Category Archives: Building with concrete blocks

My Shop ~ Part 8 ~ The Floor

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The concrete floor for my shop was the easiest and best slab I have ever poured was not without difficulties. All ultimately ended well, but as always, there is a story.

For some time now, we have had a pile of cascajo (cas-ca-ho [the letter a has a soft sound in this word] — river run sand and gravel) taking up space in the driveway. Cascajo is great for foundations and large columns. The mix as it is dug from the river has a range of sizes from sand granules to six-inch rocks. But it is not so great for floors because of the larger rocks. The rule of thumb for pouring a slab is no gravel/stone larger in size than one-third the thickness of the slab. I know we should have sifted the pile, but Armando and his crew balked. They said that sifting just isn’t necessary. If you come across a rock that is grande and causing a problem, just pull it out of the slab and throw it aside.

Additionally, most of the pile had been sitting for months and it was permeated with grass, weeds, and roots. I could foresee a problem when it came time to trowel a nice finish, but again the guys said “es normal.”

Here is a photo of the root-infested pile of cascajo:

I’ve learned to pick my fights with the guys because I can really make a fool out of myself; they usually know things that I don’t. A case in point is when two men showed up to put an internet antenna on the roof of the house we rented when we moved to Panama. They arrived with:

  • the antenna and connecting cable
  • a six-foot length of half-inch electrical conduit
  • a small coil of bailing wire
  • a nail
  • a hammer
  • a pair of pliers

I scoffed to myself. Where was the electric drill? Where were the numerous brackets, bolts, and accessories that they would surely need to mount the mast to the roof? And where was the mast? In my opinion they were missing about $129.95 in essential pieces and parts. But I watched.

They found an old tree stump in the yard to use as an anvil. Then with the hammer they pounded flat about three-inches of one end of the electrical conduit. Next with the hammer and nail, they punched a hole in the flat section, then using the bumper on their small van they bent the flat section to a right angle. Next, back to the tree stump they switched ends of the conduit and punched a hole in the conduit about two inches from the end.

Then using the pliers up on the roof they slightly unscrewed three screws that were holding the metal roofing in place, plus a fourth screw all the way. They put the removed screw through the nail hole in the bent end of the conduit and put the screw back into the hole in the roof that it came from and tightened it down. Then they wrapped some bailing wire around one of the loosened screws, ran the wire up and through the hole at the top end of the conduit, and back down and around the second screw, back up and through the conduit, and down to the third screw. They tightened the screws. At this point the conduit mast was triangulated firmly in place. Then they mounted the antenna dish on the conduit and ran the cable to the router on my desk inside the house. D.O.N.E.

So I am careful. I learn a lot from these capable and resourceful men.

But Sr. Murphy often shows up on the job. In the case of the floor slab in my shop, it seems that my image of troweled-smooth concrete is very different from their version. I like it smooth. Very smooth. I don’t want a sandy surface. They like it flattened out so you don’t trip on any of the ridges. They don’t take smooth into account because it is a long day’s work and anally troweling the floor to a mirror finish is just not going to happen.

There is more to the story, but let’s see some photos:

I held my ground on preparing for the slab. I like a nice level couple-inch layer of gravel to pour the slab on. If you pour concrete on dirt, moisture in the dirt will capillary-action wick its way up into the slab. But capillary action can’t happen through the stones because the spaces between the stones are too large. The slab will stay dry. So even though they thought I was stupid, I had a few yards of one-inch stone delivered. Sammy and I spread it level. Jabo wasn’t sure he liked it:

On Thursday, Cynthia and I put welded wire mesh on the floor to keep the slab from cracking. Here is the floor ready for concrete. My laser level is set up to level the concrete, and in the corner is a wooden bull float that I made from scrap.

The guys mixed a big pile of concrete:

And Armando and I spread it out. Because of the large rocks in the mix, it was difficult to raise the wire mesh to the center of the slab, but I got it raised about a third of the way up. Close enough. I’m using the laser level to set the grade so Armando could more easily screed the concrete. You can see he has thrown out a few trouble maker rocks:

Here Erin and Pancho take a break after using 24 sacks of cement:

In the next photo Armando trowels the floor. After wooden floating the floor, you shouldn’t steel trowel the concrete until all the water has disappeared from the surface. This way you won’t be pushing water around, washing the cement away from the granules of sand. But it was pushing 5:00 and the guys (including yours truly) were tired. So Armando pushed the envelope slightly and troweled while there was still water on the surface. I knew I wouldn’t be happy with the finished product, but it is, after all, just a shop.

We finished, cleaned up the tools, and called it a day. The next morning, Saturday, Armando had work elsewhere, so it was just me arriving on the job. I took a look at the floor. I didn’t like it and gave the job a C-minus, maybe a D. It was rough and there wasn’t enough cement “cream” on the top. It was going to be difficult to sweep it clean in the future.

