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

ICF Walls

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Posted on January 21, 2016 by

 

2015-09-02_Aaron&Simon (Medium)

ICF blocks seemed like the perfect solution for the front of my garage where they would be needed as walls for the garage and as a parapet to hold back earth over the roof, without needing any special handling for insulation. There have already been previous posts about my Fox Blocks training and my early work with these.  Now that I am all done with installing my ICF blocks, this post includes FAQs about my lessons learned, costs, etc., but first, the video

Video

Earlier Post

There was an earlier post about why I chose Fox Blocks, the training, etc.  The rest of this post will be about lessons learned since then.

FAQs

Why pour in a series of small pours?

2015-07-25_Working on 2nd half of Mudroom wall

The more concrete you pour at a time, the more pressure is exerted on the forms and the more concrete will come spilling out if anything goes wrong.  In other words, I wanted to take baby steps.

I also couldn’t pour the front wall at the same time as the back wall because I needed to leave the front open while I continued to make those big concrete ribs in the garage.

I couldn’t wait on the back wall because I needed to mount the electrical service somewhere and the pump truck was cheaper than it would be to start on a temporary structure and then move the meter.

Even brave people are limited by the physics (hydrodynamics) of pouring concrete, so I did pour the front wall in only 2 stages instead of 3.  But even with my growing experience and confidence, I didn’t sleep well the night before we did that pour over the garage door openings.

Why Scaffold Jacks on the north side, but regular scaffolding on the south side?  Why not ladders?

2016-01-16_NorthWallScaffolding (Medium)

When you are building the ICF walls, I guess you could use ladders.  It would be a hassle to keep moving them around, but it would be possible.  However, when it comes time to pour the wall, you need to be able to move swiftly along the top of the wall.  You can not keep stopping the pump truck to climb down and move the ladder .  You need some sort of working platform.

The north wall was poured in stages over a long period of time because I was waiting for times when I had the concrete pump truck coming for other reasons (such as the basement floor or the quad deck floor).  During that time, I knew I would want my scaffolds for other tasks, such as setting up the steel framework.  Home made scaffold jacks were the easy and affordable solution because I could just leave them in place and move them up as needed.

By the time I got to the north wall, I was just paying for the pump truck and doing my pours much closer together, and I wasn’t using the scaffolding for other tasks.  I also didn’t think the jacks would have worked well across the open garage doors anyway, and the driveway was nice and flat for stand alone scaffolding…  So I just used my regular scaffolding.

 

How much did it cost?

I bought the Fox blocks at Menards, so you can check their website for the prices, but they were just under 20$ per block (16 x 48 x 12 inches).  The walls then got filled with concrete that cost about $100 per cubic yard (27 cubic feet).  There were also some clips and a bunch of wood (I used a lot of scrap from earlier projects), rebar that I already had laying around, etc.   I buy the rebar by the ton, and pay something like 35 cents per ft.  If I do some fun math, and divide things out per square ft…

Fox Blocks = 3.75/sqft

Concrete (6 inches thick) = $1.85/sqft

Rebar = 0.35 cents.

—————

Total = $5.95/sqft,

Plus a few cents for clips, etc.  That is not too bad for a 12 inch thick wall, but it is about double what it would cost to frame a 2×4 wall with 4 inches of insulation and house wrap.  I didn’t have separate steps to attach vapor barrier, insulation, etc. because those are all built in, but clearly, I still spent a lot of time putting up patches, etc.

I don’t regret going with the ICFs because I think they are much better in this application as parapet (retaining wall) for the dirt on my roof. The concrete wall will be much stronger and much longer lasting without any risk of rot, etc. There is also the dynamic R value of the concrete in the wall that will keep my garage much more thermally comfortable.  My wife likes that no insects or mice will get thru it, but in the mean time, some birds are trying to make nests in the exposed polystyrene.

What I left out of the above calculation, because it is a real kicker for me, is renting the pump truck each time. Filling a 14.5 ft tall wall without a pump truck isn’t really a practical option. For the first two sections, we scheduled the wall pours to align with the basement and quad deck floors, so no additional cost there.  However, for the other two times, we just had to pay for them to come out for just a tiny section of wall…  Each pump truck visit was about 700$, which is more than the cost of the concrete we pumped.  Each pump truck also required me to order a couple extra cubic yards of concrete just to fill the hose (that all gets dumped out at the end). If we were doing a larger chunk of the house in one go (such as a whole house built of ICF blocks), we could have improved that ratio a lot.

