Go Back  DoItYourself.com Community Forums > Exterior Improvement Center > Exterior Paneling and All Exterior Sidings
Reload this Page >

Can I Stucco Over a Painted Exterior Wall? Correcting a Botched Job...

Can I Stucco Over a Painted Exterior Wall? Correcting a Botched Job...


  #1  
Old 06-19-12, 07:30 PM
L
Member
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 31
Received 0 Votes on 0 Posts
Can I Stucco Over a Painted Exterior Wall? Correcting a Botched Job...

Hello Everyone,

I live in Florida and have to fix one long exterior wall of my house. This wall was part of an addition to the home before I purchased it. The previous owner explained that the "contractor" sort of half a%$#!@ed the job. It seems that they used cement board and painted over it with elastomeric paint. They did not stucco over the cement board, just applied 4 or 5 coats of this paint.

It is hurricane season down here, and I am looking to reinforce this wall. I was considering attaching that wire lathe to the wall and stuccoing. Is it okay to do this over paint? Also, not sure the best way to attach the lathe. You can actually see where the studs are on the wall because it was never stucco'd, so I was considering nailing the lathe where I saw the studs.

Any suggestions on whether this is a viable plan? Or have any better ideas to reinforce this wall? I understand that this elastomeric paint has rubber qualities that will help in case of impact; however, I do not feel comfortable going into hurricane season with a wall that is basically studs and cement board.

Thanks!
Cara
 
  #2  
Old 07-13-12, 09:21 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
How is it that nobody answered her question? I just saw the post now. What's behind the cement board? Is it cement block or just wood?
 
  #3  
Old 07-14-12, 04:04 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,082
Received 398 Votes on 354 Posts
This is the first I've seen the post too but I was on vacation that week

I've painted a lot of houses in fla [but not in the last 21 yrs] and the typical construction was either block or wood frame with plywood and lath/stucco. I would hope that there is plywood behind the cement board because I doubt cement board by itself would have much support.

I've painted a few houses where they stucco'd painted block and the mason just applied a coat of some type of bonding agent. I don't know how well it held up long term.... and if they did in fact apply 4-5 coats of elastomeric - I wouldn't trust applying stucco directly to it. I suspect the best fix would be to nail up lath over the painted cement board and then stucco. If this builds out the stucco too far you might want to consider re stuccoing the entire wall.
 
  #4  
Old 07-14-12, 09:57 AM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,957
Received 16 Votes on 14 Posts
I don't know if I would skip a moisture resistant underlayment given there is elastomeric or not. One can certainly lath with self furring lath either woven wire lath or expanded metal lath. Hold the lath with galvanized roofing nails into the studs. 1" penetration into the stud should be enough; so if the cement board is 1/2" use 1 1/2" or longer nails. I don't have any empirical evidence for this but I think 16 or 17 ga.woven wire lath installed in as long pieces as possible will be better reinforcement against wind than sheets of metal lath Three coats of Portland cement plaster to about 3/4" thickness is the norm.

Bonding agent works. Only thing is it is only as good as what it is applied to. I would not trust 5 coats of elastomeric to stay bonded for the long term. When it lets loose the stucco will come with it.
 
  #5  
Old 07-14-12, 12:25 PM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,082
Received 398 Votes on 354 Posts
Even if the elastomeric stays put it is a somewhat flexable coating that IMO wouldn't be a good substrate for stucco.
 
  #6  
Old 07-15-12, 04:27 PM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,957
Received 16 Votes on 14 Posts
To be clear, if you use lath or woven wire that is acceptable IF you can attach the lath sufficiently to whatever is there, studs in this case. There is plenty of stucco in Florida. Someone around there can tell you what is known to work there.
 
  #7  
Old 07-16-12, 04:59 AM
L
Member
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 31
Received 0 Votes on 0 Posts
Thanks everyone, I really appreciate the information.

They installed this black cloth between the cement board and the frame. That is the only moisture barrier there was. I had to cement the bottem of the wall with a leak stop cement product.

The wire lathe attached to the studs seems the way to go; however, I am concerned now that the cement board and stucco is not strong enough after some of your comments.

There's no plywood behind the cement board, should there have been plywood behind it? Is is feasable to put plywood over what's there now? Then stucco over the plywood?
 
  #8  
Old 07-16-12, 05:09 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,082
Received 398 Votes on 354 Posts
Cement board by itself won't be strong enough
You should be able to install plywood over the cement board. You'd then tack up tar paper followed by lath and stucco [2-3 coats] That's how the wood frame stucco houses I've painted in fla were done [except no cement board]

Will the extra plywood and stucco interfere with any windows/doors?
 
