Thermal issues for the workshop.

[dbhost]

Sorry for being so boisterous on this subject, but the past HOT Texas summer, and now a bitterly cold winter across most of North America have led to the thought process here...

What are, or have you guys and gals done for thermal comfort in the workshop? I post this as I want to bounce ideas off of folks and hear what others have done before I sink too much time, effort, or money one way or another into a different thermal approach for my shop...

I have seen first hand some ideas, done some of my own, and and still hunting for ideas...

As an update, I have been busily gathering documents from my neighbors, and the City on sheds that are over the 12x10 9ft high rule from my HOA, and am expected to present a request for a waiver to the HOA at their Feb meeting. This will hopefully end up in a positive result. Since the HOA measures on FLOOR space, I will build to FLOOR space, and I will request 12x16 with a 12' 6" peak height.

As my current shop is, I have insulated the right side door with Reflectix, bonded directly to the outside of the door with Liquid Nails. The other door has OLD sleeping bags hung over it to insulate it. There is still a gap around the sides and top of the doors that I am very unhappy about, but that is another issue altogether.

Heating at present is done with a Lakewood oil filled electric radiator, which simply takes too long to warm the space up, but once warm it is quite effective. I have recently taken to, mostly out of impatience, digging my Mr. Heater Portable Buddy Propane heater out of my hunting gear, and using it on high to heat the shop. This has been QUITE effective for a small radius. It is still bitterly cold near the doors where it is drafty. Aside from the doors, and the common wall to the house, there is no insulation in my shop.

IF I am lucky enough to get approval for the 12x16 building, which would be 100% dedicated workshop space, I think I would do the following to insulate and HVAC control the space.

During construction of the skid floor, fiberglass batt insulation will be added to the floor (would this be needed? Is the conact with the gravel sufficient to create a dead air space?).
Walls and roof will use blown in foam insulation as well as radiant barriers.
Windows will be low-e hurricane rated double pane vinyl.
Ridge vent will be used on the roof.
Doors will be insulated double residential entry type.
Cooling will be managed by the Goldstar 8K BTU window unit A/C.
Heating will be managed by the radiator.

This setup should be more than sufficient to keep nice and toasty in winter, and nice and cool in summer.

I am considering using the Portable Buddy, especially when work goes outside in cooler weather...

Now the troubling thought...

What if I don't get approval for the shed?

Then I have to keep on keeping on in the garage...

This means sheetrock has to come down, to blow in insulation and add electrical service additions.
This means the garage doors need MUCH better weather stripping.
This means I have to come up with a MUCH better method for cooling. With sufficient insulation, I am sure I can simply blow cold air in via box fan from the house door... Heating is no issue...
This means that the decking that is in the attic must come out, to get insulation above the garage, and then decking goes back...

So what am I missing? Obviously the shed / shop plan is my preferred idea, but there are no guarantees on this... If I have to stick it out in the garage, what should I do to make it a nice place to be?

[just started]

Weather striping kits for the overhead doors are cheap and easy to install. I don't remember the details as it's been about 15 years, but I had a shop with a double width garage door and the landlord got a kit that had thick rubber/vinyl strips that went on the outside frame, around the sides and across the top, with staples and slid on the surface of the door and kept the wind out really well.

[Black wallnut]

What I have likely will not help but here goes. I have a small Lopi wood burning stove for heat in which I burn firewood that i mostly cut, haul, split and stack. My shop is detached and is 21' x 22' or about that insulated on four sides and a concrete floor. The ceiling is no insulated and the crawl space is not vented sufficiently so boy howdy does it build heat in the summer. I have a small window mount AC to make it tolerable in the summer. Just last weekend I had it up to 90°F in my shop and had to open a window and door to cool it down before I could work. Hopefully this summer I will be building and installing a coupula to help with cooling. I think it will be several years until I actually spring the cash to insulate the ceiling.

[jackellis]

I would not worry about contact with the ground, because the ground temperature is going to be pretty constant, especially in Texas. If you build a slab, place insulation around the edge of the slab to provide a thermal break with the air around the slab. Don't concern yourself with insulating the floor. For the most part, that floor slab is going to be your friend.

Make sure you seal the structure reasonably well. Air leakage is a big energy hog - you have to heat that air in winter and cool it in summer. You won't want to vent your dust collector outside for the same reason.

By all means ventilate the attic, but make sure there's a thermal break and a seal between the attic and the rest of the structure. Otherwise, you'll pull out warm air in winter. Insulate the attic floor to provide a thermal break. I'd suggest you add a powered ventilator connected to a thermostat in the attic that you can turn off manually. Use the lightest-colored roofing material you can.

Foam insulation for the walls is probably the absolute best kind but it may be overkill unless you plan to heat or cool the shop full time. Blown-in fiberglass is probably a more cost-effective choice. Batts are OK, but only if they are installed properly and they typically are not.

You may already know this but if you use a radiant barrier, it's only effective if there's an air gap between the aluminum foil surface and whatever structural surface is adjacent. If the aluminum is in contact with another surface, it becomes an efficient conductor. Also, if you decide to install a thermal barrier under your shingles, check with the shingle manufacturer because some of them will not honor a warranty when radiant barrier is installed under their product - reflected heat causes the shingles to fail prematurely.

[jking]

If I understand correctly, you will have a gravel base with a wood framed floor sitting on top? If that is the case, I'd be reluctant to use batt insulation as its not designed for ground contact. I'd go with the spray in foam you're planning to use for the walls. Batt insulation with ground contact may become wet, harbor rodents, etc. No guarantees rodents wouldn't get into the foam, but, moisture should be a non issue.