What to do? It is generally a bad idea to apply a skim coat of cement paste onto a concrete floor because in time flakes will spall off the floor. But our floor was still very green, still hydraulically pushing out water. I’ve read that you have a good chance of succeeding with a skim coat if you catch the slab while it is still only a few hours old. The most common reason for needing to do this is when a surprise rainstorm pops up and washes the cream away just after steel troweling a driveway or a patio slab.

So that’s what I did. I got a steel trowel, a bucket of dry cement powder, a bucket of water, and a sponge. I spent most of the day sprinkling cement on the slab, then adding a bit of water by wringing the sponge, then troweling the paste onto and into the floor. I had to take numerous breaks to stand up and straighten the old Arthur Itis knees. At the end of the day I gave the floor a B-plus. I can’t give it an A because the mesh didn’t get lifted as high as I wanted and also because there were a few dips just a bit deeper than I would have liked. Troweling the top coat was gruelingly difficult for my old body, but I am glad that I did it.

I’m spraying the floor with water a few times a day now, and will continue for a week. This will slow the rate of cure and will prevent a lot of surface cracks. Here’s my finished floor slab just after I sprayed it:

The next time I am in the city I plan to go to Discovery and buy a few gallons of garage floor epoxy. With the epoxy, a quick sweep of the broom will clean the floor “real nice.”

I need to let the slab sit and cure without foot traffic for at least a week, so depending on the condition of my knees, I should be back working on the house windows maybe tomorrow.

That’s all for now.

 

My Shop ~ Part 7 ~ Electrical, Repello (Stucco) & Pizza

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With the completion of the repello (stucco) on the interior shop walls, Armando and Sammy moved operations to the bathroom walls. Because the bathroom is so small, there was no room for me to to help.

I’ve found over the years that working in small rooms and closets doing tasks such as putting up drywall or painting can be more difficult than working in a larger space. There are still the same number of walls, angles, and corners but there is little room to turn around after you get tools and a ladder inside the space. So Armando was on his own in the “phone booth” bathroom and Sammy kept him supplied with mezcla (mortar mix).

While they were doing the repello, I took a day and cleaned up the repello-ed walls in my shop. There were some trowel marks, rough spots, and small pimples that I wanted to get rid of so the walls would take a nice finish. I have a wet angle grinder and a set of diamond polishing pads. I put the 50-grit pad on the machine and passed it over every square inch of the walls. Here’s the grinder, Hellcat brand; you hook a garden hose up to it, plug it into the wall, and try not to shock the hell out of yourself:

The grinder did a great job, leaving the walls quite smooth and ready to finish.

I’d been having a back and forth debate with myself on whether to paint the walls white or to coat them with a clear acrylic polymer. The white would be nice for light reflection, but it would get dirty very quickly with all the welding and grinding going on in the shop. Also, a good quality paint would cost a hundred bucks or more, and the paint would hide the nice look of the repello-ed walls. Ultimately, the polymer won out and I applied two coats (about $25) with a sponge that same day and the next morning. Here’s the polymer:

The guys were still doing well on their own so I decided to start the interior wiring. Before we laid the concrete block walls, I had decided that I would surface mount the electrical boxes on the walls rather than build the boxes into the walls. I’ve pulled covers off of built-into-the-wall boxes and they are all nasty with rust and corrosion from the concrete.

So after I applied the two coats of polymer sealer, I struck a level line around the shop walls for the receptacle and switch boxes. Even though they are a lot more expensive, I decided to use weatherproof exterior boxes because they won’t rust and there are no holes for spiders to enter and make cozy little nests. In this next photo I have drilled two 1/4-inch holes in the wall and am tapping in screw anchors, called tacos here.

I drilled two holes in each of the boxes and screwed them to the walls. The boxes have little lugs on the back that stand the box off the wall, so I ran a bead of gray urethane caulk around the boxes to seal yet more spider hideouts. I hate to reach for a plug and put my hand in a spider web. You can get some nasty spider bites here in the tropics.

Then I measured and cut PVC conduit and clamped it to the walls and ran it across the floor as needed. I chose PVC conduit because metal conduit would rust fairly quickly, especially under the concrete floor slab. 

I also mounted boxes for lights on the ceiling. Even though I like 4-foot strip fluorescent fixtures, I decided to use individual fluorescent bulbs because the electronics in strip fixtures get blown by the uneven electrical current here. Cynthia helped me pull wires through the conduit. You can also see how nice the concrete walls look; they have a slight shine that you can see on the wall at the left of the window blocks in the photo above.

By the time the electrical was to the point that the concrete floor could be poured, the guys were done with the bathroom walls and some other small details. But before the floor, it was time to repello the exterior walls. The exterior walls are larger than one man can repello in a day and I didn’t want any “cold” stop/start joints so I had to pitch in and sling mud with Armando. Now I can get another dollar a day in my pay envelope because Armando taught me how to apply the repello. Repello-ing is hard work!

Years ago when I was carpentering for a living, someone asked me if it was hard to install a window. I said, “No, not as long as you know what you are doing!” It’s not the same with repello. Even if you know what you are doing, it is still damn hard work.

