First post, so please be gentle.

My wife and I just landed our dream property and are planning on building a home here in NW Washington on the beach.  It will be a 2400 sq ft, 2-story home and will take a good beating from NE winds during the winter.  I come from a family of concrete, so my joy in hearing about ICF was amplified when I knew I could use it.

My brother put radiant flooring in his stick frame home and swears by them, though I haven't heard much about having it put in place on an ICF built home.  The extra benefit I have is that my cousin does radiant heating and foundations, providing me cost savings in that regard.  However, a friend of my that is a GC mentioned that with such a well insulated home I may as well put a well powered forced air system in place and let it purr at a low output.

Our source for fuel would be propane.

Thoughts? 

Also, being new... what width of forms am I going to be using?

Love the forum and I can't wait to get more involved in these conversations.

Thank you for any and all input!

Most customer's love in-floor radiant, it is warm on the feet and even. You may still want forced-air for AC.

Most of our ICF homes are 6", but depending on if there is a basement, soil type and so on you may need 8" for below grade.

Posted By ICFconstruction on 27 Mar 2012 02:29 PM
Most customer's love in-floor radiant, it is warm on the feet and even. You may still want forced-air for AC.

Most of our ICF homes are 6", but depending on if there is a basement, soil type and so on you may need 8" for below grade.

Brad, Thank you for the reply.  AC, here in NW Washington???  I don't really plan on having AC in the home, as it will never get that hot for a long enough time, especially close to the ocean. 

When you say 6", that is the actual width of the block or the gap for the concrete?  I was thinking of using Fox Blocks, so I'm imaging the full width of one of those blocks. 

As for a basement, this will most likely be on slab... unless my father has a say and convinces me to put a crawl space in.

Thank you for your reply, all the info the better!

A 6" ICF block refers to the concrete thickness. Most ICFs use 2.5" thickness EPS foam, so you are looking at 11" overall wall thickness in general. But there are exceptions to every rule. Some ICFs use 2" foam, some 2-5/8" foam, and some have different thickness on the outside foam vs. the inside foam.

Standard 6" Fox Blocks are 11.25" wide overall, so they use the 2-5/8" EPS foam on either side of 6" of concrete. One reason for using this seeming odd width is that a 2x12 piece of lumber is actually 11-1/4" wide. Therefore, if you are using full width 2x12s for window and door bucks, no ripping of the lumber is required.

http://www.foxblocks.com/Uploads/do...raight.pdf

Great if you don't need AC, just go with radiant in a concrete slab, no crawlspace. ICFs are usually referred to as the concrete thickness since the eps thickness varies from brand to brand. A 6" Fox Block would be 11.25" overall.

WOW.... incredible info! Arkie, ICF; Thank you!

I love the idea of radiant floors, but am worried about the piping in the floors and the longevity/durability of it. Seeing one vote of confidence is a good feeling, especially with the battles I have already witnessed on other topics involving these options.

6" core seems to be the standard for residential

I would approach this differently. Find out who your local manufacturers are and see what block sizes they make at the factory locally. A big portion of the price of ICF's is transportation. If you can rent a 24 or 26 foot Budget or Penske truck and haul the things yourself you saved hundreds or even thousands of dollars.

Posted By jacktca on 27 Mar 2012 05:41 PM
6" core seems to be the standard for residential

I would approach this differently. Find out who your local manufacturers are and see what block sizes they make at the factory locally. A big portion of the price of ICF's is transportation. If you can rent a 24 or 26 foot Budget or Penske truck and haul the things yourself you saved hundreds or even thousands of dollars.

Great to know!  Is this different than getting it from a local distributor?  There is a Sand/Gravel company locally that supplies the goods, so I'm not sure if that is the same as getting it from a factory or if there is a big mark-up on the blocks.

Is anyone aware of a good $ per sq/ft estimate on the cost to build a residential from ICF?  (Just the ICF build, not the entire home)

Posted By jacktca on 27 Mar 2012 05:41 PM
6" core seems to be the standard for residential

I would approach this differently. Find out who your local manufacturers are and see what block sizes they make at the factory locally. A big portion of the price of ICF's is transportation. If you can rent a 24 or 26 foot Budget or Penske truck and haul the things yourself you saved hundreds or even thousands of dollars.

I agree, pick an installer and let them pick the ICF. As far as the in-floor PEX, like everything, do it right, do it once. It is what i did on my own place.

