Heated garage and rust theory

[Mike99]

So I decided to heat my new garage. I love the idea of jumping into a nice warm car with instant heat and warm seats. But the first thing that everyone says is whoa dont heat your garage or your car will rust. I doubt that. Sounds alot like old wives tales and sour grapes from folks without heated garages. My new car warranty says nothing about avoiding parking in heated garages. The only way to prove this for certain is to park 2 identicle cars inside and outside at the same time for years and see which one rusts first. Who does that . So stfu.lol_hitti

 

[lakeroadster]

Your location? (humid climate)

If you live in a humid climate, is their poly under the slab of your garage?

Are you talking about a daily driver, or a weekend classic cruiser?

 

[Mike99]

Your location? (humid climate)

If you live in a humid climate, is their poly under the slab of your garage?

Are you talking about a daily driver, or a weekend classic cruiser?

No poly under the slab. Shes in her cage.

 

[Mike99]

Daily drivers.

 

[ALinCarolina]

I'm in the humid southeast. Here my biggest problem with rust by far is condensation. Car, tools, and anything else gets cold overnight then warmer, moist air condenses on it. Heating your garage and auto shouldn't do anything but help in that situation.

 

[LB-1911]

Your location? (humid climate)

Cut from his previous thread - Garage heat
05-07-2017

Here in Winnipeg we pay 7.9 cents/ kwhr. Nat gas is 10 cents per cubic meter, 36500 btus. Way more btus for your buck with gas and produces far more heat than electric. Its a no brainer. I was quoted $1500 to run 220 to the garage and install the heater because I need a sub panel. Im expecting a quote of around $2000 for the nat gas unit.

 

[finn]

You didn't state your location, but here in the lake effect snow belt the consensus is that no heat is better than heat as far as preventing underbody corrosion.

The main roads are snow and salt covered all winter (November through April) with outside temperatures mostly in the teens and twenties, and lower at night.

Bringing a salt covered car into a warm garage increases the humidity and the brine solution attacks the metal undercarriage.

A car will resist corrosion better if kept outside, but dealing with daily lake effect snow is a bigger issue than having to replace a good running car that is no longer viable because the undercarriage is shot.

 

[6t7gto]

I have a gas furnace in my garage that I only turn on when I am working out there.
The garage is attached to my house and never gets below 40 degrees without the furnace on.
My wife's car is 8 years old and the undercarriage is spotless.
The snow melts off overnight.
And my tools and equipment are rust free.
So...am I bringing a cold car into a heated space?

 

[Streetbu]

My wife bought her car brand new. A 2008 Mercury Milan. I always let her use the garage during the winter. I keep it heated but only to about 40°. Being in central NY there is a lot of salt used on the roads. She just sold it and bought a new car, mainly because it was rusting so bad. It was getting to the point I couldn't lift by the pinchweld on the rockers becuase it would just crush. She had 121k miles on it and washed it at least once a week, if not more some times. Year round. No rust proofing of any kind. 10 years seems to be the average a vehicle lasts around here before the rust starts taking over.

 

[APEowner]

This isn't exactly a scientific study but when I lived in Upstate NY my trucks were parked outside while my wife's cars were parked inside my heated shop (which, by the way, makes it easier to justify a heated shop) and I can't say that her cars rusted any slower or faster than my trucks.

 

[Showkey]

I suspect we will have no consensus on this topic.

I am with gto ........the last two homes in the last 20 years have had attached garages. The temp in the garage never drops below freezing and the accumulated snow always melts overnight. I think the cold preservation theory to keep the rust sleeping is keep the vehicle outside where it never thaws.

I try to wash the vehicle when a warm spell occurs several times over the winter. My thought is getting the salt off more important than the warm storage causing more damage.

Also thing the keep it frozen theory comes from the "salt spray test" is the rust testing standard and keep it frozen is the opposite of the salt spray. To add more confusion there is hot salt testing as well.

