The day after shotcrete on the perimeter walls, we got started on prepping the steel arches and setting them up for another round of shotcrete. This particular apse is special because it will eventually be my office (where I will spend most of my waking hours), and because it needs to be in (along with its retaining wall) before we can bury the garage side of the house. The work was all pretty simple compared to the bedrooms, and I didn’t take much time to stop and take pics, so this post should be short. But first, the video…
Please subscribe to get the videos directly and like us on facebook for more up to date postings
An apse is the semi-circular end of a vault. They are pretty common in earth sheltered homes because they can hold a lot of load, but usually, they are at the back, completely buried. I put mine up front and included a window. Hopefully, it turns out to be a good idea. This apse will also be my office, and I spend a lot of the time on video conference calls, so hopefully, the acoustics are OK. At least my head will be near the window and not near the acoustic focus point.
This is how the guest room looked the morning after shotcrete.
It looks warm enough in the pics, but the temp was probably less than 40 and freezing over night. I left this propane heater in the room to keep the roof warm while it cured.
I was pretty happy with how the mud room roof turned out…
This is the top of the playroom apse. Because it was out in the open, it also needed its own little parapet wall…
Hunter checking on the camera as he flipped the steel arch. He had welded 3 sides of each leg, but needed to flip it to weld the 4th.
Positioned the first arch here and took a quick pic just to get an idea of the scale of the office…
The office apse steel at the end of the first saturday…
Here I am looking quite grizzly, but happy things are working out.
Office apse with mostly just the horizontal rebar.
Michael messing with the camera… He likes moving past it very slowly so it looks like he is moving normal speed and the rest of us are high speed.
Snow stopped our progress for a couple months.
Sherri did most of the lath work during a brief warm spell in February… Sorry, no timelapse.
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.
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.
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.
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.
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.
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
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.
Last year, we got started on the steel structure. This year (2016), we got all the rebar and lath up in preparation for shotcrete. First, the video… Then some info, but mostly a larger picture gallery than usual.
This process took from 2016-05-05 to 2016-07-26, so nearly 12 weeks of the calendar. Of course we also worked on other things during that time (such as the garage which will be a separate video). Specific to this bedroom wing, we worked (at least for a couple hours) on 26 different days. The time-lapse camera (which I ran pretty faithfully) recorded 77,653 images. At one every 5 seconds, that means it was running for 388k seconds, or 107 hours. If we divided that into 8 hour days, it comes to about 13.5 days. About half the time, I was there by myself, 1/4 of the time with Sherri, and the last quarter Sherri and I had other help (Hunter, John, Bonnie, Joe & Jessica (my parents), Dan, Ethan and the plumbers).
If I had turned all 77,653 images into video at 29.97 frames per second, it would have been a little over 43 minutes of video. I edited that down to under 10 minutes (less than 1/4). In some cases, I edited out scenes, in others (such as that last interior wall), I just ran the speed of the video up to x900. You are welcome ;^)
We added rebar chairs to stiffen up the assembly and prevent “bounce”.
It is important to leave some space between the rebar and the lath for the concrete to completely encase the rebar. To achieve this, we made sure to tie the lath on loosely (leave room for a couple fingers). this works pretty well for the roof because the weight of the concrete will push the lath down and away from the rebar, but no further than the wire ties. However, in the walls, the concrete can “bounce” the lath and then fall off the wall. After seeing my setup, the shotcrete guy asked me to stiffen up the walls by adding rebar chairs where the lath was bouncy… I had these chairs left over from the quad deck floor and they worked perfectly.
Welding was great because it really stiffens up the assembly so you can climb it without fear… and it actually doesn’t take much longer than tying. In many cases, I just tied enough to keep the bars in place and pull any wide intersections close enough to weld. Then I would just weld the rest of the connections much faster than I could have tied them.
The downside to welding is that the heat can actually change the properties of the steel and make it more brittle if you try to bend against the weld… However, in my case, the welds are really just there to keep the steel in place long enough to pour the concrete. After that, it is really the concrete that keeps the steel together (and vice versa). My welds are intentionally shallow, just enough to tack the pieces together without significantly weakening the rebar.
You may find some places have building codes against welding rebar, but if you read them more carefully, they are really talking about cleaning that surface crud off the steel. You get that sort of thing with arc welding, but not with the MIG welder that I use. But in any case, there are no such rules for residential construction where I am building.
When you curve rebar, it is always trickier to curve the first and last couple feet. But the middle curves pretty easily. So, I usually curve the full 20 ft long pieces and then cut the nice continuous curve into as many pieces as I can get. If the piece has a 5 ft straight wall before the curve, then I just start curving the rebar 5 ft from the end. I usually start by “over curving” the steel a little bit and then straighten it out to get the final radius that I want.
Here is a gallery of pics. Some are just as people started or moved the go pro time lapse camera. Others are just candid pics that went by too fast in the timelapse. There are also occasional cell phone pics in there also. Thanks to everyone who came out to help.
Photo op after getting the windows in.
A view of the top of the apse after adding the rebar.
Hard to see because it is backlit, but humming birds and butterflies kept getting stuck inside the lath.
The top of one of the interior walls
After getting the first rooms studs in place.
How the bedroom wall studs were attached to the tube steel. The angle cut across the stud was so my drill could reach those screws.
This is the connection for the end of the hall. In this case, the studs were under the tube steel, so the connection was a little different.
A close up view so you can see the stud with the rebar passing thru it and the lath and fabric attached.
Michael reading in his room.
While out there, Dan did some heavier welding also. Here you can see he is pretty happy with the weld.
Here David is setting up the Camera after changing the battery.
Climbing up to get the camera…
Some times we would turn on the camera and then move it. It would get these odd pics along the way.
Some times we would turn on the camera and then move it. It would get these odd pics along the way.
It took us a while to figure out the first skylight frame, so we were pretty proud of it when we were done.
Hunter checking out the camera… Did I mention that it is a wide angle lens… Not good to get this close ;^)
Putting on the last board and we decided to pose for the timelapse.
After adding the first set of OSB boards. The neighbors must have really been wondering.
After adding the screws from the inside of the skylight, hunter would drop out the bottom… But this time, I took away the ladder.
Here I am holding the boards up on the outside while hunter is inside putting in the screws. This was so I could strip the boards out after the concrete sets.
Michael up in one of the skylights.
Kids just doing their thing.
This shows two skylight towers. On the one, I aligned the fan box with the angle of the tower, and the other I leveled with the ground. Not sure which will look better.
This white tube will allow me to draw the hot air from the top of the skylight back into the house.
View from below so you can see how the rebar is connected to the rest of the structure.
Another view of the skylight curb
The box on the side is for the bathroom fan. It exhausts up thru the white pipe and out.
David found this 11 inch spotted newt… The largest I have ever seen.
Hunter messing around with the camera. These pics are in the time lapse, but they go by fast.
Sherri all tangled up and not looking like it is fun anymore.
All tangled up.
David getting into the time lapse shot.
Michael getting into the time lapse.
Michael and I put up the last section of lath, but first I decided to tilt the camera up.
Putting up the last section of lath.
A view of the all after all the lath was in place.
At this point, we just had one more skylight to rebar.
This is the plumbing for the master bath side. It looks more straight forward than the boys room because the toilet was closer to the exit.
Rough plumbing for the boys bathroom. The pressure tester is on this end for the inspection.
This is the ceiling box for one of the bedrooms. Later we brought the wire in thru the blue ENT tube and connected the ground to the green screw.
We added rebar chairs to stiffen up the assembly and prevent “bounce”.