How about time?

Yes, I did this work over about 6 months.  Mostly that was to align pour days with other tasks that would need the pump truck.  I was also working full time and basically only building on Saturdays and some weekday evenings.  The actual time spent stacking blocks was not too bad.  How would it compare with stick frame?  Probably similar.  Certainly it will last longer.

What was with all those edge patches?

2016-02-01_AfterTheFinalPour

There are no attachment points on the ends of the fox blocks.  They attach to each other, end to end, with clips between the plastic webs.  The styrofoam just buts up against the other blocks, so it has some compressive strength, but no tensile strength for holding screws.  When you attach the end bucks, etc. you need to connect to the high density polyethylene furring strips built into the front and backs of the blocks.  To do this, I screwed boards (like 2×6 boards or sheets of particle board with 2×4 blocks) to the front and back of the ICF blocks and then I could screw the end boards to the sides of these.

I am pretty sure all the vertical end walls and especially the ones for the top of the garage door opening were critical for containing the concrete.  The patches, such as the one along the vertical seam shown in the video, were also critical.

On the top edge of the wall, I had cut a sloping shape.  When we poured in the concrete, if it was too wet (high slump), it may have simply poured out the sides again.  I knew there would be some pressure on these sides, even if it was not as great as the vertical sides, and I wanted to contain and shape that concrete.  The concrete did push at the top/side forms for the first 3 pours, but for the last pour, the slump was so low that the concrete probably would have just sat there in the shape of that hill and let me trowel it smooth.  In that last case, the boards were just in the way and made it difficult to get the concrete down inside where it needed to be.

Tips:

1) The best tool to cut the ICG blocks with was a battery powered jig saw with the longest blade you could buy.

2) Get a concrete vibrator.  Harbor Freight has a cheap one.  It makes a huge difference to the flow of the concrete, which means you can get lower slump concrete (which sets up stronger) and still have it nicely flow around all the rebar and ICF webs without any voids.

Before buying the vibrator, I had wondered if it would be worth the money.  Professional grade vibrators cost hundreds more.  As it was, I thought it was a great little investment that got me thru all my ribs and my walls and died 5 minutes before the end.  I haven’t needed it since, so I haven’t tried to fix it yet.  Maybe just a switch died?

3) Because the ICF blocks look like lego, any many of us “do it yourself” builders were lego maniacs, we some times assume that overlapping the blocks (running bond) is important.  When something in the wall makes this difficult, we might want to waste lots of time or chop up expensive blocks trying to prevent a vertical seam. But it is totally unnecessary.  Unlike bricks (masonry or lego), the little styrofoam nubs on the ICF blocks do not actually hold the wall together in the long run.  The void gets filed with a monolithic concrete pour that ignores all those stacking details.  Instead, just focus on making sure the surface of the wall is patched so the forms won’t split open along the vertical seam.

 

Gallery

Just some related pics.

Electrical Main Breaker

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Posted on December 13, 2015 by

“Nearly all men can stand adversity, but if you want to test a man’s character, give him power.”  – Abraham Lincoln.

“Never underestimate the power of stupidity”  – Robert Heinlein

OK, so maybe those quotes don’t have much to do with hooking up my main breaker, but I wanted power, even if it tested my character, and I was not too stupid to get it ;^)

In my region, the power company has set things up to favor a proper service entrance setup rather than temporary “construction” power.  The temporary setups have more paperwork and lots of rules about the setup, such as you can’t have outlets more than 10 ft from the transformer.  They also make it more expensive than hooking up the actual house main power.  On the phone with the power company, and I said, “With all this hassle and expense, why would anyone want to get a construction hookup?” and they guy on the other end just said, “Exactly.”

Of course, I had no wall to mount the electric meter or breaker on, so I would need to continue with my generator for a while longer.  I appreciated having my generator, but I didn’t like the noise and I really don’t want to make things noisy for my neighbors.  I also don’t like paying for gasoline.  Getting electricity on site just makes the whole building process easier.

