# When is Primer Not Needed for Exterior



## outsidethelines (Oct 19, 2007)

I have this idea that there is no exterior that does not require a prime before painting, with the exception of maybe using an Elastomeric paint over a basically clean, sound stucco surface. My question is; when do you decide that priming is not required? What is the decision based on? 

Also, some of the guys that I had in the past considered subbing exterior work out to have stated that they did not believe 2 coats of paint were necessary. I am having a hard time with that idea as well. Do you guys generally use one coat or two when painting exteriors? What would be the exception? It just seems to me that whether you are rolling or spraying, two coats will offer the best protection and a more solid appearance. Otherwise I can totally imagine coming back a year later only to find roller marks or holidays that were not evident when the work is first completed.

Please let me know your thoughts and experiences regarding these two issues.


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## swantucky (Jul 22, 2008)

The only time I can see not 2 coating an exterior is when going over a previously painted surface. More for decorative purposes than a protective purpose.


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## Jason Whipple (Dec 22, 2007)

Our work is always primed on all sides and at the cut ends. If this is not done the material will absorb moisture and start the rotting process.

Two coats should always go on the exterior. I've had painters tell me they only need one coat because they tinted the primer but the fact is that the exterior needs a thick coat of protection from the elements. That can only be accomplished with two coats.

We're doing an exterior with shiplap siding right now. This one I've requested to have done with a roller and brush so we can get two good layers of paint to cover the seams of the siding. If they spray it the layers of paint will be thinner and not cover the seams as well.

Some times it's about the thickness of the coverage and not how the paint "looks" when it's done.


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## Brian (Jun 9, 2004)

The manufacturer's specifications dictate when priming is needed, as well as how many coats. As a general rule, all bare substrates get primed and all surfaces get 2 coats (unless a 1 coat product, such as Duration, is used).

Brian Phillips


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## Jason Whipple (Dec 22, 2007)

Brian said:


> The manufacturer's specifications dictate when priming is needed, as well as how many coats. As a general rule, all bare substrates get primed and all surfaces get 2 coats (unless a 1 coat product, such as Duration, is used).
> 
> Brian Phillips


Have you used that paint? I saw it put on a Historical Project and it looked pretty good. Really filled in where the old paint layers weren't scraped off completely.

I'm thinking about using it on my current project.


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## gideond (May 17, 2007)

Even a product like Duration is better with two coats. I agree that you should prime all bare substrates. I don't think it's necessary to prime previously painted surfaces though unless there is an issue such as chalking that a primer would help with. If you have a good sound paint film that only needs cleaned a primer is not needed. I'd still generally do two coats of paint unless its the same color and sheen going over the previous coat of sound paint. Roof work is where I would make the major exceptions. New roofs get two coats and a primer coat of course. Previously painted get spot primed with a rust inhibitor and usually a single coat if possible. Too many layers on a roof will quickly start to peel.


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