Humidity control and keeping bugs out

[Phillip Gregory]

I am looking to build an outbuilding to expand my "floorium" but have a few questions for the experts as to how to do so without giving up the big advantages of climate/humidity control and bug control if you build an outbuilding. I am younger than the Baby Boomers and thus have had to move every time I wanted to better myself in my career (several times) and thus have had shops in basements and outbuildings. The basement shops have the advantage of if well built, having vapor barrier in the floor, insulation, and climate control with the house A/C to make the experience of working pleasant but cramped, and the outbuildings have been cheap steel buildings with no humidity control, vapor barriers, or cooling beyond a fan that I brought. I like the space of the outbuildings but like the climate control and lack of mildew/mold/bugs that a basement shop provides.

My question is there any way to keep an outbuilding adequately dehumidifed and sealed that you can reasonably keep a shop in it? I already anticipate on putting in vapor barrier around the entire structure including under the slab, but in every garage I've been in bugs have crawled in/around/under the roll-up doors. Any way to keep them out?

[Dave Cav]

Probably not with garage/roll up doors. If you can build your outbuilding to the standards of a residence you'll have much better luck, but that's going to be expensive. I took a hybrid approach; my shop is a pole barn, but we built stud walls between the poles in order to attach the interior walls (1/2" OSB), and I had the wall cavities sprayed with 7" of open cell foam. It's pretty tight and stays cool inside all day long.

[Robert Engel]

What kind of bugs? If they don't bite I would learn to live with them.

A propane torch cleans up cobwebs quite well.

When the yellow flies are bad I put screen panels in my shop doorway.

[John K Jordan]

I am looking to build an outbuilding to expand my "floorium" but have a few questions for the experts as to how to do so without giving up the big advantages of climate/humidity control and bug control if you build an outbuilding. I am younger than the Baby Boomers and thus have had to move every time I wanted to better myself in my career (several times) and thus have had shops in basements and outbuildings. The basement shops have the advantage of if well built, having vapor barrier in the floor, insulation, and climate control with the house A/C to make the experience of working pleasant but cramped, and the outbuildings have been cheap steel buildings with no humidity control, vapor barriers, or cooling beyond a fan that I brought. I like the space of the outbuildings but like the climate control and lack of mildew/mold/bugs that a basement shop provides.

My question is there any way to keep an outbuilding adequately dehumidifed and sealed that you can reasonably keep a shop in it? I already anticipate on putting in vapor barrier around the entire structure including under the slab, but in every garage I've been in bugs have crawled in/around/under the roll-up doors. Any way to keep them out?

A small AC unit will keep the humidity down and make working comfortable. I installed a heat pump in my shop for winter and summer use.

Not much will keep crawlies and ants out. There are perimeter insect sprays that work for a while and granular ant killer you sprinkle on the ground all the way around the building - Around the house I use the kind that the ants carry into the colony.

I installed good seals on the sides and top of the metal garage doors in my shop. They also have compressible seals that are squished tight against the concrete floor.

An occasional bug bomb will keep bugs from taking up permanent occupancy. A friend routinely bombs his pottery studio and is amazed at how many spiders he sweeps up.

JKJ

[Phillip Gregory]

I saw a lot of spiders, June bugs, the little "orange ladybug" Japanese beetles, bald-faced hornets, red wasps, yellow jackets, and the dark brown "outdoor" roaches in my shop when I had a steel building shop at my old house. Cobwebs showed up in about a day. I had a hornet nest in the soffit of the steel building I had previously and I had "hornet-mageddon" after spraying about four cans of wasp killer into the soffit. They just *poured* out of that soffit after getting sprayed with that stuff.

The biggest issue with the outdoor building was really the humidity. I live in SW MO and it gets very humid in the summer to the point where wood warps and gets full of fuzzy mildew, and metal rusts very quickly if left in an un-air-conditioned space.

@John Jordan,

Tell me more about your seals. My experience is that roll-up doors don't seal very tightly and bugs can simply crawl around or under the seals, if there isn't simply daylight shining through. I have done some looking and saw a device that essentially clamped a roll up door against its frame (sold as a "green technology" device to minimize air intrusion). Would that be practical? I'd just as soon only use house-type "man doors" on the building and avoid the roll-up doors but unfortunately resale is an issue and nobody would want to buy a house with a "detached garage" that isn't actually a garage as it has no garage doors. I intend to build about a 35x50 shop that masquerades as a "four car detached garage," and I would really need at least one roll-up door as my wife wants to park the mower in there vs. our overcrowded 22 foot deep attached garage. She also has mentioned a boat too...

[Peter Christensen]

Have you considered making pairs out swinging doors for each rollup door and have both (roll up and swing) to insulate and seal the openings? If anyone after you didn't like opening two sets of doors they could take the swinging doors off.