My wife and I just landed our dream property and are planning on building a home here in NW Washington on the beach

What beach? I'm in Skagit and am finishing up my ICF passive solar with radiant floors. You may want to take a look or even access the contractors I've used.

So, find an ICF installer and let them make the call on blocks? I'm a bit worried that many of the other jobs are going to be affected by the ICF build and will cause a limit on other contractors that I can use because of experience.

ICFHybrid, PM sent to you.

I'm a bit worried that many of the other jobs are going to be affected by the ICF build and will cause a limit on other contractors that I can use because of experience.

Yep, that happens around here, alright.

The good news is that if the contractor has actually done any other ICF, he will be able to tell you which subs handled it well. Some handle it well, others not so. Service contractors new to ICF will cost you extra for the learning curve unless you set out the agreed price in advance.

It seems like most people with radiant in-floor heating like it, and it does seem to be the current fad with many doing green buildings. I wear shoes or at least socks around the house during the cool weather, and have mostly hardwood floors over a conditioned crawl space and have a well-insulated house. For that situation, forced hot air is cheaper and seems suitable, and I don't have to worry about aging pipes in a foundation. Radiant heating in a concrete foundation can have a lot of thermal inertia, so it may not combine well with passive solar heating, but you didn't mention passive solar, so that is probably not an issue. Radiant may not work so well with thermostat set-backs due to the thermal inertia.

Like you, I do not need A/C, but the ductwork is nice for the heat recovery ventilation (HRV) system, and for the whole house humidifier (which I doubt you need on coastal Washington!).

So the choice might be a life-style issue, whether you want to run around barefoot in cold weather, whether you are used to themostat set-back for sleeping in a cooler house, etc., and the cost premium for radiant. Propane is an expensive fuel, so choose a high-efficiency heating system (likely a condensing combustion system) whichever route you go.

> uw91 asks: Is this different than getting it from a local distributor? 

I am in Southern California.  We have a local Reward block distributor.   He charges $16/block.   There is a BuildBlock distributor as well.  He charges $16/block.   More or less the same blocks, more or less the same specs and quality.   BuildBlock has a factory 50 miles away.  I don't even have to rent a Budget truck.   I can take my car with trailer two times and I'm done.   In contrast Reward has to ship their blocks from Colorado.   You're looking at 1/4-1/3 of a semi truck.   That's heavy equipment you're paying big bucks for.   The driver is going to require a decent wage.   You are hiring a guy for 2-3 days work.    So the Reward blocks from the local distributor cost $24/block in smaller quantities.  If I buy a bigger load, say 10+ palletes, I get a bundled cost.   I was quoted $1200 for shipping.   Same difference!    $16 vs $24.   That's 1/3 extra you're paying because BuildBlock has a factory 50 miles away and Reward's factory is 1500 miles away.  

I am building my ICF house for < $1000.   I found 2.5 palletes of Reward blocks for $50.   I found a warehouse full of IntegraSpec mostly corners for $400.   I sold about 1/4 of those corners for $600.   This allowed me to purchase $500 of straights.   Enough to do my whole house.    A little horse trading on crazedlist and you too can build your ICF house for pennies on the dollar.    Had I purchased the blocks new I was looking at $3000-4000 roughly.

Now, little tip here.  If/when you rent a penske or budget truck you'll notice that one-way rental is 20% of the price of round trip.   That's a problem because Amtrak and Greyhound doesn't go everywehre.   What I did was scout around for airport-to-airport one way car rentals.   Use search engines to come up with one-way unlimited mileage deals for crazy cheap.  I rented a car in Burbank, CA and dropped it off at Lake Havasu City, AZ.  Total rental cost: $17.  In Arizona I rented the Budget truck one-way for $150.    Had I done the round-trip rental I would have been looking at $600-800+gas.   Gas cost me $200.    Total transportation cost for a 24 foot budget truck haul (300 miles away) was $400.

Oh by the way, ICF house for < $1000 and benefits.

Being the low-life that I am I used craigslist rideshare to get people to pay for my gas when I went to Arizona to pick up 2.5 palletes of 4-inch core Reward blocks for $50. One of my rides was a young woman who needed a place to stay for 2 days. This turned out to be rideshare with benefits IntegraSpec has a plant in Reno, Nevada. That's next door to Lake Tahoe. I'm going to pick up $500 worth of straights from the factory with my trailer this weekend April 1-2 and.... drumroll... a day of skiing on 80-100 inches of real snow while I'm up there. Boody-call and ski madness. Two of the perks by products of do-it-yourself ICF construction.

