapour barrier goes against the studs before the drywall. There are plastic  shells to put switches and outlets in for vapour and the barrier is stuck to the floor with acustic sealer.
And the bottom plate does want something under it so it dosn't wick water up, plastic sheeting, sill gasket, tar paper.


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## InTooDeep (Jun 20, 2014)

Well unfortunately the walls are already framed so I can't put anything under the bottom 2x4. So just to be clear the foam board doesn't require a plastic vapor barrier over it correct?


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## nealtw (Jun 20, 2014)

That is correct. When we find wood that is sitting on concrete the inspectors or engineers always get us to treat that sill and the bottom of the studs with the same stuff that is in treated lumber to discouge insects going after damp wood. Lumber yards carry the stuff. Any other times they frown on green lumber inside the home but they say the exerier plates are outside the vapour barrier and if we do some on interior walls say just shrug and say do it just not so much.


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## nealtw (Jun 20, 2014)

I take it that you are happy with how solid the wood is now.


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## InTooDeep (Jun 20, 2014)

Well it's darker along the bottom. But it's not mushy. Just about as solid as the rest studs.


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## nealtw (Jun 20, 2014)

I would treat it to keep the bugs out. I you do want to change parts of the plate we just cut the studs up about a foot, put in the new plate and sister the studs with 3 ft peices. The outside walls  are not structural.


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