# Freezing cold floors *HELP*



## johnpma (May 21, 2009)

Have an old home built in 1900 It was one of those homes that the family added on a room for every child born. Originally only a summer home for the family.

One of the 1st floor bedrooms is on a stone foundation. The access is through a very small opening 10" x 18" There is about 20" of clearance from the ground which is all stone ruble and the floor joists. I'm torn on what to do but the floor is freezing and you can feel the air coming up through the floor.

I'm certainly not going to fit my butt in there, and I can just imagine the feeling of laying on jagged pieces of rock trying to insulate, but I do have teens 

What approach should I take. Even thought about cutting out the floor:no: Not really sure where to begin. I'll get pictures posted soon.


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## joecaption (Nov 30, 2011)

Start by having them start raking out those stones.
Your going to need to lay down a 6 mil. or thicker vapor barrier.
Insulate the rim joist first by cutting 2" thick blue foam and sealing the gaps with expanding foam.

http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table


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## johnpma (May 21, 2009)

by doing that joe you insulate the out side cold from coming through the stone work and in to the crawl space??


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## Gary in WA (Mar 11, 2009)

http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/ May need a covering, check with local AHJ.

http://www.buildingscience.com/documents/insights/bsi-064-bobby-darin-thermal-performance

http://www.diychatroom.com/f103/how-insulate-rim-joists-simply-190336/

Gary


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## johnpma (May 21, 2009)

here is a pic of what I have They put 1" thick to the floors which in my opinion does squat!! They have a heavy plastic sheet over the rock in the crawl space.


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## Chewbacka (Feb 27, 2014)

The double sided foil faced insulation is good at 2" thick. In the coldest parts of New England one needs 2" to stop the dew point from passing through into a heated space. Without sealing your foundation rim joist right down to,( in your case the existing dirt/rock/vapor barrier) the cold in the rock and at rim joist level will migrate into your living space above.
Is there any ducting or anything supplying any heat to the living space in the area in question?
The seams of the insulation need to be sealed with foil tape or spray foam, and the cement wall/rim joist needs the same treatment, or closed cell spray foam from the floor above to the foundation rock below.
Once you get it properly sealed if it's still cold, then consider a mini-split ductless heat pump, which can provide heat to -15* and AC in summer. Fujitsu makes several currently and we have two in our house. Small unit inside the room and compressor/condenser outside.


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## johnpma (May 21, 2009)

Thank you!! So are you suggesting that only the rim timber to the rock needs to be insulated or the insulation needs to be along the face of the rock as well?? There are pipes for the steam heat that run in this area however we heat with wood so the steam is hardly used.


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## Chewbacka (Feb 27, 2014)

johnpma said:


> Thank you!! So are you suggesting that only the rim timber to the rock needs to be insulated or the insulation needs to be along the face of the rock as well?? There are pipes for the steam heat that run in this area however we heat with wood so the steam is hardly used.


Basically anything that acts as a heat sink, absorbs cold and transfers it to surrounding house structure or air in the conditioned, (heated/cooled) space will benefit from being isolated by an insulation barrier. As to the ledge rocks I suppose one could cut foamboard to box in the area as best as possible to sort of cap off the cold ground/rock from transferring cold up to the room area. That would have to be a site specific call. It might not be worth the effort for the end result if you get the rest of the concrete insulated and air sealed. Sealing flow of cold air is key. This is why foam works better than fiberglass to seal out cold air. Think of fiberglass as a Brillo pad- not much air being stopped in one of those!
I can't tell from your one pic, but it looks like water is running down the concrete wall(s)? It might be easier to insulate down from digging down outside and using the Tuff-R or similar foil faced 2" foamboard, BUT unless you have a solid concrete foundation down to where the ledge appears to be outside digging can open up cans of worms, not just one can, many cans!:yes:
You can buy the spray foam packages that contain the two BBQ grill sized cans to do some spray foam work yourself, but doing it IN the crawlspace would require a professional with a full respirator.
Since you heat with wood and the steam does not get to the room a mini-split, like I mentioned might be worth the investment if the room gets a lot of winter or summer use. The insulation work is a one time cost, so the better job done saves more over a longer time, but if done poorly still costs in wasted heat and frozen bones.
Is there insulation in the walls currently? If so how much?
Can you push any heat from the wood stove to the area by small doorway arch computer type/size fan?
Access how much you use the room now and how much more you'd use it if it were warmer, for reasonable cost, or could be warmed/cooled as needed by a mini-split or other source of heat.


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## johnpma (May 21, 2009)

this particular area ins a small half bath, and my bed room:laughing: Kids are up stairs where all the heat is :thumbup: The walls are true 2X4 wall and yes they have R13 and are sheet rocked.

