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?
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?
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?
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.
Continuing over the Door Buck
The boys can’t resist the camera
An accidentally pic as we moved the go pro
Aaron out on pour day
Ryan checking out the camera
Aaron and Simon handling it
Sherri troweling off the wall
2×12 buck for the exhaust fan
On the North wall, before trimming it. This platform is 14 ft off the ground.
North wall after trimming. It was supposed to be filled along with that floor.
Pouring the wall with Ryan
By this point, I was pretty comfortable with the concrete hose.
Here Ryan is climbing up the ladder to help me by vibrating the concrete. He doesn’t like heights, so I appreciated his bravery.
Full bracing
After removing the scaffolding, bracing and patches.
Starting work on the round window buck
I stacked these blocks, numbered them, drew and cut my circle hole and then took the wall apart so I could put it up where it belongs.
Sherri messing around for the camera
After getting in the window buck… Felt pretty good.
Night shot, I appreciated the lights on the short January days. It looks like a scene from an underwater exploration movie.
The south wall, before trimming.
Picking up the camera at the end of the night, looking tired.
Inside the Fox blocks wall, there are black HDPE plastic brackets to hold the rebar, etc. The blocks are “clipped” together with wire clips.
Sherri and Michael posing on the last pour day.
After the pour.
After removing the scaffolding and most of the patches.
After the Quad Deck ICFs were installed, there was still a lot of work to do before we could pour concrete, and then still a bit of work after.
Before we could pour, we had to install the pex tube for the radiant floors, build a perimeter form to hold in the concrete, put in plumbing, electrical conduit and duct work, and generally clean up any mess from the previous steps.
While we had the pump truck there, I also wanted to pour a couple 7 ft tall columns, so we also prepped those. We also poured a section of ICF wall, but I will save that for another post…
After it was all over, we had to remove all the forms. We gave the concrete a couple weeks to cure (and gain strength) and then we removed the scaffolding and shoring.
Video
You can find the Video here:
Experienced workers and new technology
They workers are used to pouring concrete on stable ground, so they were quite nervous about pouring on the ICF forms. They started out walking very carefully and there was a lot of nervous laughter. I made sure to pass along the pour instructions I had received from the Quad Deck installers. After the grooves were filled, the guys appeared to forget what they were standing on and began stomping around as usual. We had no problems with the Quad Deck system. Everything held up and there was only a little bleed water in the basement.
The blow out
During the column pour, the weight/lateral pressure of the concrete blew out the forms. To be clear, these were my column forms, that I built, not the Quad deck forms. My heart sunk as concrete spilled into the basement.
Next thing I knew, the guys from Dysert concrete, who were working on finishing the slab, jumped into action and helped strap the form and re-level it. This was really going the extra mile because they were really only there to look after the floor. They also went another extra mile and helped me scoop some concrete out of the basement. When it was all over and guys were packing up, I tried to give them some cash for their extra efforts, but they wouldn’t take it. If you are in the SE Michigan area, I recommend these guys.
In contrast, the pump truck operator (not my usual guy who is very helpful, so I won’t blame the company), clearly did not want to be there. He was grouchy from the start, perhaps not a morning person? When the floor was finishing up and I told him the columns were next, he complained a lot because he thought he was only there for the floor. He threatened to charge me extra. At that point, we were not even half way thru the minimum 4 hour window that I had to pay for. Also, I had specified (in writing) the volume of concrete and listed the columns and the ICF wall when I booked the truck. I didn’t bother arguing all these details with the driver, but I simply ignored his threat and told him it needed to be done before he could pack up.
Amateur legal note: If a contractor tries to change the price part way thru a job without sufficient justification, you can safely ignore the threat. Legally, if it would be even more expensive to switch contractors at that point, the threat of a work stoppage amounts to extortion and puts you in financial duress to agree with their unjustified price increase. In this case, I didn’t verbally agree to the extra charge, but I did tell him to continue on, which could be considered implicit agreement. However, even if I had agreed verbally, or in writing, I would still be able to contest the extra charges in court later due to financial duress making the amended agreement invalid. In order to increase the cost mid project on a fixed bid, the contractor would need to prove that the scope of the work increased significantly beyond a reasonable expectation. For instance, my septic field guys found a 1940’s garbage dump almost as soon as they started digging. The health department got involved and ended up raising the cost of the installation by about 30%, which I agreed to and paid without an argument.
