To insulate or not

[jfw432]

So I live in GA and have a 24x35 shop that I just built. The plan was always to insulate the shop and I decided a while back that closed cell spray foam is the best choice. I've gotten 6 quotes ranging from $4600 to $9700. I signed an agreement with the $4600 company but it's been a week and they haven't so much as called me to confirm they got it so I reached out and they said they got it and maybe they can get to me next week and will let me know when they know more. I haven't paid them anything but this still seems shady...

As this company is clearly dragging their feet or they're super busy, I am beginning to question the whole insulation concept. I've got an 18k mini split ordered and the plan would be to set the thermostat around 80-85 in the summer and 55-60 in the winter unless I'm in there. So this got me thinking, will I even save $4600 in electricity over the next 5 or so years at those temperatures? That seems like a lot of money and I'm struggling to see how insulation would save even a $50 per month in electricity on a 20 seer unit. Maybe the bigger concern is that I didn't size the mini split big enough to not have insulation though.

Thoughts?

 

[racecougar]

I don't see a 18K unit keeping up in that size shop without insulation. If you're concerned about cost, you could likely reduce that price significantly by installing conventional insulation yourself.

What do you pay per kWh there?

 

[jfw432]

I don't see a 18K unit keeping up in that size shop without insulation. If you're concerned about cost, you could likely reduce that price significantly by installing conventional insulation yourself.

What do you pay per kWh there?

Average about 11-13 cents per kWh here.

 

[mike93lx]

You should absolutely insulate. I bet that mini won't get it done without it plus the insulation will help seal the building.

 

[racecougar]

Average about 11-13 cents per kWh here.

Pulling data from a 18k Gree submittal, I calculate that if the thing was running at full load 24/7, it would use that $4600 in electricity in ~1.9 years at your current price per kWh.

 

[dougf]

Don't worry about the ROI, I think that's usually not a good way of looking at things. If you insulate you'll love it out there. Especially in the winter!

As for the contractors stalling you, no advice there. I'm pretty patient and usually the busy people always get to me and do a great job. There's a reason why they are busy.

 

[Firstram]

Well worth insulating! Is the quote for walls and roof deck or walls and ceiling? How thick are they going and all foam or foam + batts?

 

[nmk_61802]

Always insulate..... It is one of the hardest items to do after the fact, and is one of the few items in a build that recoups it's own cost.

The need for spray foam versus fiberglass batts is debatable. Spray foam makes sense when you don't have space to get enough fiberglass in place, however fiberglass is easy DIY and about 1/2 the cost of Spray foam.

FYI, I had a few areas where I had to use foam due to a cathedral ceiling, I cut up foam board and sprayed the edges with expanding foam. Which is also a DIY option.

Also looks like you have only signed the contract for a week, and they said maybe next week install? That is hardly dragging their feet IMO. All Trades are super busy right now, 4-6 months wait is the new normal in my experience.

 

[dcg9381]

So I live in GA and have a 24x35 shop that I just built. The plan was always to insulate the shop and I decided a while back that closed cell spray foam is the best choice. I've gotten 6 quotes ranging from $4600 to $9700. I signed an agreement with the $4600 company but it's been a week and they haven't so much as called me to confirm they got it so I reached out and they said they got it and maybe they can get to me next week and will let me know when they know more. I haven't paid them anything but this still seems shady...

You pay them when they are done. Period. Contractors are busy. Don't pay up front.
I have a 40x60 insulated 3 years ago with open cell, about $5k. Small jobs will cost more per sqft, but I'd shop around a bit. It also depends on how much (inches) you are spraying so it's not apples to apples. We are 2.5-4", maybe R12.

As this company is clearly dragging their feet or they're super busy, I am beginning to question the whole insulation concept. I've got an 18k mini split ordered and the plan would be to set the thermostat around 80-85 in the summer and 55-60 in the winter unless I'm in there. So this got me thinking, will I even save $4600 in electricity over the next 5 or so years at those temperatures? That seems like a lot of money and I'm struggling to see how insulation would save even a $50 per month in electricity on a 20 seer unit. Maybe the bigger concern is that I didn't size the mini split big enough to not have insulation though.

