## Exterior Painting Mil Thickness and Coats

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Topic Author
DTalos
Posts: 213
Joined: Wed Apr 10, 2013 7:59 pm

### Exterior Painting Mil Thickness and Coats

Suppose a painter told you that he applies one coat, but the amount of paint coming out of his sprayer equals two coats and that the end result mil thickness surpasses his competitors that use two coats and exceeds industry standards. Would that be acceptable to you? As long as the mil thickness exceeds standards, does it matter if one or two coats are applied?

How is a homeowner supposed to determine the thickness of the paint that was applied to the exterior of a house if there is no gauge that works on non-metal surfaces for a measurement ? Whether it's one thick coat or two thin coats, how is a homeowner supposed to know how much paint was applied to the exterior of a house? I will be going from a darker color to a lighter color, so I want to make sure enough paint gets applied to cover up the darker paint to where it won't fade or bleed through in a few years. How can I as a consumer ensure this when hiring a painter?

In the past, when my house has been re-painted the same color, one spray coat was applied and it has held up well, but common sense tells me that a painter is going to have to apply two coats or a certain amount of paint to hide and cover the old dark color on a stucco surface.

fortfun
Posts: 1905
Joined: Tue Apr 19, 2016 7:31 pm

### Re: Exterior Painting Mil Thickness and Coats

DTalos wrote:
Sun Nov 11, 2018 4:10 pm
Suppose a painter told you that he applies one coat, but the amount of paint coming out of his sprayer equals two coats and that the end result mil thickness surpasses his competitors that use two coats and exceeds industry standards. Would that be acceptable to you? As long as the mil thickness exceeds standards, does it matter if one or two coats are applied?

How is a homeowner supposed to determine the thickness of the paint that was applied to the exterior of a house if there is no gauge that works on non-metal surfaces for a measurement ? Whether it's one thick coat or two thin coats, how is a homeowner supposed to know how much paint was applied to the exterior of a house? I will be going from a darker color to a lighter color, so I want to make sure enough paint gets applied to cover up the darker paint to where it won't fade or bleed through in a few years. How can I as a consumer ensure this when hiring a painter?

In the past, when my house has been re-painted the same color, one spray coat was applied and it has held up well, but common sense tells me that a painter is going to have to apply two coats or a certain amount of paint to hide and cover the old dark color on a stucco surface.
Your local paint shop should be able to calculate the number of gallons needed for the various thicknesses. You could oversee the operation and make sure that number of gallons is sprayed evenly across the house. I think two coats would be better than one thick coat. For example, make sure they spray 5-5 gallon buckets evenly across the entire house.

Topic Author
DTalos
Posts: 213
Joined: Wed Apr 10, 2013 7:59 pm

### Re: Exterior Painting Mil Thickness and Coats

fortfun wrote:
Sun Nov 11, 2018 4:25 pm
DTalos wrote:
Sun Nov 11, 2018 4:10 pm
Suppose a painter told you that he applies one coat, but the amount of paint coming out of his sprayer equals two coats and that the end result mil thickness surpasses his competitors that use two coats and exceeds industry standards. Would that be acceptable to you? As long as the mil thickness exceeds standards, does it matter if one or two coats are applied?

How is a homeowner supposed to determine the thickness of the paint that was applied to the exterior of a house if there is no gauge that works on non-metal surfaces for a measurement ? Whether it's one thick coat or two thin coats, how is a homeowner supposed to know how much paint was applied to the exterior of a house? I will be going from a darker color to a lighter color, so I want to make sure enough paint gets applied to cover up the darker paint to where it won't fade or bleed through in a few years. How can I as a consumer ensure this when hiring a painter?

In the past, when my house has been re-painted the same color, one spray coat was applied and it has held up well, but common sense tells me that a painter is going to have to apply two coats or a certain amount of paint to hide and cover the old dark color on a stucco surface.
Your local paint shop should be able to calculate the number of gallons needed for the various thicknesses. You could oversee the operation and make sure that number of gallons is sprayed evenly across the house. I think two coats would be better than one thick coat. For example, make sure they spray 5-5 gallon buckets evenly across the entire house.

