off topic, I was wondering what type of insulation I would need on the walls for the basement.

[Jakethepup]

The walls in the basement are not insolated at all, and I know I am loosing a lot of heat through the concert blocks. I was wondering what type I should use for the best insulation, or do they have some type of this insulation that look like wall covering not just that blue or white strofom stuff that you glue on.

any suggestion would be very helpful.

 

[doghouse]

http://forum.doityourself.com/


Try this web site.

 

[LLigetfa]

IMHO rigid foam is the best as it doesn't hold moisture. Others can have moisture condense on the cold side of the insulation. Rigid foam does need to be covered though for fire retardant purposes.

Rigid foam is considered to be a vapour barrier and there is a rule of thirds when vapour barrier is placed in a wall. It should be within the last third, meaning it should be on the warm side. Now foam is often used on the cold side as well but then there should be a way to vent the space and another barrier should be on the inside.

On my home I have 2 inch rigid on the outside and 5 inch glass bat on the inside between studs with poly vapour barrier just under the drywall on the warm side.

 

[Gooserider]

A lot depends on how much of your basement is below grade and how much is above, take a look at some of the articles at Buildingscience.com... In brief, they assume that all walls absorb some moisture, and must be given a route to dry - either to the interior or exterior of the house. If you have a wall with vapor barriers on BOTH sides, you will have problems caused by moisture trapped between the two barriers. Generally you want the vapor barrier to be on the moist side to keep out as much water as possible, with provision to allow the bulk of the wall structure to dry towards the less moist side.

For basements, the assumption is that any wall that is below grade is wet on the exterior, and must dry to the inside, so you need to use a "vapor permeable" foam or other material on the parts that are below grade, and NOT put up anything that would act as a vapor barrier. Walls that are above grade, if not sealed on the outside, can be covered with non-permeable material and vapor barriers, as they can dry to the exterior. If you have moisture actually coming through the walls, you also need to put up a layer of Enka-Drain or other such material to provide a way to direct the moisture to someplace where it can be dealt with... (Really you need to dry up the basement before you can do much to insulate it...)

Another option that is NOT a DIY project, and is fairly pricey, but quite nice is to contact Owens-Corning - they have a very fancy basement finishing system that essentially puts up some very nice walls, and optionally floor and ceiling finishes as well, that are very classy, and are designed specifically for basements - however they don't sell the materials, instead you hire one of their crews to come do an entire basement makeover - low effort, but bring (large) checkbook...

Another thing that you MAY need to consider, is if there is any part of the wall construction that would be damaged by insulating - there are some basement construction methods that seem to assume that you will lose enough heat through the walls to keep them from freezing - if you insulate them so that they now freeze, this can cause expensive damage. Fortunately this is fairly rare, but it should be looked at before starting a project...

Gooserider

 

[LLigetfa]

It is almost impossible to have an airtight basement with platform construction techniques and conventional poly vapour barrier. The stack effect in the home will likely create some air infiltration which means dry outside air will pass through to the interior drying the wall in the process.

On my home, the 2 inch rigid foam only goes down 2 feet below grade and then is sloped to go out 2 feet horizontally. This allows some heat to reach the weeping tile and footings, keeping the frost away.

 

[Todd]

I have 1" foam board insulation on my basement inside wall and it isn't quite enough. I will probably beef up about 34' of my exposed walkout basement block with this product. I was quoted about $800 for the job.

http://www.core-fill500.com/

 

[Gooserider]

I have 1" foam board insulation on my basement inside wall and it isn't quite enough. I will probably beef up about 34' of my exposed walkout basement block with this product. I was quoted about $800 for the job.

http://www.core-fill500.com/

Looks like interesting stuff, but while it will probably be much better than nothing, it is worth noting that what I've seen in many places about insulating concrete blocks... The claim is that the insulation is of limited value because the primary heat path through a concrete block wall is the webs inside the blocks, which filling the cavities does little or nothing about...

The website pulled a little bit of a sneaky one on their R-value chart where they said "Parallel heat flow" in the chart and "Series parallel valuations provided upon request." - Parallel heat flow is the loss going straight through the wall, but in the real world, the "series parallel value" is the one that more accurately reflects the true heat loss - as it covers the heat that travels across the face of the wall to the webs, out the web, and back across the outer face, which is the main loss path... I would ask about those "on request" values, and see if they make a big change in your value picture...

However it does have the advantage of not taking a lot of room inside or outside the structure, and it may do better than average for you since you already have the existing 1" foamboard to provide a thermal break between the interior and the wall...

Gooserider

 

[Todd]

I have 1" foam board insulation on my basement inside wall and it isn't quite enough. I will probably beef up about 34' of my exposed walkout basement block with this product. I was quoted about $800 for the job.

http://www.core-fill500.com/

Looks like interesting stuff, but while it will probably be much better than nothing, it is worth noting that what I've seen in many places about insulating concrete blocks... The claim is that the insulation is of limited value because the primary heat path through a concrete block wall is the webs inside the blocks, which filling the cavities does little or nothing about...

