i have a two car oven.

[wolflrv]

I definitely will keep ya posted about shop temps. I'm hoping to keep shop around 100 degree max with doors closed and accomplish a 10-20 degree drop with them open and fans running. That's the goal anyway. I wish I could remember back to my early childhood in Texas. My granddad had a shop that was nice and cool even in the hottest part of the summer. Would love to just look at how it was constructed, but unfortunately that was 40 yrs ago..and I just can't remember.

Classic bikes are a ton of fun to restore. It does require a lot of varying skills to accomplish the whole process by yourself, but to me that's half the fun. I have the time and since bike was free, I can afford to put a little into it. Just do a lot of research and take your time...the rewards are worth it!!

 

[wolflrv]

Well...today's temp at 3:30pm in the shop(which has been closed up all day), was 112. So that's a 6 degree drop from yesterday before door insulation and fan installed. Differences I noticed immediately were that I could actually get near the metal door to open it, without the searing heat. I also think my fan is not pushing nearly enough air through the small gable opening. In fact it seems to be blowing it at the wall which is then pushing most of it down instead of out the gable. It was distinctly hotter on that side of the shop and heat was not coming from the garage door. At this point I seriously think that the only way to make a dent is to insulate the rafters. I still want to maintain the open rafters vs installing a ceiling.

I'll be back out in the shop in a few days(had some dental extractions this morning, so recouping atm) and will see how it performs with the doors open early in the day. If it gives me a few more hrs in the shop that may be enough for my needs.

 

[BoostAddiction]

My old house had an uninsulated garage. It was always 20 degrees hotter in there than ambient.

It was awful, and I vowed never to do that in the new house.

The current house has insulation everywhere, including the doors.

Today was 90 degrees outside, and 77 all day in the garage, with no AC. That's the power of insulation. It makes running AC or heat relatively inexpensive, and you don't need to run it as often.

Listen to the advice and insulate first.

 

[787B]

No placebos, just facts. My 988 sq-ft above-ground garage has uninsulated cinder block walls, two single-pane windows, a glass-paned man door, and a 16' composite thinly-insulated door with a couple of big gaps at the bottom where the slab had cracked and shifted (it's a rental). The only insulation is the un-air-conditioned living space above it (the house proper). Without any climate control it will not get above 85° on consecutive 95° days. With just 8000 BTU of window A/C it will stay at 75° all day long. So, at least in my case, having ~12 feet of ceiling insulation (the house) makes a big difference.

No placebo, confirmed by science! It hit 97° here today. Came home to my un-AC'd house and garage, thermometer in the garage read 78°. Insulation FTW.

(And of course, immediately turned on my 20,000 BTU of AC window units in my house. Though it was only up to 88°. )

 

[georgelowcar]

Insulate...exhaust....AC....or you could try one of these....

What size are you? I am sure someone makes a human version of one of these.

In the early years i was determined to ride my motorcycle in the heat of summer. I am also very always safety concerned so i only wore leathers. Stopping, once in a while to soak my t-shirt kept me cool for a while.

 

[georgelowcar]

787B - Part of my concern of spending $$ on insulating is if you also use a garage, with cars coming and going but also use the garage as a work area. Does the insulation significantly help the inside temperature?

I understand if i DON'T open the garage door or if i cooled the area, it would maintain a cooler temperature longer with insulation. Common sense on this. i'm just worried that if the door opens/close and you don't use any additional cooling, will the temp vary much vs the cost of insulation. Also - a bit more concerned that once the heat is inside, it will stay hotter in there longer due to the insulation (like a house that is insulated and heated - keeps the heat in longer).

 

[wolflrv]

George...I agree with your concerns. I'm still working out my issues too. My biggest problem is that I do indeed have dark roof shingles. So in my mind, the best way to counter that issue vs changing the whole color scheme of the entire property, is to insulate the rafters, effectively creating not only an air flow channel, but also a radiant barrier of sorts, to prevent that roof deck heat from burning down into the shop in the first place.

