Hi,

Apologies if the has been covered...

I am planning an ICF home and am very interested in a concrete floor system (Lite-Deck, Hambro, SpeedFloor, etc).  Per other threads I have read on this forum, perhaps one could be had for little more than a quality wood truss floor system, especially if you factor in in-floor radiant heating.

However, given the in-floor heating, it would seem the concrete floor systems might not be efficient.  Every drawing I have looked at shows the concrete floor decks poured directly on top of the ICF wall such that the deck and the ICF conrete core are connected.  It seems to me that the wall concrete will act as a big heat sink, sucking heat out of the floor deck.  Simple math tells us that if the wall insulation is intact, if the inside of the house is 70 deg. and it is 0 deg outside, the concrete core center will be ~ 35 deg.  If we attach in a heated concrete floor deck at 80+ deg, we will be heating the wall concrete in the vicinity of the floor decks unnecessarily.

Of course, this can be eliminated by suspending the floor entirely via ledger boards, such that the interior insulation on the walls is left intact.  I have not seen any examples of this with concrete floor systems - only wood.

So, at this point I am leading toward wood (2x4 based) trusses which can be suspended by either ledger boards or a block-size change ledge, and the wall insulation left intact (or at least not in contact with thermal mass of floor).  The downside of this option as I see it is the implication for the in-floor heating.  Layers:  truss + subfloor + tubes + gypcrete + underlayment + floorcovering.  Seems like a lot of layers = a lot of labor = a lot of $$.

Am I missing something?  Is this the way to go?

If I do go concrete (say Lite-Deck or similar) what needs to go down between the floor at finished flooring (carpet, tile, hardwood)?  Can I tile directly to the concrete?  I have not seen a lot of discussion on this.  Do the concrete floor systems sag at all during cure and require a leveling topping?

I have asked a couple of local ICF contractors about Lite-Deck (and similar) and the concensus was that is was a very expensive way to go and no real reason to go with it.  Opinions?  It is hard enough to find ICF subs let alone Lite-Deck (and similar) expertise.

Incidentally, there is a local contractor I have talked to that developed his own steel truss system that ties into the wall concrete with metal brackets instead of the actual concrete deck - which is supported by ledger boards around the perimeter.  I am a little nervous since it is an unproved product, but maybe it is what I should be looking at.

Two other, non-topic questions:

Should I plan on an 8" basement, 6" first floor (concerete ledge to support first floor), and continue 8" on second floor and use Simpson/ledger for 2nd floor?  Or, go 8", 6", 4"?  ICF contractor did not have a strong opinion.

How about windows?  Planning on casement.  One ICF contractor pushing Schuco vinyl.  I prefer wood interior/extruded alum exterior for looks.  Opinions?



Sincere thanks in advance.

Rothemon

Well for your first question I can see that you are somewhat right in that the effeiciency of the radiant floor will lose a little energy in the perimeter icf walls. However in my opinion it would be minimal. I think that no matter what floor system you go with it will out perform its organic wood counterpart. I have done a few hambro jobs in the past with great results. Im not completely familar with the other systems, but the thing I like about the hambro system is that there is no shoring (underlay vertical supports) involved. I believe the joist can span up to 35-38'. The downside is that there is no insulation preformed in the hambro system. Depending on the application we usually just hire Sego to spray the bottom of the floor.

Yes you can tile directly to the concrete and you do not need any covering before you put carpet down.

For your basement you should contact an engineer to determine what loads the wall will be put up to after you back fill. There are a lot of factors in determining basement concrete and rebar schedules given that an engineer needs to take into consideration point loads, live loads etc. Using a suspended concrete flooring system could change the size of your footings and rebar schedule. Although I would think it would be minimal.

Anymore questions ill be glad to answer.

Hi Rothemon:

In regard to suspended floors, one way we do is to use concrete slab on metal deck supported on joists that are fastened to a ledger. I am attaching herewith a picture of the concrete work in progress on the First Floor slab over basement walls

ANAND Enterprises project SteG2yae-101 New ICF House for Gary and Pam Stehr in Highland Township Michigan

Rothemon, to answer most of your questions in my opinion a insulated deck system like Insuldeck/Lite deck is only practical on commercial or multifamily when someone is living over or under someone else. The cost for these type of systems just aren't practical for residential construction. Hambro, Dietrich with metal pan, and other metal systems that are uninsulated can under the right circumstances compete with a floor truss application. If your far from a manufacturing plant and they don't have a shipment going your way to pony up with it will still be more expensive than normal applications and not as practical for a one time situation. Most of our two stories on basement go 6" all the way up to the roof. Transitioning to a narrower block causes many unforeseen issues in exterior wall stair wells, and also it requires floor transitions at specific locations i.e. the change in block thickness. As far as windows go that's going to be your choice, were all ICF guys here.

Dave