A/C 40x60 in Deep East TX

Shovelhead · Jun 7, 2020

What I know:
40x60 with a separate framed room of ~18x26X10 that will have A/C and heat. The rest will be open area.
12 or 14' eave height, likely 14' for lean to height.
Two 12x10 overhead doors in front on 40' gable end, one 12x10 on back gable end.
Spray foam roof and walls.

What I have yet to decide:
Red iron or stick built.
Roll up or panel overhead doors.

Questions:
Is it efficient to air condition the open area with mini split units?
Who has a similar setup and how did you air condition it?

Overhead doors: I want roll up doors for the main reason of not blocking off ceiling lighting, but am concerned about them not sealing worth a chit.
Is it plain stoopid to use roll ups with my plan?

I know a finished out ceiling would drastically help in the open area but my biilfold would like to think the spay foam may be "good enough".
A finished out ceiling in a stick built is a whole different deal than in an open span red iron.

What y'all think?

930dreamer · Jun 7, 2020

Mr. Cool 36k mini split is rated for 1500 sq ft. A well done spray foam shop shouldn't take as much to cool/ heat if done correctly. I'm in the same boat as I'm working on a 40x80 with zero insulation and i need to replace ALL the metal. Wall height is 16' and peak is up there so looking at adding a ceiling.

MrSurly · Jun 7, 2020

The first question: have you considered post frame if only for comparing the pros/cons.
Are you intending to “finish” the interior walls of the larger area?
Are you looking at spray foam on the roof deck (underside) or looking at a ceiling with a vented “attic” area?
If building a stick (or pole) building, are you considering or needing attic space/trusses?
You’ll never be happy trying to climate control any room with roll up doors. There’s just no good option for sealing or insulating them.

My build in East Texas is a 30x40x14 post frame fully spray foamed with three large insulated sectional doors.
I AC it (when needed only) with a single 25kbtu through-wall window unit which is suffice until we get up around a hundred.

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Shovelhead · Jun 7, 2020

MrSurly said:
The first question: have you considered post frame if only for comparing the pros/cons.
Are you intending to “finish” the interior walls of the larger area?
Are you looking at spray foam on the roof deck (underside) or looking at a ceiling with a vented “attic” area?
If building a stick (or pole) building, are you considering or needing attic space/trusses?
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No post frame for me.

Yes, the larger area will be finished if stick built or have framed "walls" if red iron.
I would think with foam under the roofing, if I had a ceiling installed, then you could add insulation on top of the ceiling as well. Just a lot of expense to frame out a ceiling of that size.

My current shop 30x50 is red iron with the white vinyl backed insulation and two cable/winch operated ridge vents. But, the general consensus I get from all the builders these days is to use spray foam with no venting.

I still am having a hard time seeing how that's better with the amount of humidity we have. And, I'm old, set in my ways and of the mindset of change is not good for most things. LOL

Attic space is not important. Would rather spend my money and time on ground level. Plan is for the new home to have a room above the attached garage for attic space..with a real set of stairs.

Shovelhead · Jun 7, 2020

MrSurly -from your build thread --- your decision on this, the outcome, and your recommendation after you've had it a while?
Because I don't understand why some think this is better and some think that is better.
Seems to me there is only one way, the right way, for my location.

Thanks

MrSurly said:
I now have an appointment with a spray foam insulation company for next Tuesday. Now, I've got to decide which option I'm going to go with:
1" of closed cell, roof and walls;
3.5" of open cell, roof and walls;
A combo of of those;

Or 5.5" open cell on either or both.
Or (more options) 2" of closed cell.

I do wish the reasoning behind the material type selection were more clear.
Different sprayers disagree on which type is better for my application.

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MrSurly · Jun 7, 2020

Shovelhead said:
MrSurly -from your build thread --- your decision on this, the outcome, and your recommendation after you've had it a while?
Because I don't understand why some think this is better and some think that is better.
Seems to me there is only one way, the right way, for my location.