As of today we have the back side, the east side, and the front side all repello-ed, leaving only the west side that we will tackle tomorrow if I can get out of bed. For the east side, we didn’t start our work day until 11:00 a.m. so that the sun would have time to pass overhead and we could work on the wall in shadow. We finished about 6:00, at which time I flopped into my hammock for the rest of the night. I think Cynthia hooked me up to an IV frijole dip drip so I could get some nutrition while I slept. Here is a photo of the front and east walls just after I hosed them down to help them cure:

There is a tradition here in Panama that when a roof goes on, you have a roof party. So last Friday was the day. I knocked the guys off at 12:30 for a pizza lunch and the rest of the day off. Cynthia and Cedelinda had been making the dough and preparing the toppings:

It’s my job to cook the pizzas. Our fancy Bompani oven isn’t up to the task of cooking pizzas, so some time ago I went down the hill and bought some locally-made firebricks. I cut them in half with my tile saw. Then I lined our BBQ grill with the half-bricks. Like this:

A half-hour preheat turns the BBQ into a Jim Dandy 500-600 degree pizza oven. By the way, I don’t know who Jim Dandy was, and I didn’t know whether to capitalize it or not, so I Googled it. It’s capitalized. And while looking, I found a Jim Dandy BBQ restaurant in Cincinnati, Ohio. Who’d a known. I wonder if they do pizza. Anyway, a big shout out to Jim Dandy’s even though I am a 30+year vegetarian. I love Google!

At this point I put the camera down and started cooking. Cynthia’s pizzas are works of art. I got busy cooking and then planted my face in my pizza and completely forgot to take photos of the finished pizzas. Trust me, they were beauties.

We bought about a dozen pizza pans, the kind that have hundreds of 3/8-inch holes on the bottom. The crusts get nice and brown and the pizzas don’t stick to the pans. We like to have build-your-own pizza parties every year on my birthday. That and homemade chocolate cake makes me happy to be a year older. Or at least I don’t notice.

Anyway, the roof party was a delicious success. The guys were stuffed to their shirt collars and got to take home leftovers. The first time we made pizza for a work crew here each man took a slice. They clearly liked it but were too shy to take more. We had to order them to eat more, at which point they loosened up. It was great fun to see them egging each other on to eat yet another slice. There were lots of jokes about not having to eat for a week and not being able to work because they were too full.

That’s all for now. Maybe next week we can think about pouring the floor in my shop. Stay tuned.

My Shop ~ Part 6 ~ The Roof

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Now that the dry season is here, we are making good progress on my shop. All the interior walls are repello-ed (stuccoed) and the roofing metal has been delivered. Here are some photos of walls being finished:

Armando works a wall

We call this little closet "the phone booth"

Gusty winds come with the dry season, so we geared up with ropes and clamps and extra bodies to keep the 24-foot-long roof panels from blowing away. Here we are placing the first panel on the east side of the shop:

Armando and I place the first panel. Gloves are mandatory when working with these over sized razor blades.

Up goes the second panel

After lifting and placing each panel, Sammy and I go up on the roof. He sits on the bottom end of the metal to keep it from becoming airborne, and I take a straight edge and a Sharpie marker and mark locations for screws. Armando follows me, placing a few screws to keep the panel in place.

Break time at the half way mark. Sunglasses are mandatory while working on the highly reflective roofing. Later, much later, the roof will extend out another 15 feet over the carport.

After all the panels were in place, Armando and Sammy went back over the roof and placed the missing screws. What a beautiful day in the tropics!

I included a six-foot roof overhang on the west end of the shop. Below the roof there will be an outside sink, a clothes line, and space for potting plants, etc. It is also a place that Armando can wait out a rainy season deluge. Maybe a hammock is in order:

The larger window is in my shop, the smaller window is in the bathroom.

Here are some inside shots with the roof on:

Now that the roof is finished, I can remove the temporary center stick. It reduced the bounce while working on the roof.

We were finished with the roof about 2:30 so I sent the guys home. Armando proclaims the roof “listo” (LEEZ-to — done, ready):

Will he walk the plank?

Tomorrow Armando and Sammy will go back to repello-ing the remaining bathroom walls.

My job for the day will be to clean up the repello on the interior walls. There are some trowel marks and a few rough edges here and there that need attention before paint. I’m going to start out using a wet angle grinder with a diamond polishing wheel and we’ll see how it goes.

After cleaning up the walls, I’ll make the final decision — white paint or clear polymer finish? I’m leaning toward the polymer as it won’t show the inevitable scuff marks, although the white would make the shop a bit brighter.

After the walls are finished, I can mount the electrical boxes and conduit. I plan on running most of the conduit under the floor slab. I don’t like horizontal conduit because it is a dust collector.

Then we can pour the floor slab and make the front door. Move in is in sight!

That’s all for now. Arf!

Bonus photos: