I am designing a three story, +6,000s.f. house in Florida on the gulf coast in a 130 mph wind-zone and have been considering ICF’s for the exterior wall system. I have not had any trouble finding out all the positive aspects of the system, but have had a much harder time finding info on the drawbacks. Additionally, I have had a difficult time trying to weigh one ICF company against another. I like to take advantage of new products that purportedly save time and provide a better finished product, but I ‘m leery. Some of the issues that concern me the most are:
1. blow-outs during the concrete pour
2. Dimensional uniformity of the forms themselves (either in production or due to variations in temperature/humidity)
3. Difficulty achieving straight (plumb) walls.
If any of you have already been down this road and either used or didn’t use the ICF system for one reason or another, please let me know
Thanks,
BDD
Replies
Must be the night for ICF questions!
Just moved into 4500sf of ICF home.
We used ARXX Build, formerly BlueMaxx. No blowouts, but we were careful where we joined cut forms. We used lots of filament tape for reinforcement. One trick is to use 4" slump, but with lots of plastisizer. This allows the mud to flow without having to pound on the forms too much and a vibrator was not used at all.
Went with the ARXX because of the plastic webs. No thermal bridging as with metal. Didn't want to deal with the sheets of styro and assembly clips. Seemed too fragile. We were driving screws into the web for strapping after pouring with the outside temperature at -10. No splits, it takes screws well.
The forms were uniform in size during erection, but they tend to grow when you pour them full of concrete. If you have to cut the webs to accommodate windows and doors, be sure to brace very thoroughly as they will spread.
The system must be braced as any concrete pour. Some guys get lulled into thinking that the system is self supporting as when it goes together it is quite rigid. You will find that even with substancial bracing, the forms get blasted all over the place when the mud is placed.
We did some walls with rigid bracing, and some with adjustable. Adjustable is a must. Fill the forms with mud and then tilt the wall to plumb.
Be sure to make multiple passes around the building when filling the forms. Don't fill any more than about 3' at a time.
good luck.
KM
There have been dozens of discussions about ICFs on this board.
Try using the advanced search feature, and you should get a ton of threads about it.
Be happy. It is a way of being wise.
Agree with Boss.
All the ICF mfg. tout thier product as the one you want, so you need to ask some key queations when talking to them. Do the search and you will have as many questions as you have answers at the end.
The ability to pour in four foot lifts and internaly vibrate are two questions that will cull the list down to three or four product. To my way of thinking that would be important on a whole house ICF usage, because you would reduce the possible number of cold joints and voids or honey combs.
No matter what the mfg. say, it is still a concrete form. Brace it, brace it, line it and brace it some more.
Dave
I have a few years of experience building with ICF's.
You want drawbacks. Here you go:
SLOW.
Yes, slightly more difficult to get straight lines, and level surfaces but not too bad.
Occasionally a wall can bow during the pour.
Windows and doors are SLOW and use a lot of treated material for bucks. See next line.
EXPENSIVE. Yes, it adds a fair amount of cost. I personally believe you get your value back several times over with energy savings, quietness, extremely strong and solid, and very weatherproof. I'll tell you about cost savings too, but that's not a drawback. All of your connections to concrete need to be metal or treated lumber. Your top plates may be expensive, I've typically used treated 2x8's and on the last house my plates alone cost $400 for materials only.
Subs are not used to working with it. They will probably bid slightly higher. But they won't complain much if you plan ahead for them. Be sure you've got it all figured out. Minimize all mechanical needs in exterior walls. It's really tough to retrofit any wiring later.
Some of the systems could be extremely dangerous in a fire. Be careful what you use.
Bracing. You need a lot of bracing, probably two or three times as much as what you think you need. As a builder, it's no big deal for me to buy this stuff, I use it all. But you will buy it.
Kind of hard to make changes later on. Be sure you've got everything where you want it. Mistakes cost big money. If someone makes a rough opening too small, guess what?
I could probably think of more.
Want to know about a really good system?
I know this is an old thread, but yes, I would like to know about a really good system. My husband and I are contemplating using ICFs to build our new home in the spring. I have been "lurking" here for quite some time and find the information shared here invaluable. Thanks to all who take the time to share.
My opinion is to buy the blocks that are open in the center like a regular concrete form . Have plastic rather than steel web/ties. The reason for plastic over steel , why insulate the wall and then have a thermal bridge every 16" or less to transfer the coldto the inside. Also there is the rust issue ,even galvanized steel will rust fast in moist soil. As it rusts it flakes and puffs up busting your concrete, causing leaks .
