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Earthbag Village Flooring Setup, Construction, and Maintenance
Welcome to the Earthbag Village eco-flooring design and setup hub. Once we’ve finished this tutorial and open sourced all the details for the 3-dome cluster as part of our crowdfunding campaign, we’ll do the same for the complete Earthbag Village (Pod 1) and Duplicable City Center®, and then the other 6 villages.
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EARTHBAG VILLAGE FLOORING
This page will not thoroughly develop without additional help… Click here if you’d like to join our all-volunteer team If you are looking for a starting place that is super sustainable (but not durable enough for our purposes), check out the three-layer clay floor as described in Ianto Evans’ “Hand Sculpted House” book.
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We are also seeking any other sustainability-related skilled professionals, quality writers and researchers to help finish our People's Agenda 21 website, and anyone with other skills they feel would benefit our open source creative process. The people who join our team as either volunteers/consultants or members typically fit one or more of the following descriptions:
- A person wanting to live sustainably and change the world (Pioneers!)
- A person looking to gain experience and share new skills (students, recent graduates, etc.)
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FLOOR CONSTRUCTION
Once the Earth Dome has been closed in (meaning that the walls are entirely constructed), all exterior/interior stucco has been applied, and the exterior waterproofing has been completed, the excavated ground floor will be prepared for the application of a concrete floor. The envelope of the floor will consist of four components: a gravel base, insulation, a vapor barrier and a concrete slab. Sheet metal flashing will be used around the perimeter of the completed floor as a protective barrier for the rockwool vertical insulation. This combination of components will ensure that the floor is structurally stable, maintains the internal temperature and air quality of the dome, and can bear the weight of the items placed above it. The floor is constructed in the following steps:
1. LEVEL THE FLOOR
Begin by removing unnecessary debris from the floor area. Use water-based mist to keep the dust down if it is an issue. Level any uneven areas with a pulaski and shovel. Set aside any removed soil to use for backfill above grade against the exterior walls. Use a tamper, either manual or powered, to compact and level the soil.
One Community’s Video Is Coming: Floor Leveling and Tamping
2. LAY GRAVEL BASE
A gravel base is used to aid in drainage of moisture under the concrete slab and to create a barrier between the insulative layers of the floor envelope and the ground. Build the gravel base by using a wheelbarrow and shovel to place a 4″-5″ layer of ¾â€-1″ irregular-shaped gravel, as shown in Figure X. Refer to this link to calculate the necessary cubic yards of gravel required for the dome. It is important for the gravel to have irregular sides, not rounded, so they lock together when compacted to form a solid base.
Lay the gravel base in two layers, each layer roughly 2″-2.5″ thick. Before tamping each layer for compaction, spray enough water-based mist over the gravel to settle the dust. Compact each gravel layer with either a plate compactor or a hand tamper. If a plate compactor is used, push the compactor slowly from side to side in one direction then orthogonally switch directions to run the compactor over the perpendicular ends. If using a hand tamper, simply thrust the square metal plate against the gravel to pack it tightly. Compaction of a strong gravel base is required to prevent the concrete floor from cracking and shifting once it’s set.
Figure X. Floor Envelope – Click here to open full image
One Community’s Video Is Coming: Gravel Subbase Lay
3. INSTALL THERMAL INSULATION
To prevent heat loss through the floor of the dome, thermal insulation will be placed above the gravel base. Similar to the foundation, the insulation will be three-inch thick Rockwool Comfortboard 80. This product is used because it is suitable for below grade insulation applications for both insulation and drainage. Rigid mineral wool insulation drains water quickly while still having good compressive strength; it is also more insect-resistant than EPS. It does not need a protective barrier above or below it because it is designed to be placed above crushed stone and under a poured concrete slab. For precaution, a vapor barrier will be placed on top of it, acting as a layer of protection between the insulation and the concrete slab. It should be noted that a mineral wool sub slab, such as the Comfortboard 80, should not be used in areas of high ground water levels. In all cases, it should be placed above the water table. If after consultation with your local professional engineer it is decided that a higher density insulation is needed, the Rockwool Comfortboard 110 can be used.
Comfortboard sheets that are 4’x8′ will be used in this design, as shown in Figure Y. To install the insulation, first verify that the gravel base is compacted and level across all areas of the floor. Have 6 sheets of 4’x8′ insulation ready on site to begin placing the insulation on top of the gravel base. Referring to the sheet labels in the figure below, begin by removing the central compass instrumentation and place the first sheet (labeled No. 1) centered over the center of the dome. Next, place sheet No. 2 above No. 1 and cut the sheet to fit the interior perimeter of the dome, which is marked by the red circle in Figure Y. Ensure that each piece of insulation that touches the inner perimeter is installed tight to the vertical vapor barrier from the foundation. Each insulation sheet should also be tightly abutted to the sheets adjacent to it.
