Patching Holes in the
Straw Bales

No matter how precise you are with baling, there will be spots that need to be filled in.  In most situations, this takes place during the stuffing phase.  There are spots, however, that you may have missed while stuffing.  With the wire mesh in place, it can be difficult, if not impossible, to stuff straw into these gaps.  When that is the case, a few options are available.  You could simply fill the holes with plaster, but this becomes expensive and the strength of the patch is directly related to the strength of the plaster.  Most plasters are not rated for structural fill and so depending on it for such a fix is unwise.

Packing cob, a mixture of clay, sand and straw, into the holes is a great option.  It is cheap, especially if you have the materials on the site (i.e. clay rich dirt, sand for plaster, and straw), and it is very strong.  Another option is to use expansion foam.  Although less environmentally sound, it works well to fill voids.  The best example of a good use of expansion foam is in areas where cob cannot fill the entire void due to the shape of it.  In other words, areas where the opening is small but the void is large.  The foam can fit into those spaces and fill them up well.

Before the mesh is attached to the bales, you can use loose straw, cob, or a straw/clay mixture to fill gaps.  There are some cases where the material, no matter what it is, will not stay in place.  This can be very frustrating.  In these cases, use burlap patches. The burlap is fastened to the bales in small pieces and then straw is stuffed behind the patch.  This way you do not have to work behind the sharp metal mesh which can sometimes be a struggle.

No matter what type of fill material or patch you choose, be sure to keep the structural mesh free from it.  If the foam, clay or cob engulfs the wire grid, then the mesh will no longer act as a part of the plaster’s structure in that area.  Although the impact of such a structural gap would likely be minimal, it is best to pay attention to all the details, no matter how small they may seem, in order to end up with the best project possible.