When the columns failed, he was even more annoyed at the extra delay and kept saying he had another job to get to. I reminded him that he had been there less than half the minimum time I was paying for. A moment later, he started dumping concrete on the sand, we suspect it was intentional so he could leave. Sherri got mad and yelled at him until he stopped. However, as a result of the waste (intentional or otherwise), we did not have enough concrete to finish the ICF blocks in the north wall, but that is another story.
This pic is just one the time-lapse caught as I was moving the camera. It shows Sherri trying to clear the dumped/wasted concrete off the footings. Definitely not princess work, but I never asked her to do it… I was running too much to even think about it, but she separated it into smaller piles that I could move after it hardened, so I am glad she did.
Friends
You can see that a few of my friends in this and other videos and in the gallery below. Some of them actually like this sort of work, others come out and help anyway. I appreciate them all.
Working with friends makes the work go faster and the day fly by. Some of them have also taught me some good tricks based on their respective experience, or mentioned tools that would make the job easier. I will definitely have to have a big party when this thing is all done.
Pex connections
In the video, you might have caught that the pressure test dial didn’t hold the pressure when I filled it. I ended up using some dish soap from the camper to find the leaks. I had one easily fixed leak in the manifold, but most of the trouble was with the Shark Bite connections. Basically, I had not left enough extra length to reach down to my manifold (oops), so I needed to connect some short bits to make the final stretch. The SharkBite connectors are individually expensive, but easy to use without any tools, and I only needed a handful. However, try as I might, I couldn’t stop some of them from leaking. I talked to the plumbers (who use Pex for everything) and they said they prefer the crimp connections. I figured I would eventually be putting in a bunch more radiant, so I decided to spend the money on the crimp tool and it easily sorted out my issues.
Fibonacci Spiral
I had long planned to insert 1 ft long glass rods thru the Quad deck to let light thru in both directions. When it came to the layout, I went with the points of a simple Fibonacci spiral, centered in the room and leading around to a spiral stair case around the corner. Later, I can etch or mosaic in the actual curve if I want to.
These are sorts of fun little extras that make building your own home fun.
To keep the glass rods from being pushed thru the floor by the workers stepping on them, I screwed boards up underneath to hold the bottoms in place. This is why the lights turn off just before the pour in the video.
Rented Scaffolding
The scaffolding that I rented has been stacked nicely and ready for pickup for more than 4 months with no responses to my monthly texts to the builder to come and pick ’em up. You will see it in the background of various other videos ;^) It was actually quite labor intensive to remove it from the basement, so I hope the builder appreciates that that free labor. I wonder if I could surprise him with storage fees? I had to move it again recently.
Quad-Deck is a product sold by Quad-Lock, an ICF (Insulated Concrete Forms) company. It is basically a flooring (or roofing) system that uses polystyrene as a form for concrete. The panels click together and include steel beams so they can span greater distances (with less shoring) while supporting the wet concrete. The concrete hardens to form a continuous floor over the panels and the panels are left in place as insulation.
My unique earth sheltered home design includes a basement. This increased the height of the walls holding back earth. Structurally, I needed my floor to be a sheer plane that would prevent the earth from pushing in those walls by transferring the lateral loads right thru the house into the dirt on the other side. The resulting compression would be well handled by a concrete floor. I just had to find the easiest way to build one.
I could have built a deck out of wood or steel panels supported by bracing and just poured concrete over that. There are modular systems that work pretty well and are cost effective for rectangular buildings, but my curved shape would make it quite difficult and expensive. Also, those systems generally produce a uniform concrete thickness, which adds to the expense.
ICFs had the advantage of being easy to setup and easy to trim. They also use less concrete because they can form that stronger IBeam shape. The insulation is also perfect for my in-floor radiant heating and helps with more consistent indoor temperatures and reduced sound transmission.
Unlike ICF building blocks, there are very few companies that make this sort of ICF floor system, just about the only other company with a similar product is “Lite-Deck”, but they had no distributors in my region. AMDeck is a similar product that only comes in short pieces (32 inches long) so you don’t need to order custom lengths, but you need to place the steel joists separately and then place the Insulation over them and it just seemed like more could go wrong.