Thank you for the perspective. Would the level of how much the painter "thins" the paint affect how much eventually gets on the wall, even if using a specified number of gallons for a certain mil thickness?

fortfun
Posts: 1905
Joined: Tue Apr 19, 2016 7:31 pm

### Re: Exterior Painting Mil Thickness and Coats

DTalos wrote:
Sun Nov 11, 2018 7:29 pm
fortfun wrote:
Sun Nov 11, 2018 4:25 pm
DTalos wrote:
Sun Nov 11, 2018 4:10 pm
Suppose a painter told you that he applies one coat, but the amount of paint coming out of his sprayer equals two coats and that the end result mil thickness surpasses his competitors that use two coats and exceeds industry standards. Would that be acceptable to you? As long as the mil thickness exceeds standards, does it matter if one or two coats are applied?

How is a homeowner supposed to determine the thickness of the paint that was applied to the exterior of a house if there is no gauge that works on non-metal surfaces for a measurement ? Whether it's one thick coat or two thin coats, how is a homeowner supposed to know how much paint was applied to the exterior of a house? I will be going from a darker color to a lighter color, so I want to make sure enough paint gets applied to cover up the darker paint to where it won't fade or bleed through in a few years. How can I as a consumer ensure this when hiring a painter?

In the past, when my house has been re-painted the same color, one spray coat was applied and it has held up well, but common sense tells me that a painter is going to have to apply two coats or a certain amount of paint to hide and cover the old dark color on a stucco surface.
Your local paint shop should be able to calculate the number of gallons needed for the various thicknesses. You could oversee the operation and make sure that number of gallons is sprayed evenly across the house. I think two coats would be better than one thick coat. For example, make sure they spray 5-5 gallon buckets evenly across the entire house.

Thank you for the perspective. Would the level of how much the painter "thins" the paint affect how much eventually gets on the wall, even if using a specified number of gallons for a certain mil thickness?
They should NOT thin the paint at all. That would be a red flag right off the bat. If you are worried, you could take the day off an supervise the project. One very important consideration is the brand and quality of paint that is selected. Make sure to find out what they will use. It might be worth upgrading to a longer lasting (usually thicker) paint.

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Joined: Wed Feb 14, 2018 9:10 am

### Re: Exterior Painting Mil Thickness and Coats

Brush, vs spraying. Spraying is the lazy way.
Avid user of forums on variety of interests-financial, home brewing, F-150, PHEV, home repair, etc. Enjoy learning & passing on knowledge. It's PRINCIPAL, not PRINCIPLE. I ADVISE you to seek ADVICE.

fortfun
Posts: 1905
Joined: Tue Apr 19, 2016 7:31 pm

### Re: Exterior Painting Mil Thickness and Coats

Sun Nov 11, 2018 7:36 pm
Brush, vs spraying. Spraying is the lazy way.
True but the OP is talking about stucco. In my experience, a brush doesn't get into all of the stucco crevices as well as a sprayer does.

Silk McCue
Posts: 2218
Joined: Thu Feb 25, 2016 7:11 pm

### Re: Exterior Painting Mil Thickness and Coats

A little humour for this subject. I heard this joke story decades ago

It seems that there was a little old church out in the countryside:
picturesque with it's painted white clapboards and high steeple.

One Sunday, the pastor noticed that his church's paint was getting a bit
shabby and peeling. He checked out the Sunday ads and found a paint sale at
the local hardware store, and the next day, he went into town and bought
three gallons of white latex, then went back to the church and began the job.

Having completed the first side, he stood back and admired his work. It was
looking great. But he noticed that he had already used over one gallon. He
didn't want to go all the way back into town, so he figured that if he just
thinned the paint a little, it might last long enough to finish the other
three sides. So he added a gallon of water to each of the remaining gallons, and continued painting.

