Batts vs. Spray Foam

[mltdwn12]

I've received some good advise on this board but would like to confirm my thought process for the ceiling as well as ask a question or two. I finished the batt insulation in the walls and now it's time for the ceiling. My goal is to install a heater that will get the shop about 55 degrees in the winter (I'm in WV) to make spinning wrenches comfortable. So I was thinking of going with 2 x 8' corrugated steel for the ceiling. The joists are on 4' centers and I'd run the metal perpendicular to the joists. The ceiling is about 15' high, this part of the shop is ~31' x 22'. I was given a quote of ~$2100 for 2" of spray in foam. Now batts I can do myself and figured I can get about 600 ft2 of R30 for about $600. Is it worth the extra money for the spray in for a shop? The roof has 1/2" foam board on it, I assume as a reflective barrier (it was there when I bought the place) If I put in batts, do I need a plastic barrier between the steel and the unfaced batt? Or should I just use faced batts, with the face towards the steel? Thanks again for any input.

 

[seanc_mt]

I would do the metal you plan then blow in loose cellulose I did 20in of the green bags from home depot and my place is VERY evenly heated with just a wood stove....

 

[TTMotorsports]

I second using blow in. Easier and cheaper

 

[Big Al 15]

Never understood wanting to foam the ceiling to lock in all the moisture.

Put steel up and blow in 20" of cellulose. She'll breath and stay warm.

 

[W_A_Watson_II]

I agree with Metal and Blown in. I did 4" Open Cell Spray on the walls, and Blown in R50 in the ceiling.

 

[yeldogt]

Never understood wanting to foam the ceiling to lock in all the moisture.

Put steel up and blow in 20" of cellulose. She'll breath and stay warm.

??? You need a VB with any type of insulation with humidity under it.

 

[kngelv]

Cellulose all day.

James

 

[yeldogt]

I've received some good advise on this board but would like to confirm my thought process for the ceiling as well as ask a question or two. I finished the batt insulation in the walls and now it's time for the ceiling. My goal is to install a heater that will get the shop about 55 degrees in the winter (I'm in WV) to make spinning wrenches comfortable. So I was thinking of going with 2 x 8' corrugated steel for the ceiling. The joists are on 4' centers and I'd run the metal perpendicular to the joists. The ceiling is about 15' high, this part of the shop is ~31' x 22'. I was given a quote of ~$2100 for 2" of spray in foam. Now batts I can do myself and figured I can get about 600 ft2 of R30 for about $600. Is it worth the extra money for the spray in for a shop? The roof has 1/2" foam board on it, I assume as a reflective barrier (it was there when I bought the place) If I put in batts, do I need a plastic barrier between the steel and the unfaced batt? Or should I just use faced batts, with the face towards the steel? Thanks again for any input.

My guess as a thermal bridge ... nothing is going to work as well as foam ... it;s just a question of overall cost/ return. Foam is particularly good at stopping radiation in the summer.

I can stand inside next to my slate roof w/ 5" of foam and fell no heat. 100 degree day ,,, full sun.

But ... Foam is more money?

 

[Bretny]

Celious is def the cheapest. For that amount of area get enough bags to get both machines for a feee rental from HD. Easy enough to do but dusty and time consuming. Prob alot easier to do than foam board. You just have to get the hose to where you want the insulation not your self.

 

[NUTTSGT]

Personally, I'd go with white ribbed metal siding or liner panels for the ceiling instead of the corrugated metal. The metal siding is white (or any color) will reflect more light. You can also order it in longer lengths as you will want a little more over lap than what you're going to get with the 8' sheets four foot on center.


The insulation, if you can swing it financially, I would do the spray foam. I don't care for blown in cellulose but it is probably the cheapest and easiest to install.

If it were mine, I'd do the spray foam if I could afford it. If I found it wasn't enough insulation, I'd add some blown in over the top of it. Word of caution, leave yourself a scuttle hole or access door to get back in the attic space. Be sure to make it large enough to easily get in and out of or not to close to the roof line.

 

[bluegoose972]

I used spray foam on the interior of my shop and it made a HUGE difference. First, I chose to keep the roof white in color to minimize the amount of heat absorbed by the metal. There was a significant difference in the temperature of the roof vs the temperature of the red walls. You could literally feel the heat coming off the walls if within 3 ft in the afternoon.

After spraying the 2" of closed cell, it feels like your simply working in the shade. I tend to keep the doors open, but even with temperatures in the high 90's, having a fan blowing on me it's really not bad working in there as I finish the framing of the walls and begin the electrical work. Even though it's at ambient temperature, it feels 10 degrees cooler due to the shade effect of staying out of the direct sunlight.