On the outside they poured an 8" thick apron around the parimeter of the room with a slope to move water away from the home. great idea but done wrong in my opinion as it is not flashed to the home. So yes water can make it's way as can cold air between the apron outside and the timber (in the above pic) which sits on top of the stone foundation. 

Thank you for the detailed explanations your knowledge is very helpful:thumbsup:


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## Chewbacka (Feb 27, 2014)

Glad to help. I see now your band beam is not concrete, that it looks like PT?
FWIW, I would find a way to excavate down far enough outside to see if you can stop the infiltration of water. Especially since you are now insulating the crawl space, any moisture and especially water will have no place to go. Before you put down the vapor barrier on the ground the water could be absorbed into the earth. Now it will just try to evaporate and cause mold and mildew in the crawl space which is not desirable.
If you look up past episodes of Holmes on Homes, a Canadian TV production available in the US on Dish Network and possibly other places, or go to their website and look up episodes dealing with leaking foundations/basements, etc. you will find shows that show a flexible membrane being installed onto the exterior foundation wall over a foundation coating that looks like but isn't tar. These flexible plastic coverings usually are used to direct any water to the footing drainage tile,(perforated pipe) and then carry the water away to a drain/sewer system, storm water runoff drain, etc.
In your case, if you could get the flexible barrier to where your band beam attaches to your house structure then you could keep all water, or most from getting into the house foundation footprint.
Can you shoot and post some pics of that area outside/
AND, I thought maybe you could steal some heat from your kid's room above by cutting in a duct and running it into your room below. It could even be where you install a register above and below the floor in an open joist bay and then attach a reasonably sized duct to drop down to your bath/room and push the hot air from their room down through the duct to your space via small wood stove/ computer type fan.


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## johnpma (May 21, 2009)

Yeah, thought about that however this was an added room (satellite room) and there is nothing above. looked again last night and I see that there are air gaps up to 1" between the main beams and stone foundation. The beam is not PT so I'm sure there is some rot there. In the spring I will begin the task of opening up the walls from the outside to get a better look at whats really happening. joecaption offered some great help on ways to repair those rotten areas. never easy when you have a 100 year old home they did things a little different back then:laughing: I'm going to make an attempt at crawling my butt in there when it warms and getting a good look at whats really going on. 

Because the walls are 2x4 I also thought about adding a layer of 1" foam to the interior walls and installing fur strips and re-sheetrocking, and adding extension jams to the windows to increase the R factor on the walls too.....

Will it ever end:no:


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## Chewbacka (Feb 27, 2014)

Why not just tear out the existing sheet rock, and do a spray foam 1st layer then some rockwool, then re rock. Or drill holes outside and blow in cellulose, then fill holes with plugs, paint or stain, done?
Those holes are definitely contributing to heat loss and will attract squirrels, ratz, and or other pests.
It's never done!:laughing:


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## johnpma (May 21, 2009)

*Roxul Exterior Wall???*

Here are a few pics of my project. A buddy who is a contractor gave me two bags of Roxul insulation. I tore out the sheet rock on the exterior wall. The old insulation had signs of wetness from previous years. Over the summer I opened up the roof and ventilated the roof to eliminate ice damns. Put down two courses of ice membrane and re shingled

When I removed the sheet rock there was frost between the exterior 1x6 sheathing and the insulation.....why???

We used foam in a can and sealed all joints

The home is balloon framed so I ripped down 2X6's and made blockoff's and installed them between the wall studs and floor joists and spray foam all the seams

Then we began installing the Roxul. The plan after the Roxul is to run 2X3's perpendicular to the studs 16" OC and rip down foiled sided foam to fit between the 2X3's adding more R-value. Hope to finish insulation tonight.

I cannot believe how much warmer the room is just from the few things we did already.

Any comments appreciated???


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## Windows on Wash (Aug 30, 2011)

Looks good. I would opt for just putting some rigid foam tight to the sheathing in lieu of the spray foam. It will be a bit more expensive but should provide a better air seal be a bit easier to do once you get the process set up.


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## Chewbacka (Feb 27, 2014)

johnpma said:


> Here are a few pics of my project. A buddy who is a contractor gave me two bags of Roxul insulation. I tore out the sheet rock on the exterior wall. The old insulation had signs of wetness from previous years. Over the summer I opened up the roof and ventilated the roof to eliminate ice damns. Put down two courses of ice membrane and re shingled
> 
> When I removed the sheet rock there was frost between the exterior 1x6 sheathing and the insulation.....why???
> 
> ...


The frost is the dewpoint trying to penetrate the house (via air migration), because of the prior lack of insulation, the warmer moister interior air is exfiltrating to the colder outside sheathing layer, then freezing on contact when it hit's the cold surface. Your objective and task is to stop the movement of air in OR out of the heated envelope of your house, in ALL seasons. Ideally, I would have cut 2" (both sides foil faced) Tuff-R insulation to fit between the wall studs using canned spray foam to seal the perimeter of the insulation/wall stud, and then filled any remaining void with the Roxul.

