The School of Hard Knocks

This is the first of a series of articles on what can go wrong and how to avoid the problem in the first place.

1. Poor Design Leading to Fire Risks.

Here is a story on what happens when you do not use the correct technical methods of building straw bale walls.

Here is part of the article that describes mainly how this fire was fought BUT does not tell us how it started in the first place:

“The results of the recon with the thermal imaging camera TIC indicated that fire was in approximately 75 percent of the attic and that fire was traveling downward through the straw-filled walls in about 50 percent of the house. It was later determined that the top of the walls had no drywall on the top plate and that there was a space between the straw and the inside and outside wall. This flaw in construction contributed to the total loss of the building.

Because of the high winds and the exposed OSB roof decking, the 5,000-square-foot building’s attic was almost totally involved. This caused the top of the unprotected straw bales to ignite from embers and burning materials that fell into the void between the bales and the interior and exterior walls. You could see fire with the TIC on the outside walls on the top of the bales and on the bottom of the bales; there was no fire in the middle of the wall.”

Full Story here:

The Unique Challenges of Fires in Straw-Built Construction

N.B.  We always advise clients NOT to have any form of cavity between the straw bale walls and the finished wall external or internal.  That means using render on both sides of the walls before you attach any cladding, if that is your desire.  DO NOT CREATE A CHIMNEY EFFECT FOR ANY FIRES TO TAKE HOLD.

In the article it says – “The owner . . .said he was soldering in that area and that there was fire in the wall under the sink.”

So I believe it started from a soldering torch, but I don’t know what first ignited (cabinet, drywall paper, straw, wood furring, . .).  My best guess is that regardless of what ignited initially, the fire was quickly inside one of the furred-out cavities between the drywall and the bales, and then shot up to the roof framing where the fire spread and caused the most damage.

The article does suggest the reason for the cavities (foolish, of course), which is the owner wanted a smooth, straight drywall finish on the interior, and installing wood furring strips on the bales to provide attachment for the drywall seemed sensible.  They didn’t realize they were creating a fire hazard.  They of course could have achieved a smooth, straight plaster finish but they might not have thought this was possible (or was too expensive).  All of us would consider drywall over straw bale a kind of blasphemy, but that’s what they chose to do.

Thanks to Marttin Hammer from CASBA {Califronian Straw Building Association.}