Tiny House Insulation

What is the most effective and greenest insulation to use in a 2x4 wall. I am building a tiny house and looking to the highest R value in the smallest space.

I've raised alpacas. Alpaca wool is a suitable insulation. Not sure the exact R value. But I would assume it is relatively high.
Good thing with the collapse of the alpaca market you could possibly find an alpaca farmer that would give you a great discount on non premium wool if you helped shear them.

Are you building a tiny house, or a mobile tiny house? What's your budget, what are your ethics regarding renewable, recycled, or experimenal materials? What climate are you in? What is your heat source?

J.C. : This is truly an interesting topic, be sure to checkout the " similar topic " links at the very bottom of this page ! hidden within the question
you asked are several other questions specific to your location and build .

I just wanted to make sure that it was very clearly stated that the effectiveness of your insulation was related to thee amount of trapped air spaces,
simply increasing the amount of insulation packed within a specific space ( like a wall cavity ) Will have the effect of reducing the amount of trapped
air and end up retarding the R-value of your insulation rather than increasing it !

All of the tables related to insulation values assume a specific density and depth of insulation, These charts ALLWAYS assume maximum proficiency
in installing insulation without the presence of any gaps or voids in the insulation package, ether due to errors in installation, or the gradual settling
of the insulating materials, related to this is The over-packing of insulating materials within cavities, which is one of the principle causes of 'Bridging' !

While most home owners are aware of these potential pit-falls, many have learned about these specific problems through direct experience ! Include
me amongst those STILL learning the pitfalls of home (heated space ) construction, most of these problems are nonexistent when using a knowledgeable
building contractor, the caveat is in building a relationship with the builder to make sure that he/she is as dedicated to delivering a quality product for the
time/ effort and money extended !

For the good of the craft ! Big AL

Consider flammability. Wood is highly flammable.

Insulation isn't the weak link on most construction, it is the details--windows, doors, thermal bridging, drafts, etc. Get those details right and the rest follows.

Jimmy Catlin wrote:What is the most effective and greenest insulation to use in a 2x4 wall. I am building a tiny house and looking to the highest R value in the smallest space.

Are you married to the 2x4 walls?

If you want highest R-value then I think you're looking for energy efficiency. Pure R-value isn't a good way to go and 2x4's are an especially poor method. The problem is your home's heat storage becomes mostly the air inside. When you open the door you loose your heat. If there's a hole in the wall you lose your heat. If there's a window or a door you lose your heat.

What we did instead was to build a high thermal mass inside an insulating envelope and then a parge over that of fiber cement to protect it. The high thermal mass of the inside, the building, stores the heat. We can open the door, exchange all the air and the house still stays nice, cool in the summer, warm in the winter, because the energy is stored in the thermal mass.

Because of this the R-value of the insulation becomes much less important.

Our cottage is made of about 100,000 lbs of masonry with 4" of pink foam insulation on some walls, 6" on our north windward wall. It stays warm naturally through the winter needing only 0.75 cord of firewood to bring it up to the temperatures my wife likes. Very efficient. Cost was $7K for materials. See: http://SugarMtnFarm.com/cottage

-Walter
in northern Vermont

Walter J. : I agree with everything you said ! But, we are still waiting to find out if this is to be a forever home married to a more or less conventional foundation,
or is this to be a moblehome on wheels!

Your program would be excellent for a fixed house that Can have a large amount of Thermal mass, but until Jimmy C. shares more information all we know is
space and specifically space given to insulation and by extension the outside skin of his future home is an area where he wishes to be conservative.

My remarks on gaps in insulation and on bridging is something that must be carefully plotted . A house moving down the road is simultaneously experiencing
hurricane force winds and vibration similar to a minor but constant earthquake and sprung and unsprung weight has a marked effect on longevity, and the
expense of moving it !

Good job on your cost of materials and energy efficiencies ! For the Craft ! Big AL

allen lumley wrote:Walter J. : I agree with everything you said ! But, we are still waiting to find out if this is to be a forever home married to a more or less conventional foundation,
or is this to be a moblehome on wheels!

*grin* Aye, our 100,000 lb cottage is up at the upper limits of what is allowed on the roads around here!