This post has two videos (because I had too much footage) and a lot of good pics in the gallery.
The videos
The first video is about applying the scratch coat. This actually took most of the time because we spent a lot of time trying to make everything nice and smooth over the rough shotcrete and lath walls. After getting the wall the right shape, we would use a special tool to “scratch” the stucco so that the next layer would have nice ridges to grip on to. Here is that video.
The second video is for the brown coat. This is a smoother coat that we applied over the scratch coat. It was easier because most of the work to get the right shape was done with the previous layer, but it did have the challenge of getting a nice smooth finish, which was particularly tricky because we were not out there for enough hours at a time… Here is the video to explain.
The lessons learned
We really learned a lot of useful stuff while doing this project and it certainly can’t fit into the videos, but I’ll try to put some of it here….
I’ll come back and fill this in later (promises promises)
The Gallery
This is the part most of you wanted to see anyway… I try to tell a story with the captions.
Because the videos focus on the inside work, it is easy to forget that it was winter outside…
This will eventually be the guest room, but for now it has no roof and is essentially outside.
Here we are outside the north side, looking back toward the south thru the playroom apse door.
This is the north side of the house
This is actually the center of the house, but without a roof yet, it looks a lot like outside.
Here I am using the water sprayer to apply the scratch coat stucco.
We would mix our dry ingredients (sand, hydrated lime and portland) on a tarp.
In some spots we had to pack a lot of stucco in to fill the gaps between two layers of lath.
Some times the place got a bit messy…
We did a lot of mixing…
The skylights would freeze, but only in the section above the dirt level. Once we insulate them, this problem should go away.
Sherri playing with the dog while I mix
Sherri definitely did her fair share of stucco work
We took lots of pics like this before the stucco went up so we could remember where the electrical conduit and other hidden things were… Just in case.
Fresh scratch coat on the walls of the master bedroom.
Sherri checking out the camera. They often leave me these little shots to find when I am editing.
Mud dauber wasps had started building on our walls. We had to put a stop to that.
The entrances to the mud dauber wasp nests.
Lots of pics like this from the GoPro. Hard to decide which ones to throw away.
Working together
Working away in the hall and bedroom
Family time
The bedrooms were warm and humid, even though it was well below freezing outside in the middle of winter. We had no heat, but did occasionally wet the walls down with hot water.
This is a rough corner. Clearly the stucco was hard tooled with no interest in making a nice fillet. I would need to fill this with stucco instead.
The first step is to attach a board, then we pack it with stucco or mortar.
Here it is after packing with stucco…
Then we scratch it so it can hold the next layer better.
Then we can strip off the wood and stucco that section also.
Here it is after scratch coat in the fill section.
Looking toward a long evening of hard stucco work
At the end of every evening, we would need to head outside and wash out the tools.
The master bedroom with scratch coat.
The back end of the master bedroom, really the master bath, with scratch coat.
Another angle on the master bathroom scratch coat.
After we ran out of sand (those huge piles), we started buying pre-mixed stucco for $6 a bag. This was a pic of the delivery from Menards.
Another one of Sherri being silly for the camera when I am not around.
We got pretty good at ceilings during this project. Just a little slower than walls.
We tried the hard rubber float on this wall when it was still too soft and it pulled off some bits of the brown coat (so you could see the scratch coat). But I kind of liked it, so I put the date in and left it like that.
The OSB formed sections were pretty nice already with lots of good texture, so I just skipped the scratch step and applied the brown coat directly. It also went over the steel studs without a problem.
A birds eye view of the hall ceiling with fresh stucco on it.
The stucco in the foreground has been sponged. The stucco in the background is just troweled on.
Sherri Showing off her sponge finish (on the right side)
This is Davids bedroom, so we made sure he got some stucco time in.
On the floor, we mix one bag of portland, 1/3rd bag of hydrated lime and 25 gallons of sand. In the wheel barrow we add water and 1 qt of thinset to make it sticky.
Here you can see brown coat over scratch coat
Occationally, stucco falls down. This is how our faces look when it happens.
One of the bedrooms after the stucco cures and turns mostly white.
Master Bedroom with browncoat stucco patches. Each patch is one evening’s work.