Also vehicle construction and coating have had major changes in the last 20 years with double galvanized steel, ecoat full dip, chip guard to mention a few.......so comparisons over years, manufactures and even models are very difficult because of the many variables.

 

[redsky49]

All else being equal, if you raise the temperature of ambient (outdoor) air conditions, the indoor relative humidity decreases. This is the reason indoor conditions in northern climes become so dry during the heating season.

If you are driving a snow-covered car, and causing that snow to melt in an enclosed space, you will temporarily create a more humid situation. If you also have a coating of road salt, in combination with substantial snow accumulation on the car, you might indeed accelerate underbody rust, especially in older/nongalvanized vehicles.

In normal conditions, keeping your vehicle in heated storage will not accelerate rust or other damage. Plus, it encourages you to give it some love during those long winter nights

 

[finn]

All else being equal, if you raise the temperature of ambient (outdoor) air conditions, the indoor relative humidity decreases. This is the reason indoor conditions in northern climes become so dry during the heating season.

If you are driving a snow-covered car, and causing that snow to melt in an enclosed space, you will temporarily create a more humid situation. If you also have a coating of road salt, in combination with substantial snow accumulation on the car, you might indeed accelerate underbody rust, especially in older/nongalvanized vehicles.

In normal conditions, keeping your vehicle in heated storage will not accelerate rust or other damage. Plus, it encourages you to give it some love during those long winter nights

Exactly.

As the snow and road salt begins to melt, the salt goes into solution in the water .

This saline solution is what accelerates corrosion. The salt is comparatively inactive at extremely low temperatures, and again after the water has evaporated.

It's the in between time /temperatures where the salt is in solution that corrosion is accelerated.

 

[Mike99]

Yup. Agreed. I get all the science. My car isnt usually covered with snow when I park and in really cold temps they dont use salt anyway. Regular washing especially at those places that spray your under carriage should keep things in check. I cant wait for winter!

 

[Creatherm]

Have you considered floor/slab heating? PM me if you'd like some information.

 

[HoosierBuddy]

There are some interesting points here:

1. I completely agree that a car that has salt or any corrosive chemical on the undercarriage will rust faster in a heated environment, if for no other reason than the chemical reaction will happen faster the warmer it is.

2. If you heat a garage part time, it is easy to create pools of condensation under your car or tools, as the air warms up, picks up more moisture and then the warm moist air hits your cool tools (in this case "cool" meaning temperature below the dew point) and condenses. It's not just a theory, I've made it happen in my barn before.

3. If you have a fuel burning appliance without a vent...it will put a lot of moisture in a garage and can cause all kinds of issues...one of which would be increased corrosion on exposed metal surfaces. That's why I always advise against non-vented gas heaters in garages, even though manufactures market them SPECIFICALLY for that purpose.

Bottom line...for me and my stuff...nothing beats a garage heated all winter round to about 55 degrees by a nice hydronic heating system. Nothing. I lived the first 42 years of my life without a heated garage, but now that I have one, you'll have to pry it away from my warm dead fingers before I'll give it up.

Phil

 

[markzrt1]

If the cars are salty and garage is heated they will rust faster.

 

[Showkey]

There you have it ^^^^^^^.....consensus ........not.

 

[finn]

There you have it ^^^^^^^.....consensus ........not.

Corrosion is an electrochemical phenomenon, and raising the temperature increases the rate of the galvanic reaction. It's high school chemistry, and opinions and anecdoteal evidence never trump science.

 

[Showkey]

Corrosion is an electrochemical phenomenon, and raising the temperature increases the rate of the galvanic reaction. It's high school chemistry, and opinions and anecdoteal evidence never trump science.

Let's throw in the ice, snow, water and salt drip off the vehicle and dry as the Vehicle is warmed. Since the salt and water, ice and snow are no longer on the vehicle the chemical reaction is now on the floor. My experience is pushing snow, water and salt out the door with a floor squeegee and very regular basis. So is a dry vehicle anecdotal or fact.