Posted By Lee Dodge on 27 Mar 2012 11:33 PM
It seems like most people with radiant in-floor heating like it, and it does seem to be the current fad with many doing green buildings. I wear shoes or at least socks around the house during the cool weather, and have mostly hardwood floors over a conditioned crawl space and have a well-insulated house. For that situation, forced hot air is cheaper and seems suitable, and I don't have to worry about aging pipes in a foundation. Radiant heating in a concrete foundation can have a lot of thermal inertia, so it may not combine well with passive solar heating, but you didn't mention passive solar, so that is probably not an issue. Radiant may not work so well with thermostat set-backs due to the thermal inertia.

Like you, I do not need A/C, but the ductwork is nice for the heat recovery ventilation (HRV) system, and for the whole house humidifier (which I doubt you need on coastal Washington!).

So the choice might be a life-style issue, whether you want to run around barefoot in cold weather, whether you are used to themostat set-back for sleeping in a cooler house, etc., and the cost premium for radiant. Propane is an expensive fuel, so choose a high-efficiency heating system (likely a condensing combustion system) whichever route you go.

Radiant slabs work OK with passive solar if you cleverly route the loops in a N-S orientation. The diurnal temperature swings are also quite modest, not requiring as much thermal-mass management as in some other climates, but setback strategies are generally nearly useless with concrete slab radiators anyway- even when implemented perfectly the savings are a fraction of what it would be with low-mass radiation. If you go with radiant, and above-the-subfloor tubing approach (WarmBoard or similar) will have similarly low water temp requirements, but are responsive enough to get something out of overnight setbacks.

Heat loads in an R22 whole-wall house with commensurate window/slab/attic insulation are pretty modest in that climate too- it's not too tough to bring the design heat load down to between 20-30KBTU/hr, which is the sweet spot for ductless air source heat pumps (air-to-air, or low-temp hydronic- you can run a radiant floor with one if you like)  At typical winter temps there they're good for an average coefficient of performance that rivals ground source heat pumps at a fraction of the installed cost.  Because these are continuously-variable systems that have their highest efficiency when running in their lower speed ranges, overnight setback can actually INCREASE power use, since they run full-tilt (=lowest efficiency) during the recovery phase.

At western WA electricity and propane pricing, heating with ductless air source heat pump costs only about 1/3 that (or even less!) than heating with condensing propane.  (I have relatives in the Puget Sound area who have made that switch and are downright giddy about it.)  If Puget Sound Energy is your utility there is even a decent subsidy for those heating with electric baseboards/hot air, to install one, but SFAIK they don't offer anything  on them for new construction.  But at current propane pricing payback on a ductless is well under 5 years, often under 3.

Air-to-air ductless systems ("mini-split" or "multi-split") take a bit of planning to get optimal comfort  & aesthetic considerations under control, since they heat only the rooms with the interior heads, and the heads take up some wall space (a thing of beauty they're not, but they're not as ugly as window AC units, IMHO).  There are many high-efficiency 2 & 3 head versions but at 4+ heads the efficiency tends to be lower, and the installed costs higher. Doored-off rooms with big windows (==higher heat loss) may need their own head,  but with some planning and forethought many homes are readily heated by 1 to 3 heads, using the the higher-R/lower loss walls and convection within the home to advantage.  If propane is your primary other option, I strongly recommend using BeOpt or similar tools as a design aid to get the heat load under 30K (or at least under 36K) @ 18-20F outside temperatures, without breaking the bank, and taking a good hard look at ductless systems.  (Most newer 2400' homes are already in that range if they're reasonably air tight and don't have a huge window fraction.)

From a carbon footprint point of view a ductless mini-split is a slam-dunk relative to any fossil-burners,  especially given WA's mostly-renewable grid sources.  But even were the grid entirely 30% thermal efficiency natural gas burners it would still better than break-even with condensing propane boilers/furnaces.

Western WA has mid-winter dew points in the 30s F, and mid summer dew points in the 50s, so active humidification/dehumidifcation isn't needed,  even on very air-leaky homes, and latent loads/dehumidification from interior moisture sources are easily handled by adjusting the ventilation rates.

They now make mini-split heads that mount in the ceiling, too. They are much less obtrusive, but are considerably more expensive (don't know why?).