Sherri also stuccoed the office, but I didn’t record any of it on video, so it didn’t make the timelapse movie.
While we were waiting for the shotcrete crew, we continued on some side jobs. One of which was insulating the skylight curbs and protecting them with stucco. Detail on our mix recipe, etc. later, but first, the video.
The Video
The Mix
Here, we used the scratch stucco recipe of
5 buckets (25 gallons) of sand
94 lbs (1 bag) of portland cement
17 lbs (1/3rd bag) of hydrated lime
We mixed this all dry and then used buckets of the mix, mixed with water (about 20 cups) using a drill mixer. After applying the stucco (it naturally forms a layer about 3/8ths of an inch thick), we used a “scratch” tool to give it texture so the second layer would grip it well. Then we left it for a few weeks to cure and watered it often to increase the strength during the cure period.
The recipe for the brown coat was very similar, except with 10% more sand and lime to weaken it a little bit. You want the brown coat weaker so that if it tries to shrink as it cures, it will crack instead of cracking the scratch coat off the wall.
Before applying the brown coat, it is a good idea to wet down the wall. Otherwise the moisture from the fresh stucco is sucked into the scratch coat and it is difficult to work with.
After applying the brown coat, we continued to water it for another couple weeks, again to improve the cure and the strength.
Improved mix
As I mention in the video, along with our improving stucco skills, we also experimented with the mix and found that adding a quart of thinset after mixing in the water really improved the workability of the stucco. It also improved the stickiness (important for ceilings) and gave it some waterproof characteristics also.
The Gallery
Again, sometimes the easiest way to tell a story is as captions on pictures.
The skylight concrete would have leaked a lot of heat. So we needed to wrap them in insulation. But first we needed some wood to screw the insulation too… Necessity is the mother of invention.
This side of the skylight needed more insulation because it included some vertical ducts. I decided I would need to extend the electrical box a little. This was not enough.
In one of the first attempts, it became clear that the electrical would be too recessed.
So, I ended up using a bunch of outdoor box extenders… If it looks stupid, but it works, its not stupid?
Another view of my stacked electrical.
The outlet after we got the stucco around it
Eventually, we covered the wood tops of these with copper…
The style of the home is something my wife and I are calling “Modern Tuscan“. To us, this means a stucco and stone exterior. While the majority of the Quonset hut will be buried, the Fox Block ICF endwalls would be visible (and prominent) and need to be stuccoed. But first, we would need to attach lath to hold the stucco. Since the work was pretty standard, I decided to hire a professional to take care of the actual stucco work. This is the story of how that all came together, but first, the video.
The Video
Lath overlap
As always, this is a journal of my progress, not a “how to”. I don’t always do things the right way at the start, although I do usually learn from my initial mistakes. For the lath, I read about attachment details like how often to put screws in each direction (and then I exceeded it), but I didn’t pay too much attention to the part about overlapping the lath and just butt jointed everything so the surface would be flatter for the stucco. Probably I was also thinking about saving on lath. At a later point, I changed my mind, so the later pieces are properly overlapped… Either way, the professional stucco guys said we did a good job and only needed to add some J-pieces to form the bottom edge.
The window
With such a large and prominent wall, I knew I needed a window to break up the space. Personally, I think a square window would have looked stupid, so I bit the bullet and budgeted for a nice round window. At least I went with a standard diameter window so it wouldn’t need to be custom.
However, when I finally got to this stucco stage, I wasn’t ready to order the windows. I want to order them all at once to get the bulk discount, and I wanted to build all (or most) of the bucks before I order, so… In the meantime, I decided to go with polycarbonate Lexan. This is pretty basic stuff that you can buy from Home Depot less than 1/10th the price of a window. The R-value is also pretty similar to a double pane window. I figured it would at least give us a temporary solution that would keep the inside dry over the winter.
It ended up looking so good, I might just decide to keep it this way. We will see how well it holds up to UV. Obviously, if it yellows or cracks over time, I will switch to glass. But it did claim to be “UV stable” and has looked fine so far, so I am optimistic.
