Most likely we will build an ICF home, and reading Steven from Colorado Springs, CO's entries and many others who have built ICF homes has helped us to no end with our project. Frank in Columbia, MD

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Plans ready for permit

Posted to ICF-Construction by Frank in Elkridge, MD on 11/11/2011

Well, after six months which included the sale of the house and move to an apartment, and a complete change of our plans from a two-story to a rancher and MANY other changes, we finally have plans we can submit to the county for a permit. Best of all, we can start talking to subs to put our package together for the bank. At this time our plans are to break ground in the spring as soon as the weather breaks. This will give us five solid months to put our project in gear.

Now we need to find an electrician, HVAC and fire safety water sprinkler sub, and submit the plans to the county.

Here is something off topic regarding basement slab insulation. Our designer would not include foam insulation for our basement slab in the plans because he feels it's not structurally sound. His argument is that if you pour the basement slab on top of 2" foam from wall to wall, the slab will most likely crack because we would be pouring a floating slab on top of the insulation. I was under the impression the welded wire fabric steel would hold the slab together, but he said that even with the wire, the slab would crack. He's okay with the foam insulation to be leveled to the footers, but even so, he feels the workers will crack the foam as they pour the basement slab, which will negate any insulation factor.

Posted by Peter in Burlington, WA on 11/11/2011 Peter's Forum Posts: 20 Interview Answers: 36 Average Forum Rating: 4.29 Randomly Selected Image 11/11/2011	Hope I can help you with this issue. It's possible you misunderstood the designer. People who get paid to provide construction services (especially designers) should know all of this. All concrete cracks. That's because as it cures, it will shrink slightly, which sets up internal stresses. The slab solves the stresses by cracking. As you suspected, the welded wire fabric or the rebar grid will hold the slab together, so the integrity isn't compromised, but the cracks will still appear. You can deal with the appearance issue in a number of ways. You can lay in control strips. Control strips can be as simple as lightweight drywall edging pressed under the surface of the finish pour. The strips give the stresses something to congregate around and you get cracks above the strips.  The cracks are still sort of rough, but at least they are straight and where you want them. You can use strips of copper or brass. Again, the stresses will congregate around the strips, and cracking will occur under the strip. The strips look nice when the floor gets polished - like metal insets. You can use a special concrete trowel to run grooves in the concrete as you finish it. The concrete will crack at the weak points, which are directly under the grooves where the slab senses it is thinner. The only thing you see are the grooves. Again, the cracks occur under them. You have to make sure the grooves are deep enough, or cracks may bypass them. You can use a concrete saw or other special saw to make cuts in the curing concrete from 1-4 hours and 4-12 hours after the pour, depending on the mix and the conditions. I would say most builders I've seen use this method, because you get nice straight, thin lines. After the slab cures, you can even fill them with something and the joints disappear even more. Or, you can consider them decorative cuts and let them stand out. Whether you use inserts, trowel or saw, there is  a rule of thumb formula for how far apart the joints need to be in order to avoid getting cracks between them. It is about 2 or 3 FEET times the slab thickness in inches. For example, with a 4" slab, you want the joints about 8 or 12 FEET apart. A 6" driveway might get joints as far apart as 18 FEET. Don't be lazy and make the sections too large. There is nothing like making the effort to cut grooves or lay strips, only to find that they were too far apart for the mix or the conditions and you have cracks between them after all. Now, on to the next issue; the insulation. If you will have a finished basement, it is important to insulate the slab (floor) to avoid 30 years of cold feet and wasted heating energy. If you will have a heated (radiant) slab down there, the insulation is not just important, it is CRITICAL. I'm just an Owner-Builder, so I know next to nothing about code, but I think the new building code requires it for some things. Most places have 2" of insulation indicated. A few locations might get away with 1" of insulation and a number of places with cold ground or harsher winters need 3" or more. Insulation is generally rigid foam board, either pink or white. The pink is generally XPS (for eXtruded PolyStyrene) and the white is usually EPS (for Expanded PolyStyrene). Either one is fine to use. Locations that you know are going to be soaking wet might indicate EPS over XPS, but