Pros/Cons Painting Over Spray Foam

[Cruz427]

Hello All,

I recently purchased a home in south eastern Michigan with a pole barn. I would like to take care of a few things before beginning to move some of my stuff in. I am planning to do a polyaspartic floor, and insulation with plans to add a heater before next winter. I am planning on doing 2” of closed cell spray foam on the walls and roof deck. I am trying to decide if prior to having the floor done/moving stuff in I should spray the ceiling with a black paint over the spray foam once it’s complete. I may do the walls as well. I would love to hear some feedback, pros/cons of doing this and what products people would suggest.

Thanks in advance!!

 

[Hohn]

You want something more fire-resistant than paint over spray foam....

 

[JoeLee1]

2 inches of spray foam isn't much especially in Michigan.
If it were me I would fir walls out, put 6 in of insulation in and then 5/8 sheetrock.

Joe.....

 

[Hohn]

2 inches of spray foam isn't much especially in Michigan.
If it were me I would fir walls out, put 6 in of insulation in and then 5/8 sheetrock.

Joe.....

Sounds wise to me...

 

[Stelzer]

If you plan on painting it, doing it before the floors makes sense. Check codes in your area to see if you'll need some type of thermal barrier, since that'll ultimately be the deciding factor on which kind of paint to use. If codes aren't an issue, acrylics are fine. If you need a legit thermal barrier coating, then search for intumescent paints. Allow for 48 hrs after install for the foam to finish off-gassing before coating.

 

[kngelv]

I live south of Detroit and am doing spray foam in a few weeks. I would do at least 3" on the ceiling and 2" on the walls. By the 2015 Michigan building code you need to either cover the foam with a thermal resistant barrier or use a thermal resistant paint. The paint is about $100.00 a gallon. You can also use drywall and certain types of wood a s barriers.

James

 

[JoeLee1]

I've never seen anyone paint over spray foam before. That stuff doesn't end up perfectly flat.
It's usually done where you don't care about the appearance.
Painting over would make it resemble the walls of a cave.

Joe.....

 

[billconner]

Just on the all black. What are you planning to do there? I can only think of a very few activities that would benefit from this all black. Just asking are you sure?

 

[nadogail]

I have seen all Black used to hide the conduits and
HVAC ducts in an open truss ceiling in some restaurants and cafeterias.
The lights were hung below those trusses and the mechanical stuff was accessible but for all intents and purposes was hidden from view.
I can’t think of any other reason to go with a black ceiling.
I guess it you wanted to have scattered lights in your Black Overhead you could pretend that they were Stars in the Night Sky.
For a Workshop I personally would want the best lighting possible, which in my experience points to a White Ceiling.

 

[Cruz427]

Thank you all for the feedback so far!

Let’s start off with the paint lol the thought with the black paint was to cover up the not so appealing color of the spray foam. I don’t think white would be a great option as it would show anything but I realize how dark black would make it. A light gray may be a better option.

As for the thermal barrier paint, I think the cost is quite high and am wondering if it would be better to just cover the foam with something else. What meets the standard for this thermal barrier. I am thinking maybe OSB to cover the roof deck and nicer plywood for the walls.

As for the thickness of the spray foam I have been told by a few people that 2” should be a good amount as I am only planning to heat it to 45 or 50 degrees in the winter and may crank it up when I’m out there working on stuff. I’m not opposed to 3” on the roof deck and was wondering if that wouldn’t be a better option.

Thanks…Cruz

 

[dcg9381]

Spray foam looks like brain matter. The worst color to hide imperfections is black. Light color, I get it.
But I get that not everyone likes the same aesthetics, so you do you... I get painting it if you can't get fire rated foam or if it's required.

You're also in MI. Depending on what you're doing here, you may want to go traditional insulation on top of that foam.


Do the floor before you move anything in there. Absolutely. Make sure the foam guys completely cover the floor before they spray.

 

[billconner]

Here's the text from 2024 IRC for exposed foam:

R303.4 Thermal barrier.
Unless otherwise allowed in Section R303.5, foam plastic shall be separated from the interior of a building by an approved thermal barrier of not less than 1/ 2-inch (12.7 mm) gypsum wallboard, 23/32-inch (18.2 mm) wood structural panel or a material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

Here's an article on coatings and NFPA 275; https://painttoprotect.com/when-sho...umescent-paint-nfpa-275-compliance-explained/

 

[TurnipTruck]

I sprayed the foam inside my old shop with ordinary white latex. I had heard of intumescent paint, but couldn’t find any, nor could I afford any then.

