Friday, September 10, 2010

New Home Construction and ICF's

    I decided to write this post on ICF's, for those of you who are not familiar with this ICF stands for insulated concrete forms. They are used in the construction of homes, business's, and government type buildings. They are a type of Green Building, specifically for their insulating value, another reason is, they are used heavily in coastal regions for their superior structural abilities due  to withstand excessive windspeeds.They have also become very popular for basement homes for their capability to hold back the static pressure from the backfill.

    Now, the reason for this post is to explain the benefits of using ICF's and also the installation and common misconceptions from contractors and sub-contractors. Contractors are especially reluctant to use this product for two reasons, 1. they do not have the experience of working ICF's and they listen to all the b.s. out there that (what about termites), well some ICF manufacturers are pretreating their products in the manufacturing process, otherwise you treat it like any other home building practices. 2. This is the big one there are just not that many qualified installers. There a lot of contractors and or sub-contractors out there that say they can, but I would ask you to ask your contractor to prove it.I would go about this first and foremost did the ICF installer and his crew get certified training form the manufacturer.What kind of equipment do you have i.e. wall scaffolding, this one is also very important, it is not only designed to allow your personnel to reach higher it also has a turnbuckle attachment which attaches to the ICF wall as it is being installed to help keep everything straight and plum, also once you are pouring the concrete you use these turnbuckle attachments to straighten  the walls again before the concrete has a chance to set up.This special scaffolding is very expensive and separates the wanna bes from the experts real quick.Your installer should also have a transit and know how to use it, this is used to keep your wall at the same height around the entire perimeter of your home, believe me folks this is critical. You don't want to walk from one side of your home to the other and there be a 2" difference from one end to the other.The next concern is what the slump for your concrete is'(the slump of your concrete is actually how much water and how wet is your concrete), this determines how fast your concrete is going to pour. I know concrete is concrete, not quite, if you pour your concrete to fast you will most likely have a blowout, this is where one one your ICF forms comes apart usually in a corner, then you have to stop and repair, time consuming and just does not look good. The above questions should give you idea if the installer know his stuff or just giving you a bunch of fluff. Oh yeah, I forgot to tell you on your concrete when you order, make sure and tell them you want a slump of 5-6.

    Now just a few tips we learned as we became more familiar with ICF's and basements, your contractor or you the homeowner need to make your footings wider than in conventional construction, because most ICF blocks are wider than concrete block and brick combination, you should check with manufacturer about exact dimensions.I believe the standard is approximately 12 5/8", then if your new home is going to be brick you add another 5", brick is normally 4" and you need a 1" air space between the block and the brick.The next tip on basements is you know that the outside perimeter should always have a french drain, well I recommend you put one on the inside of your footing as well, kind a over kill but for the added protection for moisture control you just can't beat it.Now since I mentioned moisture control, I just can't put enough emphasis on waterproofing, please please find a qualified waterproofing company.A good waterproofing that we have worked with over the years.I would also recommend that you also use the ICF blocks to build your support for your front porch(it is going to be underground and not seen anyway) using this idea we even turned our supports into safe rooms and wine room with just a few more extra blocks.The last part is to make sure that your contractor uses clean backfill against your basement walls, I know this sounds elementary but you would not believe the number of stumps and trees I have seen used as part of the backfill just to save few buck.

    I want to move on up into the first floor, basically you use all the previous steps as mentioned earlier, except now you have to worry about windows and doors.The manufacturers usually will have widow and door jambs that are made of plastic, usually in 8' increments to use , but you still have to use some type of wood framing to support the opening while the concrete is setting up.There is another potential problem in these areas, make sure your contractor has vibrating equipment to help fill in these voids, most times you will need to cut a small hole in the plastic bucks to make sure you get all the voids filled in.The process is not hard but time consuming therefore a lot of installers especially the first time installers will miss this step.If your new home is just basement and one story you are almost finished, the finishing touches are 1. check your level across perimeter of home if it is level now proceed to installing your bolts into concrete before it sets up, let it dry and install top plate.The top plate has to be treated lumber.

    I would like to go over some of the details of extra requirements that the manufacturers don't always mention and that your contractors don't know about.I do not mean that contractors don't know anything, it's a lot of contractors have not been involved with ICF's before.When choosing your ICF manufacturer ICF check to see if they have a recommended contractor and installer for your area, if so check them out for yourself.

Listed below are some of the cost associated with ICF's :

1.ICF bLocks


3.rebar-this is structural steel rods placed throughout the entire ICF wall, both vertically and horizontally(this one can get quite expensive depending on the size of your home)

4.foam insulating product to fill in gaps or repairs

5.window and door bucks

6.rental equipment-vibratory equipment,chop saws,pump truck

7.ties- ties are used to tie the bocks together during installation to keep from separating during your concrete pour

8.lumber to support door and window openings

9.lumber for top plate

10.add at least 10% on your block calculations for waste

    This is just a brief explanation of some of the cost associated with building an ICF home.I have included a link to the manufacturer that I prefer, I don't mean this an endorsement of any kind.I have used different suppliers over the years and I found that I had less waste and much better customer service from these guys. I will tell you something most of you don't know, that is you have hundred of ICF manufacturers out there, but in reality there are only about five plants that actually produce the blocks, so another important factor is shipping charges,make your selection and then make them give you a set delivery charge. Even though I told you there are only five plants producing ICF's each one has their own specs. that the plants use to manufacture them,just wanted to clarify.

    I could give you all kinds of data that I have accumulated over the years from homeowners and manufacturers, but I believe if you have already made up your mind to build using ICF's you have already done the research so I will not get into that aspect.I only wanted to give you some of my experiences in the hopes of preparing you for the little inconveniences you will have along the way.If you have any direct questions pertaining to subcontractors or installers, builder/contractors or you are a DIY feel free to post comment and I will do my best to answer your questions.

    The last thing I would like to point out is I read an article from a contractor and I thought it was misleading so I want to share my thoughts, building an ICF home will cost you approximately10-15% more than conventional, the labor cost is not reduced it is actually more, yes ICF walls are sheetrock ready which reduces the building materials needed, but the sub contractors will charge more for working on an ICF home than for a conventionally framed home,that being said you will more than make up that cost difference in the utility savings.

    I hope you have an enjoyable experience in building your new ICF home.

1 comment:

  1. We have an excel program we use for estimating the cost for the forms,concrete,steel, and labor ,if you would like a copy hit the email link below and state that you would like your copy of ICF Estimating Formula. We will email back to you as soon as possible.