Once, when I stayed past sunset the night before a pour day, a neighbor drove by and told me to, “Go home.”  All I could do was reply, “I’m working on it.”  I shut the generator and lights down within 15 minutes and finished up the column forms by flash light.

 

This post is just the story of how I got that power hooked up. If you know anything about electrical, my mistakes will be obvious to you, no need to point them out now. Anyway, I learned a few things along the way to getting it right and ended up still saving a lot of money.

The Video

Why?

Why do it myself?

The quotes to get my electrical done were not affordable.  I tried to get other quotes, but most electricians never got back to me or told me they were not interested in bidding for such an unusual home. The few that did get back to me wanted more than $64,000.  I asked one of them about the crazy price and he said it was about triple his normal rate per square foot because he still needed to figure out how to do it.  Some of this was because I have electric backup heat and electric hot water (on demand), which increased the overall power requirements, but most of it was just because the house was not like anything they had ever done and they had to estimate high to cover their risk (understandable).

I have already wired the basement, and that only cost about $400.  I was already pretty familiar with that sort of basic wiring, and you can find tons of information in books and online, so it was no problem. Taking care of the service entrance and main breaker was the next step.  However, it was something I was unfamiliar with and most books on wiring don’t cover beyond a basic hookup.

Why those two big switches?

My house is long and the service entrance was at the far corner of the garage (closest point to the transformer).  If I ran all the circuits from that back corner of the garage, it would be a huge task to wire the house, with many of the runs going well over 150 ft.  It would be a wire-pull nightmare. Also, the cost of all that wire, especially the bigger stuff for the on demand hot water heaters, well pump, etc. would really start to add up.  The concrete walls and unusual shape would also make it tricky to run circuits between the various sections.

So, I decided to put a breaker in each major section of the house.  I figured one in the in the laundry room, for the bedroom wing, and one in the mechanical room (under the middle of the house), to cover the rest of it.  However, the total AMPs required between these breaker panels was also going to be well over 200, so I couldn’t just have a main breaker and a sub breaker.

Code requires that the power from the meter socket should not travel very far before it passes thru a breaker or disconnect.  If I was not going to have the Main Breaker right on the other side of the wall from the meter, I would need a fusible disconnect switch to turn off the power in case of a short.   You can get reasonably priced switches for 30 amp or even 100 amp circuits, but they get big and expensive for 200 amp circuits.  My 200 AMP fusible disconnects are pretty much considered “commercial” equipment and I had to special order them.

There was also the issue of scheduling.  I had the back wall of the garage up well before I could put up either of the other panels.  The wall of the laundry room won’t even exist until June 2016 (or so). Having the switches lets us hook up the main power now, but just leave the switch off until I have the panel installed.  This is why the disconnect on the left is not connected to anything.

2Switches&Breaker

The breaker panel to the right of those big switches was originally a temporary idea so I could have power during the build.  I planned to move that one to the Laundry room eventually.  However, I have since decided to replace it with a smaller panel and just wire the garage circuits from there instead of from the mechanical room.  This will save me time and money and lets me get the garage circuits going sooner.

My mistakes

Building code is important, but things are not always clear and there is a learning curve when applying book knowledge to the real world.

electrical-cautionI had passed my basement wiring inspection easily, but the service entrance was more mysterious.  What info I could find in books or online really only covered the basic situation where the meter and main breaker are just inches apart.  From reading the code, I knew I would need to add switches, but I couldn’t find out much about how to install them, etc.  I hoped those expensive switches would at least come with some instructions, but they didn’t.  I figured I could figure it out well enough.

Some of the mistakes were things that I had known earlier in my life, but temporarily forgot or just messed up in the rush to beat the ground freeze.

Oh well, mistakes were made and that is what in the inspection process is for.  I will try not to mess up like that again, but, for now, I am moving on, still happy that I saved many thousands of dollars over getting a pro to do it.  I also learned a bit more than I would have otherwise.

Turning on the power

On the first day, two trucks and 5 guys from the power company showed up.  I had booked the day off work to be there and was anxious for them to get started…  They didn’t.  Only one guy even got out of the truck to talk to us. We asked what the delay was and he said they were a bit confused about where to run the cable.  Basically, they wanted to run from a slightly closer (180 ft distance box), even though it would require digging across the driveway, which they did not have the equipment for anyway.  I had already got the power company to agree to a 15 ft longer path from another transformer that would stay far away from the drive way or any thing else and only cut thru soft sand. Anyway, they didn’t want to start until the project manager at the power company approved what I told them he had said. He wasn’t in that day, so they would just wait.

