Heated Garages in Cold Climates and Mitigating Corrosion?

2.7ecoboostFordBronco

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Hello,

Where I live the average winter low isn't too cold, 10F or so, but the roads are treated with a lot of gravel, sand, and sometimes chemicals (urea, I think, so not as bad as what some other states use?).

For the last decade or so I was driving older cars and they lived outside, I never paid much attention or noticed any corrosion issues. I recently acquired a house with a radiant floor heated garage. I leave it set as low as possible with the installed thermostat, 60F. If my vehicles have significant snow/ice build up quite a bit of water can pool up in the drain, and due to the sand/grit in the snow, the water drains slowly and the p-trap has to be periodically cleaned out.

The result is a lot of humidity in the garage during winter. I was wondering if there is some way to mitigate this? Obviously cleaning the snow off before entering the garage would be ideal? Even so there is only so much you can do when there is ice accretion and it's below freezing outside. In certain conditions even the drive between the car wash and the house would lead to build up by the time I arrived home.

Should I open a window? Get a thermostat that goes lower? Set up some kind of dehumidification system? Just live with it?

This is the frame of an 18 month old vehicle (transmission cross member area).

Unfortunately the only local under-coating place uses a product called Valu-Gard and not the usually recommended oil-type undercaoting. I have done the valu-gard on one vehicle anyway, but the one pictured below hasn't had it.

rust.webp
 
Park outside. Warmer temps and moisture in the air create an environment that will accelerate corrosion. I only park inside if the vehicles are clean or after I can spray them with salt away underneath. Fluid film in the fall - I have a 3' piece of tubing with a 360deg head on it I use to shove in all the cavities and fill them up. Paint the frames with new paint.
 
I don't have an "in-garage" solution for you, but I have thought about this a lot as I plan to build a new home in a few years.

My plan will be a Lean-to roof off of my garage roof (in-line with that roof) with concrete and a man door to it from my main garage. My goal will be to keep the vehicles parked under it year round. I feel a lot better with vehicles staying cold when its cold outside and not making the salt work from repeated hot cold hot cold cycles. This will also keep a considerable amount of snow off of them to reduce cleaning them off as much and rain when walking to your vehicle. Of course snow drifts or heavy blowing snow... it is what it is. But for me this is an idea I like a lot.

Now some family members have told me "nahhh don't do that, don't you want a warm car in the morning?" They don't get the whole lets keep a vehicle a long time and keep the corrosion at bay idea. Plus that is what remote start is for, for me anyways.
 
This garage, is it attached to a house wall? Is that wall insulated well? Is the radiant heat filled with water or antifreeze, eg could you shut the system down?

My wife's Prius brings in a literal gallon of "car water" every time she drives it in the snow. The slush bombs behind the fenders, body cavities... IDK where it all comes from. But I squeegee it into a dust pan then dump it in a bucket and can vouch for the gallon. "My" car water sticks around because the concrete slab has "cold inertia" and condenses water vapor on it anyway. Your floor should not do this, being heated, but in its present condition it might create ground level fog, which is just as bad for your truck.

Since you have a drain, I'd just set up a car wash with one of those undercarriage sprinkler wands and quickly run that under your truck if you've been driving in salt. 30 seconds, every night.

Also, you have the perfect conditions to run a dehumidifier to wring water vapor out of the air. I'd rig it with a hose to the pit sump as it'll make a LOT of water.

I suspect the thermostat doesn't go lower because the builder doesn't want people freezing pipes, or noticing the coldness coming in the shared wall.
 
Run a dehumidifier and route the hose outside. Its what I do in my garage to keep the humidity down in both the winter and summer. My 3 stall garage is fully insulated and I have window AC units for cooling and then use the infrared heaters to keep the garage around 50F in the winter. If I want to work out there I turn up the heat and use an additional heater to keep it warmer when necessary. I also don't park vehicles in my garage during the winter that are in use either, which helps reduce any water getting in as well.

I also make sure to do a full Fluid Film on my vehicles that will spend the winter outside. Once they stop putting salt on the roads and a few rain storms wash the salt away, I fully clean the underside of my vehicles to get any remaining salt off. The amount of salt they use in my area should be illegal, we get a tiny amount of snow and the main roads have piles of salt up and down them everywhere.
 
We have a heated garage. I don't use it for our two daily drivers in the winter (they stay outside in the driveway), because all that melting goop makes such a mess. I keep the garage clean and use it as a work shop instead.
It's better for the cars not to be rusting in a warm damp garage after every drive.
 
Rusting is a chemical process. It works faster when warmer.

Rust proofing treatment is key.

Don't use the under carriage wash if your car has been treated with a rust proofing treatment. Or thats what NH Coatings advises. Will wash off the treatment. Garden hose is OK. But high pressure will wash off the treatment.

Move to a state where there is not a lot of salt used.
 
Built a new house with 3 bay 1000 sq ft attached garage.

Builder asked if I wanted heated floor. No thank you.

I want a cold garage, and cars parked in the garage overnight.

They warm up plenty quick when I drive out of the garage. In any case, the unheated garage is always few degrees warmer than outside temps.
 
Heated garage here, kept at 50F unless I'm going warmer to do projects:

1. Use a dehumidifier. It'll work more slowly given the lower ambient temp, but it helps a lot.

2. Squeegee any water into your drain after a melt off that you can

3. Continue to park in your heated garage. Sounds like in your area, like mine, it isn't a salt mine. My vehicles get washed often in the winter, including an underbody spray, and I've never had issues with corrosion nor done any coatings. In my opinion, the benefits of a warmer cabin, never brushing snow or scraping frost, and the warmth for things like unloading groceries far outweigh the slightly accelerated corrosion and mess. I'm not trying to make my cars last 30 years.

Radiant floor heat is awesome...I just have an overhead forced air unit but having a warm floor is great and heats the area much more evenly.
 
As everyone else said, heated garages actually make corrosion worse :sneaky:

The best thing to do is to rinse off the salt as soon as possible (but you don't have to rinse it until it's above freezing)

Rustproofing with some kind of oil is a good idea. Krown also makes a salt eliminator to spray over the salted car; similar products may be available from others.


Rusting is a chemical process. It works faster when warmer.

Rust proofing treatment is key.

Don't use the under carriage wash if your car has been treated with a rust proofing treatment. Or thats what NH Coatings advises. Will wash off the treatment. Garden hose is OK. But high pressure will wash off the treatment.

Krown says it's ok to was the undercarriage of a Krown-treated car :whistle:
 
As everyone else said, heated garages actually make corrosion worse :sneaky:

The best thing to do is to rinse off the salt as soon as possible (but you don't have to rinse it until it's above freezing)

Rustproofing with some kind of oil is a good idea. Krown also makes a salt eliminator to spray over the salted car; similar products may be available from others.




Krown says it's ok to was the undercarriage of a Krown-treated car :whistle:
Wash or pressure wash?

NH Coatings seems to creep more than other similar products. Maybe it's stays slightly softer so it can creep. And so NH Coatings says no undercarriage high pressure washing.
 
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