Thanks

It’s now three years to the day since I broke ground on my build. There were many decisions; I believe you’re asking specifically about the foam(?)
I absolutely *love* the decisions I made re: the foam... for my purposes and plan and time and budget, yes, I have zero regrets.
What would I have changed *if* I’d had different budget limits? I would have finished the interior walls and ceiling and as part of that change up I would have used open cell all the way and even more of it.
But again, that’s only a *if I’d had the money*
Working with the constraints at the time, I did it just as I should have and the closed cell is pretty amazingly durable stuff! I have cut/welded/ground right next to it, bumped into it dropped things against it, and have been generally very rude to the stuff and it doesn’t seem to mind at all. I recently had to cut a hole for an outlet box in the lower area. I used a thin cutoff wheel on a side grinder, throwing sparks directly into the closed cell as I cut from outside. My building, despite the imaginative claims of the GJ naysayers (so far) has resolutely failed to erupt into a foam-fueled-fireball.
I hate how *ugly* the foam is. I *love* how the foam works.

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Shovelhead · Jun 7, 2020

Thanks.
I’ve read elsewhere of several comments about open cell holding in moisture and creating mildew, even to the extent of rotting out a composition roof.
Obviously I won’t have that type of roof, but.......if stick built there will be contact to the rafters/trusses, or if red iron the purlins, meaning RUST.

One thing in my favor is time, I ain’t got a bunch left, so maybe I’d outlive the rust.

Marctrees · Jun 7, 2020

Shovelhead - What town are you building near?

Marc

Jagmandave · Jun 7, 2020

I think an important question is what will you be using it for, storage? active build projects? how often will you be opening the big doors?

Why do you need that much space, do you need to park a lot of vehicles?

Lastly, maybe wall off a smaller part of it and just A/C that?

I'm in Kansas so I know what you mean about humidity, and hot!

We're currently at 95* with about the same humididitititity.

If you really want to control the heat and humidity in the whole place I think you'll need a lot of air flow - so that sounds like you'll need a pretty big house type A/C unit - maybe some ceiling mounted fans?

Shovelhead · Jun 7, 2020

Marctrees said:
Shovelhead - What town are you building near?

Marc

Hemphill

Shovelhead · Jun 7, 2020

Jagmandave said:
I think an important question is what will you be using it for, storage? active build projects? how often will you be opening the big doors?

Why do you need that much space, do you need to park a lot of vehicles?

Lastly, maybe wall off a smaller part of it and just A/C that?

boat and pickup parking, wood shop, general maintenance on my "stuff"

I need that space because I do.

read first sentence of first post.

dsimatt · Jun 7, 2020

We have a roll up door at work and it *****, any decent breeze and its banging away and doesnt seal for ****.

Shovelhead · Jun 7, 2020

dsimatt said:
We have a roll up door at work and it *****, any decent breeze and its banging away and doesnt seal for ****.

Yeah that's what I've found. I have panel doors on my current shop and roll ups on one of them 2" square tubing carport type "barn. It's 15x40 and is just out of the weather storage for a couple small tractors and a trailer.

I gotta figure out a good way to have lighting underneath of a panel door when it's raised. Something that ain't half a$$.
However if I go nuts and air condition that sucker, the doors would be closed most of the time.

Jagmandave · Jun 7, 2020

Shovelhead said:
boat and pickup parking, wood shop, general maintenance on my "stuff"

I need that space because I do.

read first sentence of first post.

Thanks I missed the bit about the separate framed room, I just saw the 40X60 part - my bad.

Window A/C with a heat strip or Minisplit will work fine for that - I have a window A/C and it works a treat!

dsimatt · Jun 7, 2020

Shovelhead said:
Yeah that's what I've found. I have panel doors on my current shop and roll ups on one of them 2" square tubing carport type "barn. It's 15x40 and is just out of the weather storage for a couple small tractors and a trailer.

I gotta figure out a good way to have lighting underneath of a panel door when it's raised. Something that ain't half a$$.
However if I go nuts and air condition that sucker, the doors would be closed most of the time.

Could buy one of those setups that the motor assembly is on the wall and then figure out how to rig brackets just under the door for the lights.

MrSurly · Jun 7, 2020

dsimatt said:
Could buy one of those setups that the motor assembly is on the wall and then figure out how to rig brackets just under the door for the lights.

I just installed three jackshaft openers. It is a really simple task to just run emt conduit under the raised door from rail to rail just use the conduit for support of four foot fixtures.

