I am going to be building within the next 12 months and like everything I have heard about the benifits of ICF construction. The only question I have is are there open air limits with ICF construction? Do the blocks lose some of their R value if they are exposed to the sunlight too long? If there is any type of delay in the construction process and the exterior walls remain unfinished, or the basement not backfilled for a few months will there be any residual R value issues?

I have only heard this from one person and they are not always accurate in their opinions and want to be sure either way.

They won't lose any measurable R value, but the foam will change color. White foam will turn quite yellow in a matter of only a few weeks. This means the surface of the foam has deteriorated. The only negative effect I'm aware of is the ability to get peel & stick material to stick. If the foam has turned yellow you need to brush off any surface you want material to adhere to, like peel & stick waterproofing membrane around door and window openings and below grade.

dmaceld is correct. The only change you will experience within the first year of exposure will be the yellowing caused by UV deterioration. It has no effect on the R value or structural strength of the forms. When you are ready to apply your peel n stick, brush the forms with a stiff bristle brush to remove the loose stuff. Then, if your supplier has it, a liquid primer, most do, to help the peel n stick stay stuck.

correct me if I'm wrong but I thougth I understood latex primer applied to the foam is recommended to help peel and stick waterproofing and peel and stick flashings around windows - this is if the foam had got to the chalky weathered stage?

 

md2020,
The mfgr RECOMMENDS the primer on every application.
It is not absolutely necessary on new, clean blocks but it helps. And I would also recommend it's use on all applications.