Coker's Straw Bale Build

INSULATION PHASE 1, INTERIOR HOUSE FRAMING and KITCHEN CABINET MEASURING

Now that the roofs were sheathed it was time to complete Phase 1 of the insulation install. The ceilings needed to be insulated before the electrician and plumber started running their wires and pipes along the bottom of the roof joists. In keeping with our sustainability goals, we chose dense packed cellulose insulation. It is made from recycled paper. Among other insulations, cellulose has a much higher concentration of recycled materials and can contain up to 85% recycled newspaper. Small pieces of paper are fiberized so they can be densely packed to prevent airflow. This should provide an R value (the capacity of an insulating material to resist heat flow) of about 40. The higher the R-value, the greater the insulating power. Out straw bale walls have an R-value of about 25-30.

Cellulose insulation

Before they blow in the insulation, they have to staple batting to the bottom of the joists. This will hold the insulation in place after they blow it in. They cut a small hole in the batting and insert a hose in order to blow in the insulation.

Installing the batting to hold the insulation

A full length run of battng

Using the hammer stapler to hang the batting

One of the keys to get maximum efficiency out of the insulation is to make sure it is blown in at a specific pounds per square inch (PSI). They brought a medium sized box truck with a big blower motor mounted in the back that they used to blow in the insulation. They had to use a long hose to reach all the way back to the casita!

It was a tight fit to get the ceiling in the casita's loft insulated!

Blowing in the insulation

Insulation Phase 1 complete

Another goal we are trying to accomplish is to make our house and casita meet the Passive House Standard. This is the leading standard in energy efficient construction. Passive houses require little energy to achieve a comfortable temperature year round, making conventional heating and air conditioning systems unnecessary. Straw bale construction is a natural fit for the Passive House Standard. One of the most important things for a Passive House is to make it as air tight as possible. We accomplish this with the use of different membranes, tapes and other sealants. The first step for us was installing the Intello Plus membrane on the ceilings.

Intello Plus membrane installed over the batting

If you have holes in the membrane it kind of defeats the purpose of the air tightness, so any holes (usually caused by an over zealous stapler) needed to be sealed. These holes are sealed by using small pieces of repair tape that are then smoothed out with a plastic "scraper" to ensure the hole is properly sealed. It was quickly decided that this meticulous, mind numbing job that required a great deal of attention to detail was perfect for Jeff! So over the course of a couple days he slowly moved his ladder around the house and casita, while developing a large kink in his neck from looking up at the ceiling and in the end ensured all the holes were sealed.

A tape patch for the Intello Plus membrane

Patching holes in the Inello Plus membrane

Intello Plus membrane patches

After the Intello Plus membrane was installed then the furring strips were installed. The ceiling planks will be nailed to the furring strips. We used 2" x 4"s in order to provide a little extra space between the membrane and the tops of the planks which will allow for the running of the electrical wires and water pipes.

Furring strips installed and patching complete!

After the furring strips were in place they could move onto framing the interior of the house. Framing the interior of a straw bale house really isn't that different than a traditional house, so it was a fairly quick process. But for us it was cool to see the walls start to define and separate spaces in our abode!

Craft room pony wall and door

View from the craft room

Craft room closets and powder room window

Kitchen wall and looking down the hallway toward the laundry room and thru to the bathroom

Bedroom door frame

Framing of the window in the shower

The next order of business was confirming the measurements of the kitchen cabinets and deciding on the final size for the kitchen island. Lew, the cabinet guy, came out and penciled in the location of the cabinets and appliances on the floor, per the measurements he had in this CAD (computer aided design) program. He also measured the heights of the soffits to ensure they were at the correct height.