This is where I diverged from recommended energy standards. My thought was that residential R standards for insulation are based on "residential use". Based on standards, I should have spent $10-15k on insulation, but I spent 1/3 of that. What I did do is install 48K worth of AC. Based on just sqft, you're going to be fine (my climate is hotter). My "rational" behind it is that residential standards are for structures that are heated and cooled 24/7. I use the shop probably 5% of total hours in a week. I'd rather pay for more electrical to cool it down for a few hours rather than "keep it cool" 24/7. If I was going to keep it cool 24/7, I'd go with recommended R values per climate zone.


You should insulate it if you HVAC it. Should you insulate it like a house (especially when using high dollar spray foam)>? That depends on how you're going to use it.

 

[jfw432]

Well worth insulating! Is the quote for walls and roof deck or walls and ceiling? How thick are they going and all foam or foam + batts?

All good comments so far. The plan is to do 2" of closed cell foam on the roof and 1" on the walls. This is what was originally recommended and confirmed through a couple different local spray foam companies. Seems like everyone thinks about the same way but the prices are all over the place.

 

[Firstram]

That will cover the air sealing for sure but, batts will be needed to give you a good R-value. Personally, I'm a fan of open cell. Better R-value per inch, seals the envelope and water (from a leak) will pass through it.

Whichever way you go, it will be money well spent!

 

[mike93lx]

That will cover the air sealing for sure but, batts will be needed to give you a good R-value. Personally, I'm a fan of open cell. Better R-value per inch, seals the envelope and water (from a leak) will pass through it.

Whichever way you go, it will be money well spent!

What?

Batts give a better r value and open cell is better r value per inch than closed?

Where did you come up with those shenanigans?

 

[Mike65]

We had a local to us company do closed cell spray foam in our 24'x25' garage/shop just so it would be a little cooler in the summer time in southwest Virginia. It cost us around $5,000 to have it done.

 

[racecougar]

What?

Batts give a better r value and open cell is better r value per inch than closed?

Where did you come up with those shenanigans?

I think Firstram is saying that the 1-2" of foam is a good start, but you'll want more total insulation than that. I won't dive into the open/closed cell discussion.

 

[mike93lx]

I think Firstram is saying that the 1-2" of foam is a good start, but you'll want more total insulation than that. I won't dive into the open/closed cell discussion.

More insulation, sure, but Batts are not needed at all. More foam would be a lot easier and probably cheaper since they would already be out

 

[racecougar]

Agreed. I'd either increase the foam thickness, or skip foam altogether for another method (like batts) to reduce cost and DIY.

 

[Firstram]

What?

Batts give a better r value and open cell is better r value per inch than closed?

Where did you come up with those shenanigans?

Foam to seal the building and batts to bring up the R-value. Insulation companies do it all of the time, or they did when I last built houses.

I got away from building when things crashed in 08 and misspoke. Open cell expands 3x as much as closed for a given volume of product. 3" of open will vive you r-11 vs 1" of closed at r-7. You get more R's for the same money.

 

[dcg9381]

Batts give a better r value and open cell is better r value per inch than closed?

I think he means open cell is a better R value per dollar than closed cell, not per inch.

Bat does have about the same (or slightly higher) R value per inch than open cell. But it's not just about R value. Foam gets into all the nooks an crannies. IMHO, it's better. It's also a lot more expensive. Using both can yield some really great results.

OP, what I'd do is foam the roof deck and do bat in the walls. Cost of batting the walls is not that much.

 

[jaw22w]

I wouldn't worry about a couple weeks wait. I have been talking to a foam installer in my area. My plan is for 2" foam. $3200 walls only on a 30x40x12 barn. He says scheduling is out 6-8 weeks. Really puts a crimp in my schedule.