I'm not buying into the whole trapped moisture concept. The closed cell is definitely adhered to the metal walls and if the moisture can't get to the metal, not worried about it being trapped. Concept similar to putting out a bottle of water and seeing the condensation on the outside. But put the same water in an insulated vessel, such as a yeti cup, and there is no moisture on the outside of the cup. Just my simple thinking.

One last thing. The closed cell made a HUGE difference in the rigidity of the building. The walls no longer have that "tin" sound. The neighbor was mowing the lawn next door and the sound was if he was in my yard. I actually walked out and looked. But once the foam was sprayed, the noise level went WAY down.

So very happy with my decision to use spray foam. $1/sf-in was expensive, but absolutely no regrets.

 

[strutaeng]

I've received some good advise on this board but would like to confirm my thought process for the ceiling as well as ask a question or two. I finished the batt insulation in the walls and now it's time for the ceiling. My goal is to install a heater that will get the shop about 55 degrees in the winter (I'm in WV) to make spinning wrenches comfortable. So I was thinking of going with 2 x 8' corrugated steel for the ceiling. The joists are on 4' centers and I'd run the metal perpendicular to the joists. The ceiling is about 15' high, this part of the shop is ~31' x 22'. I was given a quote of ~$2100 for 2" of spray in foam. Now batts I can do myself and figured I can get about 600 ft2 of R30 for about $600. Is it worth the extra money for the spray in for a shop? The roof has 1/2" foam board on it, I assume as a reflective barrier (it was there when I bought the place) If I put in batts, do I need a plastic barrier between the steel and the unfaced batt? Or should I just use faced batts, with the face towards the steel? Thanks again for any input.

$2,100 for R12 or $600 for R30

 

[yeldogt]

$2,100 for R12 or $600 for R30

You will find that the air sealing qualities of foam and it's ability to act as a radiant barrier far exceeds the batts.

Unless you have experienced foamed building ... you just don't get how good they are.

It's like a cooler ... take a cheap cooler -- how thick is the foam? It's thin .... but, it will keep ice cold in the sun!

I do more than 2" in my buildings ... but 2" is normally the flash batt thickness in my area.

 

[NUTTSGT]

You will find that the air sealing qualities of foam and it's ability to act as a radiant barrier far exceeds the batts.

Unless you have experienced foamed building ... you just don't get how good they are.

It's like a cooler ... take a cheap cooler -- how thick is the foam? It's thin .... but, it will keep ice cold in the sun!

I do more than 2" in my buildings ... but 2" is normally the flash batt thickness in my area.

Agreed. You have to look at more than just the R-value when considering spray foam.

If you've never been in a place that is foamed, it can be hard to imagine the difference.

 

[strutaeng]

You will find that the air sealing qualities of foam and it's ability to act as a radiant barrier far exceeds the batts.

Unless you have experienced foamed building ... you just don't get how good they are.

It's like a cooler ... take a cheap cooler -- how thick is the foam? It's thin .... but, it will keep ice cold in the sun!

I do more than 2" in my buildings ... but 2" is normally the flash batt thickness in my area.

Yes, I know about the benefits of spray foam (and NO, there are not "radiant barrier" qualities as you describe,) just find it funny that they are over hipping the stuff with this R12 idea.

 

[bluegoose972]

$2,100 for R12 or $600 for R30

Really not a fair comparison...apples and oranges. Factor in the cost of enclosing the walls and building a ceiling area to place the foam and you are now comparing apples to apples. For my building (red iron weld up), I would need to build a lowered false ceiling structure as there are no trusses. Then factor in the 1,050 sf of ceiling sheeting.

 

[strutaeng]

Ok, sorry for bashing spray foam; I know it is a good product (perhaps the environmentalists might disagree, however).

My point was that R12 would never meet building code requirements anywhere in the US, IBC or IRC. I really don't know if shops fall under either category; and if you are in an unincorporated area without any Code, who cares, right?

 

[yeldogt]

Yes, I know about the benefits of spray foam (and NO, there are not "radiant barrier" qualities as you describe,) just find it funny that they are over hipping the stuff with this R12 idea.

Actually -- yes it does. It's a transfer of heat ...

It's not over hyped ... you can not use it .. fine.

I was up to my current project the other day -- pushing 100 outside. And the old 3" of CCF from the previous owner installed almost 30 years ago was doing it job. I will be flashing another inch to smooth out the old and give me a bit more depth.

And you are correct on the 2" .. and the correct codes. That's typically as i said a flash batt on the ceiling. It will pass may walls. I only did one flash/batt project and IMO the added batts did not give much. R values are going to change in the future ... 2" of foam is just so superior to R19 of batts