Realtors shouldn’t operate cameras. It was actually a bright white space and was well lit.


I WON’T do another Quonset, tho

 

[Norwell Equipped]

I personally just don't care for the spray foam from an electrical point... meaning on finished walls with spray foam.... near impossible to wire within.... Our home has it throughout the walls and any new wiring for lights or additions is a real pain.
But that's my only thought.
nice space though!

 

[Hohn]

Spray foam looks like brain matter. The worst color to hide imperfections is black.

That's only true of shiny black cars and other highly reflective, glossy black surfaces. In that case, it's the gloss and not the color that is so revealing of the surface.

A matte black surface (like matte paint over spray foam) has little to no discernible texture--- ESPECIALLY if that texture must be discerned by staring up into lights that are hung below that ceiling.

Check this out:

 

[karoc]

My quick response would be that after few trips inside after newness has wore off you won’t look up that much. Especially with lights on.

 

[Toolfool]

 

[pickles]

I had my garage ceiling spray foam insulted back last fall. I painted it using a sprayer and normal house paint from Hime Depot. I was happy how it turned out.

 

[Youngandfree]

There's a reason code requires it to be covered due to the high flammability of it. It's worth it to follow code and use the proper paint.

 

[billconner]

There's a reason code requires it to be covered due to the high flammability of it. It's worth it to follow code and use the proper paint.

While I agree with you, many don't, and feel they should not have to comply with laws for things like this. I'd be curious to learn if there is a fire, how the insurance company might treat this if the could determine it was non compliant. I'd also suspect even for those buildings here with a building permit that get inspected, how many inspectors would pick it up. It's a more subtle point. Add to that these are often in rural areas where the building department may not be as well versed as an urban setting.

 

[Youngandfree]

While I agree with you, many don't, and feel they should not have to comply with laws for things like this. I'd be curious to learn if there is a fire, how the insurance company might treat this if the could determine it was non compliant. I'd also suspect even for those buildings here with a building permit that get inspected, how many inspectors would pick it up. It's a more subtle point. Add to that these are often in rural areas where the building department may not be as well versed as an urban setting.

I've seen videos of garages go up spectacularly due to foam igniting.

Investing all that money to create a volatile fire hazard seems weird to me.

 

[ludakris04]

You want something more fire-resistant than paint over spray foam....

I've never seen anyone paint over spray foam before. That stuff doesn't end up perfectly flat.
It's usually done where you don't care about the appearance.
Painting over would make it resemble the walls of a cave.

Joe.....

They have fire proof/resistant paint for spray foam.

This guy built his garage in FL and did 3" spray foam and paint.

 

[sjvicker]

It may be worth doing some research on the codes for your area as the need to cover the foam may be different for a residence vs accessory structure.

There is a good chance your trusses weren't designed to have any load on the bottom of them. So unless you have the engineering from when it was built and it says you can add around a 10psf load to the bottom cord, you might not be able to enclose your ceiling.

If it were my building, I'd spray the foam with latex flat black and then start working on a longer term project to bulk up those trusses and add a metal ceiling in there.

 

[billconner]

They have fire proof/resistant paint for spray foam.

This guy built his garage in FL and did 3" spray foam and paint.

I don't think anyone said there were not coatings that net code requirements. Having worked in design and construction over 40 years, whenever he subject of intumescent paint came up, it was often called liquid gold. Never found anyone who thought it cost less to paint than to wrap in drywall. Now, that was for rated construction, which means it was lab tested. In one family dwellings and accessory buildings, a rating is rarely required - I think only if within 5' of property line, so it may be a little less expensive.

Here's one that claims to meet code. Under $1/ SF.

DC-315 Intumescent Coating Thermal Barrier, 5 Gallons, White | Profoam

DC-315 Intumescent Coating Thermal Barrier, 5 Gallons, White (Please call customer service at 706-557-1400 for volume pricing) This fire barrier spray foam is an intumescent coating applied over Spra ...

profoam.com

 

[rsparks64]

We were in an antique store the other day that was housed in an old church building built in the late 1800s. They had spray foamed the ceilings to add insulation and painted them a light gray. It didn’t look bad. Better than leaving it unpainted.

 

[denis4x4]

I got a discount on my ceiling foam job because the installer brought two different colors. Part of the job is yellow and the rest is a sea foam green. So, if there are available colors, why would you have to paint it?

 

[Firebrick43]

I've seen videos of garages go up spectacularly due to foam igniting.

Investing all that money to create a volatile fire hazard seems weird to me.

Or have it rust out your metal and hold water against to rot the framing out.