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dsimatt · Jun 7, 2020

MrSurly said:
I just installed three jackshaft openers. It is a really simple task to just run emt conduit under the raised door from rail to rail just use the conduit for support of four foot fixtures.

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Or just listen to this guy. :bowdown:

Marctrees · Jun 7, 2020

On a panel door just mount a few of the plastic unit 4' fixtures right on the door and have a dedicated ext cord hanging on wall ready to plug them in.

Simple, cheap and done.

Marc

72Camaro · Jun 8, 2020

Shovelhead, if you’re anywhere near Forney, you can come check out my shop on a hot sunny day. 30x40x16 with 1 inch closed cell. It feels 20+ degrees cooler than being in the sun, if I want air flow I open the 3 roll up doors. Might help you make up your mind

Shovelhead · Jun 8, 2020

72Camaro said:
Shovelhead, if you’re anywhere near Forney, you can come check out my shop on a hot sunny day. 30x40x16 with 1 inch closed cell. It feels 20+ degrees cooler than being in the sun, if I want air flow I open the 3 roll up doors. Might help you make up your mind

Thanks but I'm over here on Toledo Bend.

You make a good point, as a buddy I talked to couple days ago said the same thing about a shop he was in last summer.
I'm going to try and go see in person some shops with the spray foam and talk to the owners if I can.

You have 1" closed cell on the roof and the walls?

Shovelhead · Jun 8, 2020

What I got planned or very close to it

MrSurly · Jun 8, 2020

Shovelhead said:
I'm going to try and go see in person some shops with the spray foam and talk to the owners if I can.

Just let me know if you get up to Longview.

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72Camaro · Jun 9, 2020

Shovelhead said:
Thanks but I'm over here on Toledo Bend.

You make a good point, as a buddy I talked to couple days ago said the same thing about a shop he was in last summer.
I'm going to try and go see in person some shops with the spray foam and talk to the owners if I can.

You have 1" closed cell on the roof and the walls?

Yes.

72Camaro · Jun 9, 2020

Pics of the foam and after painting it.

Shovelhead · Jun 11, 2020

I'm still researching this closed cell / open cell foam idea.
Got my first quote on the shop and they put in open cell roof and walls @ $8500. The man said it was the customers choice, one is no better than the other, except....if you are going to have a finished interior wall then the expense of closed cell is not worth it.
If shop walls will be left as built, then open cell is subject to damage.

The more I read the more I get confused and also the more I get that closed cell seems more preferable for a metal building.

Also read where if you get a roof leak with closed cell, the water will run down a wall and eventually rust the steel panel/panels.

Then there's this fire retardant subject. The stuff is highly flammable and puts off a deadly gas.

cheese and rice man!

nsula_country · Jun 19, 2020

I'm an hour across the Lake from you.

40x60x17 with the standard white/fiberglass/foil insulation. No ridge vents. 3 insulated rollups. Rollups do have a gap. I have the "flap" to seal them, but haven't installed them.

Many will recommend a Mini-Split on GJ. My biggest issue with them is that they have TINY filters and most have to have at least annual maintenance to clean coils and condensate drains. Disassembly required.

For your size building and in your climate, I'd look at 5 tons of split or package unit.

5 ton ducted split system heat pump. Struggles when sun is directly overhead this time of year. It does keep humidity down. I maintain 75*-78* cooling, 58*-62* heating.

In my signature I have the AC build out. The shop thread got hijacked by photobucket and I never got around to fixing the pics.

CT

theoldwizard1 · Jun 19, 2020

nsula_country said:
Many will recommend a Mini-Split on GJ. My biggest issue with them is that they have TINY filters and most have to have at least annual maintenance to clean coils and condensate drains. Disassembly required.

True, but they are MUCH MORE EFFICIENT than a ducted central air system. Check the SEER. It is hard to figure payback, but I'll bet it is less than 10 years. A/C is obviously the primary concern, but you are getting heat at a no cost option.

dcg9381 · Jun 19, 2020

40x60x16 near Austin.
3 un-insulated 14'x14' doors. One person door.

Moderate open cell foam - 3" walls, 4" ceiling.. Maybe R-15 to R-17 or so. My cost was around $5000 - so keep shopping around.

