About Ready to Build Insulation Question

[Jim Fitz-Gerald]

Hi Folks,

After a year following site work I am about ready to build a shop. I have attached the current quote for a 30'x40',12' with a lean-to. I welcome all comments. Right now I have the option of ply-foil insulation (bubble foil) on the roof and was planning on doing that and metal liner panels and blown in cellulose (>R38). I plan to put 3/4" plywood on the walls, run conduit wiring and then blow in insulation thru holes I will pop in up high.


Here is where I need some immediate advice - (1) will the bubble foil be a sufficient barrier for the blown insulation in the ceiling and (2) I am thinking of putting having the bubble foil installed in a similar fashion on the walls (over the purlins, under the metal) as the ceiling - will that be sufficient for a vapor barrier similar to above. As I have read other posts with issues of blown and no barriers. I am not in a posiiton $$ wise for the concrete yet, but likely will seek advice there on insulation it as well. Right now 4" of #57s stone will have to do. Any comments on the prices, I think the insulaiton and panel ceileing is high and will likely buy them myself and install rather than from this outfit. $$Metal is up but the insulation is cheaper either done myself or with a blown contractor I think. I have about $22K free right now so I was thinking bldg, lean-to, ply-foil, finish the reast as I go.

Thanks for your insights, this is a great site,
Jim

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[David G Baker]

I had double foil covered 1 inch rigid foam board installed under the metal siding. I had 2 inch rigid blue foam board added under my concrete floor. 7/16" OSB for the ceiling with 6 mil clear plastic sheeting added under the OSB and I blew in 14 inches of insulation in the attic myself. I had a 10'X10' roll up door added (if I had to do it over again I would go with a sliding door so I could add heavier insulation, the insulation I have now is the double foil bubble insulation taped to the door). I have two windows on, one on each side of the door. My roof is composition, less chance of condensation. I heat my pole barn with a natural gas fired Modine ceiling mounded 75K BTU forced air heater (if I had to do it over I would have gotten the same heater but with the unit that uses outside air for its air source rather than the one I have that uses inside air. It costs more but if you use flammables in your shop it is safer. I live in Mid Michigan where it gets pretty cold in the Winter, I keep the heater set at 50 degrees 24/7 until I work in the shop, then turn the thermostat up to 65 degrees when I work in the building during the cold months. It costs me around $40 a month for natural gas but I don't spend a lot of time in the shop during the Winter. If you can afford the cost I would go with the rigid spray in foam insulation. It isn't cheap but it is worth its weight in gold in many ways.
Good luck Jim.

[Jim Fitz-Gerald]

Thanks Dave

I will inquire about the foam board / bubble combo on the walls. I am still thinking about either bats or blown in the walls, in addition to the foam board if they do it. I have read alot about the expanding foam and I was very impressed with it. I would not have to frame out from what I can see if I went that route. In reading comments here, I saw several that suggested that the foam loses its integrety over the years and becomes a critter nesting area - any thoughts to this? I will check on the roofing as well. My feeling is that companies do one type really well and the metal is what this one tends to do best. If I go with the metal roof, should I bubble it even if I am going to insulate below as well >R38?

Jim Fitz

[David G Baker]

I have read pros and cons about using insulating foil or bubble foil directly under the roof, I am not qualified to answer this question. I have seen commercial buildings that had a lot of rust on the metal roofing due to improper insulation under the metal roofing caused by trapped condensation. Venting the attic space is important. The rigid spray foam is almost impervious to critters of all kinds according to what I have been told and have read on the Internet. It won't stop a bullet but I doubt that a normal human being can put their fist through it.

[Matt Neil]

Around here farmers use the spray foam insulation around the bottoms of their grain bins. It's exposed which makes it easy to see that critters do eat through it. If you have metal siding, the mice won't get through that. If you use wood siding, people will attach a piece of tin to about the lower 3" of the wall where it folds 90 degrees and attaches to the sill plate to keep things out of the walls.

[David Helm]

I have read pros and cons about using insulating foil or bubble foil directly under the roof, I am not qualified to answer this question. I have seen commercial buildings that had a lot of rust on the metal roofing due to improper insulation under the metal roofing caused by trapped condensation. Venting the attic space is important. The rigid spray foam is almost impervious to critters of all kinds according to what I have been told and have read on the Internet. It won't stop a bullet but I doubt that a normal human being can put their fist through it.

What David said is important. Proper ventilation is an absolute must. If you see rust on a metal roof, it is likely a goner because the rust is coming from the underside. It is a matter of controlling condensation.

[David G Baker]

When I work on the siding of my older out building I put a metal product called rat guard around the bottom of the building and the set the siding on the rat guard. As far as I know there has not been any 4 legged critters to invade my buildings. My test is the green pellets placed in several locations inside of the building, it has not been touched in the past seven years. I change the poison every few months.

