Insulation Help

[Absea]

I have a 30x40x10 pole barn with steel siding. I put up osb on the interior walls and planned to blow in cellulose insulation to fill in the 6" walls. I just read that I need a vapor barrier, but my walls are all up and I didn't put a barrier on. My walls are all painted, and finished so removing them is not an option. Any idea how I can insulate my walls without having a moistur problem? Please help!

Gary

 

[Torque1st]

Double post-

One word, -Foam.

 

[Absea]

Double post-

One word, -Foam.

Isn't 6" in a 30x40 a lot of foam, translated money? It would take care of my barrier problem though. I do appreciate the quick response. Thanks!

 

[Torque1st]

It is a lot of foam but then it may be cheaper than pulling down the walls and insulating properly with conventional products. Blown in cellulose or fiberglass works fairly well in a ceiling but in my experience it sags badly in walls. When it sags it leaves the upper wall area without insulation and the lower wall insulation is compacted which reduces it's effective R-value. It also does not have a vapor barrier, but then there is no vapor barrier when it is used in ceilings either.

 

[redsky49]

You have missed the best time to install a vapor barrier but all is not lost.

Paint actually has a degree of vapor retardation that, while not of the quality of a dedicated vapor barrier, will provide some help. Provide another coat of paint. Seal all wall openings. For hundreds of years houses have existed without vapor barriers.

The concern would be the exterior wall assembly. There has to be the means for the accumulated water to exit the wall. If you have used typical exterior wall sheathing you will likely be okay. If you have a vapor retarder/wind retarder on the outer edge of the wall you will have a situation where the tendency will be for the water to remain in the wall cavity as you have effectively trapped the moisture inside the wall by impeding its exit.

If the steel siding has no provision for moisture removal you may have some concern. What details do the manufacturer of the siding indicate for moisture removal.

Moisture travels (unless capillary action is involved) by vapor pressure differential, with the moisture moving from the wet area to the dry area. Moisture will condense in the wall during the heating system ( and in some cases during cooling), but can be lessened by lowering the interior temperature (reducing the temperature differential between the interior and exterior temperatures) and by reducing or eliminating interior sources of moisture.

As mentioned above, expanding foam may be the best solution, but depending on the severity of your weather conditions, you may be okay without it. I wouldn't lose sleep over this unless you are in an extremely cold climate.

Edit: Just saw in another posting that you are in Michigan. Foam may indeed be the best solution for you.

As always, offered only as opinion

 

[Torque1st]

At some point within the insulation the temperature differential between the outside and inside of the structure will equal the dew point of the air and moisture will condense. A vapor barrier will prevent the majority of the moisture penetration which is why it is used. Wet insulation looses it's insulation value. It is also heavy and causes the insulation to sag as well as promoting mold and corrosion.

 

[tdkkart]

Alot of what you need will depend on how you intend to heat the building. If using something like electric baseboard, electric radiant, or even a properly vented gas system your interior moisture level will be very low and you may not have a problem. However if you intend to use something like a non-vented propane space heater you will have big probelms as propane heat releases huge amounts of water vapor into the air.

So, it all depends........

 

[pcmeiners]

Cellulose...
Insulated a few homes with cellulose, including my parents home in NYC ; I would classify it as a humid area. Basically opened two holes, near top 18" down/ a third from bottom of each stud, feed each until the blower bogged down. Even with the packing, still settled 2-3" over 35 years, which is not a major concern to me. Moisture is not an issue, even with no vapor barrier ( house 100 years old..wood shingles, pink craft paper, leaky clapboard, 4" studs, 5/8 sheetrock, oil base paint).
As to a vapor barrier, oil base paint (primer) is a fairly good barrier. Had the chance to open a few studs due to needed wiring, BX wiring had no moisture issues, neither rust or powder build up.
Nice part of cellulose (at least the stuff I purchased), is the fire retardant. In 1996 my parents home had a major fire in the basement due to spontaneous combustion (contractor.. turpentine, laquer thinner on folded drop cloths), the cellulose stopped it at that level, the stuff just would not burn. House has balloon framing, without the cellulose it would have burnt to the ground before the fire department arrived. Funny part, the Fire Marshall thought I started the fire, almost arrested me for attempting to fry my mom.
Has a lower R factor then foam, but I give it a definite thumbs up.
Now with all the repairs to this house I wish it had burned completely.

