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wetech 05-13-2013 01:47 PM

Clapboard repainting - 2 coats of primer?
 
I'm getting quotes to repaint my late 1960's house with clapboard siding. I don't think it's ever been stripped, and the last paint job done by prior owner 4 years ago is peeling horribly. The last job included scraping the loose paint, spot prime, and a finish coat. Most of the house is now cracked / peeling / bubbling off.

We're going to have the house stripped to bare wood and repainted. One quote I received proposed 2 coats of tinted oil primer and 1 coat of latex finish. Is there any advantage to doing this versus 1 coat of tinted primer and 2 coats of finish? To me, 1 coat of primer and 2 finish coats makes more sense. The contractor comes highly recommended and has done a lot of work in the area.

Brushjockey 05-13-2013 04:41 PM

I agree- ask him why he thinks this is better.

chrisn 05-13-2013 04:55 PM

I am also curious.:huh:

ric knows paint 05-13-2013 06:22 PM

Quote:

Originally Posted by wetech (Post 1178421)
I'm getting quotes to repaint my late 1960's house with clapboard siding. I don't think it's ever been stripped, and the last paint job done by prior owner 4 years ago is peeling horribly. The last job included scraping the loose paint, spot prime, and a finish coat. Most of the house is now cracked / peeling / bubbling off.

We're going to have the house stripped to bare wood and repainted. One quote I received proposed 2 coats of tinted oil primer and 1 coat of latex finish. Is there any advantage to doing this versus 1 coat of tinted primer and 2 coats of finish? To me, 1 coat of primer and 2 finish coats makes more sense. The contractor comes highly recommended and has done a lot of work in the area.

It'd be nice to know the type of wood that was used for your clapboard siding. Built in the 60's, I'm gonna guess it's redwood partly 'cause that was a common wood used back then, and partly due to how you've described the paint has held up.

There were actually a couple of unique, but fairly common, practices when painting redwood back in the day...#1 was to back-prime the boards prior to installation with either an oil based primer, or more commonly an oil based aluminum paint. Back priming help to ebb the flow of moisture that is able to pass through redwood...and #2 was to apply 2 coats of an oil based exterior wood undercoater.

The reason for this was more apropos then than it is today. Oil based exterior wood undercoaters from the 60's (and before) were extremely slow-drying, linseed oil laden products. Because they were so slow drying (often times 48 - 72 hours between coats), a board as porous as redwood would absorb most all of the first coat to almost the appearance of a whitish stain. The second coat of undercoater would then penetrate only partially, and only partially would lay on the surface too. It was the build and constricting features of linseed oil products that would stem the flow of moisture that'd pass through redwood.

Unfortunately, overtime these primers (primarily the second coat) would turn brittle over the years and no longer have the flexibility necessary to stay attached to the board, thus the "peeling horribly".

To answer your q, there's nothing really wrong with the old-school system your highly recommended contractor has suggested, although there are better, longer lasting systems and procedures.

Proper surface preparation will absolutely be the key to a successful paint job...which is true of all paint jobs but especially true when painting redwood. When stripping (how?), make sure the film that bridges the boards at the lap has been broken or removed. After the stripping has been done and you've run a stiff putty knife between the boards, it wouldn't hurt to install a few siding wedges between the boards allow for better vapor transmission from the home to the outside. it also may not hurt to install a few 1" or 1.25" ventilating louvers, again for better transmission - These louvers and wedges are very inexpensive and are paint savers for redwood siding...your contractor should know where to get these and how to install properly.

Once your prep is done you'll actually be better to prime with 1 coat of a high quality acrylic coating - followed by 2 coats of acrylic finish (don't tint the primer, there is no advantage to doing so with a 2 coat finish system). Oil base products are no longer the non-drying nightmare of old, so not as much of the coating penetrates (as deeply) into the board. But, overall acrylics have better adhesion (I know I'm gonna get a lot of flak on that one...but I'm right), acrylics have better flexibility than oils/alkyds, better color & gloss retention, better mildew resistance, much much much better vapor transmission, etc. etc. etc. Make sure what you choose though is top quality and, my recommendation, is to talk to your local independent paint dealer for his or her advice and counsel. Good luck.