The website pulled a little bit of a sneaky one on their R-value chart where they said "Parallel heat flow" in the chart and "Series parallel valuations provided upon request." - Parallel heat flow is the loss going straight through the wall, but in the real world, the "series parallel value" is the one that more accurately reflects the true heat loss - as it covers the heat that travels across the face of the wall to the webs, out the web, and back across the outer face, which is the main loss path... I would ask about those "on request" values, and see if they make a big change in your value picture...

However it does have the advantage of not taking a lot of room inside or outside the structure, and it may do better than average for you since you already have the existing 1" foamboard to provide a thermal break between the interior and the wall...

Gooserider

Yeah, I'm thinking there will be some bridging through the concrete, but the same happens through 2x4 studs, maybe not as extreme? And like you said I have insulation on the inside already so I'm hoping it will help when I get those strong cold winds on the one side of my exposed walkout basement wall. Also hoping that the foam will seal up the bottom of the sill plate where I get a lot of air infiltration.

 

[Gooserider]

I have 1" foam board insulation on my basement inside wall and it isn't quite enough. I will probably beef up about 34' of my exposed walkout basement block with this product. I was quoted about $800 for the job.

http://www.core-fill500.com/

Looks like interesting stuff, but while it will probably be much better than nothing, it is worth noting that what I've seen in many places about insulating concrete blocks... The claim is that the insulation is of limited value because the primary heat path through a concrete block wall is the webs inside the blocks, which filling the cavities does little or nothing about...

The website pulled a little bit of a sneaky one on their R-value chart where they said "Parallel heat flow" in the chart and "Series parallel valuations provided upon request." - Parallel heat flow is the loss going straight through the wall, but in the real world, the "series parallel value" is the one that more accurately reflects the true heat loss - as it covers the heat that travels across the face of the wall to the webs, out the web, and back across the outer face, which is the main loss path... I would ask about those "on request" values, and see if they make a big change in your value picture...

However it does have the advantage of not taking a lot of room inside or outside the structure, and it may do better than average for you since you already have the existing 1" foamboard to provide a thermal break between the interior and the wall...

Gooserider

Yeah, I'm thinking there will be some bridging through the concrete, but the same happens through 2x4 studs, maybe not as extreme? And like you said I have insulation on the inside already so I'm hoping it will help when I get those strong cold winds on the one side of my exposed walkout basement wall. Also hoping that the foam will seal up the bottom of the sill plate where I get a lot of air infiltration.

I don't think its as much of a problem w/ 2x4's as wood has a higher R-value per inch, and there are fewer of them in a wall... However as you said it will probably help at least some for sure. As to sealing the sills, it might depend on the way the stuff is put in - I would definitely ask about that to see if it makes any difference in the way they do the job...

Gooserider

 

[NEDLAX]

My company actually does this type of insulation we are affilated w/ core foam. The R-value for a typical block wall is 12.25 10" block I think. Things to think about are this job gets messy when installed. I wouldnt have anything around the walls that was important. I actually got covered a week ago w/ it at a job it shot out of the wall 20ft, the pressure built up and shot the hose out. At least one side should not be painted before doing this type to allow drying/ curing of the foam. It does a good job for basements rather than using the blanket fiberglass insulation which if gets wet will smell. I have had to show town inspectors with the infrared camera before, you can see the webbing in the block but it insulates the whole wall not just certain feet below grade. Another option if your going the foam board way is white thermax foam board by dow chemical. Check with your state but here it passes for a fire barrier, It can be put on w/ glue or a metal track system called z fering. I am actually about to fill a crawl space with the core-foam, They also have another mix of foam that can be applyied to your above grade stick built walls, insul smart foam is what we call it. Its applied much like cellulose from the outside. We did it in my fathers house and it was the tightest house i have ever tested w/ a blower door. As for sealing your sill I would use two part spary foam closed cell. Your can get diy set ups just wear a respirator and googles while spraying. After its been sprayed we cover with fiberglass for the fire rating. Another way is cutting foam board putting in the rim joist and sealing it in with foam/ caulk. hope I helped good luck

 

[pybyr]

Another thing that you MAY need to consider, is if there is any part of the wall construction that would be damaged by insulating - there are some basement construction methods that seem to assume that you will lose enough heat through the walls to keep them from freezing - if you insulate them so that they now freeze, this can cause expensive damage. Fortunately this is fairly rare, but it should be looked at before starting a project...
Gooserider

I'm not sure I'd call that rare- I really don't know how cold Kentucky gets in the winter, or how well-drained your soil is likely to be, but in this part of New England, I've seen concrete block cellar walls that have had major long term trouble (heaving and slowly pushing in/ buckling) due to frost. As Goose notes, if you have a situation where you have a heavy soil that holds moisture, and heat loss into the soil from the cellar may be what has been keeping the soil from freezing and expanding/ contracting, then heavy insulation on the inside might bring unwelcome results. I have seen situations where folks insulate from the sill/ band joist down to about a foot below gronud level - that way you solve the largest heatloss into the great outdoors, while not taking too great a risk with structural issues.