 

[thammel]

DIY. Insulation is easy to do, just takes time. Buy a tyvek suit and wear gloves, etc. Insulation will help immensely both in the Summer and Winter.

 

[jskicet]

I have a 30x36 with 14' walls. The walls are 2x8 that are 10' on top of 4' block wall. I just finished insulating it. I paid someone to blow in R38 in the ceiling @$1500. They wanted $2800 to do the walls with R19 fiberglass. I purchased the R19 myself along with the stapler and staples for an even $800. at Lowes. I saved $2000 by doing it myself. Pretty easy job. Just time consuming when doing it alone but well worth the savings in my opinion.

 

[Leaflessshadetree]

Depends on you climate. In central Illinois it doesn't take much to save $50/month when heating or cooling.

 

[steel 35]

25’ x 36’ & Stuffing mine was the best thing I did to mine 23 years ago!

 

[dfiler2]

So you didn't get contacted for a week and now the contractor can't fit you in until next week? Man, I wish I had your problem. I've been working on getting some concrete work done and I was excited when they said they could fit me in by August.

As far as to insulate or not, you will never regret the money invested in insulation.

 

[CraigStu]

Like jskicet says, I'd forget the foam. Go to HD or L and buy insulation rolls and a hammer style stapler. Do the walls yourself. Drywall the ceiling and choose your blowin or throw down or whatever and lay 6+ inches in the attic. Forget the roof. This is how my attached 28x32 was done by the builder. It is very obvious each day that, if the door isn't opened, the garage stays in a much smaller temp swing vs whatever is happening outside.

 

[WisJim]

I've never seen a fiberglass insulated wall that was sealed as well as a foam insulated wall without taking a LOT more time over the details than most people put into the job.

 

[PoorUB]

So I live in GA and have a 24x35 shop that I just built. The plan was always to insulate the shop and I decided a while back that closed cell spray foam is the best choice. I've gotten 6 quotes ranging from $4600 to $9700. I signed an agreement with the $4600 company but it's been a week and they haven't so much as called me to confirm they got it so I reached out and they said they got it and maybe they can get to me next week and will let me know when they know more. I haven't paid them anything but this still seems shady...

As this company is clearly dragging their feet or they're super busy, I am beginning to question the whole insulation concept. I've got an 18k mini split ordered and the plan would be to set the thermostat around 80-85 in the summer and 55-60 in the winter unless I'm in there. So this got me thinking, will I even save $4600 in electricity over the next 5 or so years at those temperatures? That seems like a lot of money and I'm struggling to see how insulation would save even a $50 per month in electricity on a 20 seer unit. Maybe the bigger concern is that I didn't size the mini split big enough to not have insulation though.

Thoughts?

Always insulate, but perhaps reconsider the type of insulation. You can insulate the place yourself for a few hundred dollars. It might not be as good as foam, but consider the use, how you want to heat and cool it and fiberglass is probably "good enough". You can insulate yourself and save a few thousand dollars and still have a decent insulation.

Houses go up every day with some poorly trained grunt shoving fiberglass into the joist bays and it works just fine.

Plus, like the other post, 18K will not heat and cool it if you don't insulate, you probably need to triple that BTU number.

 

[Idle Serge]

I'll continue to beat the dead horse - insulate. I did my 10X16 side shed myself and it was all a breeze with the exception of the rafters. So I had a bid done for my 18X24 garage (since the place was to insulate to the peak) and was only quoted $2200 so I jumped on it.

For the shed, it was maybe $400 in insulation:

2022-11-16_11-23-36 by Sergio Zapien, on Flickr

 

[jfw432]

Ok so I'll stand by the original assessment of insulation is a "must do". However, I do think that most of the people recommending the DIY fiberglass insulation route have wood frame buildings and conventional roof trusses where standard insulation at Lowes or Home Depot along with ceilings are easy to accomplish and install. Metal buildings that require vapor barriers and have 5 ft spans on the frames are a different animal. I'm trying to find the 5ft insulation again that specifically makes stuff for metal buildings but I'm struggling to find that website.

