ICF- "Reward Wall system"
In looking at many of your excellent suggestions from my last post-"energy effeciency", I did speak with an energy advisor and he speaks very highly of ICF (insulated concrete) in making a home more effecient.
I would like to know what you think of the ICF- especifically Reward wall.
I understand that is more costly upfront however it provides R30+ from basment foundation to the roof. It can also stand 200MPH winds-in case of tornado....
Have you delt with this or have this in your home?
He explained to me that using ICF and a high effeciency furnace using heat/air exchangers would be much better choice economically than a 6ton geothermal unit. Use the savings from the geothermal unit and put it into the ICF. He also said the savings are over 60% in energy bills per month.
Any thoughts on this one?
thanks again you have been extremely helpful.
I replied in the other thread, but will add this here.
ICF is strong, and like you strong is necessary in my hurricane zone.
The only problem I have with ICF is that the concrete is not always
poured to fill all of the forms. Granted this is an install issue, but
in doing thermal scans of ICF homes we find many voids in the icf forms.
Hopefully I can explain this a little better.
Once walls are set up, concrete trucks come. Each wall is poured in stages.
When concrete is poured/pumped a concrete viberator is used to reduce
honeycombs in the concrete..or to get the air out and make the concrete
continous. These viberators do not reach the lower levels of the walls.
The ICF people I have dealt with say that the weight of the concrete will
push air pockets out of the lower levels..but testing shows that it does not.
For the top 3' of the walls the viberators will work, but it is the lower levels that
suffer, the walls have rebar in them and the concrete does not always settle
as is should.
Its really interesting to watch the concrete being pumped into these walls.
You should check around in your area & see this for yourself.
On several of the pours I went on the walls had blowouts.
This is where the forms can not take the concrete for whatever reason
and the walls literally blow out. It can be small..or large. Its pretty exciting
to see the crews rushing to contain the areas & get it ready for the next truck.
You know concrete moves fast..these guys earn their $$.
best of luck
The cure of the part should not be attempted without the cure of the whole. ~Plato
tall concrete items need to be poured in 'lifts' --
-- each lift being the height that can be installed properly,
-- --- sounds like for these narrow walls for houses, the limit is about 3ft
--- --- then vibrate!!
harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!
Another benefit of ICF is the thermal mass. It takes much longer to change the temp of the concrete.
UCFs biggest advantage is the strength. You have to decide if you really need walls that are that strong, because you are going to be paying for it.
It is not that difficult to get comparable insulation values and air sealing with more standard construction methods that cost less than ICFs.
A simplistic approach from an energy use only standpoint is to do comparative heatloads. One of the high I.Q. ladies/gents might even suggest energy modeling which I liken to separating fly specs from black pepper for a typical single family residence.
An accurate heatload calculation can be used to compare various building materials/assemblies and cost versues savings can be calculated. You can then determine where the cost effective investment is. Now if you throw structural strength into the picture it becomes personal judgment. Are you a belt and suspenders personality?
Just be aware of the ever present point of deminishing return and as E.R. stated the install integrirty has to be maintained or it is just money down the drain.
Oh yeah I just read, regarding heatloads; only 14% of HVAC contractors do them regularly.
Last edited by adrianf; 07-12-2008 at 11:39 AM.
I used the rewards wall ICF system on my house south of Houston, many benifits you need to investigate first,
1) reduced hvac load I have 3100 sq ft 39,000 btu pay attention to the btu needs when running the load calculation software you need to have the BTU capacity not the 3 ton condensor. IE: not really 36,000 btu is it..
2) 200 mph winds plus fire proof.
3) i used the iceneye ( sprayed foam) in rafters
the benifits to item 2 and 3 are a REDUCED rate on homeowners insurance because its almost fire proof.
I pay half of what my neighbors pay even with having the windstorm package living near the coast.
I also floated my contrcution loan thru them all fair but pay attention to details working up draws and not doing right delays funding..
you can not go wrong with the set up......