I thought that was crazy to just sit around all day, but they told me not to worry because “This has been spec’ed as a two day job.”  He basically made it clear that I didn’t need to worry about how long they took because the cost was fixed.  They stayed, sitting in their trucks, all day, but did literally nothing towards hooking up my power. I was pretty annoyed that I would need to take a second day off work, but at least the weather was good and I was able to work on other things.

PowerCompanyCrew

The next day, they were back before 9:00 AM.  They sat in their trucks for the first hour or so.  We went down to ask them if everything was OK, but they just said they would get to us soon. Eventually, a few of them came up and looked at the meter cabinet while a couple others got the trenching machine off the trailer.

During about a half hour time frame, they hand dug the first couple feet by the wall/foundation and then used the excavator arm to dig a short trench, maybe 20 ft long.  This was done by 10:22 AM.

Trench1

They said something about not having any 3 inch pipe with them and said they would need to wait while someone brought some.  This is the standard pipe that they always use, so I thought it was funny that they hadn’t brought any with them.  However, they only needed a few feet of it and I had several pieces laying around. I offered them a piece, but they said they would just wait for the delivery.  They waited in their trucks until 11:40.

Trencher

The next step was to use the trencher to lay the cable.  One guy drove the machine and another fed the wire into it by hand.  The wire was pulled down thru a plow that split the earth to lay the wire and then let the earth close up behind it.  It basically moved at walking speed, so the cable was laid within 15 minutes. The cable had been laid on the ground next to the path before hand, so the whole process looked similar to pulling up a zipper. Then they took a 20 minute break before the one guy came back up with the machine and filled in the trench at the top at 12:21.  Again, that was just a few minutes of work.

Trencher_Plow

They put the machine back on the trailer and were quiet again until 1:54 when some other guys came out to hook up the meter socket (meanwhile the trencher guys stayed sitting in their truck).

AllenHere I should note that, other than something to cut the cable, the only tool these guys need to attach the cable to the meter socket is a 3/8ths inch Allan key.  This is the same sized Allan key they need for every single service entrance job that they do.  Guess which tool they didn’t have?  I loaned them mine.

Roughly 20 minutes later, they were done.  hooking up the 3 wires.  After packing up, one guy came to tell me that I could start to use the power. That first attempt video was shot right after they left at 2:22 PM. That didn’t work. Obviously, I was pretty annoyed with the crew by that point. I called the power company and was told someone else was planning to come and finish the setup.

New_Meter_Open

After my family had gone home for dinner, a sixth guy showed up around 6:20.  He did something to start my meter (I didn’t see exactly what he did, but it was quick.)  It seemed to me that perhaps I had misunderstood the first crew and the power was not supposed to be on until this guy came and did his part? I asked him about it, but he didn’t seem to understand my question.  He quickly sealed the meter box and told me I could start using the power, and then he was on his way.  I filmed that second video, with working electricity at 6:26.

So, let’s do the math.  They were at my site for most of two days, but my time-stamped time-lapse pictures show that parts of the crew worked on my hookup for less than an hour and a half.  I guessed three hours in the video, but I see that was much too generous.  If they were doing something in that truck, I can’t imagine what.  Keep in mind that this is a private company, not even government work.  But they do have a monopoly in the region, so maybe that explains it.

Costs

The 2/0 cable was about $1.50 per foot and I needed 3 cables, each 15 ft long, so 65$.  There was also the 45$ worth from my first try that was wasted.  The ground wire was about 10$, plus 25$ for the two grounding rods and acorn clamps.  The main panel (200 AMP QO) was about 200$ and the 20 amp breaker I installed for the construction circuit was $7.  Those big switches (200 amp fusible disconnects) were very expensive at over 330$ each, and each took 30$ worth of big fuses.  There was maybe 20$ worth of 2 inch conduit. Then there were a few small things like Tapcon screws to mount the boxes, etc.  I had them already laying around, but lets say 5$ for all that.

So the hardware total is, $372 for the service entrance and main breaker, and $720 for the switches, so $1092 total.