I like the blocks with teeth that inter lock with the next row .
Cappy,
I was going to build and was considering ICF's for the basement,but have since purchased an existing home.I'd like to pass along this word of caution: There are a ton of BS artists pitching ICF products on the Web.If you go to the big ICF site the "experts" there are almost all salesmen and distributors.They grossly oversimplify the process.They make it seem like any husband and wife can DIY in a weekend.Don't believe it. I read a newspaper story about a local builder trying them and so I visited the site (yes after hours without their permission)after they had poured the walls.This builder had said in the article that the manufacturer had their representative on site to help them make sure the walls came out "straight as a string".So my wife and her brother held up 2x4 blocks with a string held taut between them on opposite ends of the kitchen/dining room wall.I measured along the string and the wall waved in and out by over an inch.Yards of wet concrete weighs tons and to put them into featherweight forms takes an EXTREME amount of skill that few have.But if you go to the ICF site it's a piece of cake.
Barry
Edited 11/23/2003 10:45:38 PM ET by IBEW Barry
I am not going to tell you that the ICFs are the easiest product to install but it os possible for a Home owner to install it themselves.
Since as you pointed to ICFs reps and Dist. are there to sell product and make it seem that it is easy to install. I am a ICF Dist and I pride myself on the end product and not on how much money, I can make. I am sorry to tell you with any product you buy the salemen will make it sound like anyone can install the product with there eyes closed. In my case I walk everyone throught the construction process and I am sorry say, I might be the exception to the rule. Like I tell everyone that is looking at ICFS to build with. Make sure you have a good rep or salesmen that will be on site to work with you on troubles or tips you will need to know to make things easier on you in the end. I will say this you will want to contact a few ICF reps to see which one you are most comfortable with. I even tell my customers to do the same. You are shoping for customer service not product in my mind for ICF system.
This could range from rental of bracing to having them check up on you daily. Like any service you will want to get the most out of the money you put into it.
Just my 2 cents
Brian
Thanks to all for sharing your experiences. We hope to keep gleaning information and make an educated decision. Brian, We live in rural mid-Missouri about 1 hour north of Columbia. Do you happen to know of anyone you would recommend in the area that we could talk to about ICFs?
Thanks,
Kim
Countour Products out of KC, KS is a licensee/manufacture.
You might want to contact them and see if they have sold to anyone in your area.
http://www.contourfoam.com/
I am sure this Site has been posted here before but, http://WWW.ICFweb.com
This is one of the better sites on ICFS and a good forum plus a list of most of the builders in the country. If you search in your part of the country you will be able to find a good builder.
I hope this helps
Brian
Barry,
Obviously, you found a builder who didn't have a straight string, But it is possible to find at least as much deviation in a "professionally" formed wall with whalers and brackets.
BTW, Just for clarification, was this wall in an inch and out an inch, leaving a total deviation of 2" or was it in and out a half inch from the line, for a total deviation of an inch. I would be less concerned with the later, but quite concerned with the former.
most DIY things depend on the abilioty and skills of the persons involved. I happen to think that a good half of those who consider themselves capable of a large DIY project art capable of pouring a foundation with ICFs and doing it right, if they can read and understand written instructions, and are willing to rent the proper whalers and braces.
It is when someone trys to take shortcuts that lousy work happens, no matter whether they are in the trades using conventional means or simple weekenders..
Excellence is its own reward!
Piffin,
The kitchen/dining room wall I checked waved in/out/in an inch in either direction(total 2").I picked the kitchen wall in particular because I know what a PITA it is to hang kitchen cabinets without flat,plumb walls.And I wanted to check this particular house because the builder stated specifically that they had on-site factory supervision for their pour.Of course I wasn't there so it could be just part of the sales pitch.
I do know that when I was doing my homework on ICF's I talked to a distributor for AMVIC that at the end of the conversation asked me if he could put my name on their builder referral list.This was after we had discussed that I'd never used them before.He said they just needed people with construction experience.
The Internet is such a great educational tool that it's much easier to investigate new building products and construction methods.People reach opinions about ICF's,SIPs,LVLs without ever touching them,just based on what they read.I know some of those people at the big ICF site have never pushed a wheelbarrow of wet concrete in their lives,and yet there they are spouting off about slumps and R values.
Barry
Point taken. Can't argue with that..
Excellence is its own reward!
I used the reward sytem and without a lot of trouble was happy with the results..
My only warning is ,
Make certain that each layer is true flush and level before going on to the next..
Oh and have the cement company add some self leveling to the mixture.. (actually a lot) Makes things go a lot easier..