Your plan to add the foil faced insulation after the Roxul, will help immensely! Make sure not to overlap the seams of the Roxul and the foil faced insulation, and definately use the metal/foil duct tape to seal all the seams. You could can spray foam the perimeter of each piece to the 2X3" laid flat studs to make the room 'bomb' proof.:thumbsup:

But, what you have done should accomplish a lot of good, and soundproofing too, which the Roxul is excellent at. Use a high quality sheetrock product that contains mold and mildew retardants, and as little paper content as possible; this reduces the chance of mold getting a hold.

Your only problem now is you won't want to go into any other rooms in the house!:no:


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## johnpma (May 21, 2009)

Chewbacka said:


> The frost is the dewpoint trying to penetrate the house (via air migration), because of the prior lack of insulation, the warmer moister interior air is exfiltrating to the colder outside sheathing layer, then freezing on contact when it hit's the cold surface. Your objective and task is to stop the movement of air in OR out of the heated envelope of your house, in ALL seasons. Ideally, I would have cut 2" (both sides foil faced) Tuff-R insulation to fit between the wall studs using canned spray foam to seal the perimeter of the insulation/wall stud, and then filled any remaining void with the Roxul.
> 
> Your plan to add the foil faced insulation after the Roxul, will help immensely! Make sure not to overlap the seams of the Roxul and the foil faced insulation, and definately use the metal/foil duct tape to seal all the seams. You could can spray foam the perimeter of each piece to the 2X3" laid flat studs to make the room 'bomb' proof.:thumbsup:
> 
> ...


Thank you very much gentlemen:thumbsup: I'm very impressed with the Roxul. I appreciate your comments as this is room one. All of your help will apply to the future rooms. That foil foam is expensive stuff!!

Oh and as far as leaving the room ummmmmm........my wife is my construction partner too


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## Chewbacka (Feb 27, 2014)

You're welcome. Glad to be of service.
Yes, the foil faced rigid foam is not cheap, but you will thank yourself time and again for using it. There is no better product, combined with Roxul to get the job done! I know, I've used it everywhere I can to mitigate loss of energy $$$.:thumbsup:


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## Gary in WA (Mar 11, 2009)

What type of siding?

Gary


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## johnpma (May 21, 2009)

Gary in WA said:


> What type of siding?
> 
> Gary


Sheathing is 1 X "whatever they had", and the siding is horizontal cedar clapboard


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## Windows on Wash (Aug 30, 2011)

I would imagine there's a good bit of solar vapor drive in that assembly during the wet seasons.

This is where a piece of rigid foam that is installed to the backside of the sheeting, with a small air gap, might do a better job of keeping moisture out of that assembly.


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## johnpma (May 21, 2009)

Windows on Wash said:


> I would imagine there's a good bit of solar vapor drive in that assembly during the wet seasons.
> 
> This is where a piece of rigid foam that is installed to the backside of the sheeting, with a small air gap, might do a better job of keeping moisture out of that assembly.


I'm not sure what you mean by "solar vapor drive"??


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## Chewbacka (Feb 27, 2014)

johnpma said:


> I'm not sure what you mean by "solar vapor drive"??


Heat from the sun extracting moisture from the conditioned space and from/through the exterior wall materials. ( I know you weren't asking me the q, but I thought I'd take a stab at the answer so you have one ...)


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## Windows on Wash (Aug 30, 2011)

http://www.buildingscience.com/documents/insights/bsi-021-thermodynamics-its-not-rocket-science/?searchterm=solar%20vapor%20drive

http://www.buildingscience.com/docu...rvoir-claddings/?searchterm=solar vapor drive

Good reads.


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## Gary in WA (Mar 11, 2009)

Thanks, guys. Even one of my links I use..... lol, I can see us old guys missing it, but the younger too.... Yes, vapor drive is a part of the answer to my siding question. Not just from solar drive, there is also pressure drive of water from outside to cavity pressure= high to low. And the tar paper (if there) is giving capillarity (drive/pull?) to wet the sheathing boards because cedar siding is a "reservoir" siding and wicks water (wet to dry) also. I really doubt the siding is back-primed, has a rainscreen or two paper layers to prevent all this. 

