I’ve followed this forum for a couple of years, but this is my first post. First of all, I want to thank some of the regular posters who have provided me with some of the insight and knowledge I needed for my project through their posts and discussions. I also wanted to let people know about my experience and maybe provide some helpful insight to someone else considering a similar ICF project. And of course everyone likes pictures, so I’ll include a few.
To start off, I’d like to have my dream home built with ICF’s in a couple years. So, about a year ago I decided I wanted to get a little experience and build an ICF storm shelter myself. I know this was a bit of an ambitious project for someone who works in a completely different industry and who had never seen an ICF block in person until I had the full semi load delivered to my yard a few months ago. I also didn’t want to take any time off from my regular job (40-50 hours a week), because I needed to pay for this little project somehow.
What I eventually settled on in my design was about a 1200sqft storm shelter that is about 18ft below grade (to the floor) and with about 7ft of dirt on top of the structure. I wanted go extra deep to reach a fairly constant ground temperature (about 68 degrees +/- 2 degrees around here). Also, I figured I wouldn’t have to worry about hail damage if I went that deep.
I started last winter with a rough idea of what I wanted, and figured I was going to need a good engineer. I was fortunate to find an excellent engineer on this forum – Jerry. He has been an enormous help with my project from start to finish. I presented him with what I wanted, and after a couple meetings, some soil testing, and a bunch of emails, he gave me a sealed set of engineering diagrams.
I managed to get a building permit from the county for a “Storm Shelter” without having to provide any details on my project or unnecessary bureaucracy. Nobody builds basements in Texas, so it is not a basement.
I spent the spring and early summer researching what I would need to know to do this project myself and figuring/planning out the details. I also researched the different ICF blocks and manufacturers out there. The internet and Google are two great tools for this purpose. I called around a few manufacturers and was able to get what I thought was good price on the ICF forms. The sales rep I worked with (Dustin) was very helpful and enthusiastic with the sales process.
I calculated the rebar and forms I would need based on the engineer’s specs. I placed my orders for materials and spent the early and mid summer cutting and bending the 26,000 pounds of rebar I ordered. If I build another storm shelter someday, I think I’ll have the supplier pre-fab most of the pieces. It was a lot of work cutting and bending the rebar from 40ft sticks, but was worth doing at least once myself.
I had planned to break ground in early August – about the driest part of the year (and also the hottest). I figured dry was the most important factor because I didn’t want my project to turn into an 18ft deep swimming pool. I could foresee the project becoming a very big mess if we got any significant rains during the construction process. Fortunately, we remained in a drought during the project and ended up with a total of only about 3-4 inches of rain during the whole 3 month building process (from breaking ground to complete burial), and nothing more than an inch at a time.
This project took some pretty serious equipment to do the dirt work – moving about 3000 cubic yards to dig the hole, and about the same amount to bury and grade the surface afterwards. I had to hire someone with the right equipment to do this for me. This was the one part of the project where I underestimated the costs some.
It took about a week for my contractor to dig the hole, and then I got to work on the sump room and foundation. The sump room is a vertically oriented 5ft diameter HDPE pipe that goes down an additional 8ft below the floor (total of about 26ft below grade). This connects to the perimeter (French) drain that goes around the shelter, and will also come in handy when I decide to add a bathroom and other pluming inside.
I got the foundation poured without any problems, installed the perimeter drain and got to work on the fun part (the ICF walls). There was a slight learning curve as I figured out some of the smaller details of working with the blocks. The outside walls are all 12” concrete, so I had knock down forms. I was a little surprised how much time it took to put the forms together. I think I spent more time assembling the knock down blocks that I did cutting and stacking the blocks to build the walls.
As the walls got taller, I put up the bracing and walkway on the outside of the shelter. I used a modified form of some wood bracing diagrams I found on this form. I had debated for a while whether to rent real bracing or to build my own wood forms. I eventually decided on the wood bracing because I wouldn’t feel as pressured for time as I would if I were renting them by the day, and I could re-use the wood from the foundation to the roof. In the end, I feel it was probably a toss-up between the two (cost vs. labor).
