IMPORTANT !! If you cover a newly finished wall with plastic to protect against rain, don't let the plastic touch the wall. Where the plastic touches the wall will leave a big white splotch.
I was very happy to find your site and hope you are able to help me with this question. We covered the side and back of the house with stucco 30 years ago. The finish wore thin and am having it recoated with a Portland, Black, Red, Brown cement, lime, sand, Acryl 60 mix. Before this mix is placed on the walls, the mason brushed on Plaster Weld, to help ensure that the new mix adheres to the old job. Tuesday, the last section was troweled on to the walls there was only about 4 hours before heavy rains poured down.
I covered the walls with plastic, but water still ran down from the roof and was able to soak the walls. I took off the plastic last night and I looked at the wall this morning. I was able to see a couple of cracks and it seems that the lime surfaced causing a white coating over the area or portions of the area just done. Should I be concerned about this section not adhering, future cracks, etc? The color also seems to be lighter than the other sections. Is this due to the rain or the white bleed through or something else?
The contractor said he is going to wash down the entire job after he is done with acid, grind out any cracks and fill them with the same mix. Because of the rain is this section weaker? The back portion of the house came up with a few hairline cracks. The day this section was done it was in the 80's. The answer to these questions and any other advice is greatly appreciated. If you need more information let me know.
Don't ever let cover the newly finished wall with plastic and let the plastic touch the wall !! The wall will splotch with big white splotches. Instead, if rain is coming, make a tent.
Usually, when rain is coming, we nail the plastic to the facsia board, and drape the plastic over the top of the scaffold. If you have a garden wall, for example, you can use the top of the wall like a tent pole and stretch the plastic out and weight it down so it doesn't touch the wall.
The plastic traps water against the wall, washing out the color of the stucco finish.
It is good you used acryl 60 in the mortar. It should be mixed half and half with water. Acryl 60 is an acrylic bonding admixture. There was no need to paint the wall with weld crete.
The weld crete did a lot of harm to the wall, also. When you paint the wall with weld crete, the wall is sealed so there is no suction. Suction is when water is absorbed rapidly from the base coat, which sets up the mortar and gives it strength. When you put on a thin coat of mortar on the wall over weld crete, the mortar never sets up all the way. You'll notice the finish is weak and scratches easily. In warm weather, the mortar will dry out and turn to powder. The color will always be lighter. This is why you had a lot of shrinkage cracks.
What to do to rescue the wall ? You want to scrape off what ever comes off easily and recoat the whole wall. You want to use 50 % acryl 60 and 50 % water instead of pure water. It is a good idea to put extra color in the new finish, we go 25 % more color.
This is a great question. It is something I learned the hard way.