RWolff 05-13-2013 09:33 PM

Quote:

One quote I received proposed 2 coats of tinted oil primer and 1 coat of latex finish. Is there any advantage to doing this versus 1 coat of tinted primer and 2 coats of finish? T
Primer is cheaper than paint, thus it stands to reason that out of 3 applications, if 2 of them are cheaper primer instead of more expensive finish paint, the money saved goes in the contractor's profit ledger line.
I've seen very few to no paints that cover well with ONE coat despite the claims on the label, you want one good full application of primer and 2 coats of PAINT. More primer over primer isn't going to do anything, you want PAINT not primer.
When I bought my 1930 farmhouse it hadnt been painted in so long that the clapboard where the paint peeled turned grey, here's the back of the house in 1997:

http://i.imgur.com/TrPi4iF.png'


I scraped all the paint off that would come off but not all of the paint to bare wood, I put on one coat of primer and 2 coats of paint, I used a 4" brush because I wanted to apply paint to the wood in a good thickness, spraying on thinned out paint with a sprayer is the garbage way to paint and I don't do it that way. The paint easily lasted a good 13 years, I repainted it last summer as some areas were peeling a bit- some of the old tight paint left in 1997 was what was starting to give out, none of the paint I applied was peeling off the white previous paint below, but 13 years I feel was a good lifespan.

http://i.imgur.com/sZ0jyGJl.jpg

wetech 05-13-2013 10:14 PM

Quote:

Originally Posted by ric knows paint

It'd be nice to know the type of wood that was used for your clapboard siding. Built in the 60's, I'm gonna guess it's redwood partly 'cause that was a common wood used back then, and partly due to how you've described the paint has held up.

There were actually a couple of unique, but fairly common, practices when painting redwood back in the day...#1 was to back-prime the boards prior to installation with either an oil based primer, or more commonly an oil based aluminum paint. Back priming help to ebb the flow of moisture that is able to pass through redwood...and #2 was to apply 2 coats of an oil based exterior wood undercoater.

The reason for this was more apropos then than it is today. Oil based exterior wood undercoaters from the 60's (and before) were extremely slow-drying, linseed oil laden products. Because they were so slow drying (often times 48 - 72 hours between coats), a board as porous as redwood would absorb most all of the first coat to almost the appearance of a whitish stain. The second coat of undercoater would then penetrate only partially, and only partially would lay on the surface too. It was the build and constricting features of linseed oil products that would stem the flow of moisture that'd pass through redwood.

Unfortunately, overtime these primers (primarily the second coat) would turn brittle over the years and no longer have the flexibility necessary to stay attached to the board, thus the "peeling horribly".

To answer your q, there's nothing really wrong with the old-school system your highly recommended contractor has suggested, although there are better, longer lasting systems and procedures.

Proper surface preparation will absolutely be the key to a successful paint job...which is true of all paint jobs but especially true when painting redwood. When stripping (how?), make sure the film that bridges the boards at the lap has been broken or removed. After the stripping has been done and you've run a stiff putty knife between the boards, it wouldn't hurt to install a few siding wedges between the boards allow for better vapor transmission from the home to the outside. it also may not hurt to install a few 1" or 1.25" ventilating louvers, again for better transmission - These louvers and wedges are very inexpensive and are paint savers for redwood siding...your contractor should know where to get these and how to install properly.

Once your prep is done you'll actually be better to prime with 1 coat of a high quality acrylic coating - followed by 2 coats of acrylic finish (don't tint the primer, there is no advantage to doing so with a 2 coat finish system). Oil base products are no longer the non-drying nightmare of old, so not as much of the coating penetrates (as deeply) into the board. But, overall acrylics have better adhesion (I know I'm gonna get a lot of flak on that one...but I'm right), acrylics have better flexibility than oils/alkyds, better color & gloss retention, better mildew resistance, much much much better vapor transmission, etc. etc. etc. Make sure what you choose though is top quality and, my recommendation, is to talk to your local independent paint dealer for his or her advice and counsel. Good luck.

