# Masonite Repair/Repaint



## chellums75 (Nov 22, 2012)

I need some advice! Here is the scenario:

I have a customer who has Masonite siding. It is solid, not rotten or warped. It has a lot of surface damage (cracks and peeling). The damage is superficial although it does go to the actual fiber once scraped and sanded. I have scraped it and sanded it to a "smooth" finish. A lot of the brown fiber is showing but again, its fairly smooth. I need to apply some type of spackle to make sure it is ultra smooth (customer insists). I have used some SW exterior spackle and painted a sample spot and it looks great. I have probably 700 sf to spackle and sand. My question is....will exterior spackle hold up if I prime and 1 or 2 coat? To add to the confusion..the customer has several gallons of oil based primer on hand and Behr Premium flat exterior. I plan on using the Behr paint for sure but can I use the oil primer or should I use something else? Shall I prime, spackle, then prime and finally paint? Can someone point me in the right direction who has experience in this? Obviously my concern is longevity but I don't want to go overboard if I dont have to! Thank you!!!


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## Gough (Nov 24, 2010)

In our experience, anything, up to and including using marine epoxy binders and fillers, is merely buying a little time. These days, we generally only propose one solution: HardiPlank. We had one client this summer who didn't want to go that route, so we just replaced a few hundred square feet of the damaged siding with new hardboard siding. We'll replace it with Hardi next time.


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## Damon T (Nov 22, 2008)

Most exterior spackles specifically say "not to be used as skim coat". You could try knife grade elastomeric compound, BM has it. Basically caulk in a tub. I would use PPG permanuzer plus for primer. Similar results as epoxy hardener but easier and more economical to work with. That being said I agree with Gough that the best route is replace with hardi or similar rot-proof paneling or siding depending on profile.


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## daren (Jul 5, 2008)

If I ever find the guy that invented masonite I'm going to give him a big ol wet kiss. That crap has made me a ton of money.

No matter what you do it's going to fail when the rain comes.


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## TJ Paint (Jun 18, 2009)

Replace the bad stuff.


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## Gough (Nov 24, 2010)

daren said:


> If I ever find the guy that invented masonite I'm going to give him a big ol wet kiss. That crap has made me a ton of money.
> 
> No matter what you do it's going to fail when the rain comes.


For the last 10 years or so, we've probably averaged one house per year where we've replaced the hardboard siding with Hardi. We have two booked for 2013.


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## chellums75 (Nov 22, 2012)

I appreciate the input, guys. Replacement is not an option right now. I'm going to warranty it for 5 years and the customer realizes that the siding will need replaced sometime. Biggest focus was knowing what type of material I could spread on that is sandable where I can seal the hell out of it and get a solid 5 years or more.


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## caulktheline (Feb 10, 2011)

So you are going to do a patch on masonite, you know it's gonna fail, and you still want to put a five year warranty on it?


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## daren (Jul 5, 2008)

Don't give her a warranty. It's going to fail in 5 months or less. It will be a constant headache for you if you do.


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## mudbone (Dec 26, 2011)

daren said:


> If I ever find the guy that invented masonite I'm going to give him a big ol wet kiss. That crap has made me a ton of money.
> 
> No matter what you do it's going to fail when the rain comes.


A big ol wet kiss?- dare you daren.


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## Gough (Nov 24, 2010)

daren said:


> Don't give her a warranty. It's going to fail in 5 months or less. It will be a constant headache for you if you do.


We've gotten 5 years or more using marine epoxy to stabilize the damaged areas and filling with epoxy putty.


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## Damon T (Nov 22, 2008)

I like to tell people right up front "I can pretty much guarantee that this house will bubble again if we don't take it all down to bare wood". I don't like taking houses down to bare wood anymore, though premier painter has me intrigued by his approach, but I always try to let people know when there could be a problem, and I don't warrantee issues like that. We warrant our paint will adhere to the surface it is applied to for X amount of years, but not the underlying layers. At least on older homes. On post 1978 houses it's rarely a problem, just not enough coats on the house yet to typically be a problem.


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## RH (Sep 7, 2010)

Masonite lasts a lot longer if you take the time to prime the back and butt ends after cutting the pieces.


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## chellums75 (Nov 22, 2012)

*Masonite Warranty*

Well, I definitely don't want to warranty something that will fail. I was just hoping to find the best compound that I could skim coat, have that sandwiched between 2 layers of primer then a coat of paint.


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## premierpainter (Apr 17, 2007)

I found that elastomeric spackle is the best bet. I would prime first to stiffen the fibers then skim it with elasto. Careful because it is not sand able. Smooth it out as best as you can and then you can use an 80 grit vibrating sander to smooth it out more. It is avail at Home Depot. Then prime and paint as you normally would. 5 years is risky considering your spackling.  Ready patch is our second go to spackle when in a bind.


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