 

[matt_i]

I believe increasing temp increases the rate of the reaction. As I recall from earlier lifetime watching a "physical test" (stationary component-ish test) run which tested ELPO coatings, they warmed the saline solution to somewhere around 80F to get the part rusting faster to get the results needed without waiting eons.

I've always parked my car outside in the cold, mostly because the garage was full but soon it won't be and I still will be parking outside.

I have 5 gallons of Fluid Film + applicator gun which is awaiting an October/November date for trial for the rest of the daily drivers.

 

[finn]

Let's throw in the ice, snow, water and salt drip off the vehicle and dry as the Vehicle is warmed. Since the salt and water, ice and snow are no longer on the vehicle the chemical reaction is now on the floor. My experience is pushing snow, water and salt out the door with a floor squeegee and very regular basis. So is a dry vehicle anecdotal or fact.

You live in the south, where winters are mild. I understand your snowmobile season typically lasts only two months.

It takes many hours for the impacted snow to melt off the undercarriage here, even in a heated garage.

Most service shops pull vehicles inside the heated shop the night before scheduled undercarriage work, and the undercarriage is still dripping the next morning. The impacted snow usually drops to the floor by morning, though.

The salt continues to attack the metal when dry, though, albeit at a reduced rate.

The automakers conduct corrosion tests at their desert proving grounds in Arizona. It's hot and dry there, so I'd imagine the car dries quickly after going through the bath.

 

[Showkey]

Agree.......over night in 40-50* garage the ice, snow and water fall off the car over night. Many do not have a real choice ( as it comes to comfort or ice scraping or snow removal) , if you have garage parking space........would you leave the car outside in the winter to hope it would not rust as much ?

When I said there would be no consensus........we could add to the discussion, if you park outside on a 0* night .........do you warm the vehicle up before driving. Another one of those questions with many facts, variables and opinions.

 

[finn]

A rusty car after five or six years of parking inside all winter, having a warm place to work on things , and not having to brush four inches of lake effect snow off the car nearly every day for five months of the year are all tradeoffs.

Personally, I choose the heated workplace / no brushing option over the reduced corrosion option, so we keep as many vehicles in the fleet inside as possible.

 

[n20junkie]

Heat ALWAYS makes corrosion happen faster. In a heated garage, what was cold or frozen water and salt, is now warm salt water. The body seams will never dry out in the course of a few days, much less over night.

A corrosion test cell is a warmed salt water environment for a reason. It is the perfect conditions to induce the electrical process to cause corrosion.

As an auto mechanic I could tell which cars were stored inside usually. The body seam corrosion was insanely bad, and when pointed out to the women usually (women care more about storing a car inside then men did IMHO) the women always said "but we store it inside every night!).

The best way to combat the corrosion is to hose the car down when new with oil on its underside so that oil makes it way into the body seams and helps to keep the salt water out. But sometimes areas like the tops of fenders just gather salt and sand, causing the fender top to rot throught.


If you store your daily driven car inside in a northern climate, it's going to corrode faster. It's just the reality of the situation.

 

[n20junkie]

You live in the south, where winters are mild. I understand your snowmobile season typically lasts only two months.

It takes many hours for the impacted snow to melt off the undercarriage here, even in a heated garage.

Most service shops pull vehicles inside the heated shop the night before scheduled undercarriage work, and the undercarriage is still dripping the next morning. The impacted snow usually drops to the floor by morning, though.

The salt continues to attack the metal when dry, though, albeit at a reduced rate.

The automakers conduct corrosion tests at their desert proving grounds in Arizona. It's hot and dry there, so I'd imagine the car dries quickly after going through the bath.

They use arizona because the corrosion tests need heat, and they have a lot of it. The corrosion cells are enclosed stainless buildings with misting spray heads all over.

