Part of my plan for my house is a sunroom and I'm not quite understanding how I can determine how much space I need to leave between window openings. The design guide includes tables describing minimum length of icf wall without openings but am I missing something? - for my one story wall supporting a light framed roof the minimum solid wall length is 4 '. There isn't any guideline (unless I've entirely missed it) in the arxx manual regarding minimum column width between windows. Thanks for any help

Delprete, Good question. With NUDURA and I think we can safely assume ARXX to be similar; if you have less than a foot of concrete between windows you treat the opening as if there is no support between windows. For example four 3050 windows with about a foot of concrete between each should be treated as a (3+1+3+1+3+1+3) = 15' foot opening. This means you would use strirrups and bottom bar from the tables as if you had a 15' opening and ignore the columns. If you are not clear on what I am saying, or actually either way you should consult an engineer. The NUDURA book requires you to consult an engineer if the opening exceeds 20'. Regards.

Also if your columns are that small consideration may be required with stirrups or a cage for the columns as well...depending on your location

Thanks very much for the replies. I'd poured over all of the literature and could only find minimum solid wall lengths.

Texas.......just curious....what is a strirrup?  Did a search and couldn't find it.

delprete,
I know I will be accused of heresy, but I would use some other type of wall system in that area of my home.
I find that forming an ICF wall column of less than about 3 feet to be a waste of time, materials, and money.
You loose all the pluses of ICF construction and magnify all the negatives. A 'sunroom' by definition should be maximum glass. So if you loose half your glass, you loose your 'sunroom'.
Depending on the height of the windows you intend to use, you can 1. build a short ICF wall to the bottom of the windows, then switch to SIPS or conventional framing around and above the windows, or 2. use alternative complete walls in these walls.

Wes has hit the nail on the head. Columns in a sun room do not seem like the best use for ICF. Use something else for that piece of wall.

Robinnc,


Stirrup "rebar" examples -- the most common is the "C" -- upper left corner.  They typically run from the bottom of the lintel (bottom bar) to the top of the lintel (top bar) and how many and spacing etc. is determined by the engineer based on loads for the lintel.    Regards.

Obviously engineered - this winecellar shows some talent and flexibility.    Regarding the sunroom -- another approach, if you want to keep the strength of the ICF is to just create a very large opening say 20' and make it all windows.   With engineering you can go up to 30' pretty easily.  I don't know how big your bank of windows is but 30' all windows is a pretty good sized sunroom.  Regards.

Posted By wes on 17 May 2011 07:36 AM
delprete,
I know I will be accused of heresy, but I would use some other type of wall system in that area of my home.
I find that forming an ICF wall column of less than about 3 feet to be a waste of time, materials, and money.
You loose all the pluses of ICF construction and magnify all the negatives. A 'sunroom' by definition should be maximum glass. So if you loose half your glass, you loose your 'sunroom'.
Depending on the height of the windows you intend to use, you can 1. build a short ICF wall to the bottom of the windows, then switch to SIPS or conventional framing around and above the windows, or 2. use alternative complete walls in these walls.

I'd been thinking of this, but wasn't certain of it's structural integrity.

Though I am passing on my plans to a building engineer for input and approval, I am working on the plans myself. I'm concerned with integrating an alternately constructed sun room extension with a main icf plan. The main footprint of the house is 28x40. The sun room extends out from the 40' South wall 7' and runs 32' before it's return. If alternately constructed (stick or timber frame) I'm concerned with expansion/contraction differences between the icf and wood-framed walls.

I agree with Wes and Ray.  Be aware that a beam may be needed above the windows.  It all depends upon the building system used and the span above the glass.

Spanning large openings is no issue at all and can increase the amount of windows in your sunroom. I recently spanned a 16' o/h door with no problems at all. Just be sure you have a thick enough concrete core and a deep enough lintel, along with proper stirrups/lintel rebar to obtain your desired opening size.

Also - TEXAS is correct in that any opening less than 1 foot of concrete (NOTE this is 1 foot of CONCRETE - do not include the bucks in this measurement) should be designed as though it is one opening. However, if any opening is 5 feet or more, you need to have at least 2 feet of concrete between the openings or it must be designed as one opening.

Thanks Texas!

I have mixed ICF walls and SIPS/conventional framed walls many times with no problems. Almost all my walk-out basements are 3 walls ICF, and one 'walk-out' wall of SIPS. Expansion/contraction is not a major issue.
And yes, you can do grand openings, as illustrated in the above photos, but why spend the time and money. Practical perspective can be a good thing.

Hmm - this is definitely not my area of expertise but can someone tell me why an 8" x 8" column cannot act as a load bearing member and thus cut the span in half? ACI or IRC or PCA100 reference would be awesome!!! I think it can... sure the pour around the rebar would be a nightmare... My reasoning is that if we can have an 8" deep lintel I don't see why we can't have an 8" column... http://img832.imageshack.us/img832/7004/unled11n.png

With the correct concrete mix, the placement of concrete in an 8" x 8" column with highly congested rebar is easy.  Either use a high-range water reducing admixture in the mix to make it flow and small aggregate or use the Agilia mix from LaFarge.  The concrete should provide all of the compressive strength and the rebar should provide the tensile strenth needed to support residential loads.  Of course, use a structural engineer when in doubt or when an application is beyond the code.

It is not that an 8" x 8" column CAN'T support the load - it is simply the fact that most manufacturers require a minimum 12" between openings. If you want to/need to build with less, an engineer is required.

I agree with Alton... theres several ICF manufacturers that have their ties @ 6" o/c or even less... so I still fail to see why limit yourself if you do not need to.

But really where do get the clause that you need an engineer for 10" of concrete between windows if you build according to IRC 611... or PCA100...

But maybe I am wrong - I never read the whole R611 section in the new 09 IRC... anyone?

look at this image...
http://img853.imageshack.us/img853/1162/unled11i.png
are you telling me that you would reinforce this as if it was a 23 foot opening... I wouldn't... plenty of ICF manufacturers out there that would agree with me... just my $0.02

Any manufacturer I have seen requires 12" between these openings or you would have to span it as though it is 23'. You and I both know that the concrete provides significant strength to this design, but since we are not engineers (at least I am not) we cannot make a decision to change the structural requirements set out by the manufacturer. Experience and common sense tells me this WILL hold, but if there are any problems down the road, I would not want any liability for the design change.