We do have additional "walls" - we framed in a large part of the building exterior walls with OSB, but no additional insulation.

I think "highly flammable" in regard to foam insulation is inaccurate. Is wood highly flammable? And indications are that wood may be more dangerous in terms of burning gasses. If you're concerned about it, sheet rock or fire break.

I'm been in tons of "barndos" - and/or private aircraft hangers in Texas. Open or closed cell - I've seen both and would do it either way.

Shop is completely "open" - we don't have enclosed walls.
I've been "living" here for about 3 months. It's HVAC'd with 2 x 24k Daikin ductless systems. It's about 74 degrees inside right now and I can push it cooler. During moderate climate, IE less than 90 degrees ambient, I can get by on one unit.

I've cleaned the filters on the systems once in the last year. I've not had any need to clean evaporator coils - I have cleaned condenser coils.

My drain is a single 3/4" gray electrical PVC line. I've not had any issues with clogging.

These units do fine for heating in Texas. No heat strips. Not hyper-heat units.

Shop is on a 90A feed - which does a hot tub, refrigerator, 2 AC units, lighting, 2hp water pump, computers, TVs, a 50A (in-service) RV connection. Zero problems with power...

Should mention we have a 6KW solar system that does supplement the main..

I agree with other that a traditional AC would provide better filtration, but it's been unnecessary. We do have a portable air filter that I run sometimes, but I don't do heavy "dirty" work in the shop - grinding, wood cutting - all that goes outside.

No issues. I spent about $2500 on the AC systems. Biggest issue I think you'll have is the enclosed rooms and tendency for the diuctless units to be somewhat directional in their cooling.

dcg9381 · Jun 19, 2020

Shovelhead said:
T
I’ve read elsewhere of several comments about open cell holding in moisture and creating mildew, even to the extent of rotting out a composition roof.
Obviously I won’t have that type of roof, but.......if stick built there will be contact to the rafters/trusses, or if red iron the purlins, meaning RUST.

I can't tell you what happens over 40 years, but I can say that there are lots of hangers still standing without rust issues in Texas that use spray foam. Some of them un-air-conditioned. For shops that have HVAC, you've got your humidity control.

Residential construction - foam is kinda preferred around here.. Biggest deal I could see is a roof leak could be hidden if closed cell was used.

MrSurly · Jun 19, 2020

Yes, the “highly Flammable” is bunk, at least in the case of my build. I can’t speak others’ though.

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Shovelhead · Jun 19, 2020

dcg9381 said:
40x60x16 near Austin.

Biggest issue I think you'll have is the enclosed rooms and tendency for the diuctless units to be somewhat directional in their cooling.

Appreciate your thorough reply. :thumbup:

Remember that Austin has a very different climate that Toledo Bend.

Could you elaborate on this directional cooling?
Do you mean since I'll have my wood shop in a separate framed room it breaks up the "open-ness" of the rest of the shop. And that would make directing the air flow from the mini splits not very efficient?

I've been pondering where the best placement would be for the unit/units, in the open part of the shop.

The long side is for boat and pickup, or machinery parking. The area in front of the framed wood shop will be for tools, workbenches, etc.

I've also scrapped the 16' tall walls idea that the first outfit kinda talked me in to. It was mainly to allow for RV parking on one of the lean to's. Waste of money for me and especially if wanting to air condition it. I have 9 acres to put up a free standing RV cover.

I'm going with 12' walls just like my current shop. The wood shop will have a 10' finished ceiling.

Still going to get a couple more bids that include stick built instead of red iron. The 12' walls may make stick built better for me, dunno. I'd like to think a well insulated red iron frame would still be fairly easy to cool without a finished ceiling in the open part.

Still beating my brains out about the overhead doors. Rather have roll up but I want my air conditioning inside the shop.

Thanks for all y'alls input.

nsula_country · Jun 20, 2020

theoldwizard1 said:
True, but they are MUCH MORE EFFICIENT than a ducted central air system. Check the SEER. It is hard to figure payback, but I'll bet it is less than 10 years. A/C is obviously the primary concern, but you are getting heat at a no cost option.

Don't get too hung up on SEER vs ROI. 14-16 SEER equipment is the #1 seller.

