Stucco over stucco?

[IowaREguy]

Hello,

I am in the middle of a rehab project. On the exterior, I am planning on replacing/repairing/overlaying stucco.

One contractor's recommendation is to bust off the loose stucco, leaving the good stucco. Then cover the entire wall with a 1/4" hardiboard (shimming the areas where the old stucco was removed to make the surface level).... Then covering with a metal mesh. Then skim coat. Then the final coat.

The existing stucco is on wood lath.

It seems like a sound plan to me. My questions are:

- has anyone done this?

- Would leaving the old stucco leave too much weight?

It almost seems like it would be easier to remove the old stucco. Then install the hardiboard. Not because of the weight concern, but the effort of trying to screw into the stucco. That's a lot of pilot holes!!

[kurt]

Whether or not stripping the old stucco is "easier" is a mildly complex question hidden inside a simple word. Maybe.

The contractors advice is the basic quick and dirty patch. It'll look like shit unless he takes maximum care and then it will only look slightly less shitty.

What's the existing stucco substrate; wood or expanded metal lath? Sheathing? Is it the stuff with the canvas on 1x6? Framing methods, i.e., balloon or platform?

Describe what you're doing with the house, how much you want to spend, you wanna go *green* or not, where are you taking it long term, and the general standard of care you're expecting.

[IowaREguy]

The old stucco is on wood lath.

Budget is unfortunately low...

[kurt]

Low budget = contractor's method. Wood lath stucco was/is a mighty lousy way to do it. The one's I see are all series of patches. Termites. There's always some termite damage somewhere in the wood lath jobs.

[mjr6550]

If your budget is low, stay away from stucco. There is no cheap way to do it right (and few contractors can do it right). I suspect the method proposed will turn into a nightmare.

[StevenT]

If... I were to attempt what you have in mind, and IF... the stucco is over wood lath, I would handle that as if it were a wood substrate and apply 2 new layers of moisture barrier.

Perhaps the first would be a liquid applied, and then the second could be something like tar paper (etc). This would be to provide a drainage plane.

The idea is that is you don't want the building to leak, make it waterproof before you apply the new cladding.

[Marc]

If... I were to attempt what you have in mind, and IF... the stucco is over wood lath, I would handle that as if it were a wood substrate and apply 2 new layers of moisture barrier.

Perhaps the first would be a liquid applied, and then the second could be something like tar paper (etc). This would be to provide a drainage plane.

The idea is that is you don't want the building to leak, make it waterproof before you apply the new cladding.

I wonder if a water barrier at that point in a wall's cross-section is a good idea for a house situated in Iowa?

What do the winters get down to up there?

Marc

[IowaREguy]

Winters here can get rather cold....

What we have in mind, is OSB sheathing, 30# felt, metal lath, then stucco.... Probably going to have to redo the whole thing. Don't see another way around it.

[StevenT]

Winters here can get rather cold....

What we have in mind, is OSB sheathing, 30# felt, metal lath, then stucco.... Probably going to have to redo the whole thing. Don't see another way around it.

Wondering is good and promotes discussion. What do you think may go wrong?

@Iowa- Regardless of if you are going over or installing new, a double barrier is needed to promote drainage. I like a primary liquid barrier because nothing will get behind it (if installed/prepared correctly). I don't like OSB so much. Bear in mind the further you get away from the tree; the more damage/effect less water will cause.

[kurt]

If it's like every other wood lath stucco I see, stripping and starting over is the best idea. If u can find it in the budget, do it. Patching just begets more patching and it looks like crap.

The best way to do it is a whole new discussion.

[Scottpat]

Winters here can get rather cold....

What we have in mind, is OSB sheathing, 30# felt, metal lath, then stucco.... Probably going to have to redo the whole thing. Don't see another way around it.

I would stay away from the OSB. The Hardboard or similar product would be your best bet and would most likely provide the highest success rate and longevity. As Kurt said, it not going to look great no matter what is done unless you start with a clean slate. Patching is just patching, similar to putting lipstick on a pig!

[Jim Baird]

...wonder if op is an owner occupant or a flipper, who won't be around for consequences after unloading the mess.