[Jim Fitz-Gerald]

What David said is important. Proper ventilation is an absolute must. If you see rust on a metal roof, it is likely a goner because the rust is coming from the underside. It is a matter of controlling condensation.
Sounds like I need to hold off on the bubble foil. As I cannot insure the install will be correct and then I will be on here venting like others about rust.

The bldg will be ventilated on the gable ends (I think 2'x2' vents) and will have a ridge vent.

At this initial "shell" stage, I just want to make sure I am not leaving anything critical out that the collective would suggest as I just know from reading tons of threads that some things I need to think about now. I am planning to fully insulate in the future (plans are immediately), and from the sounds of it sprayed closed-cell insulation for the walls and blown cellulose (as thick as I can do it) for the ceiling is where I am heading. And I can spend the $$$ from not doing the ply foil double bubble on those areas.

[Alan Trout]

I am an inspector and while common I will never ever use blown cellulose in any structure I own. I will only use blown formaldehyde free fiberglass. Much better product in many ways and not much difference in price.

Good Luck

Ala

[Jim Fitz-Gerald]

Hi Alan,

Thanks for the comment, likely the majority of folks referencing blown insulation are using the glass, for some reason I figured it was cellulose. I will see who does it when I am ready here. If you could give me a me a ballpark price scale to consider to compare when I call around I would appreciate it. I will need one for the spray foam as well.

Jim

[David G Baker]

I used blown in cellulose insulation, at the time I did the insulation I didn't know about the blown in fiberglass. If I do any more blown in insulation I would go with fiberglass as Alan Trout suggested. I had a Sun room built into my front porch and the contractor used the loose fill fiberglass and spread it by hand. It may have been made to be blown in but the attic space over the Sun room was so small it may not have made sense to rent the kit. It is 18 inches thick.

Jim F-G
The closed cell foam is quite a bit more expensive than cellulose and fiberglass bit if you have the $ I would do it, you won't be sorry except when you write the check. Try to get several bids and try to get word of mouth as to the reputation of the company that does the work. Don't even think of trying it yourself, the cost is about the same as hiring a pro to do the work that knows what he is doing. The learning curve can be quite expensive and very messy.

[Jim Fitz-Gerald]

This sounds good, I will follow up on the closed cell and FG blown. I think if I sign the contract next week the bldg will go up in October based on their current schedule. I expect the bldg and lean-to to be completed in 4-5 days. In the meantime, this will give me time to search around for the insulation folks so I know what the next series of expenses will be.

Jim

[David G Baker]

My pole barn was built in February, the ground was frozen, there was snow on the ground, the builder broke two hand post hole diggers and a pick ax. They had to broom the snow off of the roof so they could work on it. When the concrete was poured they used two heavy duty propane construction heaters, covered all the openings with 6 mil plastic and worked their fannies off.
Something for you to think seriously about, try to do most of your inside work prior to filling the building. I didn't and there is still work that needs to be done but there is so much stuff in the way it will be a pain to move it all.

[Jim Fitz-Gerald]

Good points Dave,

Sounds like I will plan on the shell then insulating, plywood, along with a ceiling this winter and then the concrete in late spring. Weather here in October is nice so they will be fine on that end. Likely I will have a well insulated bldg with a gravel floor for a bit depending on my timing to do the other stuff and finances.

[Alan Trout]

Jim in my neck of the woods R38 about 12" of blown insulation runs about $.30 per square foot which in your part of the country you probably want about 1/3 more insulation than that so I would say $.50-.70 would put you in the ballpark. I like Iso-foam in walls but not as big a fan of it overhead especially when it sprayed on the underside of the roofing material or roof decking. If there is ever a roof leak it can be a real bugger to find and then there can be moisture issues which nobody want's.

Of course where I live we deal with heat much more than cold so construction and insulation practices are a bit different. But typically a radiant barrier with about R40 insulation is a very efficient combination to keep our heat out of our homes. But if typically if it keeps heat out it will keep heat in as well.

Good luck.

Alan

[Jim Fitz-Gerald]

Hi Alan,

Thanks for the numbers. We are having a very odd year here - not that it is worse than some folks but the winter had one snow storm of 32" and another ice-sleet with accum over 22" with temps colder than my folks in Mass., the summer has been 95-101 since sometime in early to mid June so I am looking to cover both extremes and I think the blown R48 fiberglass ceiling/ spray foam wall combo will work. Anyone have an idea on the price of the spray foam? I will be calling around, would like to have an idea.

I did look at all the pole bldgs in the area made by this company, they all did well, no issues with the snow loads.

Jim

[Matt Neil]

Somebody told me this past weekend that rodents won't eat through PT material. So I think I'll butt up a 1 x 4 (or something similar) on the outside to the PT sill.