# Unheated Garages: Interior or Exterior Wall Paint



## ToolSeeker (Sep 19, 2012)

I go for the exterior for the reasons stated. Plus if you are some where that gets snow it will build up under the car then when parked in the garage melts leaving puddles of dirty water that is pretty easy to splash on the walls. I just think the Ext. would hold up better and why take the chance.


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## Brushjockey (Mar 8, 2011)

If you want to be really cheap- go straight primer like 123....


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## jsheridan (Jan 30, 2011)

Tool, did you vote? Voting is at the top of the page.
Thanks
Joe


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## jsheridan (Jan 30, 2011)

Brushjockey said:


> If you want to be really cheap- go straight primer like 123....


Non-committal? Come on BJ, it's not politics or religion. :laughing:


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## ToolSeeker (Sep 19, 2012)

I voted now sorry. I think primer would look ok for a while but not really any protection for when something needed wiped off. And might not look to good after a while.


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## ric knows paint (Oct 26, 2011)

jsheridan said:


> I want to start a discussion on whether unheated garage interior walls should be painted with interior or exterior, with a poll included. We've had two inquiries here and it seems the feedback is mixed. It matches the general info I've found elsewhere online, and haven't found a definitive rec on paint co websites. We have a consensus on paint and primer in one. I think we need a forum consensus here.
> 
> To me it's a no brainer, exterior. Even with limited exposure, they're still exposed to temperature extremes, which is all I need to vote yeah. I believe that's one of the key formula distinctions between interior and exterior paints.
> 
> ...


To begin...Welcome back, Joe - it's good to see you back in here sharing your unique perspectives on paint and application...​
I didn't vote. I didn't vote 'cause I think your options are too limited. Personally, I believe there should be at least 2 more choices - option #3 should be "Situational" and #4 be "Does it matter?".

If I were to make a broad recommendation to repaint the walls in an unheated garage, I'd go with exterior. But not necessarily for the reasons you've stated. In terms of durability and lifespan, exteriors are better products...period (and please remember, I'm speaking generally - very generally). They are better products because of their higher resin content (relative to interiors), or more specifically, their ratio of (among other things) pigment to resin (PVC). A higher level of resin generally means a more sealed surface - which means more stain resistance and easier cleaning. Also, generally speaking, exteriors usually have the advantage over mold and mildew growth than do their interior counterparts...(generally).

BUT...the reason I may recommend an interior paint is due to those same features that seem to give the edge to exterior products. An interior product, with a higher PVC, is going to yield better hiding - quality interior paints hide better than do exterior products. Also, assuming we're discussing flat paints, interior products are gonna touch up better than exteriors...Why? Back to that PVC issue, most exterior flat paints aren't really flat - in fact many would be on the eggshell level if they were to be used indoors. Dead flat paints generally don't perform as well when exposed to rain, sleet and snow as do sheened products.

So - application versus longevity. Thus the "Situational" option.

But, did you notice I didn't mention which one will perform better in an environment of temperature extremes? Once dried and cured, will an exterior outperform an interior based solely on varying (to extreme) temperatures? I'm not sure that question can be answered definitively. The performance of a cured "interior" versus "exterior" resin is pretty much equal between the temperature range of -20 degrees F to +120 degrees F . (We're talking exposure to temp ranges and extremes only here - NOT exposure to direct or constant sunlight / UV rays).

I've mentioned before that there really isn't a great deal of difference between interior and exterior resins anymore. The ratio of pigment to resin, the types of pigment, common additives and rheology modifiers are just as important in determining a product's use designation (interior or exterior) as is the type of resin itself. Matter-o-fact, many companies (including SW & BM) commonly cross-label interior and exterior products (same product, different label) for reasons of the raw material management, inventory control and simplification....and this doesn't necessarily apply only to high end, top drawer products - Sherwin's Pro Mar 700 (a truly horrible product) is listed as an "interior/exterior product.

...and thus the reason for option "Does it matter?"

So...if I were to vote, I'd check all 4 options - Interior/Exterior/Situational/Does it Matter? But then, I'm also the one who wouldn't be so quick to label the Paint & Prime products as elaborate marketing BS either...


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## Gymschu (Dec 12, 2010)

I voted EXTERIOR, although it's not for every garage. I ask the HO if they plan on cleaning cars or scrubbing the grill using a garden hose to do these tasks. And, of course, having a center floor drain to wisk away the water helps too. If they use their garage (especially in winter time) to clean or even to cut trim or if they use it as a pseudo-workshop, I like exterior on those walls. Just a tougher finish IMO.


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## Brushjockey (Mar 8, 2011)

I was going to say what ric did, but he beat me to it! lol..


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## Will22 (Feb 1, 2011)

Depends on the climate, on the environmental exposure. Interior paint would suffice for the most parts of the country , although exterior paint is probably a better choice where there is extreme climate change (especially in an unheated garage). I agree with Gymschu that exterior is better for a "working" garage.


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## Will22 (Feb 1, 2011)

Just a point to add, that products labeled "Interior/Exterior" are interior paints, which do not have mildewcide in them.