It worked out great. He finished the last three sides with the remaining paint.
That night, it rained: and it rained HARD. The next morning when he stepped
outside of the parsonage to admire his work, he saw that the first side was
still looking great, but that the paint on the other three sides had washed away.

The pastor looked up in sky in anguish and cried out, "LORD, What shall I do?"

A voice came back from the heavens saying,
"Repaint, and thin no more.”
Cheers

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Location: Kansas City, MO

### Re: Exterior Painting Mil Thickness and Coats

fortfun wrote:
Sun Nov 11, 2018 7:34 pm
They should NOT thin the paint at all. That would be a red flag right off the bat. If you are worried, you could take the day off an supervise the project. One very important consideration is the brand and quality of paint that is selected. Make sure to find out what they will use. It might be worth upgrading to a longer lasting (usually thicker) paint.
That's not completely true thinning the paint depends on the sprayer, some spray systems require thinning or it will clog the gun. If it's being rolled or brushed on then yes you wouldn't want to thin it in general depending on the type of paint and there's allot more than just what Home Depot & Lowes sells.

My farther was a home and building (sand blasting/painting) painter most of his life and I helped him every summer ... with that said I think the OP is way overthinking this. Hire a bonded painter that gets good reviews in your area and it doesn't really matter how he/she does it.

Generally the more coats the better the finish looks but that depends on the type of paint. There's a big reason I went with seamless siding and gutters.

Nate79
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Joined: Thu Aug 11, 2016 6:24 pm
Location: Delaware

### Re: Exterior Painting Mil Thickness and Coats

They make small feelers to measure the thickness of wet paint (at least according to google).

edge
Posts: 3365
Joined: Mon Feb 19, 2007 7:44 pm
Location: Great Falls VA

### Re: Exterior Painting Mil Thickness and Coats

Make sure they are using top quality paint if you do one coat like that.

Aura or Emerald for example. But really I would only do this with Aura.

fortfun
Posts: 1905
Joined: Tue Apr 19, 2016 7:31 pm

### Re: Exterior Painting Mil Thickness and Coats

Sun Nov 11, 2018 8:34 pm
fortfun wrote:
Sun Nov 11, 2018 7:34 pm
They should NOT thin the paint at all. That would be a red flag right off the bat. If you are worried, you could take the day off an supervise the project. One very important consideration is the brand and quality of paint that is selected. Make sure to find out what they will use. It might be worth upgrading to a longer lasting (usually thicker) paint.
That's not completely true thinning the paint depends on the sprayer, some spray systems require thinning or it will clog the gun. If it's being rolled or brushed on then yes you wouldn't want to thin it in general depending on the type of paint and there's allot more than just what Home Depot & Lowes sells.

My farther was a home and building (sand blasting/painting) painter most of his life and I helped him every summer ... with that said I think the OP is way overthinking this. Hire a bonded painter that gets good reviews in your area and it doesn't really matter how he/she does it.

Generally the more coats the better the finish looks but that depends on the type of paint. There's a big reason I went with seamless siding and gutters.
I've never had to thin paint with an airless sprayer. I have had to thin paint with a sprayer that uses an air compressor but that's not the type of sprayer used on houses.

Bogle7
Posts: 145
Joined: Fri May 11, 2018 9:33 am

### Re: Exterior Painting Mil Thickness and Coats

JoinToday
Posts: 815
Joined: Sat Mar 10, 2007 9:59 pm

### Re: Exterior Painting Mil Thickness and Coats

DTalos wrote:
Sun Nov 11, 2018 4:10 pm
Suppose a painter told you that he applies one coat, but the amount of paint coming out of his sprayer equals two coats and that the end result mil thickness surpasses his competitors that use two coats and exceeds industry standards. Would that be acceptable to you? As long as the mil thickness exceeds standards, does it matter if one or two coats are applied?
...
This sounds like BS to me (Bravo Sierra for the sensitive ones here). It is bad to put too thick a coat of paint on.
https://www.quora.com/When-painting-a-r ... -two-coats

