Information about design and construction of earth sheltered homes and a journal of my own progress

Shooting the Scratch Coat onto the wall

Putting up Stucco with the Mortar Sprayer

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Posted on April 24, 2016 by

I needed to mount an electrical panel in the mechanical room in the basement.  But first, I needed to stucco those walls.  The walls were really too rough to use metal tools (the stucco just falls off) and packing it by hand was too slow.  After trying both, we decided to spend the money to buy a Mortar Sprayer from Tool Crete.

Here is the video

Enough Air?

These mortar sprayers use air pressure to blast wet concrete/stucco/mortar from the bottom of the hopper on to the wall, so obviously having enough air is critical.  For maximum flow, I would need a decent air compressor and high flow fittings and hoses, but without spending too much money.

My little pancake compressor, with its quarter inch fittings, definitely wasn’t going to be sufficient. Larger compressors can get expensive and the mortar sprayer was expensive enough on its own. Fortunately, my father let me have his old one.  He must have had that thing for about 30 years and I remember hating it as a child… Not just because it was annoyingly loud, but because he would sometimes ask me to turn it on or off and the switch was strangely placed on the inside and I would have to reach under the bench over the electrical connections, between the motor and compressor and way too close to the spinning belt that connected them…  Regardless of my past (totally reasonable) fears, I was quite happy to get it now.

Next, I would need to find the right fittings.  Larger is better, so I was looking for 1/2 inch fittings. These are not available at any hardware stores near me, so I was checking out places like Grainger industrial supply and they were pricey.  Fortunately, I didn’t get around to buying anything before I realized that the compressor outlet was only 3/8ths of an inch.  There is no sense in having larger connections downstream of a smaller one, so that outlet bottle-neck set my max. When I adjusted my search to 3/8ths inch fittings, I found that Home Depot had plenty in stock and they were much more affordable.  My fathers old hoses were also 3/8ths, but with 1/4 inch fittings, so, I just swapped out all the fittings.

The last hurdle was 220 volts.  My generator has a 220 plug, but it couldn’t keep up with the demand I expected from the compressor.  This meant I needed to wire in a 220 plug and make up a long enough extension chord. At least that was pretty straight forward. I also had to swap out the plug on the compressor to match. While rewiring the generator, I discovered that the original wiring didn’t have a properly connected ground, somewhat further justifying my childhood fears.

Once that was all done, I bought the stucco and waited for a rainy day.  No sense wasting a good sunny day down in the basement.

Mortar Sprayer Tips

I found the mortar sprayer pretty easy to use, and you would probably figure these things out yourself if you picked one up, but I will write them down anyway.

1) It is clearly designed to scoop from a wheelbarrow, so you might as well just mix the stucco right in the wheelbarrow.  I do have a paddle mixer (attaches to my drill), and a barrel mixer, but it just seemed easier to do it directly with a hoe in a wheelbarrow.  Proper “mixing hoes” have two big holes in the blade to help reduce drag and improve the mixing, but the light weight stucco mixed easily with a standard garden hoe.

2) Mix consistency is important.  If the mix is too thick it doesn’t slide down the hopper to where the air nozzles are.  I found I could sometimes shake it down, but that was tiring.  On the other extreme, if the mix is too thin, it slides down the hopper and some of it starts to drain out the holes before you can shoot it on the wall.  With a little trial and error, we worked out a water ratio and mixing process that worked pretty well for our conditions.

3) Ladder work is sometimes required.  The hopper empties quickly and climbing up and down the ladder with the mortar sprayer and hose is a bit tiring.  We found it worked best to stay up on the ladder and pass the sprayer down to someone who could scoop it and pass it back up.

Shooting the Scratch Coat onto the wall

Shooting the Scratch Coat onto the wall

4) The scoop action is easy if the mortar is all piled in the right place in the wheelbarrow, but near the end of each load, we found it saved time if the second man used a trowel to help push the mortar from the corners into the “scoop zone” while the sprayer was shooting onto the wall.

5) The sprayer does make a bit of a mess and things are much easier to clean up if you can put down some plastic, etc.  In the video, you can see I even covered the water pressure tank in a garbage bag.

6) After getting the mortar up and smoothing it off (with a tool or by hand), you an let it set for several hours (depending on environmental factors) and then come back with a grout sponge when it feels pretty stiff.  These are tougher than a regular sponge and you can find these in the tile section of the hardware store.  I used a bucket of water to keep in wet and wiped down the walls to smooth them significantly.  The difference between the sponge smoothed walls and the walls I didn’t smooth is pretty dramatic.  I am just glad that I will be putting a lot of duct work, etc. in front of the rougher walls.

Gallery

A gallery of pics.

 

Electric Service to the Mechanical Room

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Posted on April 16, 2016 by

We needed to run 200 amps of electricity from the meter on the back corner of the garage to the mechanical room in the middle of the house.  This part of the process was necessary and lessons were learned, but it was a smallish stand alone project, so here is the shortest video segment yet…

Cable run:

Code requires that 200 amp service needs at least 2/0 copper cable or 4/0 aluminum.  I went with the copper, even though it is a little more expensive, because it is much thinner and easier to work with.  The rooms are not that far apart, but since I had to start in the back corner of the garage and travel a long path up and along walls, I ended up ordering enough for a 125ft service run.

The run requires three of the heavy 2/0 cables (220 volt service) and one smaller 4 gauge ground wire, so the total weight on the spool was about 200 lbs.  We attached conduit to the steel Quonset hut with 3/8ths inch bolts that could support the weight (and the tugging).  Actually, these were bolts left over from assembling the Quonset hut.  On the back wall, we attached to the Fox blocks with wood screws every 8 inches.