Thanks for the advice. Not sure of the siding is cedar or redwood, thought was cedar. Stripping will be accomplished with a disc sander, with a second pass of fine grit to smooth out the texture left by the first pass.

I was going to ask the contractor about siding wedges as well. We currently have some fairly severe moisture problems in the house. The siding is pretty well sealed shut with 5-6 coats of paint. Hoping that we can alleviate some if these issues by restoring some of the permeability to the walls.

chrisn 05-14-2013 04:27 AM

here is what you need

http://www.wedgevent.com/

chrisn 05-14-2013 04:30 AM

Quote:

Originally Posted by ric knows paint (Post 1178666)
It'd be nice to know the type of wood that was used for your clapboard siding. Built in the 60's, I'm gonna guess it's redwood partly 'cause that was a common wood used back then, and partly due to how you've described the paint has held up.

There were actually a couple of unique, but fairly common, practices when painting redwood back in the day...#1 was to back-prime the boards prior to installation with either an oil based primer, or more commonly an oil based aluminum paint. Back priming help to ebb the flow of moisture that is able to pass through redwood...and #2 was to apply 2 coats of an oil based exterior wood undercoater.

The reason for this was more apropos then than it is today. Oil based exterior wood undercoaters from the 60's (and before) were extremely slow-drying, linseed oil laden products. Because they were so slow drying (often times 48 - 72 hours between coats), a board as porous as redwood would absorb most all of the first coat to almost the appearance of a whitish stain. The second coat of undercoater would then penetrate only partially, and only partially would lay on the surface too. It was the build and constricting features of linseed oil products that would stem the flow of moisture that'd pass through redwood.

Unfortunately, overtime these primers (primarily the second coat) would turn brittle over the years and no longer have the flexibility necessary to stay attached to the board, thus the "peeling horribly".

To answer your q, there's nothing really wrong with the old-school system your highly recommended contractor has suggested, although there are better, longer lasting systems and procedures.

Proper surface preparation will absolutely be the key to a successful paint job...which is true of all paint jobs but especially true when painting redwood. When stripping (how?), make sure the film that bridges the boards at the lap has been broken or removed. After the stripping has been done and you've run a stiff putty knife between the boards, it wouldn't hurt to install a few siding wedges between the boards allow for better vapor transmission from the home to the outside. it also may not hurt to install a few 1" or 1.25" ventilating louvers, again for better transmission - These louvers and wedges are very inexpensive and are paint savers for redwood siding...your contractor should know where to get these and how to install properly.

Once your prep is done you'll actually be better to prime with 1 coat of a high quality acrylic coating - followed by 2 coats of acrylic finish (don't tint the primer, there is no advantage to doing so with a 2 coat finish system). Oil base products are no longer the non-drying nightmare of old, so not as much of the coating penetrates (as deeply) into the board. But, overall acrylics have better adhesion (I know I'm gonna get a lot of flak on that one...but I'm right), acrylics have better flexibility than oils/alkyds, better color & gloss retention, better mildew resistance, much much much better vapor transmission, etc. etc. etc. Make sure what you choose though is top quality and, my recommendation, is to talk to your local independent paint dealer for his or her advice and counsel. Good luck.


I am assuming you mean a primer? Wish I had known this a couple years ago when I stripped the redwood on my house.:furious:

jsheridan 05-14-2013 04:55 AM

Quote:

Originally Posted by chrisn (Post 1178944)
I am assuming you mean a primer? Wish I had known this a couple years ago when I stripped the redwood on my house.:furious:

You should have come here and asked. :laughing:

jsheridan 05-14-2013 04:59 AM

I was taught to apply two coats of long oil on badly weathered wood, wood that's been exposed to the sun for a long period. For the same reason that Ric states.

ric knows paint 05-14-2013 05:02 AM

Quote:

Originally Posted by chrisn (Post 1178944)
I am assuming you mean a primer? Wish I had known this a couple years ago when I stripped the redwood on my house.:furious:

oops...yup, I meant primer. Not to be confused with the "paint and primer in one", nor the "no surface prep, paint & primer & stain block with baldness and acne cure in one"...