Topic Author
DTalos
Posts: 213
Joined: Wed Apr 10, 2013 7:59 pm

### Re: Exterior Painting Mil Thickness and Coats

Bogle7 wrote:
Sun Nov 11, 2018 9:51 pm
Answers may be at http://www.city-data.com/forum/house/29 ... kness.html

This forum usually provides more superior responses to questions

Info_Hound
Posts: 299
Joined: Wed Mar 23, 2011 9:47 am

### Re: Exterior Painting Mil Thickness and Coats

Just paid a company to paint the exterior of my home. Used Sherman Williams Emerald paint. That is the top of the line for SW products. Painters sprayed on a primer then two coats of top (color) coat paint. The South and West facings of the house get brutal sun all day, the color fade and caulk (cracked) was terrible. I am a fan of Behr paint normally but did go with SW Emerald for its superior UV non-fade proprieties. Got a 10 year warranty on the materials and work. No thinning or watering down of paint, that is a no no. The paint company has been around for over 30 years.

Also go with the best grade caulk you can. I chose DAP UltraFlex for its flexibility (we get high winds often) and its ability to withstand UV degradation. Again another product with a much longer lifespan than regular caulk. I am a bit of a nut about keeping the outside, outside.

Neighbors used a different company and different materials. They did one coat of top coat, same color as original. 3 months later streaks between the sprayer stokes are visible.

The basic cost breakdown in this area is 1/4 of the cost is materials, 3/4 of the cost is labor. Easy to see why you don't want to pay to do this job any more than you have to. To answer your question about 1 thick coat or 2 coats, go with 2 coats with dry time between coats.

barnaclebob
Posts: 3547
Joined: Thu Aug 09, 2012 10:54 am

### Re: Exterior Painting Mil Thickness and Coats

My industry uses what we call witness panels to ensure paint quality in certain cases. A witness panel is a piece of material that the painter paints at the same time as the product. The witness panel is then examined to make sure it meets quality specs and its assumed that the product does as well. The masking tape could maybe serve such a purpose if you break out a micrometer and measure the difference between unpainted masking tape and painted masking tape.

Topic Author
DTalos
Posts: 213
Joined: Wed Apr 10, 2013 7:59 pm

### Re: Exterior Painting Mil Thickness and Coats

Info_Hound wrote:
Mon Nov 12, 2018 3:53 pm
Just paid a company to paint the exterior of my home. Used Sherman Williams Emerald paint. That is the top of the line for SW products. Painters sprayed on a primer then two coats of top (color) coat paint. The South and West facings of the house get brutal sun all day, the color fade and caulk (cracked) was terrible. I am a fan of Behr paint normally but did go with SW Emerald for its superior UV non-fade proprieties. Got a 10 year warranty on the materials and work. No thinning or watering down of paint, that is a no no. The paint company has been around for over 30 years.

Also go with the best grade caulk you can. I chose DAP UltraFlex for its flexibility (we get high winds often) and its ability to withstand UV degradation. Again another product with a much longer lifespan than regular caulk. I am a bit of a nut about keeping the outside, outside.

Neighbors used a different company and different materials. They did one coat of top coat, same color as original. 3 months later streaks between the sprayer stokes are visible.

The basic cost breakdown in this area is 1/4 of the cost is materials, 3/4 of the cost is labor. Easy to see why you don't want to pay to do this job any more than you have to. To answer your question about 1 thick coat or 2 coats, go with 2 coats with dry time between coats.

Thank you for the information. Did the painter ask for the square footage of the interior of your house and give a quote based on that or did they actually measure the exterior square footage to be painted before giving you a quote? Did you do the caulk work yourself to save money?

Info_Hound
Posts: 299
Joined: Wed Mar 23, 2011 9:47 am