Then with the foil facing as the vapor barrier inboard, drying can/will only occur to the exterior. Not to mention any rainy days with the AC on, if you have that kind of summer. Similar to the "unvented brick frame wall with a poly vapor barrier" in your Zone 5; http://www.google.com/url?sa=t&rct=j&q=oriented+strand+board+next+to+insulating+foam+sheathing+moisture+diffusion+problems&source=web&cd=22&ved=0CFEQFjABOBQ&url=http%3A%2F%2Fwww.ornl.gov%2Fsci%2Froofs%2Bwalls%2Fstaff%2Fpapers%2F143.pdf&ei=G_P0T_CfD-Lj0QGuyvmPBw&usg=AFQjCNHnJQGqBm_YLikw097AhZCgy4ETIg&cad=rja


Poly (or foil) is not a good idea, IMO. 
Gary


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## Chewbacka (Feb 27, 2014)

The foil on both sides of 2" rigid insulation keeps moisture from the house exterior from passing to the interior. The inner foil and the 2" thickness keep warm moist air from passing from the conditioned space to where the dew point would allow that same moist air to freeze and later thaw when atmospheric/weather conditions and pressures change.
Unless everyone with older houses, built various ways as 'technology advanced' were to strip off their siding and redo the materials to make for the absolute best weather impervious house, and at great expense in the process, most people trying to conserve energy $ spent while gaining the most benefit in terms of comfort/warmth will opt for those products which properly applied keep the heat and cold in the living space, as needed. Some exterior surfaces may not get the attention they need, but mold and moisture issues can be controlled better by reducing random air flow into the conditioned spaces by blocking water/moisture/ dew point migration at places like sill/rim joist interfaces. Proper gutters, roofing methods, siding choices, and their ability to shed excess water are all important factors too.

I don't prefer the use of plastic for vapor issues because often it gets put in the wrong place in the house envelope and can then cause more issues than it was intended to solve.
Double faced foam is an entirely different animal, and like all building materials it can have huge benefits when used and placed in the proper position in the sandwich.:thumbsup:


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## Windows on Wash (Aug 30, 2011)

In many of these applications, the interior moisture is not the significant issue.


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## Chewbacka (Feb 27, 2014)

True. However indoor air quality should trump exterior issues from the standpoint of occupant health and comfort.


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## Windows on Wash (Aug 30, 2011)

The concern with a potential vapor trap is that if you don't allow that exterior wall to dry out in both directions you can potential he have mold, mildew, and rot issues.

In those moisture sensitive cladding scenarios, this is why I prefer putting the foam between the studs.

These older type wall systems can be tricky to make efficient and dry.

Drafty was always a safe bet to keep dry.


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## Gary in WA (Mar 11, 2009)

I would not recommend the foil facing as it too low a perm rating; stops all drying to inside from incidental water (wet reservoir wood with flow-through wet building paper with wet solid wood sheathing) with R-27 in front of it. Inside face of sheathing is same as outdoor temps; wet, cold wood. Wet for longer periods of time, longer to dry out, unlike OSB or plywood sheathing that will retard the moisture drive. Drys in summer. The interior foam board is fine, just the facing that bothers me, as brought out in Figs. 6 and 7= *no poly*; high OR low moisture content. Read page 8; *Zone 5*..... http://web.ornl.gov/sci/roofs+walls/staff/papers/143.pdf

It's the outside wetting, not the minimal interior vapor diffusion that bothers me; poly is way over-kill, a newer report that will surprise a few readers; http://www.buildingscience.com/docu...ermeance-vapor-barriers-roof-wall-performance

In your Zone 5, I would rather see a drywall primer+two coats of paint (5 perms) OR a vapor barrier paint (1+ perms) to allow some intrior drying of the studs/sheathing. Compare the foil faced (Poly) to others in Fig. 3; http://www.rci-online.org/interface/2010-04-gatland.pdf 

And ADA the drywall; http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

Depending on location, may not need worry about the summertime interior moisture drive (when sheathing is wet and trying to dry inward, wetting the studs;
"
Summer temperatures are delightfully comfortable for the most part, and summer averages are quite 
uniform all across the State. Long term averages for July range from 67 to 70° F in the Western Division and in the islands off the coast, from 70 to 74 
elsewhere. Hot days, those with maxima of 90° F or higher, generally average from five to 15 per year. The number of 90° F days varies considerably from place to place, but also from year to year. They can range from only a few days in cool summers to 25 o
r more in 
hot summers. Record number of 90 or higher days was experienced during summer of 1983 when 20-30 days were observed across the State" From; http://www.cocorahs.org/Media/docs/ClimateSum_MA.pdf

Make sure your siding is well painted, especially the drip edges to stop any capillarity, and at windows/doors; renew the caulking/backer rod when needed; http://www.energyoutwest.org/eow_library/__past_confs/EOW_2008_Presentations/Tsongas_Damage.pdf

Cedar siding problems with a house wrap; OP may/may-not have tar paper; http://www.greenhomebuilding.com/pdf/RainScreen.pdf

My 2 cents, take it or leave for others.... Gary


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