The Video
The Process
1) The quad deck panels are cut to length (according to a cut sheet I provided) in the factory and shipped to the site.
2) The installers (in my case, Dan and Brian), started by setting up scaffolding spaced across the floor. Beams were placed across the scaffolding and the scaffold legs were adjusted to level the beams across the space.
3) My curved walls required both ends of every piece to be shaped to fit. This was done with a measuring tape and a saws-all. Occasionally a big cutting wheel was used.
4) Each piece was pushed up against the previous piece before being screwed in place so that they would be held tightly together. The screws were “toe-nailed” thru the wood shoring and into the steel reinforcement.
5) Spray foam was used to seal the gaps between the top edge of the wall and quad deck material.
6) Rebar was placed in the channel and across the quad deck according to the drawing. Rebar chairs were used.
7) A perimeter form, plumbing, electrical, HVAC, radiant floor PEX, etc. were added later (next post).
Surprises
In my region, it seemed like I pretty much had to go with QuadDeck if I wanted this sort of product. To make matters worse, QuadDeck only had one single installer in my region. I asked for a quote on both the quad deck and the ICF walls of the garage. The wall quote from this builder was not even in the top 3 and several times more expensive than doing FoxBlocks myself. But they were the only quote for the Quad Deck, and I thought special bracing was needed, so I decided to go with them for that portion of the build. The quote was for “Quad Deck install, labor and shoring rental.” I called for further clarification and was told it would get the quad deck ready for the pour, but did not include the actual concrete or labor to pour and finish the floor. I would need to call a separate contractor for that. The price was high, but acceptable for a company with specialty experience and equipment, so I put them in my estimate.
Later that summer, after back-filling around the basement, it was time to get the quote updated and call the crew out. I sent in pictures of the basement (including zoomed in shots of the edge of the wall), along with a cut-sheet and images from my 3D model, calculations from the QuadDeck manual (it is a pre-engineered product), etc. They updated the quote, but said they wanted an engineering stamp before they would start work.
My engineer had retired (still young, but wanted to stay home with his kids), so I contacted the builder’s engineer. He was willing to check and stamp my work and he was very affordable, but he was also very old (eighty something) and only worked face to face (no computers). I would need to take him drawings and he would hand calculate and stamp them if he approved. There was a funny telephone episode where I was asking him his address (so I could google map it), but he just kept repeating how to get to his office via landmarks. Before I could get out there (he lived 4 hours away), he had a stroke and retired. I didn’t want to pay a new engineer to learn about QuadDeck, so I began a search for someone with experience. The builder wasn’t much help. I even called quad-lock company headquarters and they just forwarded my request back to the builder. I called QuadDeck back a few times and asked for other regions until I eventually found an Engineering company in the southwest that was licensed to stamp a drawing in Michigan. It ended up adding a surprise $1200 to my estimated cost, but may have saved me some money because my version would have used twice as much rebar (I was being conservative with the Quad Deck load calculations).
I still couldn’t schedule the builder to come out. I tried to go around him, but it turned out he was also the only builder in the surrounding 4 states. He had a monopoly and ran his business that way.
Eventually, we got the quad deck panels ordered. I knew it would take weeks for my order to be cut and then delivered. They were supposed to call me with a delivery time 24 hours in advance so I could organize to unload. Instead I got an annoyed call from the driver at 6:00 in the morning wondering why there was no one at the building site. Surprise, my 10-year-old and I hopped in my car and drove the hour out to the property, but there was no way to organize any other help in that short time. When I got there a little after 7:00 AM, there was a large 18 wheeler trailer full of QuadDeck planks waiting for me. It was the closed in kind with big double doors at the back, so I could not unload with my fork lift. The panels were stacked to the roof and would need to be removed by hand, slid out one at a time. I had to get a 13 ft ladder just to reach the panels. The driver was impatient, so David and I got to work without setting up the camera. The driver complained that we were taking too long, so I told him that he could have called to let us know he was coming (as he was supposed to do) or he could help. He helped a little with a couple of pieces that David could not physically lift, but generally speaking, he just paced back and forth. Eventually we got them all out of the truck and the driver shook David’s hand before he left. I think he was impressed with David, but was also still pretty annoyed with me for not having a real crew.