[John K Jordan]

@John Jordan,
Tell me more about your seals. My experience is that roll-up doors don't seal very tightly and bugs can simply crawl around or under the seals, if there isn't simply daylight shining through. I have done some looking and saw a device that essentially clamped a roll up door against its frame (sold as a "green technology" device to minimize air intrusion). Would that be practical?

Phillip,

The doors I bought are not the "roll up" type that literally roll up around a shaft above the door opening. I don't know how you would seal those. With 9' ceilings in my shop I didn't have enough clearance above the door for those. I bought insulated industrual/commercial steel garage doors, four rigid panels. When properly installed the doors press snugly against the inside of frame on both sides and top when completely closed, making them easier to seal. Also, to make the door fit tightly I built the frame carefully so the inside edges were straight and all in one plane.

Under construction, doors installed:
shop_bay_doors_IMG_3047.jpg

The seals are a non-flexible strip with a flexible rubber-like seal. There are three of these seals, one on each side and one across the top. The non-flexible strip is perhaps 1"x1/4" and fastens to the frame on the outside of the door. The flexible part presses tightly against the outside edges and top of the door when completely closed.

IMG_20160715_174058_547_cs.jpg
(Color is off, doors are grey, not blue)

These doors have a thick flexible tube mounted on the bottom which deforms to seal against the concrete floor. They are designed to take up at least an inch of irregularity.

I can see no daylight at any point. (There was at first but I readjusted the doors for a better fit after the installer left.) I have occasionally seen a few ants (and spiders can get into anything) but I've never seen any of the other insects you mentioned in the four years or so since I built the shop.

BTW, I initially ordered residential insulated metal garage doors but I found out I could get the industrial doors for about the same price. The industrial doors are thicker, better insulated, and are made from heavier steel. My shop has heat and air so well-insulated doors were important to me. I had a door company install the doors (three in all) but I did the wiring and installed the openers.

The three garage doors are in the maintenance end of my shop, a 24'x22' area separate from the rest of the shop. The other external doors I installed in my shop are also insulated steel: two "man" doors and three double steel doors that open to 5' wide (to make it easier to move things in and out), two in the wood area and one in my little welding room so I can more easily weld outside. If the shop were all for woodworking, I'd probably would have put in one large insulated garage door and two other doors, at least one a man door for the main entrance. I like to have more than one way to get out of any building in an emergency. This may be required by code, I don't know, no permit or inspections needed here.

One other thing I did related to doors which has been very well worth it: I installed Schlage keypad deadbolts on each man door so I never have to carry a key with me. I also like to use non-locking passage levers instead of doorknobs so I can open the door with my elbow when my arms are full.

Third door on "llama" side:
shop_llamas_IMG_20150422_08_re.jpg

JKJ

[Bob Bouis]

A/c helps with lowering humidity, but the side effect of lowering temperature is increasing relative humidity. So the A/c is fighting itself to dehumidify. Most also don't have humidistat controls and thus can't really be set up to fight humidity during the times it's the biggest problem (which is generally when temperatures are lower, not higher).

A dehumidifier, on other hand, increases temperature as it dehumidifies. That increases the relative dehumidification effect. You can also have them fight your air conditioner on temperature (but this actually helps with dehumidification).

[John K Jordan]

A dehumidifier, on other hand, increases temperature as it dehumidifies.

Completely off topic: one place this really comes in handy is when processing honey. If the water content is too high the honey can ferment so it must be dried before bottling. I turn off the AC and run a dehumidifier in a small room - it's surprising how quick this will pull water from a 5-gal bucket of honey.

JKJ

[Yonak Hawkins]

I saw a lot of spiders....

Phillip, I consider spiders some of the good guys. They help control other bugs and they are easy to live with.

[mark morgan]

I am planing a mini-split heat pump for my new shop. They not only control the temp, but many of them can be set just to bring down the humidity. Make sure the attic is vented properly, and the plastic under the concrete is a must.

[Bob Bouis]

As a dehumidifier, the mini split still suffers from the same fundamental problem as other air conditioners: it cools the air, which increases relative humidity. But modern mini splits are better dehumidifers than most air conditioners because they have variable speed compressors, which allow them to run continuously and not cycle on and off, which means the interior coils stay cold and condensation drains continuously instead of evaporating back into the air every time the machine cycles.

Mini splits also often have modes that are supposed to improve dehumidifying, but I recently contacted a manufacturer about how they work and the gist of it was that it locks the evaporator fan speed on low. Keeps the coils colder and increases condensation. But that's it. They don't have controls based on relative humidity and generally can't be programmed by the hour without buying a separate proprietary thermostat.

TLDR: mini splits aren't dehumidifiers. If you want your shop to match the average daily humidity of a house, the best thing to do is get an actual dehumidifier.