Good vid and info on the siding wedge, btw.

Matthewt1970 05-14-2013 11:07 AM

Quote:

Originally Posted by ric knows paint (Post 1178666)
Once your prep is done you'll actually be better to prime with 1 coat of a high quality acrylic coating - followed by 2 coats of acrylic finish (don't tint the primer, there is no advantage to doing so with a 2 coat finish system). Oil base products are no longer the non-drying nightmare of old, so not as much of the coating penetrates (as deeply) into the board. But, overall acrylics have better adhesion (I know I'm gonna get a lot of flak on that one...but I'm right), acrylics have better flexibility than oils/alkyds, better color & gloss retention, better mildew resistance, much much much better vapor transmission, etc. etc. etc. Make sure what you choose though is top quality and, my recommendation, is to talk to your local independent paint dealer for his or her advice and counsel. Good luck.

Well, you are gonna get flack because you are not right. If you are worried about it drying to quickly you can get slow drying oil. Oil primers still penetrate better and have better adhesion. Yes latex has better flexibility but oil primer doesn't form the type of film that a paint will that needs the flexibility. Plus look at a dent in a car. You won't get a much more brittle paint than what is on a car and that paint will bend/flex/expand right into the dents. You can also look up the maximum expansion of wood by type on the internet and you will find that a 12 foot piece of wood has a maximum expansion rate of less than a 1/2". Oil base paint can expand well beyond that. Lets not also forget that one of the main purposes for oil primer is wood tanin blocking which latex primer absolutely sucks at.

*EDIT* Go talk with some people who used to paint all oil if you can. Keep in mind latex paint wasn't even invented till the 40's and before that houses didn't rot away from not being able to breathe and the paint didn't peel off from not being able to expand.

ric knows paint 05-14-2013 03:20 PM

Quote:

Originally Posted by Matthewt1970 (Post 1179183)
Well, you are gonna get flack because you are not right. If you are worried about it drying to quickly you can get slow drying oil. Oil primers still penetrate better and have better adhesion. Yes latex has better flexibility but oil primer doesn't form the type of film that a paint will that needs the flexibility. Plus look at a dent in a car. You won't get a much more brittle paint than what is on a car and that paint will bend/flex/expand right into the dents. You can also look up the maximum expansion of wood by type on the internet and you will find that a 12 foot piece of wood has a maximum expansion rate of less than a 1/2". Oil base paint can expand well beyond that. Lets not also forget that one of the main purposes for oil primer is wood tanin blocking which latex primer absolutely sucks at.

*EDIT* Go talk with some people who used to paint all oil if you can. Keep in mind latex paint wasn't even invented till the 40's and before that houses didn't rot away from not being able to breathe and the paint didn't peel off from not being able to expand.

Hmm...where to begin? If I'm suggesting acrylic, why would I be concerned that it'd dry too quickly? 'Specially when I said the oils of yesterday dried too slowly which can be part of the problem...and while it's true that acrylics have better flexibility, that really has little to do with why acrylics work better as a primer for redwood (in this scenario). I'm aware of how much a board will expand, I'm also very much aware of the flexibility of both oil and alkyd coatings. If you're gonna correct me, you need to listen to every thing I've said.

And as long as we're correcting each other, this is the second time you've remarked on the flexibility of the auto paint finish, and correct me if I'm wrong, but you kinda are implying that auto paints are oils? alkyds? Care to guess what the auto industry is actually using on cars? (Hint: it ain't oils or alkyds).

