[plainpainter]

Ah the eternal question...

There is no benefit if the finish is in sound condition.
I guess if you can get away with one finish coat after a full prime, you will save a couple bucks on materials. I think it is better protection if you do two finish coats instead of just one.

I painted a home in late '05 that was entirely resided with pre-primed clapboard siding and pine trim and then weathered for 1-1/2 years before I got the job. Pressure wash, full oil prime and one topcoat. And it's still in perfect condition.

Another job I did that year was a horribly peeling house with semigloss paint flaking right off the clapboard siding. Again washed, scraped, spot sanded, all bare wood got a spot prime of oil primer - then the whole house got primed with a tinted 100% Acrylic primer and then one topcoat. It will be a 7 year old finish in perfect condition in a few months.

Another home, same process, spot primed with oil, no whole house primer, one topcoat of paint - again in great shape.

I could go on and on - but my experience is that a properly prepped home with a quality topcoat of paint can go 7+ years and still not be in need of a repaint with just one topcoat finish.

 

[plainpainter]

So one coat is equal to two?

I am not saying that, often you need two coats for the sake of coverage or changing color. I just no longer believe that if your goal is to have homeowners paint every 7 years, then you don't need two coats of paint. If two coats is better than one coat - then the average homeonwer will go 15+ years before a repaint.

I am not sure that mil thickness is b/s as chris pointed out {or perhaps he was being saracastic.} But I don't spread 'thin' coats of paint. Neighbor next door is getting her home painted and I am watching these hondurans spread paint using those whizz rollers - they spread out the paint like 2-3x more than I do when I hand brush. Just to give you an idea - I spot primed this home 7 years ago with white oil primer on a Benjamin Moore 'Cottage Red' house. I applied one coat of Cottage Red over it and completely concealed the spot primes from the remainder of the home in one coat for a completely uniform finish.

 

[plainpainter]

I agree Dean, the more paint buildup on a home - the worst it becomes. This is apparent with those homeowners that have semigloss used on their homes - the buildup is rapid, and so is the failure. If you spot prime, spot paint, then whole house paint - then you affectively have at least 2 coats of protection everywhere. I only have one home that had a 2 coat over spot prime in 2005 - that job is 7 years old at the end of this April. The paint is in such great shape - it will easily go another 7-8 years before this homeowner or the next considers repainting.

After having 7+ years on my jobs out there and seeing the competition's work over the years and homes I have bid on over the years - I no longer believe 2 coats is all that great, certainly not at the expense of prep. I'll take 2-3X more energy spent on prep vs. a second coat of paint any day of the week. If there is a 'problem' home, then a full house latex prime and one topcoat is much better than two coats of topcoat on just spot prime. I've seen homes that I did at the same time as my competition on newly sided homes. I did a full oil reprime over the existing pre-primed siding and one topcoat of paint - the competition did two topcoats over the existing factory primer - both pressure washed - their job is gone to hell, mine is still perfect. I believe a 2nd coat on all my jobs would be even better - but if your goal is to have homes painted every 7 years - then doing two coats is pointless.

New homes, I agree two coats is preferable. But if it was my home, it would be washed, then 100% Acrylic primer tinted applied over the entire house over factory primed siding, then one topcoat of paint. Oil primer if the siding weathered for any substantial period of time.

 

[plainpainter]

I came a across a a similar discussion in a recent thread but cant seem to find it.

Im looking for opinions on the difference between a complete priming of an exterior with a tinted primer followed by one top coat as opposed to spot priming followed by 2 topcoats.

Is there any benefit to priming over paint that has already adhered to the surface.

Matthew, if you feel a home has a 'problem' finish - one in which after all your preperation work, you still feel there are areas that remain 'problems' - that's when I like to substitute a full latex prime for the first coat of paint, if doing two coats. There are many types of problems, but one problem finish I encounter alot are areas of cracking in the paint that isn't removed by scraping, by that I mean the finish in that area is still intact after scraping - scraping didin't remove anything - but you know that painting over al those micro cracks won't seal the surface. A full reprime helps better - and if it's really bad then you skip over to those ultra type primers like XIM. Those cracks for instance always seem to be where the next instances of peeling happen - even if they don't peel, those cracks migrate right through the new layer of applied paint and act as many mini water ingress to help the finish deterioate faster. Obviously grinding/sanding back down to wood is an even better solution. But if you are doing anything more than feathering where you scraped - then it becomes an enormous job.

 

[plainpainter]

Matthew - the basic problem with painting is that you can only affect the paint you apply - the paint that is there prior to you is beyond your control. Sure some areas scrape up easy enough down to bare wood, but the section that didn't scrape up is still a problem. Sticking isn't the real issue when deciding to do a whole house prime. It's usually the ability of the smaller resins in primers to seal up areas effectively eradicating a potential water ingress. 99% newer paints stick just fine to the older paint, it's just whole sections let go down to bare wood that is the problem.

To make this more understandable - have you ever put those face tightening creams that women put on their face to reduce wrinkles? If you have, or can imagine it, it feels like your skin is under a lot of tension. This is what older paint on homes feel when a fresh coat of paint is applied. This tension is enough in some cases to lift up whole areas of paint that a scraper or pressure washer couldn't touch. Short of grinding everything back down to bare wood - it's a hit or miss situation. I don't think whole house repriming is so much for better adhesion, new paint will adhere fine in most circumstances, especially if you pressure washed with TSP. Situations where the adhesion is handy is if going from a chalky surface, even if it's pressure washed - you want an oil primer to reclaim the chaulkiness into it, and then you can convert over to latex paint. Or if you are dropping down in sheen, like home is semigloss and you want to drop down to a flat paint - that's where I use a primer after washing

 

[plainpainter]

On repaints, if it's in good condition, I just use paint.

If it's bad, prime and paint.

Dan, I get what you're saying but to say that your jobs are standing up well after 7 years and then to say because of this they will for sure hold up for another 7 years is a bit of a stretch. I'm not knocking your abilities and such, I'm just saying that the first 7 years is a lot different than the second.

TJ - my point is that with my single topcoat finishes looking great after 7 years, and my prior experience with how fast finishes degrade once they start peeling. I'd say most homeowners in my neck of the woods probably wouldn't consider a repaint until year #12. And it probably won't get done until year #14 or year #15. I am not saying they'll look great at that point - but that's how long the cycle will last. If two coats are better than one, then this cycle could last possibly 30-40% longer, then we're looking at 16 years before folks consider a repaint. My next door neighbor just had her home painted between snow storms - last time it was painted was in the 70s. It was peeling like crazy - but that's how far she put it off. If the average job lasts 16 years then in any one year you can only expect about 6% of all homes up for a repaint - what do you think that does to the laws of supply and demand?

OF course I am not saying my finishes will hold up for another 7 years, but the pattern I see folks tolerating a certain amount of peeling before another repaint - that's my extrapolation. Another neighbor across the street had their home painted in '00, it's peeling quite a bit now - but still 'ok' as far as New England is concerned - so that's 12 years before a repaint. And that finish was done by a competitor, it was a major scrap job followed by a whole house prime with oil primer, and one topcoat of paint. So far the 'cycle' has gone 12 years with no repaint - a second coat would only lengthen that cycle further further reducing the 'supply' of homes ready for painting. And we all know that high supply is what makes more profits for us.