that shouldn't be an issue with a well-drained dry build, right? Pink board, or XPS, has an R-value of about 5 per inch of thickness and the EPS is a bit lower, or about R-4 per inch. As I mentioned earlier, some locations require R-10 insulation, so you can imagine that XPS might be seen a bit more on job sites as a 2" board that meet requirements, while it would take 2-1/2" of EPS to get to R-10. Common names for the XPS is "FOAMULAR" for the pink Owens-Corning product, or "Geofoam" for the white EPS product by Insulfoam. Each type of foam comes in a number of different densities, indicating how resistant the foam is to compression, which is what it sounds like your designer is worried about. Typical compression ratings for foam destined for residential construction are about 15 PSI. Note that is POUNDS per square INCH. For example, the Owens Corning product most often seen is the FOAMULAR 150, which has a compressive rating of 15 PSI. Occasionally, you might see the FOAMULAR 250, which indicates a rating of 25 PSI and so forth. Let's think about the loads that could be on this foam for a moment. Reinforced concrete weighs about 150 pounds per cubic foot. That means that a 4" slab, 1 foot square, weighs about 1/3 of that or 50 lbs per square foot. Recall that the compressive rating of the foam was 15 pounds per square INCH. There are 144 square inches in a square foot, so if you multiply 15x144, you get a rating of 2,160 pounds per square foot. As you can see, our 1-foot-square 50-lb chunk of slab exerts a small fraction of the total load (2,160 lbs) it would take to compress the Styrofoam. As you can see, there is no problem with foam supporting a concrete slab. Your designer is right about one thing, though. As the workers walk about on the foam board, occasionally you hear sharp cracks, which is the board breaking under the uneven pressure of a foot. At 240 lbs, I do that more often than most of the workers.  :-) Unfortunately for his theory, there is no harm to the structure of anything. All the weight bearing is directly downward and it does not matter that the board is cracked. The insulation is not negated. He should know this if he has ever had anything to do with construction of an insulated slab. I would make sure the entire slab floats on the insulation. The foam needs to go over the footer, too. You do not want contact between the slab and the footer as the heat will be lost downward. Don't forget the 6- or 10-mil plastic vapor barrier under the foam board to keep the damp down.
Posted by Frank in Elkridge, MD on 11/12/2011 Frank's Forum Posts: 11 Journal Entries: 5 Interview Answers: 59 Average Forum Rating: 4.00 Frank's Selected Image 11/12/2011	Peter, thank you for your detailed information, we really appreciate it. We are definitely installing 2" XPS foam under the basement slab whether he likes it or not. Our current plans do not include finishing the basement, but in five years we may want to and we wouldn't want to deal with a cold basement after the fact, since now we have the opportunity to make it warmer. I sum it up by saying that he has never done foam insulation for basement slab in his 25 years of construction experience so, I as a new O-B can teach this old dog a new trick. Thanks again.
Posted by Peter in Burlington, WA on 11/12/2011 Peter's Forum Posts: 20 Interview Answers: 36 Average Forum Rating: 4.29 Randomly Selected Image 11/12/2011	Let me just add a couple things. IF the foam insulation is not going to show up on the plans, make sure you take the two extra inches of thickness into account for everything. Even though 2" seems like a small amount now, it can affect things later. For example, if you have 8' ceilings planned and someone forgets to take it into account, you will have 7'-10" to sheetrock, which will require a rip on every sheet. Little things like that. Second thing is that if you are going with hydronic radiant heat in the home, don't forget to tube the basement slab in anticipation of future use. It is a little bit of cost and effort now, but when you go to finish (and heat) the basement later, you will be very, very glad you did it. AND, if you do tube the basement slab, make a very good plan (with measurements) of where the tubing lies, so that you know where you can and can't shoot in concrete anchors for the walls in the future. Good luck.
Posted by Penny in Idaho Falls, ID on 11/16/2011 Penny's Forum Posts: 0 Interview Answers: 4 Penny's Selected Image 11/16/2011	Hi Frank - just found this forum; We are in Idaho Falls and bought a foreclosure 1.5 years ago that we are in the process of finishing. Our house was started in 2006 and has never been heated (which will hopefully change tomorrow). The ground floor (3,200 sq ft) is built slab on grade with hydronic heating and the walls are TF vertical ICF. The plans show 2" of foam insulation under the slab. Our floor has minimal cracking, with one large crack due to a floating hydronic line - and that's with no expansion joints anywhere in the slab. We worked with an architect/energy rater and he thought an insulated slab made a huge difference. Penny

Time Switch

Posted to ICF-Construction by Frank in Elkridge, MD on 5/2/2011

Here is a question for electricians. I'm testing time switches and occupancy sensors in my current home to be used in the O-B home and I ran into a problem. My old house includes three terminal aluminum wires, black, white and ground. I purchased four occupancy sensors (Decora Cat. No. ODs10-IDx), two for the basement and one for each bathroom. They work great for the basement unless you forget to turn on the sensor and you find yourself in the dark after 20 minutes. I've heard plenty of "FRANK TURN ON YOUR CRAZY SWITCH" with other choice words. They also work in bathrooms unless it's a small bathroom like ours and the heat and A/C air pressure turn it on.  Waste of energy.

I purchased two Pass & Seymour, TR1 time switches to replace the sensors, but they require four terminal wires, black (power from the box), red (power to fan), white (neutral) and ground.

Does anyone know of a three-wire time switch I can purchase? We will have the up to date wires in the new O-B home, but in the meantime I would like to install the correct switch.

Frank

Looking For Subs

Posted to ICF-Construction by Frank in Elkridge, MD on 4/7/2011

After meeting with 7 designers, today we are meeting with our designer to sign the contract, and in two to three weeks we should have a set of plans we can start using to talk to subs. We made our decision based on hands-on experience and knowledge of working with the HoCo permit office. We hope to hear from the MD group for suggestions: Elizabeth, Tom, John, Joe and anyone from this neck of the woods. 

Two weeks ago we visited the BaCo HG show, and this weekend we visited the HoCo Home and Garden show and we found it quite useful to talk to local contractors about our construction ideas. We (mostly me) also plan to visit construction sites near the lot and talk to subs who are actually working. Since I'm fluent in Spanish, it shouldn't be a problem to find good subs but recommendations are definitely welcome. 

We are almost sure we're building with ICF, so if anyone knows of an ICF house under construction in the area, let us know.

New Geothermal Idea

Posted to ICF-Construction by Frank in Elkridge, MD on 3/25/2011

Here is a good idea to save money on a horizontal geothermal system if you're building with a basement. I received my current Solar Today Magazine last week and I read an article about an energy-saving study in Tennessee by the name of ZebrAlliance. In this particular study, they have built four different houses applying many energy-saving ideas. Two of the houses includes a horizontal geothermal system using the foundation wall excavation to run the loops (houses 1 and 2). In addition to the foundation wall excavations, they also used the utility trenches to extend the lines. I thought it was a good idea to share: zebralliance.org

Since we are considering a geothermal system, it might save us some money. I know this type of idea may require additional planing and coordination; we'll just have to up the recommended planning hours from 1,000 to 1020. No big deal!!!

Designing Stage

Posted to ICF-Construction by Frank in Elkridge, MD on 12/11/2010 12:39:40 PM

We are in our home-designing stage, and would like to know the best way to search for a designer in our area. We are looking to build a 3,000 to 3,400-sq-ft house with a dual master suite, one on the first level and another on the second floor for a total of four bedrooms. The idea is that our elderly mother(s) can stay in the lower master suite when they visit and we can use it when we retire in 10 years. Since we know exactly what we want, we can save money by having a designer help us with the house plan.

Posted by Rich in Suffolk, VA on 12/16/2010 Rich's Forum Posts: 38 Journal Entries: 18 Interview Answers: 69 Average Forum Rating: 4.03 Image from Rich's blog 12/16/2010

Smart thinking by considering how you will use it in the future. Now is a good time to hire a designer, as winter construction/planning is always slow and the housing market slump is creating lots of good deals. I like to search Craigslist and lately, Angieslist as well.