I am about to have a home designer draw up plans for my new house.  At this point I don't yet know if I will use ICFs, SIPs, or conventional framing.  After I have shown the plans around and received some quotes, I'll pick which method of construction to use.

Question: will I need to go back to the designer to make any changes based on using ICF's or SIPs, or will the builder/manufacturer provide any needed revisions?  For example, who designs the roof structure to support a SIP roof?  To me it almost seems like a chicken and egg scenario - can't get a firm quote without plans, but can't finish the plans without knowing how it will be built.

Hope this makes sense!

Posted By awhite on 15 Apr 2010 02:37 PM

I am about to have a home designer draw up plans for my new house.  At this point I don't yet know if I will use ICFs, SIPs, or conventional framing.  After I have shown the plans around and received some quotes, I'll pick which method of construction to use.

Question: will I need to go back to the designer to make any changes based on using ICF's or SIPs, or will the builder/manufacturer provide any needed revisions?  For example, who designs the roof structure to support a SIP roof?  To me it almost seems like a chicken and egg scenario - can't get a firm quote without plans, but can't finish the plans without knowing how it will be built.

Hope this makes sense!

awhite;

you should choose which system you are using first, get the appropiate details for that system and give them to your designer to incorporate them during the planning stages, especially things like wall thickneses wil greatly afect your plans

I agree with Chris...that said, an experienced ICF contractor should be able to work with plans even if they are listed as a frame envelope. Normally you go by the interior wall deminsions and "bump out" the footer/exterior area, due to the wall thickness. If you elect to go ICF and the plans are finished, it is also vital that ICF walls stack on top of eachother. If you have the 2nd floor exterior walls are set back behind the 1st floor walls, ICF will not really be possible without getting exceptionally expensive...so in that senario, plans would best be changed.

Easiest route is pick system design accordingly.

renangle

From a designers' point of view. I much prefer to know ahead of time what structural systems are being used.
I would go further and say that I would prefer to have a brand of product chosen. This is especially true of ICFs, where there are several different size forms available. In knowing this information, it is possible to design to the systems' maximum potential while reducing waste.

I just got my icf plans finished. You need to make sure as mentioned above that icf walls stack above if you are doing a two story, otherwise it is doable but gets more costly and complicated. I also had my architect spec out to the dimensions of my icf brand. I don't think that is critical but it helps reduce waste and some labor costs. For example, my house will be exactly 17 courses high, so we don't have to cut block at the top or bottom

I know your predicament regarding pricing but if you can get an idea if one is more costly than the other up front, you are better off. There should be some general consensus. Icf distributors and contractors can give you a good cost estimate per square foot. Make sure if you design for sips and want to go to icf later that you will not have a problem expanding your walls out to keep interior room dimensions the same. You could have an issue with setbacks or with coverage from the town ( I had the issue with coverage as we were at the max when I decided to do icf).

This chicken and egg scenario is something you are going to encounter with everything, you can't decide what to use until you get bids and you can't get bids until you have finished plans. It is really hard and I have not found any solution. My plans are finished and I am getting the bids now and still don't know how much this house will cost.

Make sure in estimating costs you are talking to people who are in the field and know. Many people act like they know prices and have no clue. My architect is still convinced that my house is going to cost $2 milliion dollars because it is icf!! I'll let you know when it is done.

If I have a customer on the bubble about which system I have the designer just do  very preliminary floor plans and elevations for pricing , once they get their ICF , SIPs, and conventional quotes. then they can move forward with a full blown set of plans with proper connection details, wall thickness etc.

It all depends. Not enough information was given for an answer to your questions.

I have an ICF home, from basement footer to top plate. The walls are 11 inch overall. My truss manufacturer did not want to make me the trusses that I wanted (10/12 pitch) scissors with a 40 ft span. He told me that his software would not allow this. Naturally it would not, as the program is programed for wood walls and the lateral force is to great. I told him to override the program because of the ICF wall and the rebar installed in the ICF wallwould be sufficient.  IAt the time worked at a major University at the time (Penn State) in Engineering and told 84 Lumber that it would be fine. Needless to say, My roof and ceiling have been fine and I do not have settlement cracks as I would have had in wood construction.

When you go to price your ICF against any other method of construction, just do not look at the price for the walls alone. The construction costs begin to spiral downwards with ICF's. Smaller furnaces, easy drywall installation, quicker electrical installation and most of all lower utility bills.

What you plan to build is an "Engineered Structure" have an engineer or energy rater help you through your decision. It will be the best money you could ever spend..

We are Penn State!

If the person who is drawing up your plans can't size your beams or do your structural drawings / fabrication drawings what are you paying them for.  Most SIP companies know how to do the drawings and should provide all engineering for you.  I did this in the past but don't have the time.  Dan with Earthen Concepts in Kansas City is a good person also, he does estimates, drawings and construction.  I would also work with a company that can do energy analysis on your building to make sure you size the right equipment and know which system gives you the most value.  You should consider your CAPEX and lifecycle costs.  I work with several; GWS in Oklahoma City is a good Engineering firm.  Worth every penny.

Jeremiah
AEC Applications Engineer
Applied Technology Group.

My plans were designed for icf by an architect and I still found a need to have them engineered by an actual engineer experienced in icf so that it is more cost effective to build. I think you should count on needing an icf experienced engineer to review your plan, no matter who draws it up. An architect can go by tables, but I am being told by the icf subs that there is a lot of overkill and areas needing improved design to save on costs, although I could technically build as designed by the architect.

I agree you should decide which method of building you are going with first. I however did not alter my plans for my SIP's house. It was a purchased plan from a designer and I decided to go with SIP's. The loss is a minor amount of space due to the SIP's wall being a little wider. I was however completely involved with the building, i.e. I hammered the nails, etc. so I was always aware of the slight differences. Also note my house plans were not overly complicated.