Building Materials

System

When browsing on this forum I came across a building material called Rastra.
I'm curious to know about other alternative building materials now. It would be nice if there was some thread devoted strictly to alternative building designs/materials.

I will start by adding another material that help increase your R-value, Supertherm
http://www.laytonenergy.com/thecoatings/sutherm-descrip.html

Philip

lamplight

Re: Building Materials

i would love to hear how much money this paint saves you, so youre going to buy some and insulate with it?
some comments on it here: http://www.epinions.com/content_2452594820/show_~allcom

niel

Re: Building Materials

phil,
i agree with matt that they are bs. here is a quote from the site you linked on supertherm.
Provides R-19.3 insulation factor from a single coat

i know of nothing that could insulate that well and be that thin. i say buyer beware here. what is usually done, at least in the past, is to use a sprayon urethane foam and then paint over that to protect it from the sun's rays which does destroy the insulation. these foams are on the order of r7 or r8 and maybe nowadays even r9, but that is per inch of application. the thickness of paint is miniscule in comparison to an inch and would suggest insulation capabilities that are in the r500 to r1000 range per inch. i'm sure NASA would be interested in it if it were real as they still use spray foam.

System2

Re: Building Materials

This is why I like forums, I've never used the material, just something I read on the internet.

Another product I just read about is Strong Enviro Board, any opinions on this?

Philip

Mangas

Re: Building Materials

I built my ranch house out of RASTRA. 4,200 square foot single story. Architecture garde standing seam metal roof.
Combined with Anderson triple pane windows (some 10 feet tall) the house's temperature varies very little.

Let me know if you have questions how I built mine.

System2

Re: Building Materials

Mangas,
It sounds like a very interesting building material. Is it hard to find a contractor to do it for you? How does the cost per sq/ft compare to traditional building materials?

Philip

Mangas

Re: Building Materials

The manufacturer should be able to give you contractor recommendations for your area. You need to use a designer and a contractor familiar with its construction. There are several best practices methods I learned as we went along.

We figured it cost us about 10% - 15% more than if we framed exterior walls but the substantially increased R factor will recover the differential. Once finished, the home is not only well insulated but extremely quiet e.g. wind noise.

Since we're 100% Off Grid, high efficiency central HVAC components are very important too as solar is powering everything..

We chose an architectural grade standing seam metal roof over composite or tile for durability and weather tightness as well as Anderson triple pane glass. Only the interior walls were traditionally framed and bat insulated. We used 5/8" drywall throughout.

All of this combined gave us an R factor of about 36 (my estimate).

Telco

Re: Building Materials

The only negative I've seen with Rastra is if you are depending on mass for solar heating. Rastra forms stay in place making both sides of the wall insulated which means no solar mass available to heat. If you are depending on solar mass and want concrete walls, then dry stack building is something else to check into. And, dry-stack can be hand-built, no need for contractors to do the work if you can handle the labor. Dry stack is how I'm currently planning to build, with a nice 3-4 inch thick spray on foam on the outside for insulation and brick over that for a conventional appearance. Since I've discovered the solar heating shed I'm no longer planning to use solar mass heating, but still plan on doing the dry stack since I'd be able to do the labor myself, and buy the blocks as I have the money for them. Between solar heat and solar panels, I should have a pretty efficient place up by the time it's all said and done.

If you want the Rastra system and still want solar mass heating, a Trombe wall would be the way forward.

System2

Re: Building Materials

Mangas,

R-36 is pretty impressive! You wouldn't happen to know how much power you use in a month for cooling?

Telco,
I will look into the dry stack building also. The one thing about living in the South, a high R value can be much more productive that solar mass heating. We only have a hand full of days where I wouldn't be comfortable in shorts and a t-shirt

Speaking of heating, on those days we do have a cold front come through, I was thinking of using one of those IR heaters, like http://www.edenpurestore.com

They are claiming to cut your heating bill by 50%, any users of this product?

Philip

Mangas

Re: Building Materials

Phillip,

My overall home R factor was estimated. I estimated Rastra only to be near R 30. My back of the envelope target for the house was about 30% more effiecient than if I used 2x6 frame construction and lower efficiency HVAC, windows etc.

I never had a meter on the solar system but my HVAC power usage is probably much less than a framed structure using less efficient components. Despite extreme summer/winter outside temperatures the house is so well insulated that interior temperatures seem to vary very little summer to winter (thermostats set summer 79 winter 72). I probably get less air infiltration too.

