Formwork

In the typical construction project, I suppose you need to start with the ground and move upward. I took the opposite approach and started form the roof, and moved through the skylights, doors and windows, walls, flooring, foundation, and earth. I’ve already selected the windows, skylights, roofing product, and building system, but have not selected the foundation yet.

I thought it would be easy. you have two choices in general in seismic design category D, continuous foundation walls, or concrete masonry units (CMU). I’ve investigated all sorts of technologies in anchoring a structure to earth. Everything from metal helical rods, posts and grade beams, and every type of gluing scheme. The foundation not only holds up a home, but acts the interface between the earth (air, water, fire) and your dry structure. It has to prevent moisture buildup underneath, hold fast during movement, and last longer than what stands on top of it.

I got the definitive word form APEX block that their lightweight composite ICF solution is not approved nor likely to be approved in the city of Los Angeles for many months. I have to select a plan B, which is either a tradition six inch formed footing and stem wall, or an alternative forming system, like an ICF. My idea is to eliminate concrete, or at least reduce it. The APEX system took this structure down from 6.63 cubic yards (cu yd) of cement to just 4.70 cu yds. All other systems reduce concrete use, but the next best system I could find was a waffle grid ICF called American Polysteel PS 3600, which will use 5.70 yards of concrete. Why this matters is concrete should be used where needed, and not extravagantly, because it has a extremely large carbon footprint in its manufacture. Concrete is also very, very heavy, and takes a lot of diesel to transport. That’s why CMU’s are out of the question.

The Polysteel forms weigh in at 7 pounds, compared to a CMU at 60 pounds. I calculate I’ll need around 75 blocks, saving over 2000 pounds from a flatbed truck. I’m hoping to design a monolithic pour of the footings and stem walls using some materials I found on the internet from Award Metals. they make a novel footing brace and monolithic strap that should accommodate the ICF forms. I chose the waffle grid, which by simple by having a irregular mold shape, it uses much less concrete than a form that has straight walls. I’m also hoping that since the walls will only be 22 inches high, my building and safety department will not require a stamp of a structural engineer.

I do have a few engineer names that specialize in ICF foundations, just in case. It’s always down to the budget. My time is basically free. This project has cost very little so far, but with professional consultants, I’m sure the fees go from zero to $1,500 really fast. I found the names through the newsletter of the Structural Engineers Association of Southern California. I hope I don’t need to call them.

I thought I could whip out a foundation plan in three days, but like the SIP structure, the foundation structure needs the approval of a structural engineer. There may be a loophole of some products, using a prescriptive method for insulating concrete forms in residential construction, but I’ll have to check with LA Building and Safety. It does look like I will have to visit the department with the drawing I have and ask for some advice.

I was planning on specifying the Nudura plank style ICF, but when I checked if it was still legal to use in Los Angeles, the company failed to renew their research report approval, and their product has lapsed. Since I have to start building in two or three weeks, I can’t wait around for them to renew. In the interim, I’ve discovered several other styles of ICF: block, panel, and plank. The material used to make the form can either be EPS or some hybrid or composite material (wood fiber and cement or EPS and cement).

I’m now steering this project toward a composite ICF, as only the stem walls of the foundation need reinforcement, and the larger EPS forms, though greater insulating factor, will not come off the ground much. The composite ICF that I like, is currently not approved in Los Angeles, but there are older styles that have gone through all the testing.

With the new millennium, we get new technology is mobile phones, mobile internet, computers, and cars, but where technology has not touched too much is home building. If I were to tear open the walls of my house, it would expose a dimensional lumber construction style developed in the 19th century. With progress in almost everything else in the world, our built environment must take advantage of the research and materials of the 21st century. I’ve been researching these alternative materials for many years, hoping that production builders would start to use them, but so far no Home Depot or Lowes sells anything other than lumber or concrete blocks as a house building system.

The building comfort level is certainly there, but the experience and details of fine home building are lost on most. My home addition will use the latest in durable, lightweight, and super energy efficient products as a demonstration project to at least document what can be achieved with not too much extra money.

The walls, floors, and roof are compromised of Premier Building Systems structural insulated panels, and today I start my design on a Nudura insulated concrete form (ICF) foundation system. if concrete were not as environmentally taxing, you could make an entire first floor out of concrete, but the manufacture of concrete is extremely environmentally hazardous, taking over 10% of global greenhouse gas emissions (mining, manufacture, transportation, use). Concrete offers many advantages in seismic areas that no other material allows, so it’s OK to use, but must be use wisely.

Initially I tried getting a manufactured foundation, which is available on the east and central areas of the USA, but the west coast with earthquakes, manufacturers are hesitant to release and certify the product. The next best thing is designing the use of concrete to present its inherent strength and longevity into cavities and forms. This is what an ICF product allows. Just enough concrete for performance, but not excessive amounts, like in a typical foundation system.