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## jsheridan (Jan 30, 2011)

Brushjockey said:


> I was going to say what ric did, but he beat me to it! lol..


I know, right. He does it to me aaaaalllll the time!:laughing::laughing:


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## chrisn (Dec 23, 2007)

Brushjockey said:


> I was going to say what ric did, but he beat me to it! lol..


 
me too:whistling2:


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## jsheridan (Jan 30, 2011)

Thanks Ric. We all bring our unique perspective to the forum. You, unlike most of us, understand what's in the cans we take for granted every day. I appreciate that. I have no understanding of or background in chemistry, and therefore have to keep it simple. 

Steamy environment - bath paint or some form of sheen
Kiddies with PB&J on their hands - something washable
Naturally dark or small room - light color
Temperature extremes - an exterior finish

Very simple. And because I have a simple mind, I can't understand why some can be so intent on using interior in that kind of environment. Outside of chemical characterisitics of the two, is there something about using one versus the other that I don't grasp? It's not a personal decision. Temp extremes are not an interior phenomenon. 

As a professional, I wouldn't take a chance. *IF*, something did happen, the customer could turn to me and say it's because I used interior, whether it truly is or not. And because it's such a gray area, I would end up with the responsibility. It's a cover your bases type of thing. I see zero difference between using the two, other than personal preference. And when it comes to performance or function, personal preference takes a back seat to professional judgement. Just saying.
Rock The Vote!


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## jeffnc (Apr 1, 2011)

ric knows paint said:


> Also, assuming we're discussing flat paints, interior products are gonna touch up better than exteriors...Why? Back to that PVC issue, most exterior flat paints aren't really flat - in fact many would be on the eggshell level if they were to be used indoors. Dead flat paints generally don't perform as well when exposed to rain, sleet and snow as do sheened products.


Which is exactly why I wouldn't put flat paint in a garage to begin with - I'd use eggshell (or "matte" at a bare minimum). So the poll ought to be eggshell interior vs. exterior. That makes it a lot closer in terms of performance.

But it does raise the question of comparing apples to apples. If you really want a true flat finish in your garage, then you should use interior paint. You might want that purely aesthetically. Or, you might prefer touching up over cleaning, where flat has an advantage.

Other than that, I guess my next garage will be painted with exterior paint.


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## ric knows paint (Oct 26, 2011)

jeffnc said:


> Which is exactly why I wouldn't put flat paint in a garage to begin with - I'd use eggshell (or "matte" at a bare minimum). So the poll ought to be eggshell interior vs. exterior. That makes it a lot closer in terms of performance.
> 
> But it does raise the question of comparing apples to apples. If you really want a true flat finish in your garage, then you should use interior paint. You might want that purely aesthetically. Or, you might prefer touching up over cleaning, where flat has an advantage.
> 
> Other than that, I guess my next garage will be painted with exterior paint.


Bear in mind that in my original post, I did say I'd recommend the exterior route - for all the reasons listed so far from each responder...Most of my comments then regarding the use of flat paints or interiors is largely to generate discussion of why we'd recommend either and what arguments we'd have to back up either suggestion. 

Perhaps when describing option #3 "Situation", I should've compared Aesthetics versus Utility (rather than lifespan). From a utility perspective, flat paints would be the worst recommendation, yet that's what I've painted my garage with...Why? Laziness, I s'pose. In my man cave/workshop/den of solitude & solace (otherwise known as my garage), I can admit that in my 26 years in this house I now reside, I've never once taken a rag to the walls in the feeblest attempt to clean 'em (and I don't think I'm alone here)...I just paint over 'em without any surface prep. Again, why? Because I can - and I am very well aware of possible consequences - as well as whatever corrective measures are necessary in the very real probability that those particular consequences will come to life. 

But here's the difference...I would never, ever recommend my system to anyone who actually has to purchase their own paint, especially if they have any kind of performance expectations. And we're really speaking from 3 different perspectives here...(1) what would you recommend to a homeowner doing their own work (as has been posted here many times), (2) what would you, as a professional, recommend to the homeowner that has contracted your services with expectations of a better job than he/she could do themselves, and (3) (and be honest here) what would you do in your own garage?

From perspective #3, I've already told you what I do...and from #2, I absolutely, whole-heartedly agree with JSheridan - that, as a professional, if I am putting my name (signature) and reputation on this agreement, then I absolutely must focus my priorities to first address the performance and utility issues - with aesthetics being secondary...To address perspective #1 - rather than attempt to pound square pegs into round holes with what you think may be best, it's necessary to determine what is the desired objective of that particular homeowner or DIYer before making a final recommendation.

In other words, neither system is necessarily right or wrong - both (either) would work, but each will provide somewhat different outcomes.


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## jeffnc (Apr 1, 2011)

ric knows paint said:


> And we're really speaking from 3 different perspectives here...(1) what would you recommend to a homeowner doing their own work (as has been posted here many times), (2) what would you, as a professional, recommend to the homeowner that has contracted your services with expectations of a better job than he/she could do themselves, and (3) (and be honest here) what would you do in your own garage?


Yup.

It probably should be in a FAQ here.


