Painting new siding question

Tooner

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I have re-sided a mobile home. Tore off the old LP type and installed new Hardi-panel (4x8 sheets). The Hardi-panel is pre-primed. It is nailed off every 4 to 6 inches. The nails are not galvinized and they are set flush to the siding. Do I need to cover the nail heads with some kind of rust resistent primer before painting? If so, what type of primer? I would imagine that the Hardi is primed with a latex product and I will be using latex paint. Are there latex primers that stop rust? I don't know if I could use an oil based primer over the latex primer, then cover that with latex paint.

Maybe I don't even need to worry about it. If not, that would be great, but I wouldn't want a million little dots of rust to show up a year from now. Thanks for any advice.
 

scott.cr

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My folks did their house with pressboard siding about 20 years ago using common nails, painted with latex paint (airless sprayer) and it's never had problems. Ever.

That's in California though. We have had a number of heavy rain storms since then, plus a fair bit of time where one of the lawn sprinklers was overspraying and soaking the house.

Your Hardi product is probably a LOT better than the pressboard siding we used, so I think you won't have anything to worry about.
 

BIGIRON

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I really like the cement siding. Probably in Oregon, you'll have moisture and potential rust spots. I'd buy a couple of spray cans of Kilz (sealer/primer -- good stuff) and spot the nails. Or, if you've got a lot of nails, you might just want to buy a quart or gallon and spot them by hand. If you're going to use latex paint, I'd use the latex based Kilz, not the oil based. And the latex is way easier to use and clean up.

edit - just re-read your post. Nails every 4 to 6 inches? That's a lot of nails. I would probably just roll or spray a coat of Kilz over the entire job instead of trying to spot all the nails. It'll be a bit expensive, but then you'll have a really good paint job.

Also, anti-mildew additives are available to mix with your cover paint. I've used them and they seem to work. It's controversial, but a tablespoon of Malathion per gallon of paint is supposed to keep bugs away. I'd rather have the bugs than the insecticide.
 
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Sub_Umbra

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When I used to sell paint (in a former lifetime) the paint company's lab guys always said that primers harden so much after thirty days that they advised repriming before applying paint. With something like a pre-primed siding that may have sat hardening up for months (and months) in a warehouse it may be difficult to find a latex primer that can grab that surface and provide a proper 'tooth' for the finish coat to hang on to.

Yes, an oil based primer may be used over a hardened latex primer and often it will take an oil based primer to latch on to an over-hardened latex primer to provide a good base for a finish coat. A test of the particular oil based primer on a small spot of the pre-primed Hardi would be prudent.

Yes, latex paint can certainly prevent rust. Sometimes there is an oil film on new metal products (nails, gutters, etc) that may make it hard for paint to stick.
 

matrixshaman

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Best thing you can do is put a dab of silicone (paintable kind) on each nail head. Use those harbor freight cheap latex gloves and smash down the silicon with a finger. This method was required at one place I worked and it's how I did the house I built in CA. That way not even a driving rain can get moisture in under the panels. OTOH if you are going low budget I'd say just brush on extra exterior paint over the nail heads.
 

mspeterson

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Here's what I would do:

Make sure the new siding is clean and not covered in dirt/dust. Take a 3 to 1 mixture of mineral spirits and Boiled linseed oil, and using a cotton cloth, apply to all nailheads in a circular wiping motion. Its best to wear gloves, and to properly dispose of linseed oil rags (think spontaneous combustion). Next, using a 1 1/2" angled sash brush, coat all nailheads with a good quality oil based primer, being sure to fill any voids around the nail and to coat the flat on the nailhead. Next, after a day or two for drying, apply a coat of the same primer to all of the new siding. A few more days to dry, and complete with two coats of finish paint, latex is o.k. (if you must!) :shakehead:poke::grin2:

Just my .03!

+1, Sub_Umbra is spot on!!!:twothumbs

BTW, stainless steel fasteners rock!!!:green::rock:
 

BB

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I would use something else besides "paintable silicon caulk"... As it rarely takes paint that well unless it is weathered.


-Bill
 
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