 

[Augus7us]

I did batts in my walls and then I had 5.5" of open cell spray foamed on the underside of my roof. Made a huge difference.

As pointed out open cell has less r value than closed, but leaks will show through.

 

[gleman]

I have a 30x36 with 14' walls. The walls are 2x8 that are 10' on top of 4' block wall. I just finished insulating it. I paid someone to blow in R38 in the ceiling @$1500. They wanted $2800 to do the walls with R19 fiberglass. I purchased the R19 myself along with the stapler and staples for an even $800. at Lowes. I saved $2000 by doing it myself. Pretty easy job. Just time consuming when doing it alone but well worth the savings in my opinion.

I did my basement and garage myself also. Not a fun job but reasonable to do.

I like your ceiling too!

 

[Sturgeon]

I'm to cheap to pay for spray foam, so insulated to today's code and neighbors are even committing how nice and cool it is. So very happy with it being insulated.

 

[gleman]

Always insulate, but perhaps reconsider the type of insulation. You can insulate the place yourself for a few hundred dollars. It might not be as good as foam, but consider the use, how you want to heat and cool it and fiberglass is probably "good enough". You can insulate yourself and save a few thousand dollars and still have a decent insulation.

Houses go up every day with some poorly trained grunt shoving fiberglass into the joist bays and it works just fine.

Plus, like the other post, 18K will not heat and cool it if you don't insulate, you probably need to triple that BTU number.

I borrowed a buddys Temp gun while i was planning a minisplit install and was shocked by the garage door heat coming into my garage.

I agree insulation before AC

 

[bdbecker]

I know this may not apply to the OP, but since DIYing batt insulation has popped up a few times... If you are going to be installing kraft faced batts on your walls and you also have an air compressor, do yourself a favor and pick up one of these staplers:

Arrow PT50 Pneumatic Staple Gun PT50 - The Home Depot

Complete your upholstery, framing and crafts work easily and quickly with the help of this excellent Arrow PT Staple Gun.

www.homedepot.com

Besides saving on hand fatigue, it make the install go so much faster. I had a little bit of buyer's remorse on the way home after I bought it, but that went away.within a few minutes of using it. Its not a frequently used tool, but its definitely one I'll always keep around.

 

[Metal-Marc]

I had a little bit of buyer's remorse on the way home after I bought it, but...

This is GJ. Never have buyer's remorse when buying tools.

But I agree with you. I have one just like yours, and it's so much easier to use than a manual stapler.

 

[Metal-Marc]

I've never seen a fiberglass insulated wall that was sealed as well as a foam insulated wall without taking a LOT more time over the details than most people put into the job.

This.

Comparing R values between bats and spray foam does not tell the whole story.

Spray foam does seal perfectly the space. There is zero air leaks. You need to seal the place before thinking about insulating.

If you just staple batts in between studs, like those pictured above, you don't have a proper seal. Batts need to be installed in between two sealed surfaces to be efficient.

 

[mepstein]

Either wait for the foam or diy with rockwool.

 

[Metal-Marc]

As far as to insulate or not, you will never regret the money invested in insulation

Insulating a residential garage is not an investment, it is an expense.

An investment is when you bring in a revenu every month.

 

[finn]

I have spray foam in our house addition, including the basement, and utilized it to seal up the rim joists in the crawl space in another house. It’s a good product.

Having said that, I am not convinced that it’s an end all necessity in a shop building, especially one with a typical metal roof. I see big problems when (not if) the metal roof leaks and there is foam against the metal.

I would seriously look at conventional bats and blown cellulose. It’s time proven and cost effective, albeit not as trendy as spray foam.

 

[dfiler2]

If it's being heated and cooled it's absolutely an investment.