Exterior Paint!!

[Brake]

I have several out buildings that were built by my Father. They are pine lap siding and were last painted about 25 years ago in a nice heavy oil paint and have weathered pretty well.

But it is time for a repaint. The prep work I can handle. My question is what kind of paint do I use? Oil, latex, built in primer?

No primer was used the first time and I plan to use a paint sprayer. All help is appreciated.

 

[simpler=better]

Oil usually sticks to oil

Latex always sticks to oil

Latex always sticks to latex

Oil never sticks to latex.



I like latex because you can clean up with water, but that's just my $0.02

I also like vinyl siding

 

[Brake]

Thanks for the reply. That information helps.

 

[Kaizen]

definitely latex with a sprayer. I think I used Sherwin Williams 2010 when I did mine 10 years ago. just starting to get some peeling now. that paint was like glue. I would wash with tsp first.

 

[theoldwizard1]

How much of the old paint is peeling off ?

A pressure washers will do a good job of blowing off loose paint, but you will have to wait at least 24 hours to start painting.

Bare wood should be primed and I prefer oil based primer. When you say spray, I assume you mean an airless sprayer. Buildings are no place for typical air spray gun ! Latex is the way to go. You will still have over spray. I like Sherwin-Williams paint, but wait for a sale. They usually have one around labor day.

Do NOT paint in direct sun (unless it is early AM) or extremely hot weather. Just before dark is not good because dew can get to the paint. If you get pushed into late fall, do not paint if the overnight temps are below 50.

 

[rlitman]

Oil usually sticks to oil

Latex always sticks to oil

Latex always sticks to latex

Oil never sticks to latex.



I like latex because you can clean up with water, but that's just my $0.02

I also like vinyl siding

Good tips, though I don't care for vinyl siding.
No paint sticks to peeling paint though, and paint doesn't stick all that well to dirt either. The devil is in the details of prep.

How much of the old paint is peeling off ?

A pressure washers will do a good job of blowing off loose paint, but you will have to wait at least 24 hours to start painting.

Bare wood should be primed and I prefer oil based primer. When you say spray, I assume you mean an airless sprayer. Buildings are no place for typical air spray gun ! Latex is the way to go. You will still have over spray. I like Sherwin-Williams paint, but wait for a sale. They usually have one around labor day.

Do NOT paint in direct sun (unless it is early AM) or extremely hot weather. Just before dark is not good because dew can get to the paint. If you get pushed into late fall, do not paint if the overnight temps are below 50.

I would say that 24 hours in full sun is still nowhere near enough time after pressure washing. I'd recommend at least a week. More on a north facing wall (in the northern hemisphere). Otherwise moisture will still be in the wood, and can lead to poor adhesion and blistering/peeling.

24 hours is enough time if you use a hose-end chemical sprayer and soft wash with TSP, followed up by a hard scrubbing to remove anything loose. This is the gold standard for prep.

Oil based paint works fine even in cold temperatures. I've Kilz (oil based) primed many wood things in my garage in the winter below freezing. But your advice is still sound. You especially do not want latex paint drying at the wet edge as you apply the next stripe, which means avoiding the direct noonday sun in hot weather.

Like you, I too am partial to oil based primer on wood. And latex is your best choice for an exterior top coat nowadays.

Sherwin Williams runs a LOT of sales. It's best to go there and sign up with your email address to get the most discounts. 40% off is not unheard of.

 

[billspit]

I always heard latex would not stick to oil based paint. Guess I was wrong.

Years ago a paint guru warned me not to buy oil-based paint, which is what I was in his store to buy, because no R&D had been done on oil-based paint in the previous 20 years. All R&D had been put into latex. So he mixed me up some Pittsburgh paint and added extra stuff to it, and sold me a special primer. Before that I had used the best Sherwin Williams exterior paint and it lasted exactly one year before it cracked and peeled. The stuff he sold me has been good paint, but I brush or roll it on.

 

[grissom]

No, latex does not stick to oil without proper preparation otherwise it peels and is a damn mess.

 

[draglink]

no, latex does not stick to oil without proper preparation otherwise it peels and is a damn mess.

exactly!!

 

[draglink]

Oil usually sticks to oil

Latex always sticks to oil

Latex always sticks to latex

Oil never sticks to latex.



I like latex because you can clean up with water, but that's just my $0.02

I also like vinyl siding

You need to change this to "Latex almost never sticks to oil base"

That being said. Prime over the oil paint and latex is fine.

Also in SOME exterior situations, if the oil paint is well worn, lost its sheen, not peeling, safe to use an exterior latex directly over it.

 

[Whitworth]

I always heard latex would not stick to oil based paint. Guess I was wrong.

Years ago a paint guru warned me not to buy oil-based paint, which is what I was in his store to buy, because no R&D had been done on oil-based paint in the previous 20 years. All R&D had been put into latex. So he mixed me up some Pittsburgh paint and added extra stuff to it, and sold me a special primer. Before that I had used the best Sherwin Williams exterior paint and it lasted exactly one year before it cracked and peeled. The stuff he sold me has been good paint, but I brush or roll it on.

That's similar to what I've been told. That all that was good inside of oil paint that we used to use has been removed due to new VOC rules and regs over the past 10 years.

 

[draglink]

I always heard latex would not stick to oil based paint. Guess I was wrong.

Years ago a paint guru warned me not to buy oil-based paint, which is what I was in his store to buy, because no R&D had been done on oil-based paint in the previous 20 years. All R&D had been put into latex. So he mixed me up some Pittsburgh paint and added extra stuff to it, and sold me a special primer. Before that I had used the best Sherwin Williams exterior paint and it lasted exactly one year before it cracked and peeled. The stuff he sold me has been good paint, but I brush or roll it on.

The 'paint guru' was correct. The ONLY places I use oil are on my INTERIOR trim, bc I like a HIGH gloss oil finish, and my exterior metal roof.

Exterior oil paints are horrible these days. I get 3-5years max on my roof. Used to get 10-15 years easy

 

[jdsac]

Latex over PROPERLY prepared & primed as necessary base. The reason is latex is flexible and over a properly prepared & caulked surface won't split.
Don't skimp on the paint- within reason a heavy 2 coat job will move with the house. Oil based paint when aged, doesn't flex so it cracks and lets in water which tends to lift the paint.
As always, prep is everything- no short cut to a good job.

 

[Brake]

So what about the Latex with built in primer? Any good? Or is it just to good to be true?

 

[draglink]

So what about the Latex with built in primer? Any good? Or is it just to good to be true?

I have used it outside on a few things (railing etc) with good luck.

 

[hogdaddy]

Use oil paint you will thank me years down the road.
Brush it on.

 

[rlitman]

That's similar to what I've been told. That all that was good inside of oil paint that we used to use has been removed due to new VOC rules and regs over the past 10 years.

Not quite. The EPA regs have just removed the word "paint".
But the stuff in the can is not changed. It is just no longer "paint". They sell oil based primer, oil based finish, oil based enamel, oil based stain, oil based sealer, oil based coating, oil based anything other than paint.

However, while oil based paint has great adhesion to previous coats of oil based paint, no matter how old or poorly prepped (something that can only be achieved with latex in ideal conditions after much prep), it also suffers from brittleness and chalking, and simply does not age or weather as well as a modern exterior latex.

So what about the Latex with built in primer? Any good? Or is it just to good to be true?

It isn't evil. It just is not a substitute for a good primer either.
In ideal conditions, it's useful. If you're re-painting an interior, you can put it straight over the latex paint that's been on the walls for years, and expect good results without priming. But I would not expect it to guarantee adhesion to weathered oil based paint without any other prep.