The outside walls were of course all ICF, but I had decided to do some internal walls with ICF’s as well. When all the walls were up and my internal wind resistant doors (and zombie resistant as one of my brothers pointed out) were in place, I proceeded with the wall pour. Having never done or seen an ICF pour before (except for what I had seen on You Tube), there were a couple things that I learned doing the wall pour myself. First, I didn’t realize how messy it would be. I should have covered in plastic everything inside the structure that I didn’t want covered in a half inch of concrete splatter. I had some tools, doors, and other materials around that required quite a bit of clean-up after the wall pour. There is no fine control on the concrete flow coming out of the pump truck, and there was a lot of rebar sticking out of the top of the walls. Every time we moved the concrete pump hose, the concrete stream would hit rebar and splatter all over.
The second issue I ran across is that I had several “T” intersections in the walls, and I made these intersections myself by cutting the regular, straight blocks. I failed to anticipate the extra bracing I would need on the outside (top area of the “T”) and I did have a single moderate size blow out. That set us back about 20-30 minutes for cleanup and a quick re-enforcement job on the other intersections. Let me stress that the blow out was completely my fault, and not a problem with the brand of blocks I used. In fact I was very impressed with my ICF blocks. They had arrived well packaged and in excellent condition. There was good quality control throughout all the blocks and I would definitely use the same brand again.
The rest of the wall pour went without problems. After several days of cleanup, I started waterproofing the walls. I had looked at both the peel and stick and paint on waterproofing products designed for ICF’s. I did a fair amount of research and I felt it was kind of a toss-up between the two. It came down to the company that had the more responsive sales rep, and I went with a paint on product. In the end, I felt I made a good decision and would go with the paint (roll) on product again.
It might have been overkill, but in addition to the paint on waterproofing applied directly to the ICF, I added a layer of house wrap, followed by ¾ inch polystyrene insulation panels (to protect the ICF from the backfill and provide an extra drainage plane), and finally a layer of 9 mil plastic sheeting. The multiple layers of waterproofing and drainage planes and the French perimeter drain will hopefully prevent any water issues down the road. Fortunately we never ran into any ground water (even down 26ft at the bottom of the sump room) despite the fact that the structure is only about 120ft away from a pond I put in a few years ago.
Finally, I got to work on the roof. I went with the ICF decking product sold by the same manufacturer that provided the wall blocks. I followed the manufacturer’s recommendations on wood shoring, but added OSB on top of the 2x6 and 2x8 framing. I felt a little uncomfortable working with the polystyrene decking sitting on just the stick frame below and I felt it would be a little easier with some of the roof openings and a large center beam that were in the design specs.
The roof pour went without any problems. I used the same paint on waterproofing for the concrete roof and added a layer of the 9mil sheeting. After about 3 weeks we took down the internal wood scaffolding, and after the full 30 day concrete cure period I had the dirt guys cover it up.
This is not a project I would recommend to the average do-it-yourself guy out there, but it can be done. To be honest, I did have a couple people help me with the project – one of my brothers, and a local laborer with some concrete experience. But neither had any ICF experience (or had even heard of them), so I was the ICF expert on the job. I did do most of the labor myself to keep costs down and for the experience.
In a year or so I plan on putting my dream ICF house on top of the storm shelter. I’d like a good size house (about 6500-8000 sqft). Now this is more that I can build on my own, so if there are any good ICF architects / builders in the Dallas area, feel free to contact me.
There are two entrance/exits to the shelter. One is an ICF ladder well that will go to the outdoors and the other will be a spiral staircase attached to the future house. The spiral stairs will go through an additional section of the HDPE pipe sticking out of the top of the shelter.
There were a couple minor issues, but overall I think it went very well for my first ICF project. The basic structure is built, but I don’t plan on finishing / furnishing out the inside until later. I paid close attention to the costs and did some shopping around to try to make sure I was getting the best prices I could. In the end it cost about $75 a sqft to build the storm shelter (it would have been under $65 if I didn’t have to do all the dirt work). It will cost a little more to finish out the inside, but still think the total cost will be at or under $100 a sqft.
Thanks for taking the time to read about my project. And again, thank you to all the contributors on this forum and especially to my engineer - Jerry. I think it is a sign of a good engineer when he comes out to your inspect your final concrete pour, picks up a shovel and a float and helps out with the concrete pour for a couple of hours at no extra cost. Thanks also goes to my wife who watched the kids and put up with me spending most of my free time the past few months working on what she labeled my “man cave”.