14-16 SEER equipment vs higher SEER 2 stage and variable speed equipment (split and package) will not pay off during lifetime of equipment in energy savings. They can provide better "comfort" in a properly designed system.

CT

nsula_country · Jun 21, 2020

Shovelhead said:
Appreciate your thorough reply.
Remember that Austin has a very different climate that Toledo Bend.

Could you elaborate on this directional cooling?
Do you mean since I'll have my wood shop in a separate framed room it breaks up the "open-ness" of the rest of the shop. And that would make directing the air flow from the mini splits not very efficient?

I've been pondering where the best placement would be for the unit/units, in the open part of the shop.

The long side is for boat and pickup, or machinery parking. The area in front of the framed wood shop will be for tools, workbenches, etc.

I've also scrapped the 16' tall walls idea that the first outfit kinda talked me in to. It was mainly to allow for RV parking on one of the lean to's. Waste of money for me and especially if wanting to air condition it. I have 9 acres to put up a free standing RV cover.

I'm going with 12' walls just like my current shop. The wood shop will have a 10' finished ceiling.

Still going to get a couple more bids that include stick built instead of red iron. The 12' walls may make stick built better for me, dunno. I'd like to think a well insulated red iron frame would still be fairly easy to cool without a finished ceiling in the open part.

Still beating my brains out about the overhead doors. Rather have roll up but I want my air conditioning inside the shop.

Thanks for all y'alls input.

Mini split head is a single point of origin for both supply and return air. Some have louvers, some have motorized louvers to try to disperse the supply air. Still a single point and directional. Not to mention, no way can a mini split evap head throw air 30'.

Mini split heads also do not move 400cfm/ton like a conventional split or package. Less air exchange per hour through the evap coil. They are sized on BTU not CFM. Research if curious.

I have gathered that the extream following for Mini Splits on GJ is the DYI aspect rather than proper system design. Anyone can measure sq/ft of a space and order a unit from a chart online. Brown truck drops it off and weekend warrior puts it together. Most DYI don't have tools or knowledge to spect out a ducted system.

I am not againt mini splits. I'm enclosing a screen porch and building a 16x20x8 room inside the 40x60x17. These areas will have a mini split installed.

As for doors, I do not regret insulated roll ups. DBCI brand is what I ordered. One day will install "gap flaps" at top.

CT

dcg9381 · Jun 24, 2020

Directional cooling:
Basically, if you put one unit on one end of your building, it's the same as having one duct at that end. Part of the advantage of ducted systems is that you can choose where and how to distribute the air.

Ductless systems basically put out cold air directly in front of them. Mine has a baffle that rotates up/down - so you get some variation in the direction of the cold air (or you can set it to be fixed) - but it's cooler at one end of my shop where both ductless systems are than it is at the other end. If I want to balance it, I need to add fans or otherwise move cooling through the building....

Other things I'n d like to note - at my house, the new 2-2.5 ton ducted systems use 30A breakers. I can tell you that my Daikin 2 ton units can start and run on 15A breakers (they're spec'd for 20A). I haven't measured actual draw, but even with 17 SEER systems - my cooling costs of a 2400 sqft building with 3 14x14' crappy doors that leak - it's substantially under the costs of a residence of the same size.

aventino68 · Jul 2, 2020

Interesting thread, the trouble I see is that in summer I want to use the garage, have the doors open and that defeats the purpose of having the A/C keeping it cool. Winter the place stays sealed up, insulated well and warmed by heaters so it doesn't matter. What do big warehouses in places like Tx do to keep cool in summer? I'm thinking a bunch of fans for getting air movement in summer and the propane vented heaters to keep it comfortable and above freezing will sort the climate in my garage in Ontario. Tx would be tough.

My Old Tools · Jul 2, 2020

I have a 30x40x12 red iron building near Tyler. I can tell you that foam is not required for a well insulated building. Mine has plastic backed roll insulation wrapped on the frame before the sheets were installed. We then added another 6" layer to the ceiling only. That pretty much eliminates the heat radiating through the roof. I have 7 large windows, 5 across the back to see the lake, along with a 12x12 insulated overhead door and a man door. I haven't air conditioned yet, but it is noticeably cooler inside than out on a hot day.

A/C 40x60 in Deep East TX

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