Today the framing of the second floor began, and measures were taken to provide proper drainage from the building.
Click here to view the entire Nauhaus Prototype Construction Chronology.
Tim uses a custom tool to measure for Hemcrete.
David Madera stopped by to discuss Hemcrete.
A strip drain is placed at the bottom of each wall.
Gravel is shoveled into the Eastern trench.
Wast Wall Framing
This week, Matt and his crew continued to frame. The bottom plate was bolted to the slab, and the TJI joists were installed.
Click here to view the entire Nauhaus Prototype Construction Chronology.
Detail of Bottom Plate at Termite Barrier
The bottom plate is bolted to the AAC through the Advantek.
North wall framing with termite barrier visible.
The second floor structure starts with 16" TJIs.
East and North Framing with Rim Band on Top
Today, Matt and his crew started framing the lower level walls. The 2×4 wood studs are placed 2′ on center rather than 16″ because the 12″ of Hemcrete will provide enough stiffness to the structure.
Click here to view the entire Nauhaus Prototype Construction Chronology.
Matt frames the Southeast window.
Matt works on the top plate.
Framing the South Wall
The lower level is nearly completed at the end of the day. To the right the well is visible.
Matt Schillig and his crew completed the termite barrier today. It consists of 2 pieces of brown aluminum flashing, a continuous adhesive membrane, 1/2″ Advantek and caulk.
Click here to view the entire Nauhaus Prototype Construction Chronology.
Pieces of the aluminum termite barrier are laid over the AAC block.
Inside view of termite barrier and adhesive membrane over CMU wall.
Elijah installing Advantek over adhesive membrane
Matt installing Advantek
Termite barrier and Advantek on, overlapping spray foam insulation on CMU wall
After the Advantek is installed over the adhesive membrane, sealant is applied to prevent air leakage.
Matt Schillig
Today, the concrete slab was scored on a three foot grid, to prevent cracking. David Madera and Greg Flavell of Hemp Technologies also helped us to perform a full-size Hemcrete test.
Click here to view the entire Nauhaus Prototype Construction Chronology.
Scored Concrete Slab
Scored Concrete Slab
Hemcrete Mix
12" Hemcrete Form
Completed Hemcrete Wall
This posting concerns Cordwood Maintenance, specifically about log loosening. Air infltration is not a good thing to have in a cordwood home (or any home for that matter), but sometimes a log loosens in the wall. There is a most excellent remedy for log loosening out there in ‘log home land.’ Permachink (and Log Jam) are water based, acrylic co-polymers that are easily applied to the mortar and wood. They are elastic and move with the log ends as the seasons change. Orignally designed to be used for chinking on horizontal log cabins, Permachink and log Jam work wonders to eliminate air infiltration in a cordwood home. See www.permachink.com and www.sashco.com for further information on their products.
This posting is taken from the most wonderful blogsite My Amazing House by Maria & Toby http://tobiascrawley.net/house/ There is a co-joined blog site about all things herbal and home by Maria called Dirt Under My Nails http://dirtundermynails.com/ Both are very good reads. Positive, earth affirming and energetic.
Here is their latest post.
Winterizing
September 9th, 2009
This weekend we got started on the project we’ve been dreading for the last year… winterizing the house. With a cordwood house, there is a lot of shrinking in the wood that goes on the first year. So, after the first winter, you need to go back and seal the nooks and crannies that have opened up. We weren’t looking forward to this large amount of detail work.
Well, I’m happy to say that it’s not nearly as bad as we thought it would be!
We purchased some Permachink (a sealant often used on log homes) from a dealer not too far from us. It comes in huge tubes that you squeeze onto the wall. Toby would squeeze the ‘caulk’ around each log end and I would go behind him and smooth it out. The color is an exact match to the white of our walls… unfortunately, the lower part of the exterior walls has some red mud splash back from the rain… so the caulk really stands out here. I figure I’ll get Kaia to go splash in puddles near the house next time it rains and that caulk should be nice and dirty in no time
permachink on left, none on right
Smoothing it out
We were able to do almost 2 sections (out of eight) this past weekend (with many interruptions!) So, we will hopefully be able to finish this in a few weekends. Then, it’s on to the chicken coop!
Thank you Maria & Toby.
flato@aol.com
www.daycreek.com/flatau
715-212-2870
Cordwood Bookstore
http://www.daycreek.com/dc/html/dcrflatau3.htm
Limestone
Marble is the same stuff because it is the metamorphic rock that forms when limestone is subjected high temperature and pressure.