 

[jfranco]

Could one not just use a dehumidifier if the concern is there or is it just not workable with the varying temperature/humidity as the doors open/close?

 

[6768rogues]

Warmth accelerates corrosion from salt. If you live in a salted road region, your car will rust out faster in a warm garage. I live in salt country, but I keep my garage heated to about 45 degrees. That is warm enough to melt all the snow and ice on my car overnight and warm enough to have a bearable car that warms up fast, but not so warm as to cost a lot to heat. I just got rid of a pickup that was so rusty I could check the washer fluid through the hole in the front fender. I had to replace the brake and fuel lines. It had 220,000 miles and my nephew is still driving it. Nothing is forever.
Add a couple of ceiling fans and your floor will dry much faster.

 

[Mike99]

I lease my cars. Get a new one every 4 years so not too worried about rust. Guess it might be a concern if you plan on keeping your car for 20 years.

 

[Showkey]

Guess it might be a concern if you plan on keeping your car for 20 years.

True.....^^^^^^^. But .....Then there is 20 years and 15-20k miles a year makes for other decisions on fixing the other issues. 20 years in the salt belt will take its toll.

 

[Firebrick43]

Let's throw in the ice, snow, water and salt drip off the vehicle and dry as the Vehicle is warmed. Since the salt and water, ice and snow are no longer on the vehicle the chemical reaction is now on the floor. My experience is pushing snow, water and salt out the door with a floor squeegee and very regular basis. So is a dry vehicle anecdotal or fact.

The areas that rust are the ones that don't dry out. Areas such as rocker panels, wheel arches and tube frame rails. The water can't drop off. Sand, organic debris such as leaves, and the salt make a mushy composition that literally takes days to dry out, even in a heated garage.

Obviously cleaning out these area helps (many don't, and no an automatic car wash does little for these areas). But sub 20 degree and corrosion starts to drop off dramatically. At around zero it happens extremely slowly.

 

[Mike99]

Im in the process of adding a 180 cfm exhaust fan in my garage. Mostly for smoke comtrol over the electric grill but also to help keep any humidity under control. This will be my first winter with the heated garage. Should be interesting.

 

[BADSIX]

I think the salt is going to kill your car no mater what you do. so if you want a warm car then do it.

 

[73fxe]

How about the fact that all of the salt and water that comes off your car will cause the rebar or wire mesh in the concrete to rust and ruin the concrete?

 

[tym]

During the winter months I run the car through the auto car wash about every 2 weeks to cut down on the caked-on salt and ****.

I park outside, but my folks have an unheated garage. Especially in the winter when it's cold, there is a lot of humidity within about 6 inches of the cement floor (no poly underneath when it was built decades ago). If I were to heat it, I'd use one of those ductless A/C systems that also can heat, to keep the humidity under control.

At the moment, my Dad's vintage Camaro lives in the garage; I've set up a small fan to come on for 15 mins about 4-5 times every 24 hours to keep air circulating under the car. This leads to another question--if the OP ran fans to circulate air, my suspicion is that this would help keep surfaces dry and reduce the rate of rusting.

 

[Jazz1]

I never park in garage however in your case no salt being used so not a issue. Heated garage is necessary in my neck of the woods but parking in garage the thaw/melt cycle will cause deterioration on any vehicle.

 

[Mike99]

My buddy told me today he has a heated floor in his 3 car attached garage and he keeps it 5 degrees above 0 all winter long. He lives in my area. Has never had rust problems on any vehicles or tools in 14 years! And he doesnt even vent it.So there you have it! And another buddy has a propane bbq in his 2 car garage with a heavy duty vent over top and hasnt killed himself yet. So there you have it again! Cant believe everything you read on the internet.

 

[Mike99]

Oh yah 73 fxe. His rebar hasnt rusted either. How long should I tell him to wait for that to happen?? And badsix should I tell him he shouldnt have had a warm car for 14 years because his car could have rusted?? Sheesh!