Insulating my shop

[Rubberdown]

Well, my wife said today to get the shop fully insulated and get AC/Heat in there. Im all for it. Shop is 50x50. It currently has that white fiberglass roll insulation on the walls and ceiling, but the eves and the ridge vent are open on the ends. I don't know if the currently installed insulation is going to be adequate, if I just need to install insulated doors and plug the ridge vent and eves on the end, or what its going to take. I would like to get it fully insulated with spray foam but am curious about that being applied over the fiberglass insulation. Don't know what I don't know so can you guys give me some advice?

Thanks

Ryan

 

[racecougar]

Any idea what R-value is already present? It's odd that the builder went to the trouble of insulating the building but has soffit and ridge venting open to the interior space, completely defeating the purpose of the insulation.

Spray foam over the existing insulation won't work out.

 

[NUTTSGT]

Don't spray foam over the insulation already there.

 

[Rubberdown]

I dont have any idea what the R-value is. I looked at it and cant seem to find any makers information or whatever. The paperwork just says insulated roof and walls but gives no details and I haven't heard back from the original builder. I guess I need to reach out to some metal building people and get some information.

 

[My Old Tools]

You are good in Houston except the roof. Mine is similar, but I had an additional 8" of roll insulation applied to the roof with metal strapping.

 

[kngelv]

What does it look like under the roof insulation> You should have baffle going all the way from the soffits to the ridge vent based upon how that looks. If you plug them you will just cause huge problems in your garage because there will be no venting. Is the roof insulation just place against the ceiling. If you look up and can see the ridge vent open to the outside then you have poorly installed insulation.

James

 

[racecougar]

What does it look like under the roof insulation> You should have baffle going all the way from the soffits to the ridge vent based upon how that looks. If you plug them you will just cause huge problems in your garage because there will be no venting. Is the roof insulation just place against the ceiling. If you look up and can see the ridge vent open to the outside then you have poorly installed insulation.

James

From the photo in the OP, it sure looks like the ridge vent is open to the interior space.

 

[billconner]

What does it look like under the roof insulation> You should have baffle going all the way from the soffits to the ridge vent based upon how that looks. If you plug them you will just cause huge problems in your garage because there will be no venting. Is the roof insulation just place against the ceiling. If you look up and can see the ridge vent open to the outside then you have poorly installed insulation.

James

Not necessarily in Houston where the condensation is the outside moist air. I'd guess the metal roof is pretty good moisture barrier and the inside air is dryer. Not at all like north where the concern is moist interior air condensing on the roofing or roof sheathing. While ventilation may have marginal effect on cooling, its less critical in climates like Houston.

 

[billconner]

From the photo in the OP, it sure looks like the ridge vent is open to the interior space.

If it is, I agree with whomever said seal it.

 

[Rubberdown]

What does it look like under the roof insulation> You should have baffle going all the way from the soffits to the ridge vent based upon how that looks. If you plug them you will just cause huge problems in your garage because there will be no venting. Is the roof insulation just place against the ceiling. If you look up and can see the ridge vent open to the outside then you have poorly installed insulation.

James

there is a baffle from the ridge vent to the outside to keep out bugs, etc but I don't believe there is one from the soffits to the ridge. The insulation is just under the metal roof.

 

[Rubberdown]

From the photo in the OP, it sure looks like the ridge vent is open to the interior space.

It is. As are the soffits on the end walls. I can see light through all of these areas when the lights are out.

 

[Rubberdown]

You are good in Houston except the roof. Mine is similar, but I had an additional 8" of roll insulation applied to the roof with metal strapping.

Did you have this insulation installed after the building was built? I wonder if there is anyone in the Houston area that does post construction installations of insulation.

 

[racecougar]

It is. As are the soffits on the end walls. I can see light through all of these areas when the lights are out.

Thought so. That makes zero sense. It's like running the AC with all of the windows open.

 

[WildBill]

I'm not sure on the insulation but I really dig your projects and space. Much classier than my ratty stuff. Maybe use one of those laser temp guns to check the surface of the insulation and get an idea of how its is working. I would think you will need more on the roof at least, but maybe its OK.

 

[My Old Tools]

Did you have this insulation installed after the building was built? I wonder if there is anyone in the Houston area that does post construction installations of insulation.

It was done by my builder, but at the end. I would talk to metal building contractors as well as insulation contractors. My first two shops didn't have the additional insulation on the roof, and you could really feel the radiant heat. My shop is 22 feet tall at the peak. My loft is at 9 feet. I set my MrCool at 9 feet. The loft doesn't get cool, but it's just storage. In winter I run a box fan pointing down to bring the heat down. It works pretty well.

 

[Rubberdown]

I'm not sure on the insulation but I really dig your projects and space. Much classier than my ratty stuff. Maybe use one of those laser temp guns to check the surface of the insulation and get an idea of how its is working. I would think you will need more on the roof at least, but maybe its OK.

That’s super smart. I have one sitting there but never thought to check the temps. Thanks on the projects. I have had that old Chevy since I was 12. It’s a nice old car, needs freshened up now as I redid it 29 years ago and I didn’t have much money at all back then. The Rover I got right before mom got sick 7ish years ago and it went straight into storage until I got this house last year after she passed. . Once I can function in the shop it’s going to get a new frame and made into a fun driver. Been building that mezzanine slowly but surely. Picked up the railing pieces from my friend that has a cnc plasma a couple days ago. I think that’s going to be pretty neat, I designed in all in fusion 360. Gotta get all the electrical done and this AC figured out. I’m to old to be dealing with the heat anymore.