 

[Absea]

I will be heating it with a vented hanging Hot Dawg heater. I have one coat of oil based Kilz on it and two coats of Lucite interior paint. Anyone care to guess how much filling it with foam will set me back? I plan to keep it at 40 degrees and heat it to 60 when working inside. I have a standard white steel siding on the outside and 1/2 osb with a 6" cavity to fill. I don't want my paint peeling off or the steel rusting, but money is tough to pay for the foam. Thanks for the suggestions guys.

 

[Absea]

Any more ideas?

 

[mad57]

Well your beat, your best bet now is to caulk every seem of the wood and try not to let the heat out. does your metal have the trad vertical running seems looks like it in pic, moisture will run down that and mostly out side. At this point shy of taking down the board, the only other idea which will cost alot but cheaper than blown in foam would be to install plastic over wood temparaly for winter months or maybe plastic than foam board taped at seems and decorative paneling over that??? Worst thing you could do is pack those walls tight with what ever touching the metal that will cause it to hold moisture and rot the building. i have a pioneer building and put non crafted insulation in it and kept it about 2 maybe 3 inches from outter wall, i doubled r-11 in walls so i have 7 inches of insulation, i plan on putting plastic vapor barrier over that than sheet rock. Hopefully this weeks or so. I f it helps i have an office in another pole barn with and open ceiling and i put up foam baord and taped the seems it hold s heat great. Good luck just my 2 cents here. Hope you keep those heating bills down maybe a wood stove would help?

 

[walrus]

I will be heating it with a vented hanging Hot Dawg heater. I have one coat of oil based Kilz on it and two coats of Lucite interior paint. Anyone care to guess how much filling it with foam will set me back? I plan to keep it at 40 degrees and heat it to 60 when working inside. I have a standard white steel siding on the outside and 1/2 osb with a 6" cavity to fill. I don't want my paint peeling off or the steel rusting, but money is tough to pay for the foam. Thanks for the suggestions guys.

Thats a nice looking garage, why did you wait until you had interior finished to think about insulation? if you could get 1.5 inches of foam on exterior steel and then fill the rest with cellouse you'd be fine IMHO.

 

[Absea]

Thats a nice looking garage, why did you wait until you had interior finished to think about insulation? if you could get 1.5 inches of foam on exterior steel and then fill the rest with cellouse you'd be fine IMHO.

I thought about insulation and planned to blow celulose down the 6" walls. I'm a retired police detective, not a builder, and didn't know I needed a vapor barrier. Are you saying to remove the osb and spray 1.5 inches of foam on the metal, fill the rest with cellulose and then put the osb back up? Would the 1.5 inches of foam be enough?

Also, looking at all my options....

If I took the osb off, what else could I do to install a vaporbarrier that was cheaper than foam? I'm afraid foam may be priced out of my league.

Thanks for the response!

 

[walrus]

I thought about insulation and planned to blow celulose down the 6" walls. I'm a retired police detective, not a builder, and didn't know I needed a vapor barrier. Are you saying to remove the osb and spray 1.5 inches of foam on the metal and then put the osb back up and fill it with foam? Couldn't I fill the whole thing with foam? Or would that be too expensive? Thanks for the response!