Since we are 100% Off Grid the solar system powers everything. In summer, I seem to remember each 2 1/2 ton variable speed central AC unit (August daytime 105 degrees) pulled only about 8 to 12 amps or so when the compressors were running. The surge start amperage is higher but the four larger inverters handled that easily. For us, key was using maximum efficiency HVAC units and wiring it all up where each HVAC zone ran off different sets of inverters. It's amazing how little power these new high efficiency HVAC units actually use.

niel

Re: Building Materials

mangus,
could i have a link to look over this rasta as i've had no luck in a search.
phil,
on the infrared heating it still can only produce up to 3.14btu per watt, but some say it helps for you to feel warmer because of the heat hitting you in a radiant form just as the sun makes you feel warmer in its radiant heat. make no mistake about it that when the surrounding materials you touch are colder they will negate the warming effects you feel from the infrared just just like a brilliant sun on a cold winter's day. personnaly, i like the feel of infrared heat, but it will not save you 50% on your bill as the heat produced is at best on par with that of any other electrically produced heat. it may in fact cost you far more if your original heat source is not electric. electrically produced heat is a poor usage of the electricity and a very expensive thing comparatively. it is good to get that big chill out of your bones on a nasty cold day, but i have found that a nice warm bath will do that too and do it quicker. i use natural gas so the bath is much cheaper for me to do in such a case. you may want to try a small propane radiant heater too. i don't know of the cost effectiveness of a propane heater though, but if used only to offset a temporary chill in one's self it may work well as would the electric infrared, but only as a possible alternative to raising the thermostat for the whole house. even at that, in some cases it could be cheaper to raise the house thermostat depending on your heat source and costs rather than burn the electric or propane in one isolated area for an hour.

mike95490

Re: Building Materials

Rasta, or the Rastafari movement, is a religion that accepts Haile Selassie I, the former Emperor of Ethiopia, as God incarnate, whom they call Jah.

Rastra is an insulating concrete form (IFC) used to make walls for buildings
http://en.wikipedia.org/wiki/Rastra

niel

Re: Building Materials

don't forget about his second in command wattup bro.:roll::D

thanks for the link mike as i believe i was spelling it wrongly.
in following the link to the company itself i'm still not getting a good picture in my mind on it as all of the pics were of asthetics and not necessarilly of the product and its forming details. i also see they don't give possible r factors with the product and that i'm assuming can also vary depending on the actual blending of the product as higher insulation with higher r factors will have less concrete in the mix for strength and visa-versa. $30 for a sample block is, indeed, very high priced, but i guess they included shipping. the company claim of handling a cat 5 hurricane is not a good claim to make as at best a block of this stuff without insulation would be the strongest structurally with all concrete and i've seen too many pics of concrete block walls torn apart by even smaller hurricanes and tornados.

lamplight

Re: Building Materials

mon! de insulation be fiiiine for yeh home .

i bought a roll of that aluminum foil/bubblewrap stuff (as mentioned by BB in another thread here) i intend to use on the INSIDE of a drywalled kneewall with 1" foamboard strips for support and go over that with 3/8" beadboard plywood. the R values vary great depending on application , we'll see but im sure it will help at least some.


these window inserts are pretty cool: i bought one off a small shop online a few yrs ago: its a doublewalled vinyl window inserver witha foam border so it fits snug, installed into any window. i liked it alot but they were too expensive to get a lot. better than plastic as it provided 2 extra airspaces. you could tell the thing was sort of homemade but was well done. im interested in similar (but more affordable) for other windows.


oh: the company i bought from is here
http://www.windowinserts.com/products.html

Mangas

Re: Building Materials

Niel,

Rastra.com

Rastra blocks are an insulated formed block laid down in lifts with their cells filled horizontally and vertically with rebar and concrete for a monolithic wall structure. The raw blocks come in varying sizes .

System2

Re: Building Materials

Did anyone attend the West Coast Green event in SF? They debuted the prefab MK Lotus home and also provided a list of vendors who supplied sustainable materials.

t12zh

Re: Building Materials

I have ran a concrete pump truck and filling foam block walls is hard.
They seam to have a lot of problems when filling to keep them straight and the taller the harder.
I have been arround the concrete walls and floors for a while now and was going to do the fome pannel in the midle of the wall untill i seen a spray foam machine we have work. You can spray the extior of the wall below grade and that is best i have seen so far. So the foundation guys get in and out right away, then you just come along and spray the wall after the perimiter drain is in place. Just my 2 cents.
Greg