 

[Rubberdown]

Thought so. That makes zero sense. It's like running the AC with all of the windows open.

I figured the insulation was to keep condensation of the walls and ceiling. But yeah it didn’t make any sense to me. But I obviously don’t know much about it.

 

[Rubberdown]

You are good in Houston except the roof. Mine is similar, but I had an additional 8" of roll insulation applied to the roof with metal strapping.

Hey did you add that beam in down the center after your shop was built? Thats pretty handy.

 

[WildBill]

That’s super smart. I have one sitting there but never thought to check the temps. Thanks on the projects. I have had that old Chevy since I was 12. It’s a nice old car, needs freshened up now as I redid it 29 years ago and I didn’t have much money at all back then. The Rover I got right before mom got sick 7ish years ago and it went straight into storage until I got this house last year after she passed. . Once I can function in the shop it’s going to get a new frame and made into a fun driver. Been building that mezzanine slowly but surely. Picked up the railing pieces from my friend that has a cnc plasma a couple days ago. I think that’s going to be pretty neat, I designed in all in fusion 360. Gotta get all the electrical done and this AC figured out. I’m to old to be dealing with the heat anymore.

I hear that on the heat, I feel like some sort of royalty being able to check my shop temp on my phone from anywhere, and then crank the mini split to whatever temp I want before I even go out there. I had it about 65F in there last weekend because I was moving a bunch of heavy stuff around, was awesome. Even when not set that cold it pulls the humidity out and makes it so much more pleasant to work.

 

[My Old Tools]

Hey did you add that beam in down the center after your shop was built? Thats pretty handy.

No, it was engineered into the design to support a 1 ton load.

 

[chinboys]

From Google,
Here are some insulation requirements for warehouses in Houston, Texas:

City of Houston


City of Houston Minimum Property Standards (2)[1]

Exterior walls are to be provided with insulation and the minimum R factor shall be R-19 o...

The minimum R-factor for exterior walls is R-19, or R-15 plus R-5 foam. An air infiltration barrier, like Tyvek, must be installed on all exterior walls.

Roof insulation
The minimum R-value for insulation installed above the roof deck is R-30.

From your recent history of temperature swings... I would add another R-15 to the roof.

Heat always moves towards "cooler" surfaces and environments.
The bigger the temperature difference, the greater the heat transfer gradient.

In the summertime, your building will gain heat from radiation and conduction heat transfer.
Likewise, in the wintertime, you will lose heat from conduction and radiation.

You will also gain heat or lose it via convection heat transfer.
The most energy consumed by an AC, mini-split, or heat pump system is to remove the relative humidity at the given temperature (latent heat) before less energy is consumed to lower the temperature (sensible heat).
You need to have a blower door test done to determine how leaky your building is and to fix it.
You can be well insulated but still have heat and humidity migrate inside due to air leaks.

Get a Manual J cooling and heating calculation done based on what you have now and when you get the insulation work done to determine your cooling and heating loads.

Watch the R&R Building YouTube channel as the owner/operator built a big shop and went to town to properly insulate it.
He could probably cool his place down with a hundred pounds of ice and a ceiling fan or heat it with a can of Sterno... just kidding.

 

[Rubberdown]

I heard back from the builder. He says:

We have customers conditioning the buildings all the time, the 3” VRR is an R-11, the ridge being open will not effect the a/c at all. Thats is a continuous ridge vent with a 3” wide x1 1/2” profile pads between the roof and ridge. A/c will never get that high although if you plan to heat your shop it will let heat out.
You can see day lite on the gable end soffits also should not be a problem, your roof extends 12” past the wall, drops down 8” then your soffit is there, the day lite your seeing is reflection of lite from the bottom of soffit, if you want to have these areas sprayed it will not cause a problem with anything on the building .
The doors will probably need to be changed to sectional insulated, I don’t remember is your doors were roll up or sectional, if they are sectional they can spray them also, maybe 2”.

 

[My Old Tools]

A lot depends on whether you will heat/cool 24/7. I turn mine on when I head out to the shop. In 10 minutes it is already cooling down and lowering the humidity. 24/7 usage will see more payback on insulation. Roof insulation is the biggest payback in Texas for cooling. I suspect you won't heat much at all in Houston. I heat some in the Tyler area when we have a cold front. I leave mine on Freeze Protect in the winter, about 47 degrees. I would plug your roof vent at a minimum for heating. He's right, it won't be a player in cooling.

 

[Rubberdown]

I guess my question at this point is how much is the humidity going to be affected by leaving the ends open? I should be getting a quote in the next few days to spray foam end wall soffits, and the ridge vent. I think that’s the best course of action and the most ideal in my situation. After I air condition if I don’t see enough return, I might add more insulation to the ceiling and put on insulated doors

 

[My Old Tools]

Good point on the humidity in Houston. One of the best things about AC is dehumidifying. The less outside air the better. The first two days I ran mine, it pulled gallons out of the shop.

 

[Rubberdown]

Waiting on some quotes. This isn’t going to be cheap.

 

[Max]

Waiting on some quotes. This isn’t going to be cheap.

If you are out in your shop a lot you’ll love it once you spend the money. I live north of Atlanta so not as hot and humid as you get - but it’s still pretty darn hot and humid. I added insulation to my doors and added a mini split and its great.

If you are comfortable you’ll spend more time in your shop.