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## kennykenny (Sep 23, 2007)

I am looking at using SW interior eggshell on my unheated garage walls? What opinions does everyone have on using this? Good/bad? Does it really matter either way? Interior/Exterior? 

Also, the walls have are textured. What type of roller should I use that will allow me to get in the textured areas?


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## ToolSeeker (Sep 19, 2012)

I don't think the interior/exterior makes that much diff. and it depends on what texture is on the walls as to what nap roller. orange peel 1/2", knock-down 3/4" up to 1 1/4" depending on how heavy the texture is.


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## reanman (Jan 17, 2017)

My vote is for exterior, it just makes sense. Both because if you leave the garage door open...for whatever reason, and for whatever season you are in....indirectly it will be exposed to some parts of the outside elements. And as one earlier poster said, it's not a big increase of cost, if any at all, so why not. Heck you can even wipe that "OOPS" off the wall before the wife gets home.


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## Gymschu (Dec 12, 2010)

This old thread reminds me that Joe Sheridan no longer posts on here. He was a great contributor to the painting forum.


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## 78Vette (Nov 25, 2009)

The humidity in both heated and unheated Garages will be high enough to justify Exterior Semi. That said, i used Interior Semi (simply because i had lots on hand i wanted to use up) in my own heated Garage/Shop and i keep the humidity in the 40% range.


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## kennykenny (Sep 23, 2007)

kennykenny said:


> I am looking at using SW interior eggshell on my unheated garage walls? What opinions does everyone have on using this? Good/bad? Does it really matter either way? Interior/Exterior?
> 
> Also, the walls have are textured. What type of roller should I use that will allow me to get in the textured areas?



I ended up using SW Superpaint Interior Satin on my garage walls. Got a GREAT DEAL on a 5-gallon bucket. The paint has worked out excellent. No problems, with great coverage.


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## ddawg16 (Aug 15, 2011)

Exterior semi-gloss or high gloss. 

Much easier to wash down and saw dust, or any dirt for that matter will not stick to it as well as a flat or egg shell finish


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## Aaron1085 (Mar 8, 2015)

I have 2 full unfinished walls in my garage, basically the exterior walls that ARE the sides to my 3 car garage. I'm wondering if I'd be best to finish it off with plywood and insulation or drywall? 

I don't need a high end finished look, but more of a finished look while keeping it durable is ideal. It's a nice garage, but a garage at the end of the day. 


Sent from my iPhone using Tapatalk


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## WIKim (Nov 22, 2018)

This thread is dated, nonetheless, My two cents on this...

In a detached unheated garage, I would probably go with exterior grade paint unless the paint store advised otherwise. Then again, in my last detached garage we didn't spend much time there other than to park our cars and then walk to our back door. 

In an attached garage, whether heated or unheated, I would go with interior grade paint though the interior grade might be the appropriate option in both cases due to the toxins released from exterior paints that are meant to be on outside surfaces. 

ither way, painting the interior AND exterior of a garage provides a moisture barrier. In our last home, we had no drywall in our detached garage and the wood on the interior looked awful from moisture and sweating. The wood exterior was painted. Had we stayed there, we would have painted the interior exposed wood too. 

There are arguments here how exterior grade paint would be the better option, however, it's not even a valid argument. It's unnecessary considering your interior walls won't be battered by weather. Sure there will be weather extremes but is there any literature that specifically states that interior grade will fail in an attached unheated garage once cured? I've never heard of that. 

I've seen on multiple pro-painter websites how you should use an interior paint inside a garage. The bigger question - eggshell, satin or semi gloss finish?


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## woodco (Jun 11, 2017)

Dude, this is like the 3rd time this thread has been resurrected. Let it die, already. You can use ANY paint inside a garage. It doesnt get sun or rain, so interior is fine, and people generally dont spend a lot of time in it, so toxicity of exterior isnt too big a deal. Thats it. case closed.


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## jeffnc (Apr 1, 2011)

woodco said:


> Dude, this is like the 3rd time this thread has been resurrected. Let it die, already...



He said, as he continued to add 2 cents further....


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## marrymaid12 (Aug 17, 2020)

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*Paints for Inside Dividers:* 

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*Oil Based Inside Paint:* 

*Vinyl-Acrylic Latex Paints: *They are the most economical and reasonable for most inside dividers as they have sturdy shading and better grip. 

*Vinyl-Acrylic Latex Inside Paint:* 

*Polishes:* It is a kind of oil based paint with better bond characteristics. It is sensibly strong and stain safe. It gives delicateness and sparkle to the surface. It has preferable bypass vinyl-acrylics.


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## woodco (Jun 11, 2017)

Oh, good Lord...


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## RanK2 (Feb 19, 2020)

ric knows paint said:


> To begin...Welcome back, Joe - it's good to see you back in here sharing your unique perspectives on paint and application...​
> more specifically, their ratio of (among other things) pigment to resin (PVC).


PVC stands for 'Polyvinyl chloride', it is used for water lines and fittings, among many other things. As far as I know it has nothing to do with paint.

And for the OP ..... interior is fine, at least a 'satin' finish for some flex. You really don't need the exterior paint mildicide evaporating in your garage. And THAT is the main difference in the products and the cost.


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