Styrofoam and concrete foundations
My wife and I recently went to the local Home and Garden show in the Cleveland area. We are considering building a ranch (SIPS would be nice) with a walkout for us to retire in. We are energy conscious and prefer efficient design to conserve heating expense and yet have a reasonable level of comfort. At the show, we noticed at least 4-5 variations of styrofoam block type of foundation designs that incorporate concrete in the structure. One design had interlocking styrofoam panels in which concrete was poured. Other designs had metal inserts to bridge two exterior panel walls of styrofoam and concrete is poured between the walls. Has any particular design style proved to be superior to another or are they essentially variations on the same theme with none being better than another? Are the exterior walls waterproofed? Are these designs as energy efficient and durable as promoted at the show?
Replies
Maclf 2922
absolutely!
I built my house using a combination of SIP's and ICF's (for pictures go to 85891.1 & 94941.1) in retrospect I would build the foundation and walls with ICF's and use the SIP's only on the roof.
I used Reward brand forms but there are plenty of forms out there.. some are good the rest are great.. none that I've heard of are bad.. What you should look for is either the company that will be selling you the forms or the contractor you intend to use..(ask me for more details)
The company that will sell you the forms should have a team of people to walk you through the steps if it's a do-it-yourself approach (very user frendly way to build even for complete novices). In my case they came out and checked the day before to make sure everything was done properly.
Nothing will beat the durability of a ICF wall and while they are a tiny bit less energy efficent than SIP's they have advantages that SIP's don't have.. The slight loss of energy efficency can be easily made up if that's critical but they are still massively more energy efficent than typical stick built homes are..
If on the other hand if you want to contract this out, you should know that at first there was as much as a 20% premium to build with ICF's then that was reduced and reduced as people got more familar with them and the ease they go together .. Today you can get a bid to stick build a house and a bid to Build it with ICF's and they should be nearly the same..
Some of the homes I've seen go up around here are exactly the same bid price without regard to stick built or ICF.
As for energy savings.. My own well insulated stick house used to be 1/2 the size with 1/3 the windows I have now. It used to cost me $500 to heat it in dec. and $500 to heat it in Jan..
Today using that exact same furnace My costs for those two months is down $300 per month. or about $200 a month.
In the summer when it's 90 degrees outdoors it's only in the 70's in my house.. annual air conditioning bill is about $15.. (a year!) I only use A/C on days that approach or get over 100 degrees.
Edited 2/9/2008 1:22 pm ET by frenchy
I recently poured a basement foundation for my stick built home using the Polysteel ICF form system. I am very pleased with the results but we are still in construction stage so I cannot comment on energy efficiency and such. I can say the ICF system was very easy to use once we got through with the first couple panels. The absolute must have is a good set of panel jacks for plumbing and bracing the walls and it is helpful to work with an architect who is familiar with the type of ICF you are planning to use as the dimensions make it either amazingly easier or incredibly more time consuming to finish depending on the amount of cuts or the placement of cuts to the form system. As a first time DIY - I could not be more happy, even with the relatively high cost of the ICF blocks themselves.
http://www.pathnet.org/sp.asp?id=1014
Some good information at the above site, or just Google Insulated Concrete Forms. You will get a ton of hits.
Many people on this site have built with ICFs and have their favorites, so I doubt you will get a consensus on any one product. If you are going to DIY, you need to do the research and narrow your choices down a little, then contact the manufacturers as another sorting process. If you are going have the home built by a builder you still do the research, but on the products they may use. Also go look at some of their ICF homes and talk to the owners of them.
ICF aren't idiot proof. They are easy to build with, but the same precautions need to be taken with them as with any concrete foundation work. You can have crooked, out of sguare/plumb/level wall with ICF just as easy with ICF as a standard formed and poured wall. Get references for the builder and the foundation sub he uses, then talk to the framers that work behind them. They are the guys that have to straighten out the mess a pour foundation guy leaves behind.
regardless of what type of foundation you use it isn't a diy project (depending of you abilities), and should be left to the pros. we're talking about the foundation, what everything is built on, not trimming or installing cabinets. try to save a few bucks on a foundation, can lead to hugh dollars down the road.