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Basement Insulation help needed


ccarlson

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I need advice. I have a 7 year old house. Decided to finally dig in and started to finish the basement today. The basement is mostly block that is already studded out. One full wall is a walkout with wood construction, windows, sliding door etc. That walkout wall has been insulated with fiberglass bats and then covered with a plastic vapor barrier. The block portion is not insulated at all. I plan to have mostly sheetrock walls with some wood part way up the walls in spots.

I know a lot has changed in insulating theories over the past 7 years and was wondering what I should do with insulating the block wall portion of the basement.

First thought was to hire out an insulating company to spray in closed cell foam insulation. Draw backs include cost and convenience as I just realized that in order to do the spray foam, I need to gut all the stuff that has been dumped in the basement over the years so the entire area is pretty much free to work and spray.

Second thought is to just go ahead with bats of fiberglass insulation on the block wall portion. Pluses include cost and the ability to finish the basement piece by piece starting with a storage area which I could then put all the loose stuff we accumulate and then move on to the bedroom and living space as time allows. Concern with fiberglass bats is mold and mildew problems.

What would be the best way to do it? If I go with bats, do I go without any vapor barrier (keep in mind the walls are already furred out so getting a barrier right next to the cement block is not possible.

Thanks for any advice.

ccarlson

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If you can't get a vapor barrier next to the block wall, DON'T use fiberglass. Your only option according to the building officials will be to use closed cell insulation. I would get 2" Dow board or Styrofoam. The R value is 10 and you won't end up with a mold problem. You will have to cut the foam to fit the stud cavities and caulk or foam seal it in place.

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There may be many suggestions here, but here's mine.

First off, if you are like most people, you should get a dumpster first and throw out what you don't need. Not implying anything here, just a hunch. I don't know, maybe all your stuff in the basement is valuable. Just a suggestion. \:\)

After that, the next step is getting a building permit with your county, city, or township, depending on where you live. The inspector will probably help you through the code compliance questions. Then, you can go on and make your decision as to how you plan on getting it done and what materials to use.

If you have already thought of this, just disreguard my post.

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Like roofer said the B.I.will give some advice. It is best for you to contact the Building Inspector,If you have no const.experience doing this,There is more than just rigid insulation I think now you'll need a double moisture barrior,block to wood.Call the local building Dept.

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Good luck, I could never get a straight answer on this, even from the inspector.

I used a kraft faced paper type insulation, stapled to the studs and that is it.

Right or wrong, I don't know.......

I couldn't keep straight all the agruments I was seeing about vapor barrier this R Value that.

So I just did it.

Can't say I recommend that. But guess what? It's done grin.gif

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If you use fiberglass, poly on the block side only to keep moisture away from the fiberglass. Then use non backed or no paper fiberglass bats. Then just sheetrock right over that. The fiberglass if wet will dry through the drywall. If you poly over the fiberglass you will cause a seal and no moisture will get out and then you will have problems.

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dtro,

That's exactly why I asked. I get the same thing, nothing consistent. It's funny you found the same to be true. I appreciate all the info so far though.

I stopped in at two lumber yards/building centers. They both said using bats shouldn't be a problem. One said I might want to seal the block with a brush on sealant first since I can't get a layer of plastic on the block due to the studded walls already in place. He warned of strong odor and drying time though.

I called the county planning and zoning who said not only did I not need a building permit but that there were no codes or inspection I needed to follow, they just hoped people would follow the state codes for which they could not provide me with much of that information. Two phone calls to a city building inspector and I couldn't get through. I don't live in the city but thought I'd try.

If it helps at all, we have no moisture problems with the block but still want to do it right without breaking the bank by paying for someone else to spray foam.

Roofer, you seemed to be the only one that mentions a state energy code. I looked up info on that briefly today but couldn't see where it specifically stated the actual recommendations.

ccarlson

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Wow!!!!!

I know you are in Nisswa, but they still have zoning permits. Maybe it isn't needed, but they are breaking the law.

I would say, get it in writing and get it done ASAP!

Not pointing out any individual, but this is how houses get ruined. No codes to follow??? No energy code to speak of??? That's incredible. This stuff has been pushed for the last 10 years.

At least you are trying to find out the right ways of doing things. Thumbs up to you.

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The Poly Vapor Barrier should always go on the warm side of the insulation. Its purpose is to stop moisture from migrating into the insulation. With it cold outside and warm inside, the dew point will be found within the insulation cavity somewhere and thats where the moisture will condense and freeze.