Posted By uw91 on 27 Mar 2012 06:02 PM

Is anyone aware of a good $ per sq/ft estimate on the cost to build a residential from ICF?  (Just the ICF build, not the entire home)

Ballpark costs for ICF blocks, rebar, labor, and concrete is around $9-$12 per sq.ft. of exterior wall space.

Posted By uw91 on 27 Mar 2012 01:06 PM
My wife and I just landed our dream property and are planning on building a home here in NW Washington on the beach.  It will be a 2400 sq ft, 2-story home and will take a good beating from NE winds during the winter.  I come from a family of concrete, so my joy in hearing about ICF was amplified when I knew I could use it.

My brother put radiant flooring in his stick frame home and swears by them, though I haven't heard much about having it put in place on an ICF built home.  The extra benefit I have is that my cousin does radiant heating and foundations, providing me cost savings in that regard.  However, a friend of my that is a GC mentioned that with such a well insulated home I may as well put a well powered forced air system in place and let it purr at a low output.

Our source for fuel would be propane.

You are engaging in a little bit of chicken and egg situation. You really need to have some fairly defined plans for the house and then have a competent HVAC contractor perform heating/cooling load calculations to find out what your real expected heat load will be. Then you can revise your house plans to incorporate the chosen heating system. This will include comparing insulation options for the attic. Find a contractor who uses Wrightsoft for the calcs. It is a very good program, pricey, and includes parameters for ICF. I don't know if it's been upgraded to give you hour-by-hour heating/cooling loads like a free program called HEED does, but that's not critical anyway.

I think what you will find is your heat requirement will be well below the output of most small gas furnaces. This will create a problem of short cycling if you use a gas furnace. Radiant heat can get around this because the heat delivery medium, water, can operate at a lower continuous heat output rate than the heat input system. But you will need a good control system. Radiant is doable, and will give you a very comfortable living environment, but most likely will be quite costly for the size of system you need.

How expensive is propane? You need to compare its cost on a Btu basis against electricity, but I'll bet it's close to the same. If you use a heat pump the energy cost per Btu will be cut at least in half, if not even down to 1/4 to 1/3 the base cost of electricity or propane.

I have a Daikin 3 ton air-to-air heat pump for my 2000 sq ft ICF house. The thing I like the best is it has a sophisticated control system and a variable speed compressor. It runs only fast enough to move the amount of heat needed to keep the house at temp. I almost always have one on/off cycle per day. It normally turns on about midnight and off about 10 AM to noon. Daikin has recently come out with a version with a water heater exchanger for radiant heat supply. The Daikin outdoor unit will operate several indoor units so you could explore the option of having radiant on the first floor and small wall units in the upstairs rooms. Or you could do radiant for both floors, or wall air units on both floors. Refrigerant lines run from the outdoor unit to each of the indoor units. One large line from the outdoor unit gets divided into smaller lines to the individual indoor units. It's a very versatile system.

I installed a single ceiling mount unit in my crawl space and dump the warm air directly into the crawl. It comes up through registers in the floor all around the house perimeter. The air handler runs continuously so I have air circulating all the time through the house. This scheme also gives me a quasi-radiant heated floor so we never have cold floors. Interestingly, the air in the crawl space has never been above 86° with the house at a constant 74°. What this means is that the temperature level of the heat supply in the house is only a few degrees above the desired house temperature. I think you will experience much the same as your outdoor temp is fairly mild all winter, right?

I could be wrong but I think Daikin is the only system with a really good variable speed compressor. Mitsubishi makes a good split system but their compressors run in fixed stages. Lennox has come out with a split system but I don't think it supports multiple indoor units like Daikin and Mitsubishi do.

Another option for a heat source is a geo source heat pump. From the standpoint of cost of operation it very well may be the most economical. But it has a big downside of being pricey to install.

Have you been to the radiant heating and geothermal heat pump sections of GBT? If not check them out. You'll find a lot of good information you can use to plan your approach for ICF home heating.

The main thing you have to be careful is to not oversize your heating/cooling system, especially if it's a typical discrete on/off operation. And choose a system where the capital cost is in line with the operating cost. If your projected heating cost is $3000 per year for straight resistance electric heating and you can cut it to $1200 with a heat pump, why spend $25 to $30k more for the heating system? It would take you 20 years to pay back a system that may need replacing at 20 years. That would be a zero sum game.

One downside of energy efficient home construction is that finding a proper capacity heating/cooling system can be a challenge.