August 29, 2018 in Beginner, Code Approval
To cover my "arse": This article is for education purposes ONLY. Nothing here should be considered legal advice.
An all to frequent statement is "I cant build with AirCrete in the USA because its not code approved. This is true and untrue. A commercial product is called cellular concrete which is in the building code. Its a similar product, but its cured at high temperature with steam. IF, and this is a BIG IF, your code official is a reasonable person you can get an exemption for your building by having a sample of your material tested at a geo-science lab where it is crushed and the pressure of failure is recorded. With this data in hand many friendly code officials will approve the material. The trick with home-made AirCrete, however is to keep the blocks wet and covered under black plastic in hot weather for 30 days before the test and to build with only cured blocks. When making test cylinders for crushing be sure you cure the sample properly. Provide multiple samples of both plain cylinders of specified size as well as cylinders with wrapped and "glued" reinforcing fabric. The crush test that come back show amazing strength.
No Guarantee
Law and procedure is irrelevant. The Inspector IS the law for your area!
- You must be willing to fight without a lawyer. Never Take No For an Answer!
- There are legal work-arounds such as building a "Un-Occupied"structure under 400 Square Feet. Look for and use your options!
- Move to Free Country!
ASTM
10-1.44 LIGHTWEIGHT EMBANKMENT MATERIAL (CELLULAR CONCRETE) This work shall consist of constructing a lightweight embankment material (cellular concrete) to the lines, grades, and dimensions shown on the plans, in accordance with the Standard Specifications, these special provisions and as directed by the Engineer. The Contractor shall furnish a mix design which will produce a cast density (at point of placement) of 3.7 to 5.6 kN/m3 with a minimum compressive strength of 551 kPa at 28 days. The Contractor shall provide the Engineer with a Work Plan, including the equipment and procedures proposed, including working drawings for form work for the lightweight embankment material (cellular concrete) showing work areas which shall be formed in segments such that they can be filled in less than 2 hours, at least 30 working days prior to placement. Items in the submittal shall include: 1. Material list of items; manufacturer's specifications for those items; 2. Mix design(s), including laboratory data using the mix design verifying mass and strength requirements. 3. Form work for the installation of the lightweight embankment material (cellular concrete), including permanent structure and temporary form systems, shall conform to the manufacturer's specifications. Form work shall be water tight and must be capable of supporting lateral loads of 3 times the calculated load of the lightweight embankment material (cellular concrete). 4. Working drawings for the form work shall conform to the provision in "Working Drawings," of these special provisions and be subject to the Engineer approval.
With test results in hand along with examples of alternative building codes from New Mexico many code officials may often approve your material when you can show them its exceeds the ASTM C 495. Sometimes you need to pay an engineer to stamp a document stating the method of production as well as the test results. The 551 KPA is just under 80 PSI. Our Crush Test consistently achieved 151 PSI failure strength after 30 days wet & warm cure time. Did you know the compressive strength of two #2 pine 2x4's commonly used as studs is 2,152 PSI? What does that mean? Well if you take the common example of a 2x4 wall on 24" centers you get an area of 84 Square Inches. In the same area of AirCrete you get a compressive strength greater than 12,684 pounds! So is AirCrete as strong enough for a home? When coated with reinforcing fabric for tensile strength, Yes it is! The fabric we use is commonly rated at 75-90 pounds of tensile strength per inch. This means the failure tensile strength across a 96 inch wall is 7,200 pounds and 1,800 pound across the 24" direction.
Sometimes no mater what you do a code official will not approve the building. At this point you have 4 choices. 1) give up and do something else, 2) move to a friendly location, 3) do it anyway, or 4) take legal action. I suggest you seek out YuShuf El of High Frequency Radio!
You can very successful challenge and win in court with the right attitude and knowledge. However, you must do it without a lawyer who is only an officer of the court and will do nothing to jeopardize his money!
Also consider Joining The Lighthouse Law Club
Most of us would not stand for our rights, so the second best option is to simple build a post and beam structure where the AirCrete is non-load bearing with a bond=beam on top. So, now you have the tools and the rest is up to you.