Carnation Walling - Better ICF
ICF is great, but you can do something even better.
Use Carnation Walling rather than traditional ICF
This page describes in detail the steps to use the Carnation Walling method to build each level of your house including the Carnation Flooring above that forms the concrete ceiling. This technique is repeated 3 times in the process of building a three story house such as mine.
If you want to use traditional ICF there's a page here that details the benefits of ICF, and a page here that describes suitable ICF blocks to buy. If you are using traditional ICF then here are the steps (but I urge you to follow the steps below instead).
ICF is great, but it has a negative in that some of the polystyrene is on the inside of the concrete wall structure. Building science tells us that it is better to have all the insulation on the outside of the structure, ie external to the concrete. This is why I use what I term "Carnation Walling". You can think of this as IFC (Insulation Formed Concrete) rather than ICF (Insulated Concrete Forms). Using regular sheets of EPS is also much less expensive than buying ICF blocks.
I do my own concrete wall forming using regular EPS sheets. These are a commodity item and as such there is competition between suppliers that keeps the price down. "Carnation Walling" is a *method* of building rather than a proprietary product. The method puts all the insulation on the outside of the concrete and relies on removable re-usable plywood to hold the concrete on the inside. The details on this home made "ICF" system and the building science behind it are here and you should read this in detail before proceeding.
I am using 6" thick EPS sheet as the main layer of EPS with an additional 2" thick EPS sheet glued with foam adhesive to the outside with staggered joints to avoid there being any exposed joins for concrete to leak through. On the inside, Carnation Walling uses a thin layer of smooth plywood and a thicker layer of construction grade plywood with staggered joints.