I'm like you...if I'm in the shop..most of the time the doors are open. So AC cooling just isn't feasible, even though I have a window unit. I think a missing piece here is that in my research, I found out that if you do the baffles and insulation in the rafters, you need to make sure you have soffit vents(which I do) and also a full ridge vent. I think the presence of the ridge vent alone would eliminate any hot air "getting trapped" the way you're describing it.

I'm also concerned with the overall cost vs the final temperature change. At this point it will cost me about $400 in materials plus another $200 or so in labor. I've got a guy coming out today to give me a bid on the ridge vent install and I'll use my handyman kid that helps me out on other stuff, to hang the baffles and insulation...he works cheap.. That still doesn't include the cost of insulating and chipboarding the rest of the shop walls, but I think it will make the biggest difference in the heat buildup.

My process is to just start with the easiest and least expensive items and buildup to eventually having a fully insulated shop that I could indeed run the AC unit in, assuming I closed the shop doors. Right now, having only a 5am-10am timeframe to work in is severely limiting to my ability to use the shop. If I forget something and have to close up the shop and run to town and back...I've lost the day and the heat builds up so fast, I have to wait till the next day to venture out there and try again.

I've had this shop for almost 6 yrs now and I love being out there in the winter, spring and fall, but summers just drive me back inside the house. If I can just knock 20-30 degrees off the temp, somehow...I'll be able to work in there year-round, any time of day.

 

[Milton Shaw]

Any chance of getting shade on the west side of the building and roof. Insulation, with roof vent panels and then insulation on them. Thermal barrier above ceiling joist will make a difference. You might not believe this but just setting a yard sprinkler on the roof will make a big difference in just a few minutes as the water evaporates. Are there any windows on the sunny side, if so mirror film and reflective shades keep out the heat. Yes it rough trying to work at 100 plus heat in a garage. When I am working outside in that kind of heat I can soak through three sets of clothes by noon, sweating so badly. My shop is insulated well, partly under gound on two sides, and sitting under an air conditioned room. Stays about 75 or so it there. I also have a duct from the upstairs air conditioner to open if I need it. Stays workable in there until I open garage door and all that cold air is gone, or turn on 4,000 cfm exhaust fan while welding. Still use a ceiling fan for circulation within the room and can usually work without sweating clothes through. Keep hydrated while sweating this summer, and don't drink more than two Gateraid type drinks a day use straight water instead you can get too much electro-lights from more than two.

 

[georgelowcar]

I would think...

#1) laying down insulation batts, or blown insulation + sheet rock over an existing exposed ceiling joists.

would create a cooler climate than ....

#2) tacking up insulation batts on the roof rafters (with baffles running from ridge vent to soft vents)?

I'm thinking this because of a larger air buffer between you and the heat source.

Any opinions if #1 would make a huge difference over option #2 in cool temperature w/o AC and occasional opening of the garage door? It would have to been a pretty significant temp difference for me to loose quick access to the open rafters.

thanks again everyone for their opinions. Even the guy who said to paint my roof

 

[wolflrv]

George...I can tell you that we had a 2-car attached garage in Atlanta that was fully sheetrocked and insulated, that stayed about 10 degrees above ambient temp. It was never cooler than outside. The garage door on that house was the heavy wood composite, not metal. It was however not as hot as the shop I have now is.

In my mind, the reason for this is that there was never anywhere for the heat to escape. However you say that you already have a ridge vent installed in your garage, so maybe that isn't the issue. We both want to use and have access to the rafters. I store stuff up there and also store 10-12' wood stock too, so I don't want to lose the space. My rafter trusses are also the prefabbed kind so they criss-cross all over the place and it would be a royal pain to just string radiant barrier rolls or even some type of foam board. The baffles and bats at the ceiling is the easiest and cheapest solution for me. I realize in advance that the best I can accomplish is about 10 degrees above ambient(same as house in Atlanta), but I also know at that point I can open the doors and let some air in and feel like I'm in the shade, or leave them closed and knock out that 10-20 degrees with my window unit not having to work so hard.