In the case of a subgrade block wall, now you have the chance for moisture to come from 2 directions.

One good question would be what kind of foundation waterproofing was installed on your house? If it was a good product and properly installed, you shouldn't have moisture problems from the outside.

I guess if it was my place, I would be installing rigid insulation (the pink or blue stuff). If its furred with 2x4 studs, suppose a guy could layer 2" & 1 1/2" rigid to fill the cavity, then put on the poly vapor barrier, then rock. You'll have more R-Value than you'll need with 3 1/2" of rigid.

Other option would be to rip your furring out, and reinstall either 2x2 wood furring w/ 1-1/2" rigid insulation or go with metal stud framing and 1-1/2" rigid insulation. Could use Z-Furring or regular studs. With rigid insul and metal framing, you'll never have to worry about anything getting wet and rotting.

My only concern with batt insulation is "if" it gets wet, it'll stay wet. Mold and a musty smell are then a possibility.

Edit: Thought I read what your block wall was furred with but on second look, I can't quite tell. Is the block furred with 2x4s?

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Just to clarify a bit because I just actually remembered what I did.

I built a 2x4 wall and attached it to the floor about 1" away from the block wall, then used kraft faced insulation. This way, there is no contact between the block (moisture) and the inside wall.

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 Originally Posted By: Roofer
The energy code wants a vapor barrier on both sides just for that reason....to seal up the wall.

I know, it never made sense to me, but that's what they want.

Thats right Roofer! But to explain and all the other bad advice,I left it alone.I dont understand why its written that way and I disagree.But Mold in basements will always be a problem!I havent heard any reports about OwensCornings new system other than costly.but its new and it'll take years before its proven either way

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If you use rigid insulation (the pink or blue stuff), you don't need or want to use a vapor barrier on the inside. The insulation is closed cell and IS your vapor barrier. Every year in continuing education for the contractors license, we deal with this same issue. If you use fiber glass, you need poly on both sides of the wall in a basement. With rigid insulation, you need to seal it to the block wall between each stud. If you don't do this correct, you will have a mold problem at some time. This isn't a big deal until it gets out of hand. Some mold problems have led to houses being condemned and inhabitable.

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That's right Roofer, I was surprised too. Crow Wing county has "not yet adopted the MN codes" and only "hopes that builders and owners follow them." It's not like people are building little shacks up here either.

To answer the question on the block wall exterior, I did treat the exterior block below grade with the best quality sealant available at the time, installed a drain tile on the exterior footing and backfilled with sandy soil. Any clay content was spread over the yard away from the house. We have good drainage and I've never had any moisture intrusion.

In one sense I can see why someone would throw their hands up in confusion and just spend the extra 4-5 grand and do the spray in closed cell but on the other hand, that is not so time proven either and who knows what the results will be long term.

Like one post said, I think there may always be a little mold no matter what you do and I can only do what I can to prevent it from being a major problem. My guess is that in my situation, I'll be fine and won't see a worse case scenario since I've had 7 years to see if there would be moisture present.

ccarlson

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cc well heres 1 way that will pass a code check,on block apply foil backed rigid Ins,tape all seams & joints with the approved tape (I think its pink or red same as on exterior barrior)This is first vapor barrior.Do your framing insulate,apply 3mil vapor barrior,finish with your board, wood, drywall of choice.If your wood framing is now on block your out of luck unless you remove it and follow above instalation instructions.Your out of luck only if you wish to have it inspected and your area has adopted the current Mn.codes.

Just reread your first post.the studs on or exposed to block wall are for sure a mold magnet if enclosed and no air circulation.

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For those reading along, there is also the "interpretation law", where you can 'bend' codes in your favor if it is ok'ed by a group of 7 people, 3 of them building officials, commissioner....blah blah??????? It is in the code book and is rather new.

The whole thing makes no 'common' sense. There should be building codes and laws that are enforced. That would make things alot less confusing for everyone.

Sorry to interrupt and not really help the question asked. \:\)

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Only thing worse then a musty smelling basement, is a musty smelly basement with a cat living down there. grin.gif

What walleyeseeker suggests with the rigid insulation against the block is the way I'd go. As far as the framing, anything that touches block should be treated.

Watch your humidity levels.