Not sure if there is a way to get the foam on the metal without taking the osb down but if there is, I'm saying put 1.5 inches of foam on the metal and then fill the rest of the space with celluose. Be Cheaper than filling the whole the space with foam and the foam should keep the celluose from getting wet as warm moist air won't condense on the cold metal. Best talk to a foam installer and see what they say. If not I'd say fill the space with celluose and don't worry about it

 

[Absea]

How about removing the caulked and painted OSB (sigh), and stapling 6mil plastic over the perlins I installed on the inside to nail the osb to. Could I then reinstall the osb and blow in cellulose?

 

[Torque1st]

If you remove the OSB just put in fiberglass blankets.

 

[Absea]

If you remove the OSB just put in fiberglass blankets.

I have 4' between studs and I put up inside perlins to nail to.

 

[Torque1st]

Use 4' blankets and slide them in between the purlins. They come with vapor barriers and reflective or white facings also.

 

[Shocker]

Ditto what Torque said. The blankets you can buy come in 4-6ft widths for steel buildings.

That seems like the best option.

 

[Absea]

Use 4' blankets and slide them in between the purlins. They come with vapor barriers and reflective or white facings also.

Ok, just to make sure I understand you. Do they go right up against the steel? Do I still need a seperate VB or does the facings work as the barrier? Do they get stapled onto the purlins?

 

[D KRAGER]

Caulk all your seams, paint the inside with oil based. Then blow in the cellulose like you wanted to do. I've read that cellulose is not affected as much by moisture as is fiberglass. I've read lots of info that a vapor barrier is not needed with cellulose, although there is big debate over it.

 

[Kevin54]

Caulk all your seams, paint the inside with oil based. Then blow in the cellulose like you wanted to do. I've read that cellulose is not affected as much by moisture as is fiberglass. I've read lots of info that a vapor barrier is not needed with cellulose, although there is big debate over it.

If there is moisture, cellulose would hold the moisture moreso than fiberglass. Fiberglass is just that....glass strands. A few years ago they had problems with cellulose insulation because it was damp when sprayed in so it would stick. Then they would take a straightedge, scrape it down the walls even, then put a vapor barrier over the top of it. Black Mold After that they put a vapor barrier up and would blow it it. The vapor barrier was to hold it in the wall cavity. You hear all kinds of things about vapor barriers. Put them up, leave them off. For every person that says put a vapor barrier up, you'll get one that says leave it off so the wall will breath and not give a greenhouse effect. If you are not going to be having a lot of moisture in your barn and your floors are done, I'd say just blow the insulation in and be done with it. On a pole barn I would rather have the vapor barrier between the steel and the insulation and not the insulation and inside wall.

 

[RPH]

I looked into 4 inches of closed cell foam and the estimate was $3.00 per square foot covered. Took that out of consideration quickly.

 

[rburke65]

You could call a few insulating contractors and see what they tell you. Tell them that you are a retired police detective....and you need a little help here...

 

[Absea]

Now I am staring at an empty 8.5" space in my garage walls with steel siding on the outside screwed onto 1.5" purlins attached to a 6x6 pole. I also have 1.5" perlins on the inside wall to nail my osb onto. I am thinking of stapling rolled 6" backed fiberglas on the inside perlins and then covering with 1/2" osb. This will give me a couple of inches clearance between the steel and th insulation. The siding is ribbed, so moisture can run off the steel. Since I am using backed insulation, will I need to add an additional vapor barrier before installing my OSB? I will be heating with a vented propane hanging wall heater.
__________________
Gary

 

[mad57]

How about removing the caulked and painted OSB (sigh), and stapling 6mil plastic over the perlins I installed on the inside to nail the osb to. Could I then reinstall the osb and blow in cellulose?

If you remove the osb then yes just insulate the bays but dont dont let the insulation touch the metal you need the air flow to help keep things dry, then plastic over the nailers then board over that again.