  #9  
Old 07-16-12, 05:31 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
If it weren't so costly, I would like to see that wall rebuilt completely, maybe with cement block. Other than that, Marksr's idea should work.
 
  #10  
Old 07-16-12, 05:42 AM
L
Member
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 31
Received 0 Votes on 0 Posts
Actually, there are no windows along the wall and just one door. It would be possible to do what you are describing. It sounds like that would certainly fix the problem. Any particular plywood you would use?
 
  #11  
Old 07-16-12, 05:45 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 48,082
Received 398 Votes on 354 Posts
I would think 1/2" plywood would be ok but I'm a painter not a builder or stucco guy
You might check with your local building inspector to see what they expect you to use.
 
  #12  
Old 07-16-12, 09:18 AM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,957
Received 16 Votes on 14 Posts
Time was in California almost all walls were stuccoed over open framing. The walls were erected fire block installed half way up and diagonal wind bracing let in and then the paper then the woven wire lath and stucco. Now days we use paper backed lath. There are millions of acres of this kind of construction. You have the added advantage of the cement board for backer. Now I am pretty sure that cement board does not have the shear strength of plywood but the wire and cement plaster should have plenty of strength. You need to balance the ration of additional strength to additional cost. If you add plywood use long enough nails and use long enough nails for the wire.
Now there is an added consideration when you add plywood and that is the bottom of the plywood has a raw edge. There are a couple solutions. One is a piece of metal flashing turned to the foundation to cover the raw edge then the stucco weep screed and so on. Another is to carry the paper and wire under that edge and put on a corner bead and then stucco that little bottom. People don't like to do that kind of squat work. Or leave the plywood up a little and carry the paper down onto the foundation or slab and the wire below that and stucco right down into the ground. This used to be done a lot but it is an invitation to termites.

Seems like nothing is as simple as we wish. Talk to the building officials. They can tell you what it supposed to work.

What are the dimensions of the wall?
Is it tied to other walls?

Do you intend to try to stucco this wall yourself? It is not rocket science but it is strenuous work and not especially amateur friendly but fairly easy to pick up once you get toughened in to it; about the time you are finished.

BTW it is lath not lathe He who laths last laths best.
 
  #13  
Old 07-16-12, 09:43 AM
L
Member
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 31
Received 0 Votes on 0 Posts
Thank you marksr and tightcoat. And thank you for the spelling correction...

It's a pretty long wall, about 30 feet. It runs parallel right into an existing cement block wall on one side, then meets another cement block wall at a 90 degree angle on the other side. I plan to do it myself, and it would certainly be a lot of work.

The reason I would consider the plywood is because we get hurricanes here in Florida. Where the wall is, is not particularly vulnerable, but it may be a weakness when I try to resell the house.
 
  #14  
Old 07-16-12, 09:50 AM
S
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,630
Received 98 Votes on 86 Posts
It sounds like you're not going to be satisfied without the plywood so go ahead and do that; it's not a bad idea, just may not be necessary.
 
  #15  
Old 07-16-12, 10:18 AM
T
Member
Join Date: Jul 2003
Location: California
Posts: 1,957
Received 16 Votes on 14 Posts
Are you more concerned with flying debris hitting the wall and making a hole in it? Cement board, plywood and stucco will be very strong.
Are you concerned with the whole wall blowing in? I think you need to look at how the roof is attached and how the wall is tied into the block walls. I am not sure anything you are contemplating will keep the whole wall from blowing in unless it is tied into the blocks very well.

Another consideration: is the wall now flush with the block wall? If so you need to terminate the stucco with some kind of stop. You can't neatly stop stuccoing unless you have something to stop against. There are special trim pieces to do this.

But if the wall is flush now, think about carrying the wire over onto the block a few feet then stopping. It might crack at the joint, it might not if you put paper over the joint to allow a little movement behind the paper. Use masonry nails or concrete screws to hold the wire to the block.

This is what I mean by a stop: AMICO Metal Lath and Vinyl Bead Building Products > Casing Beads

You might also want to put a control joint where the plywood and block meet if they will be flush. AMICO Metal Lath and Vinyl Bead Building Products > Expansion / Control Joint

If the two planes will be offset you might have to improvise. Or simply bend or taper the stucco.

This is the weep screed I mentioned above. AMICO Metal Lath and Vinyl Bead Building Products > Foundation Weep Screed

You also might consider these pieces in vinyl rather than galvanized metal.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: