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Jawbreaker

Insulated Concrete Forms (ICF) residential construction.

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ICF home construction

I am considering building a new home with ICF external walls. Wondering if any Glamis folks have any opinions/experience with this type of building.  These walls have 2.5 inches of insulation on each side and 6 inches of rebar strengthened concrete inside.   High insulation values with high thermal mass makes for a cool quiet comfortable home. Around 15-20% more expensive than stick built walls. Combine with high quality windows, well insulated roof structure and high efficiency  HVAC seems to make sense for the Phoenix area.  There is a local company that will design the structure, pull permits, sell the Foxx blocks, rent equipment scaffolds braces, etc, or send a team out to set up and pour, or even build the whole house with subcontractors.  I  am bidding out the shell of the house, then can finish myself (with a little help from friends in the trades).  I have my lot and am using cash to build, no bank/construction loan rules to deal with. Any energy saving tips for a 2000-2500 sq/ft single story ranch type home? Thanks!

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I oversee the inspection side on a large community college program and we are currently building a project using these. Its been a long road with a lot of speedbumps and testing/sorting out installation issues just to get to the point of placing concrete (walls are about 30' high with steel roof beams/structure).

What I have seen is that this system is best served for a basement or below ground pool application. General above ground installation is much cheaper to do with conventional construction (CMU block or wood/stucco, etc). Just my opinion. Salesmen/company reps may tell you different but that's their job to sell the product. For example...After it's installed and you want to hang a picture or mount something on the wall (like cabinets), you'll have to go through the 2.5" foam before you hit something solid and that's a lot of leverage to hang something on a screw that is not supported for 2.5".

Our ICF forms were thicker than the 2.5" that you're mentioning so placing concrete was easier as they were not as prone to blowing out as a 2.5" system would be.

 

Good luck.

Edited by xtream1

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I had this talk with a fellow contractor  a few months ago. It has its benefits but it also has its downfalls.

This video explains a lot about the product and process.

 

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I built 2 ICF houses with FOXX blocks and sold them 3 story 1 below grade.. On the same street I live on.  Like mentioned the basement portion was where it saved money sq ft wise. I stamped the concrete with  a tile stamp I have. The 3rd story 2nd above ground is framing.  Should of framed everything except the basement.  We subdivide the lot so went down to gain sq ft. Being So Cal the weather does not justify the use of ICF like AZ would.  

 

 The previous ICF project I did the basement was only ICF used framed the top. Used ARRX blocks on that 1. 

 

 Any questions ask. If I was in your area I would help you out.  It's not hard and it is one solid house when complete. 

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1 hour ago, Jawbreaker said:

ICF home construction

I am considering building a new home with ICF external walls. Wondering if any Glamis folks have any opinions/experience with this type of building.  These walls have 2.5 inches of insulation on each side and 6 inches of rebar strengthened concrete inside.   High insulation values with high thermal mass makes for a cool quiet comfortable home. Around 15-20% more expensive than stick built walls. Combine with high quality windows, well insulated roof structure and high efficiency  HVAC seems to make sense for the Phoenix area.  There is a local company that will design the structure, pull permits, sell the Foxx blocks, rent equipment scaffolds braces, etc, or send a team out to set up and pour, or even build the whole house with subcontractors.  I  am bidding out the shell of the house, then can finish myself (with a little help from friends in the trades).  I have my lot and am using cash to build, no bank/construction loan rules to deal with. Any energy saving tips for a 2000-2500 sq/ft single story ranch type home? Thanks!

The only advice I can give you is I highly recommend using mini split air conditioners instead of a regular central air system. The system I installed used about 1/3 of the power that my old central air system used, and it kept the house much cooler, much faster. I could come home, the house was at 85* and within 30-45 min the house was nice and cool at 77* or so. At night, I could turn off the living room/family room/dining room/kitchen unit and just run the master bedroom unit. I'd set it for 69* and it barely used any power. I found that 9,000 BTU indoor units were plenty for any size bedroom (unless it's a mansion) and my main unit was 18,000 BTU and it could keep the entire 1850 sft house cool at 75 or 76* if I left all of the bedroom doors open.

My house is an older house, poor insulation, aluminum window frames and 4 sliding glass doors with aluminum frames. Now with the summer electricity bill dropped from over $400 down to $200 (normal fall through spring bill is $100-125) I've decided not to spend the money on efficient vinyl windows because the savings just wouldn't justify the cost. Compared to the measly $1100 the entire mini split system cost me, the windows are far too expensive.

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I have wired a few home with this type of product. Rastra was first home we did 20 years ago.

a friend from town moved to New Mexico and built over 100 homes with Rastra. 

Post tension slab & killer roof and your home will last forever. Very quite homes. 

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Thanks for pointers.  I think the thermal mass of a concrete 11 inch thick exterior wall is worth the extra money. Luckily I found Castle rock builders in Litchfield park, AZ. They started 10 years ago and have experience. Also they are two retired Air Force Master Sergeants that have also built churches and military buildings.  I like the mini split idea for HVAC with no loss to duct work. I installed a 23 SEER Hitachi/Carrier mini split in our master bedroom. We sleep at 72 all summer for a few bucks of electricity.  Inverter based and variable speed compressor that runs at low speed. Still looking at vented verse unvented roofs, white standing seam metal verse cement tile roof, etc.  Finalizing floor plans. Might make a good build thread (not as cool as John and his green machine build). Thanks

 

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Look at a company called Mikey BLock.  they are made in Tuscon.  It uses half the concrete and  you can hang cabinets and pics every 12 inchs up the wall. also has better R value then most others.  Concrete is a 1ft grid not the whole 6" center.   cost was going to be way cheaper then stick build when you consider insulation and stucco savings.   also mini splits are a great Idea on these homes.  We built my brothers house with them and he used normal HVAC and his house is too tight.  also his units don't cycle enough.  way cheap elec bills and very quite house.  Mikey block is for the home owner /builder   you can build your home in a weekend.   well at least all the walls.  Stupid simple and strong.  My engineer did my plans for a 24ft high wall in the RV garages.    

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The Fox blocks were very fast and easy to assemble.  Issues I had were with the Engineer and the city inspectors. Neither had seen it before.  It is pre engineered but our engineer added more steel than it called for.  City inspectors did not know anything about it and were skeptical of the foam being the form.  The hardest part of the build was the plumbing. 

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ICF forms have equal insulation on both sides of the concrete negating thermal mass. Which for you is a good thing as once it warms up it'll stay warm longer. So if thermal mass is the selling point to you make sure you are getting it for the reasons you think you are.

There are multiple ways to address thermal bridging and making a wall efficient. Zip makes a r-12 insulated panel that replaces the exterior sheeting. That along with a 2x6 wall can give you an r-36 wall cavity or more if you used closed cell foam. It will address the thermal bridging, cost less and be as efficient.

As for roof structure, give yourself as large as an energy heal truss or rafter as you can. I suggest 18". Be certain any roll blocks are placed to the exterior portion of the wall. Then do at minimum a foam air seal on all ceiling penetrations. Cap it with a r-60+ blow in.

Triple pane windows, long overhangs to keep the sun off the wall etc will all aid in keeping a home cool.

I dont deal with hot climate roofs so any advice I could give would just be conjecture... However while I like metal roofs for many reasons, they are noisy.

 

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6 minutes ago, Jscc said:

ICF forms have equal insulation on both sides of the concrete negating thermal mass. Which for you is a good thing as once it warms up it'll stay warm longer. So if thermal mass is the selling point to you make sure you are getting it for the reasons you think you are.

There are multiple ways to address thermal bridging and making a wall efficient. Zip makes a r-12 insulated panel that replaces the exterior sheeting. That along with a 2x6 wall can give you an r-36 wall cavity or more if you used closed cell foam. It will address the thermal bridging, cost less and be as efficient. There is no way to be cheaper doing 6in of close cell foam.  That is at least 3 buck per foot to 6 bucks per foot for 6in of closed cell foam. 

As for roof structure, give yourself as large as an energy heal truss or rafter as you can. I suggest 18". Be certain any roll blocks are placed to the exterior portion of the wall. Then do at minimum a foam air seal on all ceiling penetrations. Cap it with a r-60+ blow in.  Totally agree makes a huge difference out there in the sun. 

Triple pane windows, long overhangs to keep the sun off the wall etc will all aid in keeping a home cool.

I dont deal with hot climate roofs so any advice I could give would just be conjecture... However while I like metal roofs for many reasons, they are noisy.

 

check this out http://mikeyblock.com/.   got good guys for spray foam if you need them. 

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this stuff is all Greek to me,  sounds like a mini tilt up?  can someone break this language barrier down for me--what is it?  if its good for basements, is it good for an underground  bomb shelter?  sounds interesting.  Is this not done much in So Cal?

Edited by John@Outfront Mtrsprts

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 No pictures on my phone. They are foam blocks that clip together.  You build the walls with rebar inside then fill with concrete.  Similar to pour in place but the foam forms stay and are the insulation.  Great for basement construction.  Here in So Cal the benefits are not as good as the freezing areas or super hot AZ weather.  The basement is 8" thick concrete inside the forms so it would be like a bomb shelter.

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Great tips on the raised heal trusses and 6 inches of spray foam insulation. I am pricing out white standing seam metal roofing with high solar reflectance against Eagle brand S barrel cement tile. One benefit to standing seam metal is it is easy to attach framework for solar panels. I would never want to walk on a tile roof! Fox blocks come in 6 and 8 inch cement widths plus 5 inches of insulation.  For you guys in California-ICF homes are bullet proof, haha.

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Bullet proof shit more like RPG proof. There could be a drive by out front and with the windows closed you would not hear it. 

 

  Had Hanson truss make the roof trusses and used r30 insulation and new reflector series composition shingles it . New code R38 insulation.  Had to leave the roof clear for future solar installation now code is solar system installed with new construction. 

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23 hours ago, Squatcher said:

check this out http://mikeyblock.com/.   got good guys for spray foam if you need them. 

It looks like they solve the large thermal mass problem with the typical ICF. I would be curious about cost comparisons to the wall cavity I stated above.

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4 hours ago, Jscc said:

It looks like they solve the large thermal mass problem with the typical ICF. I would be curious about cost comparisons to the wall cavity I stated above.

It uses half the concrete and rebar that is needed with other ICF block .  I was building 10,000 sf under roof with RV garages.  total for the block, concrete, and rebar for materials was going to be under 30k.  that was 3 years ago.  They can also assemble wall sections for you and ship them complete.   The product is for sure a do it yourself.  I went down to the plant to check it out.  very cool how it is all done.  he makes block mixed with cement so it is fire proof.  His outdoor BBq for the shop is made of it.  He made two story steps out of foam and nothing else to show how strong the foam alone is.  check it out. Owners name is Dave.  He also recommends Mini split units.   I love the mini splits I have about 6 of them on different properties and love them.  

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Had a buddy build a rather large house out on the west side of town.  It's been a few years and between his EFFIS ( Stucco) , foam,concrete, foam, drywall exterior construction and his large solar array his house is always cold a funk. I know when he was building it the cost overages were high and he did about 90% of all the work himself, It also took a lot longer to complete than he originally planned.

He did not go the mini split route he has two rather large air handlers, both his supply and return ducts are underground.  It makes for a real open feel to the house  not having to hide duct work. He also has an option that he can just pump fresh air thru out the house using the underground pipes.

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