We used the SkidSteer to move the blocks up behind the house and stacked them and covered them with a tarp… And then waited. Every few weeks, the builder made up some excuse and moved the date back. The list of back and forth texts is quite ridiculous. Eventually, 3 months later, he said he would be able to slot me in before the end of Sept (one week away). He asked if I had the rebar on site, I did. He asked if I had the full list of building materials he needed… I had no idea what he was talking about. He sent me a list, which added up to $1700. Surprise! The list included 4×6 beams, 35 lbs worth of screws, 3/4 inch plywood, 2x4s, 2x6s, a case of spray foam, anchor bolts, etc. I called him and asked if he was planning to build the shoring? I was obviously annoyed, which annoyed him and he said we could just call off the whole thing and I could look for another builder.
Of course, I already had the material on site and he knew he was the only builder within 1000 miles that had ever installed this stuff before… I gave in and we proceeded. He then told me that his quote did not include the perimeter forms that would also be needed before we poured, but he could do that for an extra cost. I was so annoyed, I didn’t even want to discuss the extra costs or argue that he never mentioned this before, so I told him I would take care of that myself.
I asked how many days it would take for what was included in the quote, he said 6 or 7 days for a crew of 3 people.
Anyway, as you can see from the video, it took 1 day just to set up the shoring (which turned out to be regular scaffolding and my 4×6 beams, leveled). Then 2 days to put in the quad deck. There was also a short 4th day of just a couple of hours when they finished the quad deck off and were gone by 9:00 AM to work on pouring some other wall somewhere else. Then the last day was just putting in rebar and spray foaming. The main boss never even made it out to the property.
After the job was done, he sent a final bill that included about 2000$ extra costs for “unexpected extra work” including putting in rebar and spray foam and “gasoline for the generator”, etc. I was sick of the surprises and fought him on most of it. He kept asking me to “meet him half way”. Instead I went thru my emails, texts and time-stamped-timelapse photos and wrote up what could easily have been a trial defense. For instance, I pointed out that he had estimated 7 days for 3 people, but got the job done in 4 days with mostly 2 people, how could he justify “extra costs”? He eventually gave in on most of the bogus extra charges, but still got his “36$ for gasoline for the generator”. I just wanted to move on.
Then he hit me with the scaffold rental. He wanted several thousand for that. I told him that his quote said “labor and scaffold rental”. He said that was just the first 2 weeks, I had kept the scaffolding for 3 weeks longer than that to finish getting it ready for pour and then leaving the scaffolding in for 2 weeks while the floor set. He wanted $15 per unit for those 3 weeks. I eventually agreed, but then he defined the units as half sets (so twice the cost). Arg! long story short, I ended up paying an additional 810$ to rent that scaffolding for 3 weeks. For perspective, I paid $1200 to buy my other 5 sets of scaffolding, and that included 6 decks, 8 wheels, outriggers, a grouser bar, etc.
Anyway, as much as I liked the idea of QuadDeck, I would never work with that builder again. I have some quad deck left for the roof of the mezzanine. I plan to install it myself.
Bonus fun facts…
1) The scaffolding that I rented has been stacked nicely and ready for pickup for almost 4 months with no responses to my monthly texts to the builder to come and pick ’em up. You will see it in the background of various other videos ;^) It was actually quite labor intensive to remove it from the basement (next video), so I hope the builder appreciates that that free labor. I wonder if I could surprise him with storage fees?
2) At the end of each day, the guys did a great job cleaning up the site. They used a leaf mulcher to suck up and bag the little broken bits of Styrofoam so they wouldn’t blow all over the place and they carefully stacked the other trash.
Cost
The original quote was about 4$/sqft for quad deck materials. That turned into 6$ by the time we placed the order (including freight). Then another $7/sqft for labor and shoring rental. I also budgeted about $1 for rebar and 2$ for concrete, plus 3$ for labor to pour and finish the floor. Then I had the surprise of just over 1$ for engineering plus just under 2$ for extra materials (some of which I was able to return unused and much of which I will reuse elsewhere in the build). Then, finally, that ridiculous “additional” scaffold rental at the end, which divided out to just under 1$/sqft. That comes to about ~22$/sqft by the time we were done. Quite a bit over-budget, but survivable.