I s'pose we could argue all day about whether oils or acrylics have better adhesive properties, but we won't convince each other of anything - so you stick with your romantic notions about oils of yore and I'll continue with my beliefs based on science, testing, history and the general consensus of virtually every paint manufacturer in the known universe.

So, speaking of "latexes"...I know when they came into existence - I know of the original resins used to create those very early product offerings (shoot, I even know the makeup of water-based paints used by settlers in colonial days)..(not that that has any more bearing to this conversation than does statements about when "latex" paints came into existence). I know the advantages of "latex" over oil, and (believe it or not) vice versa. I also know the trap one falls into when one insists on using terms like "oil" and "alkyd" and "acrylic" and "latex" as though they are synonymous terms - they're not.

...and as much as I enjoy talking to true craftsmen of this trade about old time systems and products (I do so on a pretty regular basis), don't mistake me for some young pup in this industry with only 20 years or so experience, all from the application side...I was makin' paint when many of these craftsmen were in their prime.

Matthewt1970 05-14-2013 10:16 PM

Quote:

Originally Posted by ric knows paint (Post 1179397)
Hmm...where to begin? If I'm suggesting acrylic, why would I be concerned that it'd dry too quickly? 'Specially when I said the oils of yesterday dried too slowly which can be part of the problem...and while it's true that acrylics have better flexibility, that really has little to do with why acrylics work better as a primer for redwood (in this scenario). I'm aware of how much a board will expand, I'm also very much aware of the flexibility of both oil and alkyd coatings. If you're gonna correct me, you need to listen to every thing I've said.

And as long as we're correcting each other, this is the second time you've remarked on the flexibility of the auto paint finish, and correct me if I'm wrong, but you kinda are implying that auto paints are oils? alkyds? Care to guess what the auto industry is actually using on cars? (Hint: it ain't oils or alkyds).

I s'pose we could argue all day about whether oils or acrylics have better adhesive properties, but we won't convince each other of anything - so you stick with your romantic notions about oils of yore and I'll continue with my beliefs based on science, testing, history and the general consensus of virtually every paint manufacturer in the known universe.

So, speaking of "latexes"...I know when they came into existence - I know of the original resins used to create those very early product offerings (shoot, I even know the makeup of water-based paints used by settlers in colonial days)..(not that that has any more bearing to this conversation than does statements about when "latex" paints came into existence). I know the advantages of "latex" over oil, and (believe it or not) vice versa. I also know the trap one falls into when one insists on using terms like "oil" and "alkyd" and "acrylic" and "latex" as though they are synonymous terms - they're not.

...and as much as I enjoy talking to true craftsmen of this trade about old time systems and products (I do so on a pretty regular basis), don't mistake me for some young pup in this industry with only 20 years or so experience, all from the application side...I was makin' paint when many of these craftsmen were in their prime.

Well by all keep recommending painters use latex primer on exterior raw wood. You are almost guaranteed a repeat customer in 3 years or at the very least a different company gets the work of coming back and fixing it.

ric knows paint 05-15-2013 06:02 AM

Quote:

Originally Posted by Matthewt1970 (Post 1179642)
Well by all keep recommending painters use latex primer on exterior raw wood. You are almost guaranteed a repeat customer in 3 years or at the very least a different company gets the work of coming back and fixing it.

As I've said before, if you work a system that works for you, change nothing - I don't care. But you really need to understand that times and technologies are a-changin' - You obviously don't keep up with the changes and advancements regarding the tools of your trade (and not only paint, but paintable surfaces as well), but yet you still seem hell bent on arguing with those of us that have...The statements I make regarding these "new" technologies are based on actual application, testing data, scientific structure and formulations from the best product engineers, chemists and manufacturers in the industry.

I recommend acrylic primers - when appropriate...and I recommend alkyd primers - when appropriate. Both have advantages and, equally opposite, disadvantages... and neither is the right primer in every situation. Your broad-brushed claims regarding "latex" primers are completely unfounded, so it's no surprise that many of your statements regarding "oil" primers (and their specific behaviors) are equally void of fact or basis other than what you believe they should be.


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