The cables have a slightly slippery coating that makes pulling easier, but I still didn’t think my wire puller could handle the load.  Instead, we used the wire puller to pull a rope thru the conduit, and then we used the rope to pull the heavy two-ought cables.

Code limits the maximum number of bends because it just gets too hard to pull the wire if there are too many.  My run was below the maximum, but I still didn’t want to try pulling the whole thing at once.  Instead, we put up the first section with just a single 90 degree bend and pulled the wires just thru that.  Then we added sections, threading them over the cables and working back toward the breakers.

The quick time-lapse makes it look easy, but it really didn’t feel like it at the time and I was very glad to have hunters help.  Don’t try this sort of thing on your own.  At one point you can see us both trying to support the weight of the cable while we add screws for the brackets in that back corner. Lots of sweat.

I just liked this pic that the timelapse camera took of the arches while we were organizing the wires

I just liked this pic that the timelapse camera took of the arches while we were organizing the wires

My parents came out that weekend to help with setting up steel (that’s another video), but also jumped in to help me wrangle the wires into conduit and fit those in place between the garage and the mechanical room.  The trickiest part here was that both ends of the assembly were fixed and we had to get the conduit measured just right and then, with the wire already in side, fit between the two ends. Fortunately, it was just flexible enough.

This last section of conduit is “outside” now, but eventually the kitchen floor will be poured over it.

Introduction:

 

Hunter is my new helper with a great sense of humor

Welcome Hunter M. to the video.

Hunter is an 18 year old college student (just finished his 2nd year of film school) with a side interest in building.  His personal interest is in a tiny house project, and, hopefully, he will build his own some day.

Hunter is a great worker, with a very optimistic attitude and a great sense of humor. He is also great at paying attention, he learns fast and he anticipates what I will need next. He has been a great help so far this summer and I am sure he will do well in life. I would be happy to recommend him to anyone, just not on Saturdays when I need his help.

Tips:

1) Be careful about the direction of your conduit.  I put the first section in backward and my first attempt to pull the first cable failed because the cable was hitting on the inside end of the pipe in the connection. Fortunately, I was at least consistent and could go around and pull the cable from the other direction.

Pull the cable in this direction, and never mix directions with the conduit.

Pull the cable in this direction, and never mix directions with the conduit.

This sort of rebar bender can help you move service entrance wire

This sort of rebar bender can help you move service entrance wire

2) Similar to the service entrance, I found that using my rebar bender helped me feed the wire thru that hole between the inside and outside.  It is tough to describe without catching it on video, but you can make the thick/stiff cables move like an inch worm around the corner and through the hole.

3) Code requires all the cables for a run to go thru the same conduit.  This is to keep all the cables the same length so that the sin curves for the AC current stay in sync between the black and red cables…  If anyone wants to know more, I could come back and put in an illustration to explain that here.  I did know that and put all the cables through the one conduit.  The second conduit is so that I can later come back and run other things (Ethernet?) from the garage to the mechanical room. When building a concrete, underground house, a second wire chase is a good idea.

Dry-stack block walls

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Posted on March 11, 2016 by

Blocks

For some strange reason, I have always wanted to build a block wall.  So of course, I had to work at least a bit of that into the plans.  I chose to build the bathroom out of block because it was all internal walls and I liked the idea that it may slightly brace the quonset hut before we added concrete over it.  We also had this idea that the garage would be finished first and it would be great to have a bathroom in there so we could use it during the rest of the build…

Also, I have often joked (only half kidding) that I would like the bathroom to be waterproof so we could clean it with a power washer. And that would require no drywall…

First, the Video…

Glass Bottle Wall

I have also wanted to make a glass bottle wall for a long time, but with a low R value, they are not practical as an exterior wall in Michigan.  Instead, I plan to finish the gap between this bathroom wall and the Quonset ceiling with glass bottles…  This way, it will be an internal wall and will let light in from the garage skylights while still finishing off the bathroom wall to the ceiling to provide privacy. Video to come later… much later. Maybe after we move in.

Pro-tips

1) Buy half blocks, etc.  When you go to price the blocks, you will find that the full 8″x8″x16″ blocks are pretty cheap.  In my case, they were 86 cents each.  But then if you look at half blocks, you will find that they cost almost twice as much for half as much block.  At first, I said, “No way, those are for suckers, I’ll just split the full blocks.”  And while it is true that some of the full blocks come designed to be split, it was not easy and I wrecked half the blocks that I tried. Eventually, I realized that those half blocks were expensive because they were worth it!  I also bought 4x8x8 blocks and cut those in half for some quarter blocks.

2) Pay for delivery.  Blocks are heavy and it took hundreds to make even my small bathroom.  You could make a bunch of trips with a pick up truck (be careful not to overload it), but for the money you would pay in gas, you could just have them delivered all at once and without risking wear and tear on your vehicle.  Delivery also saves you time, and time is money.

Get your blocks delivered.  They are heavy and delivery is cheaper than all the trips it would take to carry these safely in my pickup truck.

3) Cut the blocks for electrical as you go.  I guess we were just so excited to be building that we forgot to do that.  When I came back later, it looked pretty easy in the video, but…  If cutting the block had cracked it, how would I have replaced it?  It was also pretty challenging to get the ENT boxes to fit in the holes with the conduit attached to the tops, and then I had to run the conduit and wires all the way up to the top of the wall and back down again, which wasted a few extra dollars.  Plus, you just look silly for forgetting.

4) Make sure your concrete dye is a nice liquid or powder so you can mix it accurately.  Mine was a lumpy semi-solid mass that had been sitting on the shelf at Home Depot well past its expiry date and this made it very difficult to get a uniform color.  I found that I could blend the color by wet sponging the wall later, but it still doesn’t look quite right.

 

Gallery

Here are some pics from along the way…

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