Rusted stucco weep screed

I inspected a home that is only 1 year old. Stucco weep screed is rusted in several areas around perimeter of home. Grade is good, no obvious reasons for galvanized metal to rust in such a short time. No sprinklers, fertilizers or stucco problems. Any suggestions? This was not a full inspection. Client called me out for exterior only. He is trying to get the builder to make repairs and they are balking.

Mary Ann,

Your picture shows several interesting things. Installation of screed section to the right blocks a weep hole and there is a gap between the screed and foundation. The left section has rusted out a portion of the screed.
Unfortunately without destructive evaluation of the wire mesh behind this area it is difficult to tell if all the rust is from the screed or if some is from the wire mesh. There is a small vertical crack in the stucco directly above the rusted area, relationship to rust unable to be determined by photo alone.

I would recommend evaluation by stucco professional. One year after build to reach this level of rust is unusual unless significant water intrusion and poor drainage has occurred. Also the weep to foundation needs to be sealed on section to right.

Any pics of the other areas?

Thanks Jeff. I agree that someone in the stucco industry needs to take a look at it. The builder is telling the owner that this is normal and they just need to do maintenance on screed. Wow. What is kind of unusual is the areas where the weep screed is about 1/8" of an inch away from stemwall, there is no rust. Just where it is flush against concrete stemwall. Could it be possible that there something in the concrete mix that could be causing this reaction? I’m stumped. I know what to call it out as, but I guess just for my own knowledge I would like to know the cause.

Mary Ann, Try over here>>>

Sign in to the message board, these guys know their stuff.

Looks to me like the paint got knocked off during installation and is is now rusting. Needs to be wire brushed and re painted.

What is above the spot? Do you have a full picture of the wall?

I do not have a picture of wall above. All stucco looks good though. Just minimal roof overhang, maybe a foot bumpout.

Damaged during installation. Repair or replace as necessary. (wire brush and a coat of paint)

My gut is saying that moisture is getting behind the stucco, particularly since the stucco is cracked in that area and the corrosion is pretty extensive. Water can get through small cracks, and in fact the cracks help pull water in through capillary effect. A moisture meter would help define a possible cause. But, no matter what the reason, it needs repair. Hopefully, a drainage plane was installed behind the stucco.

Stucco is not waterproof…

Good luck explaining that one BK. How about the “blocked” weep holes :wink:

Mr. Pope,

I was describing several observations found in the OP picture. Your :wink: and “blocked” make me wonder why you have included it in your comment.
If you feel that covering a weep hole is an appropriate installation practice I would like to see the reference please. All reference material and installation procedures I have ever read always state weep holes are not to be blocked.
I agree that one blocked hole is not an issue and as such did not do anything more than refer to it’s presence in the image.

This bead is now required by most building codes and by ASTM C1063 on all framed walls as part of a drainage system for exterior stucco applications. The 3½ inch nailing flange serves as a flashing when water resistant breathable building paper or paper backed lath is installed over the flange. The “V” stop is punched with holes primarily intended as keying mechanisms. These also offer minor moisture weeping capabilities. As stucco cures it will shrink slightly away from the “V” stop allowing moisture to flow down the building paper and exit down the sloped surface. Available in galvanized steel and zinc alloy (by special request) in 10 ft. lengths. Packaged 10 pcs. per bundle,100 bundles per pallet.

Painting and or caulking the little gap where the stucco shrinks back from the front edge of the weepscreed is a problem. The hole in the picture that is covered by overlapping of the screed is not an issue. There has to be moisture there for rust to be present, and once the end/edge is cut it is just raw metal no coating of any kind present.


It wasn’t meant to offend you Jeff. I apologise if I did.

As Carl pointed out. The “weep holes” don’t really do much with regard to the function of the weep screed.

Many people (IMHO) are overly concerned with minor and typical cracking in stucco systems, along with covering of the weep holes at the bottom of the weep screed.

I agree with Carl and BK that this rust is likely inconsequential. Clean it and move on.

Not a problem Jeff. (was a very late night)

ever wonder what’s right above this location…often seen below dryer vents or sillcocks

I don’t agree that the rust is inconsequential. If you look harder at the picture, you can see that the metal is corroded almost completely through. That kind of corrosion indicates that the problem could be chronic. In which case, other materials behind the area could be involved, including framing if the moisture barrier is missing or inadequate and depending on where the moisture is getting behind the stucco. Further, the moisture appears to be coming out behind the weep screed, which means that it could be behind the moisture barrier if it is present. The water could be coming from pretty much anywhere up the wall. I believe further investigation is definitely needed.

:shock: I wonder if they used the correct nails on the lath maybe some green horn used a couple of non galvanized nails.

On this I agree my gut wants to agree with Matthew, although a larger picture of the entire wall is needed.

It’s only a year old… if there’s no other obvious reason, one would need/want to determine if an underlying cause is present.

just .02