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One thing I did (15 years ago) after buying my older home(was built in 1938) and finding out the basement had leaked in that time period for many years,smelly mold smell etc,was to divert the water build up from away from the exterior foundation around the entire house.... it was not an easy job as I had to haul in fill and "tapered" the the yard a "few degrees" downward away from the house(used to have some standing water next to the basement walls )...I also "plastic'd" the entire ground area with triple folded black and clear "thick mill"plastic....I did that for any water "roof runoff" ...keeps the dirt next to the basement exterior walls dry...I "tarred" the plastic to the outside of the basement walls first (about 6" down the wall) and about 5'-6' lay on the ground all around the basement outer foundation THEN I covered that(plastic) and sloped it a few degrees with fill "class 5"...and then covered that with 3/4" crushed rock(and patio blocks in some areas) for landscaping....end result of this was no water in the basement after years of smelly moldy basement water problems....I also installed "seamless" gutters(not those 4' sectional types which leak) and "piped" the downspouts out onto the lawn about 10' away from the house(why have water pouring down next to your foundation potentially wetting the basements footing)......one of the most important additions to a dry basement was our purchase of an "energy star" dehumidifier...that sucks any moisture out of the basements blocks and even the dirt around the foundation...that dehumidifier we never turn off from spring to fall(winter months it's turned off of course),runs steady and "pulls" gallons of water out each day!.......we have a dry,non smelly basement! absolutely no mold!,with no mold "smells" at all!...people have even commented on how "clean" our basement smells!...oh ya! my wife even "sealed " the inside of the basement walls with UGL water proofing white paint ..It works!....our basement is as clean as our upstairs !......definitely purchase a dehumidifier and use it!....yes, we have 2x2 studded walls and paneling in the basement(half of it) and no mold....this system certainly worked for us!..... grin.gif

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About codes, permits, and inspections. If in doubt ask. Before you begin a project ask if you'll need one or more of the following permits. Building, Electrical, Plumbing, Roofing, and HVAC. Ask who you say. Look in your city phone book, it'll be there. Depending on where you live, one or more or all of the above will be need and inspection. You'll find that out when you ask about a permit. No matter where you live you'll need an electrical permit and inspection. In this case finishing off a basement I'd for sure get the electrical. What can they do if you get caught? You could pretty much be doing your remodel over, thats after you take it all down first. Of coarse the Tax Man won't be happy with you either because he wasn't notified(through the permit)about the home improvement.

I'm rural, and follow State Codes. City Codes can vary and you'll know which applies to you after your phone call.

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jonny_redhorse very good point about proper slope around the house.

Thats the best way to prevent a leaky basement. Don't let the water get there in the first place. Hydraulic pressure will find a way into the best water proofed basement eventually.

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C,

You've gotten enough advice about the walls to keep your head spinning for a couple of weeks. Three thoughts:

Maybe you should use the sheetrock that doesn't have cellulose paper. I've read a bit about it and apparently that's one way that mold will get started. I didn't do it and have a problem in the basement.

The other thing that it seems most people forget is how cold the floor can be. In one area of my basement I put down plastic, 2X2 strips with styrene between, and then a sheet of styrene going the opposite direction. I then covered the whole works with 1/2 inch plywood, and then carpeted over that. It made the room much more comfortable. If I were to do it again I would probably forget the poly and go with the closed cell foams that are now available. THis is going to kick up the cost but in my opinion the comfort it provides will mean the area gets used a lot more.

Finally, a number of years ago on TV a guy installed windows in the walls and backlit them with some florescent fixtures. The windows had some sort of plastic put on them to diffuse the light and make it look better. The idea was that you get rid of the 'cave' effect many basements have.

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Thanks for all the info so far. Here is an update and question.

After reading one post on how the stud walls should not come in contact with the block I did more looking around. The wall was constructed about a half inch away from the block so the wood does not contact the wall. I can get my fingertips in between the studs and the block. I actually think I can work the plastic vapor barrier between there. 90% of the block wall space that is furred out has no wiring or plumbing (it's all over head) so that is not an issue. I'm going to shoot for like a 12 foot span at a time to make managing the plastic more do-able. This may work!

Then I would plan to use friction fit fiberlass bats rather than cc foam boards. Would that be best at this point?

Question is now, once I wiggle the plastic into place, should I just run a bead of sealant along the top edge and seams to hold it up and then let it hang free behind the stud wall or do I seal more of the surface and the bottom edge as well? The bottom plate of the 2x4 wall is treated wood which is nailed and glue sealed (pl 200 I believe) to the concrete.

ccarlson

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