[Armini]

I would not worry about contact with the ground, because the ground temperature is going to be pretty constant, especially in Texas. If you build a slab, place insulation around the edge of the slab to provide a thermal break with the air around the slab. Don't concern yourself with insulating the floor. For the most part, that floor slab is going to be your friend.

I'd have to disagree with this if you are building a slab. Take a lot at how radiant floor heating is done in slabs - not that you need that - but the layer of rigid foam underneath the slab will isolate the thermal mass of the slab, making your shop hold heat in the winter and cooler in the summer (providing it is shaded). The additional cost is tiny compared to the overall cost of putting a slab in. I haven't even finished the functional part of my radiant floor, but already see a difference simply because of the slab.

[jackellis]

Turns out we're building a house with a radiant floor in a cold climate (Lake Tahoe) and the ground floor slab is insulated for the reasons Armini notes.

The only reason I suggested slab insulation would not be a factor is that it rarely gets below about 60 degrees in Texas City. The much bigger factor down there is heat, and it seems to me the thermal mass of a concrete floor that's thermally coupled to the ground would be a moderating influence. OTOH, rigid foam insulation for the slab is pretty cheap.

Different story if the shop has to be heated constantly during winter.

[dbhost]

On the slab vs. Skid issue, the shed, no matter the size, will be built on skids due to tax issues. Shed on skids = temporary structure, and therefore not counted in the SQ footage of the house, or even as a property improvement for tax purposes, shed on slab = permanent structure, therefore adds $$ to the tax man...

I know, not like I am going to knock down a skid foundation shed. In all actuality, it will be hurricane strapped down, and twist anchored in a minimum of 18" deep...

Not worried about heat gain / loss through the ground so much as the gaps between the gravel and the skids allowing breezes in...

[LarryG]

If it were mine, I'd probably insulate the floor, somehow. You could cover the bottoms of the joists with aluminum sheet to keep the critters and weeds at bay. This would introduce some construction headaches (i.e., you'd most likely want to prefab the floor in sections and flip them into place) but for the long haul, I think it would be worth doing. The same foamed-in-place insulation you're planning to use in the walls and roof could be used in the floor.

You said you're going to use foam insulation in the roof; and have a ridge vent. That sounds mutually exclusive. Will you have ceiling joists forming a flat ceiling and the insulation at that plane; or will the insulation be at the pitched roof? I would do the latter: pitched roof, cathedral ceiling inside (with exposed collar ties as needed, for structure), roof joists foamed full of insulation, no roof venting. This way if you have overhead lumber racks and the like, everything will be inside the conditioned envelope.

[dbhost]

If it were mine, I'd probably insulate the floor, somehow. You could cover the bottoms of the joists with aluminum sheet to keep the critters and weeds at bay. This would introduce some construction headaches (i.e., you'd most likely want to prefab the floor in sections and flip them into place) but for the long haul, I think it would be worth doing. The same foamed-in-place insulation you're planning to use in the walls and roof could be used in the floor.

You said you're going to use foam insulation in the roof; and have a ridge vent. That sounds mutually exclusive. Will you have ceiling joists forming a flat ceiling and the insulation at that plane; or will the insulation be at the pitched roof? I would do the latter: pitched roof, cathedral ceiling inside (with exposed collar ties as needed, for structure), roof joists foamed full of insulation, no roof venting. This way if you have overhead lumber racks and the like, everything will be inside the conditioned envelope.

I am thinking something along the lines of a Tuff Shed Pro Tall Barn design-ish...


Of course with the door on the front of the building instead of the side...

Like I said, fishing for ideas here. I am pretty sure the building will have to breathe somehow, so I figured a ridge vent would be appropriate. Maybe not? If you are familiar with LarryL's shop, I am wanting to build basically a smaller version of that... Of course if I had the space, and no HOA restrictions, I would be wanting a bigger version, but that is not in the cards at my location...

[LarryG]

I am pretty sure the building will have to breathe somehow, so I figured a ridge vent would be appropriate. Maybe not?

Again, this depends on where you put the overhead insulation. If it's at the ceiling line, the ridge vent (in tandem with either eave vents, or gable-end vents) will be venting the attic space, which is good. But if the insulation is at the roof line, you'll be venting all your heat to the outside -- NOT good. In this case, you don't want a ridge vent.

[Don Rideout]

I moved from a one car garage shop to a 2+ car garage and I'm absolutely pulling my hair out. My little 240v 20a construction used to work wonderfully but now, it is sadly too small for what I need. On days where it dips down around -15C (~0F) and I'm basically stuck in the house shedding tears. Right now with the cold snap hitting the northern States and most of Canada, I'll be lucky to see my garage in about 4 or 5 days.

The garage has open rafters, allowing the only window in the upper gable to pour in some sunlight, something I really enjoy. I had the ceiling (15 ft) spray foam insulated last year, hoping it would make a big difference but to no avail.

Two things I am planning;
1) bigger/better heating, either infrared or forced air, both natural gas solutions.
2) biting the bullet and covering the rafters, losing my natural light.

I hate winter......

[dbhost]

Okay, I think I got it...

I am planning on insulating the entire space, not just at the ceiling line... If I end up going with the shed route that is. The garage of course will only be at the ceiling...

[tamfflcommissioner]

You need info from here

buildingscience.com

Insulating the ceiling only is a waste of time

-Jeff

[twistsol]

On the insulation in the floor, fiberglass batts will become useless if they get wet and they will wick moisture from the ground. A vapor barrier will help but can easily be damaged by rodents etc. If you use a rigid foam, it won't degrade performance even if it gets damp and will dry out much faster since it won't absorb moisture.