The price to get the power hooked up was reasonable…  820$ up front covered the meter box and all the hookup, including the 195 ft of cable from the transformer. Since it took 5 guys a couple days to get it done, I am guessing it cost the company more than that to do the work, but they plan to get the rest from me over a lifetime of electric bills.

It was going to cost an additional 3$/ft if the ground froze (nearly 900$ more).  So, after getting the back wall completed in october, I was in a rush to get the service entrance installed and inspected and the hookup scheduled.  That rush may have contributed to the mistakes.  It was only due to the merciful “Al Gore” winter that let me delay into the middle of November without the ground freezing.

 

So total to get the service entrance and switches up and running is ~$1910.  A big chunk of my electrical budget, but only a tiny fraction of what the professionals would have charged.  Of course, thee were also a few evenings worth of time to get it done and then rip it out and do it again properly.

 

 

 

Finishing the Quonset Hut

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Posted on October 24, 2015 by

The Video

Its a short one this week, and the end is rather abrupt, but here it is anyway…

 

Why a Quonset hut?

My house design is an experiment with a variety of different arch forms.  Since it is a self build, I kept most of my spans shorter than 15 ft.  The exception is the garage.  I wanted a 3 car garage for practical purposes and decided to use a Quonset hut to form the wider span.

The quonset hut could probably support a significant earth load, if it were carefully distributed, etc. But in my design, it is really just fancy formwork to hold up the rebar and shotcrete that will actually support the earth.

My build also required a workshop to build the other components, and the Quonset hut is something that could be erected quickly, early in the construction, and provide that place.  I have used it to weld steel arches, store materials, and most importantly, to form my large concrete ribs.

Why build it in two stages?

The rib forms needed to be built on a large flat surface, out of the weather.   But we would also need to use a crane to move them to where they needed to go.  The ribs weigh 5000 lbs each, so I couldn’t roll them out across the gravel or dirt.  Instead, I needed to keep them on the slab, but also needed open sky above them for the crane.

The solution was to build only 2/3rds of the Quonset hut on the slab floor.  I could use that sheltered space at the back to form the ribs.  I would then jack them up and pull them forward to the open 3rd where a crane could lift them up and over to where they needed to go.

RibPulledOut

 

RibStillIn

When the crane came out, it did lift them straight up and over, but I noticed that it actually had a telescoping arm.  I asked the operator and he said that he could lift them up and pull them out of the building if I finished it…

The ribs were taking me a long time to make and closing off the building would save me a lot of hassle, so that seemed like a good idea.  It had been almost a year since the first 2/3rds were erected.

The final 3rd

My parents came down to visit and to pick up their camper. Anyway, it was windy and we didn’t want to try erecting Quonset sections with just the three of us. However, that is a good number for assembling the steel arches, so we spent most of the afternoon doing that.

SteelArchAssemblyParents

 

The following week, I put out help requests on Facebook and at work. The first few days, I was worried that I wouldn’t have at least 4 people there at one single time.  By the end of the week there were lots of people volunteering and I was buying a few extra half inch sockets and wrenches so there would be tools for everyone.  One co-worker even volunteered his whole family of very capable teens.

Bee_Bolting

Bee_ReadytoPull

 

The steel ribs went up very quickly.  7 in under two hours.  We were actually done before the Pizza lunch I ordered arrived.  No worries, we had other work to do (not captured on film).

Mistakes

Because these new steel arch sections were were bolted to the rest of the Quonset hut, which was already bolted and concreted to the slab, and because they were very heavy, I wasn’t too worried about the new section blowing away. With 13 people working in parallel to bolt the sections together, I didn’t want to interrupt that flow and make everyone stand around while I drilled and bolted the steel sections down.  I figured I would come back and take care of the anchor bolts next time…

However, by the next time I went out there, I found that the wind had lifted the front third of the Quonset out of the groove.  We ended up wasting several man hours and a lot of sweat getting it back into place.

OutOfGroove_1

 

OutOfGroove_2

OutOfGroove_3

I should have known better because this is a pretty typical fluid dynamics problem that I had to do several times at school.

QuonsetFlow

Another “mistake” that I pretty much accepted was that my building was a little longer than it should have been and ended up hanging over the edge by a few inches.  I ended up cutting that off so it wouldn’t get in the way of the end wall, but that is another story.

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