Lime used as a soil amendment (aglime) is usually limestone ground into small pieces rather than the chemical lime used in construction.
Heating limestone above 1500 F it gets rid of impurities and releases CO2 to the atmosphere to leave pure calcium and magnesium oxides. (if you heat it above 4300 F it glows, and before electricity they used to light theater stages with it – limelight). The reaction is called calcination:
Quicklime (CaO)
Hydrated Lime (Ca02H2)
There are six forms of hydrated lime used in industry:
| Type of Lime | Solids | Water |
|---|---|---|
| Dry Hydrated Lime | 100% | 0% |
| Lime Putty | 70 – 55% | 30-45% |
| Lime Slurry | 35 – 25% | 65-75% |
| Milk of Lime | 20 – 1% | 80-99% |
| Lime Water | 0% | 100% |
| Air-Slaked Lime | 100% | 0% |
Construction lime is generally available in two forms: putty or hydrated. They both have the same Ca02H2 structure. The only difference between them is how the hydrogen is added. Putty has been soaked in water (slaked) and is sold in a mixture of roughly 50% lime and 50% water.
Prior to the invention of the hydration machine in 1930 all lime was sold as either quicklime or putty. Shipping water is expensive, so quicklime was the preferred method. That meant the user had to slake the lime. Quicklime is available in various sized chunks like gravel. Smaller pieces hydrate more quickly because it’s easier for the water to get to every molecule of CaO. However, eventually large pieces will break down into a fine powder due to the hydration reaction.
The longer the slaking time the better the stickiness, plasticity and water retention of the lime. A minimal modern slaking lasts several weeks, but two years was traditionally considered minimal. Five years was traditionally considered optimal. Lime that hasn’t been slaked long enough still has unreacted CaO in it. If it is used in plaster or mortar the hydration reaction will take place in the wall. As it pops it will blow little pits in the wall.
The hydration machine allowed for the slaking to take place at the lime plant. In a hydration machine, just enough water (steam) is added for the hydration reaction to take place, and hydrated lime is sold in dry powdered from, normally in 50 lb bags. Water is still added to it at the site, but because it is pre-hydrated, it only needs to slake for a short period.
Type N – Normal
Type S – Special
Carbonation
If the mix is wet or the wall is too thick, air can’t get to it and there’s no CO2 to react. Carbonation is a slow process that takes many years depending on how well air can penetrate the lime. Sometimes air can’t get to the center of a wall until it’s demolished, and carbonation takes place then. Uncarbonated lime has been found in the center of walls 1000s of years old.
Lime is extremely caustic with a pH around 12 when wet (calcium hydroxide = 12.4, magnesium hydroxide = 10). As it drys and carbonates it becomes neutral.
The Lime Cycle
Alite and Belite
Hydraulic Lime
Naturally occurring argillaceous limestone typically has a content of 15-35% clay. Hydraulic lime is hydrated with just enough water to hydrate the quicklime, but not enough to cause the calcium silicate to set.
While still widely used around the world, hydraulic lime has fallen out of favor in the United States where it has been replaced by portland cement. In 2007, hydraulic lime was 15% of the total lime produced.
However, there is still a hydraulic lime standard: ASTM C 141 – 67; Standard Specification for Hydraulic Hydrated Lime for Structural Purposes
Cement
Pozzolanic Cement Additives
Historic Limes
Then the hydration machine also changed the quality of lime. When lime is partially hydrated at the plant, it can be sold in powdered form and relive the user of the need to slake. However, as soon as it’s hydrated it starts to carbonate. The key to using hydrated lime is to get it fresh (less than a month old). The older it is the weaker it will be after it is applied.
Lime Mortar
Cement Mortar
Hydrated lime is typically added to cement mortar as a plasticizer, meaning it controls the mortar’s setting time and shrinkage by retaining water.
Modern mortar is so hard on old brick which is softer than today’s brick because the clay was fired at lower temperatures. Feebly hydraulic lime is softer than brick, so it was used as a sacrificial material. Any moisture in the wall went to the lime mortar and evaporated out of the wall. Eventually the lime needed to be replaced, but the brick was fine. Old brick fails quickly when repointed with modern cement mortar because the moisture in the wall has to leave through the face of the brick. The old brick becomes the sacrificial component. Salts (mainly from the cement) exiting through the brick are the cause of efflorescence. The salt also expands inside the brick and can knock the faces off of them.
Lime mortar is also self healing. It has high plasticity, so it tends to flex instead of crack. Small fractures to occur from a shifting building get filled in as CO2 is sequestered out of the air to turn the calcium hydroxide back into limestone. Modern cement mortars do not have the plasticity to flex nor do small cracks heal. Cement mortars crack allowing moisture into the wall.
