Earth sheltered homes normally get very scaled down heating systems (some even skip them entirely). Where I live, a heating system is required for occupancy, so rather than get an expensive furnace that I would hardly use, I decided to go with an inexpensive “on demand mini boiler” hot water radiant system. I got quotes for install that were as high as $60,000, but figured I could do it for a small fraction of that, so I decided to pull my own mechanical permit and do this myself. I read a couple books and planned it out. Then I bought the manifolds and supplies from PexUniverse.com (less than 400$ for the basement).
We got it all installed and inspected (our first mechanical inspection) and then had Dysert Concrete handle the actual pour of the floor.
Installing the radiant floor was easy, but some of the recordings didn’t work out, so the final video is shorter than usual. You can read the story below for the details that wouldn’t fit in the narration.
The Video:
The Story:
I started with working out the layout on the computer. Building code requires that no circuit be longer than 300 ft, and most experts recommend that you balance the lengths of the radiant tubes, so you definitely want to plan it out ahead of time.
I tried a number of different plans that ran the tubes thru the hall to the various rooms, but it was just too inefficient and cumbersome to get things “zoned” well that way. In the end, I decided to drill some 5/8ths inch holes thru the base of the mechanical room wall to simplify the layout. With the right tools (DeWalt hammer drill and a long 5/8ths inch bit), that was pretty easy.
We had leveled out the pea stone after the “underground inspection”, but David helped me do some final leveling of the peastone and then Zack helped get the 6 mil plastic down. This plastic is important for keeping water vapor from the ground out of your concrete floor and is required by building code. It also helps keep the radon out, etc.
Six MIL?
A mil is not a millimeter. Six MIL is six thousands of an inch or roughly 0.152mm. Before most English speaking countries switched from the imperial measurement system to metric, they would have called it a “thou”, based on the Germanic route word for “thousandth”, but for some reason, America decided to go “romantic” language based with this one and called it a “MIL” instead (based on the word for “thousandth” in languages like French or Italian). This is a similar etymology to how the rest of the world got the word “milli” for the Metric system, hence the similarity.
We don’t use “MIL” much in the USA, except for quantifying thin film thickness.
Since it is difficult to imagine things in thousands of an inch;
1 MIL = grocery store bag
2 MILS = Garbage Bag
3 MILS = Husky Contractor Bag
17 MILS = Pond Liner
35 MILS = Credit Card
JigSaw Puzzle
David tossed us some sheets of insulation and we got started on the jigsaw puzzle. My rooms are unusually shaped and since they didn’t actually stock those shapes at Home Depot, we cheated by cutting pieces. We started with measuring, but usually ended up trimming each piece iteratively until it fit. We taped all the pieces together and shoved trimmings into any gaps along the wall. Not too hard, but certainly more time consuming than a square room might have been. This probably wasted about 15$ worth of insulation, so not too bad.
Radiant tube
I marked the radiant tube layout directly o n the insulation based on that balanced plan I had carefully worked out on my computer. I used piece of scrap wood marked with the right size increments and a can of upside down surveyors paint. In addition to basic tic marks to follow, I also painted in the end loops so the whole plan would be pretty easy to follow.
Stapling the Pex tubes down was easy and fun, Sherri and I took care of most of it, but the boys were very eager to try it themselves. I imagine it would have been quite a lot more difficult (and much less fun) without that commercial grade tool we used. The tool cost quite a bit (~200$) but is very well built and I will use it a lot… I also plan to sell it and recoup most of the money at the end of the project anyway.
Connecting the pex to the manifold was straightforward and easy. There are some simple little brass connector bits and you just tighten a nut to hold it all together.
I got the Manifold, Pex pipe, the Pex stapler, staples and the pressure tester from “PexUniverse.com”. I had looked at lots of other sites (including sites that put it all together for you, such as Radiantcompany.com), but this one had the best prices and the best hardware. There are also easy to find “coupon codes”.
John (my brother-in-law) and Zack helped me finish off the third loop.
My sister Bonnie was in town and mostly helped me with the ICFs (another post/video), but she made it into this video by helping me to fill the tubes with water so they wouldn’t float in the concrete. I had been trying to pour it from the bucket into the funnel, but she had the idea to siphon it from the bucket, which was much easier and didn’t get us as wet.
Then we pressurized the system (according to building code) so we would know if anyone punctured the pipe before the concrete set.
Concrete
Concrete day arrived and the guys started with putting down some six by six wire reinforcement. This was left over from the garage floor and will help prevent cracks from growing. It also helps protect the pipe and keep it all down under the concrete.