Still, I wanted to make sure that the window opening was ready for proper glass so that the stucco edge would all be done correctly. We used wood strips to form a curb, and then put two layers of the tar paper to protect the wood and then a strip of lath to hold the stucco. Lots of screws…
Getting a Contractor
I have had many struggles with getting contractors to work on the more unusual parts of my build, but I was surprised to even have trouble getting something as basic as “stucco over ICF”. Very few of these companies advertise properly, probably because most are kept busy by professional builders and are not actually looking for work. Eventually, I went to the stucco supplier and asked for a list of names and recommendations. One of those paid off, but even then I had to wait quite a while to fit into the schedule.
Of course, the contractor, Hoffman Plastering, did a great job in terms of how nice and flat the wall was (they certainly had to compensate for my less than professional ICF job). Their classic worm finish was also excellent.
Cracking
However, in the months after the stucco was applied, we did get a bunch of fairly obvious cracks in various places and we have not been able to get them to come out and take a look. On the phone, they said that it was probably my fault. Essentially, they blamed the copper cap and said that water probably got behind the stucco and froze, but I was able to find pics showing the start of the cracks before the first freeze, also the cracks look more like ones that are caused by expansion and contraction of the stucco its self. Basically, I imagine that if the south wall expanded in the sunshine, this narrow region would be the highest stress concentration and the most likely to crack. The inspector thought it may have been that the top layer was applied too soon after the brown coat. The contractor may have rushed that step because the work was done in October. The cracks are not wide enough to get the edge of a coin or screwdriver in there, but are still concerning. The conclusion of this story is still on hold, but I should probably do something before winter when water might actually get in thru those cracks and cause further problems when it freezes.
Future Stucco?
I wish I could hire a contractor to stucco the rest of it. Their work was excellent (other than the cracking) and the quote to handle the rest of it was probably fair per square ft. The problem is just the large number of square ft required. The majority of the cost is the professional labor, the actual materials are a very small fraction of the cost. Therefore, I am guessing I will need to do it myself. With any luck, my skills will grow quickly.
Gallery
As per usual… A collection of pics related to the lath and stucco.
Lath is ready on the north side…
Working with Hunter Mitchell often made me smile.
A view thru the Polycarbonate Lexan window
The window ready for stucco
I put a septic hookup on the front of the house for friends with campers.
This was the stucco setup. Scaffolding ready in the back and a stucco mixing station in the front left.
I took pics of the ingredients. Basically, it was just cement, hydrated lime and masonry sand. I’ll probably have to do this myself next time.
The bags of hydrated lime looked pretty old ;^)
The stucco sample. I would say it looks pretty much exactly like the final work.
Scratch coat near the ends of the walls.
Scratch coat with the light base.
Scratch coat near the north garage door.
Scratch coat on the north side
Since I couldn’t come out (busy working to pay for the stucco), Sherri and Boys would go out to check on things and set up my camera.
Sherri and David posing while they set up the camera.
The wide angle GoPro always makes things look different.
Brown coat, first 7 ft.
Hoffman plastering did a great job with the stones.
Stone arch is in. Note the stones are not really wedge shaped, but it still looks good.
Stone arch is in
Scratch done.
A little progress pic of the brown coat, scratch coat and final stone work all in one shot.
Brown coat finished on the front.
This is a section on the north side by the garage door that was still only scratch coat 3 days before they were totally done. I suspect they rushed these last steps and the result will be that the final stucco will crack along with the base coat instead of being applied after it cracks.
This ugly spot will be covered over by window trim, but I wanted to show you how the guys from Hoffman plastering went the extra mile. The back wall had some issues with being plumb and straight near the rear windows. I thought it was just the way it was going to be, but they just went really thick (~2 inches) until they got it all nice and plumb again.
Suddenly, final stucco
Final stucco coat
The final job looked really excellent.
Stones above the door.
A close up of the top of the column between the stones. The white patch is just the electrical box for the lighting.
Final stucco near the round window. They did a great job on that edge.
A close up of the final stucco
A little while later after adding the lights and copper trim… (notice cracks are already starting to form to the left of the light)
The skid steer just barely fits under the stone arch… I hold my breath every time I go in or out.
Cracks started to firm. Here is a pic with my hand for scale. This is on the north side.
On the south side, the main cracks were across this narrow space between the corners of the doors and the outer edge. I can imagine that this is due to expansion finding the weakest part to crack…
Similar geometry on the South West corner leading to a similar crack.
