Hi all.  Still working on floor plans and quotes for a new ICF home.  Exterior living is something I need to incorporate, however because of financing, I may need to build my dream deck with fireplace 3 or 4 years down the road.

I know how ledger boards are attached during construction, however, how are they attached down the road?  What about roof rafters?    I could plan for these now, however I'm  not sure how the siding detail would work with these boards attached.

Thanks

You can recess ledgers flush with the outer skin of the ICF and side right over them awaiting your next expansion phase. You will take a little hit in R value in this area, but IMO load bearing members, particularly those where loads are concentrated(deck ledger) should be in contact with the concrete, not foam...

You could also cast beam pockets into the walls for deck or roof rafters(I personally like this better than a ledger). You basically make a foam plug(pink 25 PSI XPS) to simulate the beam you would install. you could wrap the plugs in celophane so the CC would not adhere to the foam plug. These plugs would be flush with the outer ICF and you would side right over them. When you are ready to expand, you remove the siding, cut out the foam plugs and install your beams. you would have to remove some of the ICF foam adjacent to the pockets to install brackets to tie the beams to the walls(Like Simpson HGAM 10 ?) for out of plane restraint. The brackets could be foamed back over after installation.

It is doable, you just have to plan carefully, particularly the interface between the plan phases...

Is there a rule that says the deck has to be attached to the house. If not, then build a self supporting deck? That might be simpler.

I did what Alton suggested, even though I built my deck at the same time. I wasn't happy with the way I wanted the framing to run, so I built the deck as a free-standing one, even though it's in contact with the house. It just requires some additional bracing, since the house isn't being included in the structure.

A self-supporting deck will require more columns. Columns adjacent to the exterior wall should be placed to miss windows and doors. Usually no problem unless the wall is a window wall (full of glass). If the deck is deep from front to back, then if necessary to miss a door or window, columns can be added midways so the beam above can be cantilevered towards the house. When I design a self-supporting deck, I leave a gap between the the house and deck and then call for a drain grate to be installed there to bridge the gap. A solid deck should slope slightly away from the house since it cannot drain through cracks.

A self supporting deck will prevent thermal bridging.

With concrete there is no such thing as "in this area." Concrete is so conductive that all the btu's in the wall will drain out of "that area" if there is not a steady stream of replacement btu's. If there's a hole in a bucket, does only the adjacent water drain out of the hole or does the whole bucket empty?

Posted By FBBP on 28 Jan 2017 09:56 AM
A self supporting deck will prevent thermal bridging.

With concrete there is no such thing as "in this area." Concrete is so conductive that all the btu's in the wall will drain out of "that area" if there is not a steady stream of replacement btu's. If there's a hole in a bucket, does only the adjacent water drain out of the hole or does the whole bucket empty?

FBBP, very interesting analogy. Respectfully, I would suggest that if these BTUs (energy) are replaced with more BTUs they will go too ;) Two buckets of BTUs will go through the hole. Regards

Tex- Exactly right.
You have to take the analogy one step farther.
If you keep pumping enough water into the bucket so that it over flows, no one notices the leak!

Stand alone deck. Keep your thermal envelope in tact. The extra columns aren't much $$ and you only pay for them once.