The concrete was pumped in from overhead (renting the pump truck cost ¼ of the job, but was well worth it in terms of making things go easier), and spread level. They came back an hour later and hand troweled it smooth.
Costs
In all, I paid less than 1$/sft for the insulation, radiant tube, manifold and supplies, then 3$ for the concrete work plus an extra ~500$ for the pump truck and ~1100$ worth of concrete… So, not bad.
I hope to get the “quad deck” in soon so we can put another concrete floor over this basement.
Basically, the basement of our earth sheltered home was filled with approximately 11 cubic yards of concrete slag that needed to be broken up and removed so we could prep for pouring the basement floor.
It was something we have known we needed to do since last year, but were putting it off for obvious reasons.
Here is the video:
Why did this mess happen?
All this concrete was wasted shotcrete that wasn’t on the walls and should not have been on the floor either.
As you may recall, I had used steel studs to frame the basement and then placed metal lath on the inside to “catch” the shotcrete. I had been told (by the shotcrete guys) that the lath would be enough to prevent much of the shotcrete (peastone) from blowing thru. I was told to expect a thin layer of concrete on the inside, thin enough that it would break up into small fragments just by walking on it and that it would actually save me from needing to add as much pea stone later.
Watching the shotcrete being applied, it did appear that not much passed thru when it was applied at a downward angle onto the previous shotcrete. They did do it this way for the first couple levels, and actually raised a scaffold jack platform twice as they went. But then they got a bit tired and started shooting horizontally and even at an upward angle. This allowed much more shotcrete to pass thru.
The effect was cumulative with blow thru coming from so many different angles, each adding its own layer of concrete. The round central room was especially bad for this with at least 3 layers of 2 inch thick concrete across the floor.
And once the crew was working on the inner walls, there was also “rebound”, shotcrete that doesn’t stick to the wall, and “trimmings”, concrete that is cut off the wall because too much was applied in the first place.
All this concrete (that I paid for) ended up on the floor, but not in a good, “wow, you got bonus concrete floor along with your shotcrete” kind of way. On average, I would say we had about 3 or 4 inches across most of the floor (in several layers), and up to 8 or more inches near the walls, especially in the corners. It was uneven and lumpy and even had boot prints in it. The whole feeling was somewhat “war torn” and more than a little depressing.
When I setup the main level, I plan to back the metal lath with fiberglass screen. The metal lath will still provide the strength to catch the shotcrete, but the fiberglass screen will prevent any material from passing through.
Gallery
Thought I would try to put some extra pics in here…
David working on the concrete slag floor, he did a great job and filled up 33 5 gallon buckets of rubble.
David helping to tear out the old mess
And the Story.
I like to include the text of the video, along with some extra info that doesn’t fit in a narration, so that the content is google searchable.
For this job, I had hired some teens, rented a jack hammer and taken the day off work to make the long weekend even longer.
The big question was, “How would I get this slag out of the basement?” The final solution that I came up with was a Bagster dumpster that I got from Home Depot for 30$.
The plan was to load it up and use my trusty skid steer in to lift it up and out of the basement.
It took a bit of trial and error to figure out the best way to lift the bag and to empty it, but fortunately, we had lots of tries to get it right. You can see how we did it in the video.
The bagster is supposed to be for only a single use, but it held up very well, load after heavy load, for a number of days. The only tear was caused by dragging it up the rough wall in the first lift.
This first day, we were mostly focused on the edges where the thickest concrete was because I didn’t want to rent that 75 lb jack hammer for a second day. The heavy jackhammer was actually very effective on the thick concrete, but kept getting stuck in the thinner stuff. For that, the 11 lb breaker was much more effective. My Dewalt hammer drill also got a work out. At the start of the day, I couldn’t get the teens to touch the power tools, but by the end of the day, they were much more comfortable with me and the tools and were taking turns on the jack hammer.
On Saturday, my parents were in town, even though I warned them that we would be taking on the worst job of the build so far. I also hired Zack again, he was one of the teens from the day before.
My father got to cutting a slot in the footings (doorway) for the radon tube while the rest of us got cracking on the concrete slag. Our radon tube was made of a 4 inch corrugated drain pipe, wrapped in landscapers fabric to keep dirt out. It just gives radon an easy way to escape so it won’t build up under the basement floor.
Then my father and I worked on the floor drains while the others just kept right on cracking up that concrete. In order to get the slope correct from the floor drain in the central room all the way to the outer wall, we had to cut open the tops of the footings.