Also the roofing guy came by today and gave me an estimate. $150 materials(I didn't realize you shingled back over the vent) + $30 labor. So $180 installed. He'll be out next week to do the job! His comment on walking into the hot shop was that I definitely needed the ridge vent...he said this shortly before running back outside the shop...LOL! It's definitely not a working environment! Temp was only 110 this time.

 

[georgelowcar]

wolflrv - there is some good info in your last post.

how can you beat $30 labor! I hope it cools things down for you. If that roofing guy says that a ridge vent will make a noticeable difference, i can't imagine how hot my garage would be w/o one. Its just hot. I don't know, perhaps i need to confirm my ridge vent is venting properly. how?

Also if the best i can do is 10+ over outdoor ambient fully insulated (from your atlanta garage) - then i will not bother targeting fully insulating the entire garage unless i'm ready to start supplemental cooling. Until then, i will probably do similar what you're doing, insulating at the ceiling (with baffles for condensation for airflow between soft vents and my ridge vent). Its cheap, i can do the work myself (once temps drop) and it should reduce radiant heat.

There is a housing being built near us. It already has its windows installed (which are still closed while they were transporting them), roof+shingles are also up. It also has a ridge vent. It is also not insulated yet. I'm going to take a poke inside and see if its any cooler than my garage - you would think it should be similar. If that house is cooler than my garage, i will somehow need to prove to myself that my ridge vent in my garage is vacating heat properly. I don't know, shoot smoke through it...something.

Around here, most homes have ridge vents. Only homes with a Hip Roofs, don't have them. They typically have either a gable vents or roof exhaust fan.

The good news is summer is just starting. I have another 2+ months to debug the garage temp.

 

[wolflrv]

Was reading another thread on ventilation testing. Simplest way to see if your ridge vent is drawing the air up is to get up in the rafters with a candle and test the airflow direction. Go about half way to the center of one side of the peak, up at ceiling level and use candle to observe air flow...if it's tipping towards the ridge vent then it should be working properly. You can also test closer to the soffit channels and see if it's pulling air in like it should. They also suggested that the soffit should be cleaned with a bristle brush occasionally to keep the holes clear. No water necessary, just brush them. This would be good prep work to do, before installing baffles and insulation, so you know the air flow channels are clear then.

I wish I had another 2+ months to work this out...summer has hit here 2 months early with a vengeance! I can't imagine what July and August will be this year!!

 

[Milton Shaw]

Be very careful with the candle. TVA found out that they can catch stuff on fire at Browns Ferry Nuclear Plant. It cost billions to fix. Get some canned smoke or blow smoke from a cigar or something else not a candle.

 

[wolflrv]

Just an update...they installed my ridge vent today. Shop was mostly closed up. Inside temp has not broken 100 since installed. We'll see how it does later in the day, but so far with the fan, garage door insulation and ridge vent, it's made almost a 20 degree difference! I do think I want to insulate it too..but later this year..when it's really cooled off.

 

[787B]

That's good news! See, we wouldn't lie to you.

 

[georgelowcar]

Excellent, wolflrv. 20 degrees is huge.

I tried to detect any airflow mid roof, but no luck. Either the soft vents are NOT letting enough in, or the ridge vent needs wider opening or its tough to measure airflow midpoint near the roof.

My roof is built with a ridge beam, not a truss design. However, from the ground i can see a cut on both sides of the ridge beam as it should be in my application. I can't tell if its 3/4 inch on both sides (spec), but its got to be a fair amount if i can see from the ground.

I have been reading about ridge vents. There was no wind outdoors when i tested, so it possible i wouldn't measure squat on the interior roof.

Today i picked up a thermostat w/ a 10ft cord for second probe. I need to get a little better data.

 

[wolflrv]

Take a look at www.vent-a-garage.com

wow..thx for that...but I think my 20" walmart box fan in the gable is moving way more hot air than that would!! LOL!