 

[mad57]

Just talked to pioneer.. the theroy is that the ribs in the metal allow air to flow up past the wall, up past the soffit, then thru the roof line then out the ridge vent(if you dont have one) then out the soffit. allowing the metal to stay dry. and the building to breathe, the vapor barrier (plastic) works best behind the wall covering(sheet rock,osb ect)to keep any sweating moisture ect from rotting the wall covering. the rest behind it will dry because of the air flow. the insulation i used was un crafted no paper or plastic just insulation. very easy for this to air dry if it sweats , nothing to mold. but i need to install plastic barrier over the perlons, then sheet rock.

 

[Absea]

Just talked to pioneer.. the theroy is that the ribs in the metal allow air to flow up past the wall, up past the soffit, then thru the roof line then out the ridge vent(if you dont have one) then out the soffit. allowing the metal to stay dry. and the building to breathe, the vapor barrier (plastic) works best behind the wall covering(sheet rock,osb ect)to keep any sweating moisture ect from rotting the wall covering. the rest behind it will dry because of the air flow. the insulation i used was un crafted no paper or plastic just insulation. very easy for this to air dry if it sweats , nothing to mold. but i need to install plastic barrier over the perlons, then sheet rock.

Thanks Mad57. I am using backed insulation and there will be a couple of inches between the insulation and the steel. I wonder if I should put plastic over the studs as a vb when the paper is backed.

 

[walrus]

the insulation i used was un crafted no paper or plastic just insulation. very easy for this to air dry if it sweats , nothing to mold. but i need to install plastic barrier over the perlons, then sheet rock.

Also very easy for air to blow thru, defeating the purpose of the insulation.

 

[mad57]

Also very easy for air to blow thru, defeating the purpose of the insulation.

What i used is m41 pro pink 3 1/2 sound attenuation insulation, its good for basements and interior walls. I also doubled it in the walls so its 7in worth of insulation, then ill put plastic then 5/8 sheet rock. I used this because i got it new and for free!!!!!!! for my 30 x 80 pole barn, saved me big time. Its super dense help keep down the garage noise for night work. Oh did i mention it was free!!!!Any way after the plastic is installed it will work as good as the paper or plastic on regular bat insulation, for keeping out or in the air, with out the worry of molding in the walls, my good buddy does it for a living and agrees 100%. Once again i used his because it was free in your garage regular bat will work great. My buddy says still use the plastic, he buys his at a farm store, by the roll cheap at least here in nj. good luck again.

 

[mad57]

Thanks Mad57. I am using backed insulation and there will be a couple of inches between the insulation and the steel. I wonder if I should put plastic over the studs as a vb when the paper is backed.

My dad built a pole barn as well years ago, he packed the walls with regular crafted insulation i mean packed it in there no air gap nothing!!! no vapor barrier either,, after over 15 yrs now no mold. no sweating. not rotting steel. he heats and cools the interior 2 story walls, has shower water ect.I would guess it all depends on the area you live in, call local builders/ insulators see what they recommend. the other post of my garage is what guy from pioneer suggests nowadays.

 

[Absea]

Well, I have my OSB all down and have insulated. Today I put the vapor barrier up and re-hang my OSB. Hopefully it will soon look like it did before I realized I messed up and didn't put up a vapor barrier. Bet I don't forget VB again! I had planned to blow in my insulation, but since I had the osb down I put up 6" fiberglass and kept it about 1.5" away from the steel siding.

Thanks for talking me through this fix guys!

 

[redsky49]

Remember to seal the vapor barrier top and bottom, and to overlap and seal at all the locations where you join two pieces of VB. Best to make continuous barrier if at all possible. A little harder to apply for the ceiling - usually takes two people. Also provides a good workout with a manual stapler!

Take pics of the ceiling install. Usually good for a laugh.

Sounds like you are headed in the right direction.

As always, offered only as opinion

 

[Dawgfan]

Use closed cell foam and you won't need a vapor barrier. Then use fiberglass blankets to fill the remaining wall cavity. This is what I did on a building similar to yours. I have osb interior wall also. The spray foam is well worth the money with the exterior metal walls. It really seals things tight.
Put your osb up with screws, it is easier than nails.