Lime Plaster and Stucco
Lime Wash
Applied like paint, limewash is a mixture of 15-20% high calcium hydrated lime in 80-85% water. Limewash is typically mixed in a large container (ie. 32 gallons) to insure consistency, and transferred to smaller (5 gallon) containers for application. Filtering the liquid thru a 30 mesh (0.6 mm) sieve when transferring to smaller containers insures that any remaining grit is removed. A typical limewash would be a 50 lb bag of Type S hydrated lime mixed with 30 gallons of water in a plastic trash can.
When applied it is translucent, but over time it becomes opaque. Unlike paint, unpigmented limewash remains partially translucent light able to enter the calcite crystals where it is refracted. The light is split into two rays, one fast, one slow. The intensity of the light is not affected, but the light emitted from millions of tiny calcite crystals results in a bright, vibrant surface with a subtle mottled internal texture.
Because of it’s high pH, compatible oxides are used as pigments. Light colors and pastels are typically used to retain the vibrant quality. Pigment concentrations over 5% tend to come out of suspension resulting in uneven coloring. The first few coats are usually unpigmented to maximize adhesion. Layers are built up in thin applications to avoid cracking and chalking. 3-5 base coats are typical with an additional 2 coats of pigment.
It is often recommended to shade limewash to avoid flash drying due to direct sunlight. However, experimenting on a project in the Mojave desert, Peter Mold discovered that cycles of quick drying and rewetting during application resulted in thorough carbonation and a very strong finish.
Sources:
http://www.buildinglimesforum.org.uk/The%20Lime%20Spectrum.pdf
http://www.scribd.com/doc/15884987/HempClay-towards-zerocarbon-housing
http://www.cheneylime.com/
http://www.graymont.com/what_is_lime.shtml
http://www.lime.org/BLG/Mold.pdf
http://www.cheneylime.com/limefact.htm#1
Why is Type S Hydrated Lime Special?
The Natural Plaster Book
Wikipedia
Taking a cordwood workshop is one of the best ways to learn the ins & outs of cordwood masonry construction. Valuable information is passed on, questions and answer sessions are important to cement down cordwood concepts and the hands on portion becomes the bread and butter of how to build a cordwood building.
The host & family with timber frame mallet
The interaction between attendees is not to be overlooked. At our last workshop we had a doctor, lawyer, judge, police officer, vet, pianist, three general contractors, three teachers, a factory worker, a biker and a host of homemakers. The give and take was amazing. Friendships were formed and a cordwood blog group was organized to help keep in touch.
Here is a link to the workshop in Custer, WI. The project was the cordwood infill of a Colonial Hall & Parlor style timberframe which was modeled after the first timberframe home in the US. The cordwood infill was 17″ northern white cedar with a Lime Putty Mortar mix. Lime Putty Mortar uses only sand and Type S builders lime which has been hydrated for 5 days. Similar to how the good ol Roman’s built their buildings.
http://www.daycreek.com/dc/asp/forum2002/display_topic_threads.asp?ForumID=2&TopicID=2036&PagePosition=1
We will be teaching a cordwood workshop in Hendersonville, NC on Oct. 10-11, 2009 at the home of the editor of Backhome Magazine. The project will be the 18″ cordwood infilling of a post and beam frame greenhouse. The link to the registration form is athttp://daycreek.com/dc/pdf/Cordwood%20Workshop%20Asheville,%20NC%202009.pdf
Richard Flatau
Cordwood Construction Resources, LLC
W4837 Schulz Spur Dr
Merrill, WI 54452
flato@aol.com
www.daycreek.com/flatau
715-212-2870
Cordwood Information and books
http://www.daycreek.com/dc/html/dcrflatau3.htm
The Colonial Hall & Parlor Timber Frame using 18 ' Tamarack & Pine
The diverse and intelligent crew at the Custer, WI Cordwood Workshop in August 2009
Timber frame with stackwall corners using lime putty mortar & cedar. Anne takes a break after a hard days cordwooding.
Cordwood Information and books
http://www.daycreek.com/dc/html/dcrflatau3.htm
This is Ecovative Design’s mycelium (mushroom roots) packaging material mulching Sue Van Hook’s garden at the end of it’s life. How awesome is that?
We’re going to try out their SIPs building panels made the same way on our prototype project. I owe them plans, so don’t tell them I’m doing this instead of getting their drawings done.
This seems to be a good hemcrete mixer.
And here’s papercrete being pumped.