We had planned for holes in the footings to run these pipes, and I had even come prepared with 4″ PVC to use to form them. However, the guys doing our footings told me they brought their own 4″ corrugated drain pipe, which they nailed in place very quickly. The problem was that the flexible pipe “floated” up in the middle when the footings were poured. Instead of being a straight sloped hole thru the concrete, they bowed to the point that we couldn’t even get the 2″ pipes thru. I guess they were not used to the footings being so wide. Narrower footings probably wouldn’t have as much deformation due to “floating”. You may recall this same issue cost me time and money during several other stages of the build. Hopefully this was the last of it.
Then we came back out again on the holiday Monday, just my wife and kids. Sherri and I cracked things up with the 11 lb “breaker” and the boys scrambled to collect the pieces into the buckets. When the buckets filled up, one of us would dump the bucket in the bagster. The boys were motivated by being paid 1$ per 5 gallon bucket. They worked for several hours before wearing out.
With the big chunks finally removed, we raked the smaller bits and then brought in some pea stone, which is required by code in my area.
I came back on another afternoon with Zack and my friend Aaron to get the second half of the pea stone down and rake it all level. At one point in the video, you can see Aaron intentionally took a pea stone shower, just to see what it would feel like. I don’t think he will do that again.
The final product was a a peastone under-floor that meets building code. The black pipes are to channel radon out of the home and the white pipes are plumbing or drains. The inspector approved the work and we were able to rake the pea stone level and move on to the next step.
Next step is to get the vapor barrier, insulation and radiant floor tubes down here so we can pour the basement floor.
This video could have been about a lot of things… It could be about appropriate ways to get you kids involved in construction… Or about how I tried to hire for this basic task so I could focus on the trickier parts of constructing my earth sheltered home…
But in the end, the worked needed to get done, so I got my 10 year old to start on it one afternoon after work/school. David is a pretty good worker, but I didn’t mind him taking breaks (lots of breaks) with the bee bee gun. On another cool spring day, I went out there with my younger son. Generally speaking, they are very different personalities (Michael is also younger and therefore less suited to digging or working independently), but I was still pretty proud of how well Michael worked. He also enjoys the bb gun, but he actually spent most of the evening with me working on the rib forms (a separate video). On each of these evenings, we took a break to go walking (and shooting) in the woods.
That Saturday, the whole family came out. While I was working on welding steel arches (another video entirely), the rest of them got to digging. My wife, Sherri, did the majority of the excavation until the bedroom footings were completely uncovered.
I took the following Monday afternoon off work and came back out. This time, I managed to hire some students to excavate while a friend helped me with welding. These two teens were scratching their heads as they uncovered my footings like archaeologists with no idea of what layout to expect.
Side note here… I had some trouble with my generator (mentioned in another video) we ended up taking the carburetor apart, etc. It turned out the carb was fine. The oil level was just a tiny bit low and the “low oil” sensor was “almost” shutting things down as the oil was drawn up into the engine.
It took the teens several hours to clear the footings. My wife thought that was money well spent. Next I had them switch to clearing all the bracing wood out of the basement. We ended up moving it away with the skid steer. I offered them a 3rd job, but they were pooped and decided to go home instead.
Now that the wood is out of the basement, we can try to get these teens back to help clear the concrete slag out of there.
We don’t use “MIL” much in the USA, except for quantifying thin film thickness.
Stapling the Pex tubes down was easy and fun, Sherri and I took care of most of it, but the boys were very eager to try it themselves. I imagine it would have been quite a lot more difficult (and much less fun) without that commercial grade tool we used. The tool cost quite a bit (~200$) but is very well built and I will use it a lot… I also plan to sell it and recoup most of the money at the end of the project anyway.
I got the Manifold, Pex pipe, the Pex stapler, staples and the pressure tester from “PexUniverse.com”. I had looked at lots of other sites (including sites that put it all together for you, such as Radiantcompany.com), but this one had the best prices and the best hardware. There are also easy to find “coupon codes”.
This first day, we were mostly focused on the edges where the thickest concrete was because I didn’t want to rent that 75 lb jack hammer for a second day. The heavy jackhammer was actually very effective on the thick concrete, but kept getting stuck in the thinner stuff. For that, the 11 lb breaker was much more effective. My Dewalt hammer drill also got a work out. At the start of the day, I couldn’t get the teens to touch the power tools, but by the end of the day, they were much more comfortable with me and the tools and were taking turns on the jack hammer.
The final product was a a peastone under-floor that meets building code. The black pipes are to channel radon out of the home and the white pipes are plumbing or drains. The inspector approved the work and we were able to rake the pea stone level and move on to the next step.
