Tag Archives: rebar

“Social Innovation Rockstar”!!!!

Just because it isn’t happening here doesn’t mean it isn’t happening.

On the surface it appears nothing much is happening with Ubuntublox these days.  Nothing could be further from the truth.

Just yesterday we were named a  Social Innovation Rockstar.

Here’s some of the things we are working on.  We are working on using polypropylene line instead of wire to bind the bales of film and foam plastic into blocks.  This cuts the price of the individual block from approximately fifteen cents for the wire to less than a penny for the polypropylene twine.  We still want to use the wire in the wall construction of course.

One of the other things we are working on is the woman centered rebar bender.  This is important.  Women use lower body strength for work; men use upper body; male showing off maybe?  Rebar benders as we know them now are designed for male workers so they depend upon pulling and pushing with arms, upper body stuff.

Let me inject a little personal philosophy here.  Common wisdom says that since rebar benders have always been designed to use upper body strength, then we need to teach women to use upper body strength too.  I disagree.  The objective is to bend rebar, not make women into men.  So the smart thing to do in my book is to modify the rebar benders so that women can use them naturally.  That means we modify the bender so that they’re operated using lower body muscles.  We make them where they are stepped on instead of pulled or pushed.  The added benefit of this is we enable children, male and female, to contribute earlier to work if needed.

We are also working on the woman centered concrete mixing tub.  One of the things that irritated me beyond measure was our forcing the Haitian ladies to mix concrete the way men do when we were working on the Ubuntublox house.  It was unfair; it was unkind; and, it was altogether wrong on our part to put them through that.  One of the good things about the experience is it forced me to get serious about modifying the tools instead of the workers to get the same job done.  I believe this thing will do as much to empower women wanting to have control of the construction of their home as Ubuntublox itself.

We are also working on a design of a good foundation and floor for an Ubuntublox house that is not made with concrete.  I’m very excited about this because the potential benefits are beyond huge.

We are also looking at the recycling process a lot closer.  What we are trying to do is look at everything in the stream of recyclables as a positive instead of a negative.  For instance any food stuffs found on the dinner trays could be used for food for hogs.

So a lot is happening; the excitement is growing; we had our biggest visitor day ever, Wednesday the 27th.

Recycled Plastic Block wall drawing

Dr. Owen Geiger has sent us drawings of  an engineered wall using recycled plastic blocks.

The first drawing has elevation showing foundation, windows, and doorways.  Click on the drawing to make it larger

Dr. Geiger shows using horizontal wall reinforcement.  (click on drawing to make full size 

Horizontal (Joint) CMU Wall Reinforcement:    (link to source of drawing below)

    1. Purposes:To strengthen the wall against “bowing” in due to lateral pressure (earth, wind, seismic)
    2. To make the wall more ductile (i.e., less brittle) and hold it together in extreme events such as earthquake or hurricane.

        b.  Horizontal joint reinforcement consists of heavy wire welded together to take the shape of a ladder (or truss), and is usually selected as follows:


    1. 10 Gage wire – for light duty interior or exterior applications
    2. 9 Gage wire – standard duty
    3. 8 Gage – heavy duty for use in seismic or other high-stress applications
    4. 3/16″ diameter wire – extra heavy duty for extreme conditions

        c.  Horizontal joint reinforcement placed in horizontal mortar joints as follows:


    1. Placed in every CMU course if used for foundation wall
    2. Placed every 2 or 3 courses for above-ground walls (or more if necessary)

The Recycled Plastic Block doesn’t have cavities for vertial supports like CMU blocks have.

Vertical CMU Wall Reinforcement:   (link to source of information below)

  1. Purpose – Greatly strengthen the wall to accommodate larger vertical loads as well as resist lateral loads.
  2. Vertical CMU wall reinforcement consists of inserting steel rebar (usually #4 or #5 rebar) into open cores of the wall, then filling those cores solid with a concrete-like grout.

We get the same vertical support by placing the rebar outside of the Recycled Plastic Blocks in our walls.  (see Dr. Geiger’s drawing at the top of the page)  The rebar is tied to the blocks it contacts and to the opposite rebar with wire ties.

We are working to get a local engineering school involved in the Recycled Plastic Blocks.  One of the facets of the Recycled Plastic Block wall that we want to study is the R value provided by the plastic blocks inside a plastered wall.  Intutition suggests that it will  provide a greater R value than CMU block construction.

3.  Possible disadvantages of CMU buildings: (link to information below)

  1. Expensive labor – CMU construction is labor-intensive. Depending on localities, labor CAN be very expensive.
  2. Heavy – Masonry buildings weigh more than comparable steel-framed and wood-framed buildings.
  3. Absorbent – CMU, like any other cementitious material is absorbent to water penetration and must be weather-proofed.
  4. Modular – Typical CMU has modular 8″ x 8″ x 16″ nominal dimensions, and is a bit difficult to have walls that have odd dimensions or smooth curves.
  5. Difficult to insulate – Block has a very low “R” value and generally, walls must be insulated by adding width to them – decreasing available floor square footage.

Most of the disadvantages of the CMU block construction don’t apply to the Recycled Plastic Block concept.