Use the remainder of sheet No. 2 for sheet No. 3, which is placed below sheet No. 1. Place sheet No. 4 to the left of sheet No. 3, with the top of it running through the centerline of sheet No. 1. Cut the excess insulation off sheet No. 4 with a hand saw or sabre saw. Move onto sheet No. 5 by placing it above sheet No. 4 and trim the excess. Place sheet No. 6 in line with No. 5, but mirrored over sheet No. 1. Trim the excess material. Position sheet No. 7 below sheet No. 6 and cut the excess. As shown in Figure Y, the remainder of sheet No. 6 can be used for the top half of the area labeled No. 8, and the remainder of sheet No. 7 can be used for the bottom half of that area. Likewise, the remainder of sheet No. 5 can be used for the top half of the area labeled No. 9, and the remainder of sheet No. 4 can be used for the bottom half of that area. To fill any gaps in the insulation layer over the gravel base, such as those between sheets No. 6 and No. 8, No. 8 and No. 7, No. 4 and No. 9, and No. 9 and No. 5, use excess trim pieces from previous sheets.
Seal the joints of the insulation between each sheet and between the interior perimeter with aluminum foil tape, as was discussed in Section 5.5 for the vertical interior insulation in the foundation. Again, the 3M Aluminum Foil Tape 3369 is recommended. This tape will stick well in both high and low temperatures; it also provides good UV and solvent resistance to provide a strong, lasting and reliable bond. It will act as a vapor barrier to ensure the integrity of the insulation. The tape can be ordered in bulk through the linked website.
Figure Y. Placement of 4’x8′ Insulation Sheets Per Dome – Click here to open full image
One Community’s Video Is Coming: Thermal Insulation Install
4. INSTALL VAPOR BARRIER
As shown in Figure X, the next layer in the floor envelope above the insulation is the vapor barrier. Again, the ‘Perminator 10-mil polyolefin vapor barrier will be used in the design. The vapor barrier helps reduce the penetration of moisture and water vapor through the slab and into the dome. It will help reduce fungus, mildew and mold as well as reduce radon and methane gas from entering the dome through the ground.
As previously mentioned, this product is available in 15′-wide 200′-long rolls. Begin by cutting a piece of vapor barrier that is 15′ x 20′. Install the vapor barrier by placing the 20′ long edge of the membrane parallel to the long edge of the 4′ x 8′ insulation sheets, as shown in Figure Z. Cut the vapor barrier around the interior perimeter of the dome such that enough remains around the edges to fold the barrier up the remaining 4″ of the foundation to overlap the foundation vapor barrier. Ensure that the area is free from dust and debris, then seal the joints and ends of the barrier with Perminator Tape. Roll press the tape to ensure optimum adhesion. Use two excess pieces of vapor barrier that are 10″ x 4′-5″ for the two sides of the 15′ wide barrier where the membrane just touches the interior edge of the perimeter.
The two additional strips are required to ensure that the vapor barrier lines the vertical perimeter dome floor. As shown in Figure X, the vapor barrier layer is placed above the 3″ rigid wool insulation. This means that when it is placed on the floor it will be 4″ lower than the top of the foundation. The concrete slab floor will then be poured inside of the vapor barrier, with the barrier lining the slab underside and perimeter edges. To ensure that there is enough vapor barrier to line this vertical 4″ around the floor, the two additional pieces are needed to fold up the 4″ vertical section. Overlap the membranes by 6″ on the surface of the floor and extend it 4″ up along the foundation membrane as shown in Figure ZZ. Follow the same process as previously mentioned to secure the joints and barrier ends with tape.
Figure Z. Vapor Barrier on Dome Floor – Click here to open full image
Figure ZZ1. Section Cut of Vapor Barrier Placement on Floor Edges – Click here to open full image
Figure ZZ2. Section Cut of Vapor Barrier Placement on Floor Edges – Click here to open full image
One Community’s Video Is Coming: Vapor Barrier Install
5. PLACE WELDED WIRE FABRIC
To increase the tensile resistance of the concrete floor slabs, they will be reinforced with welded wire fabric (WWF), also known as remesh or reinforcement mesh. This is steel wire that is welded together in a square grid pattern. It is important to increase the tensile capacity of the floors because concrete is naturally weaker in tension than it is in compression, and tensile forces can lead to the concrete slab cracking.
For this design, 6×6 10×10 mesh will be used. This designation means that remesh is spaced at 6″x6″ squares and that 10 guage steel wire is used in both directions. The remesh will be installed 1 ¾â€ above the vapor barrier, and 2″ away from the foundation’s vertical insulation around the perimeter. The WWF should be cut prior to installation so that it fits in the 15′ diameter floor with 2″ of space provided between the circumference of the floor; a 14′-8″ diameter circle of WWF will satisfy this (15′ – 2″ on each end = 14′-8″), placed in the center of the floor area. Cutting the WWF can be accomplished by using bolt cutters or a grinding wheel. To simplify the process for all domes on site, a jig could be constructed to expedite the cutting process. We will design, build, and share the jig plans here once we are on site. The WWF is positioned slightly below the halfway point of the 4″ thick concrete floor that will be poured around the remesh. It is important to place the WWF in the lower half of the concrete slab because when the slab is loaded, the bottom portion will be acting in tension. This means that it is experiencing tensile load from the weight above. Concrete does not perform well in tension. Steel does, and this is why the remesh is placed in the lower half of the slab – because it provides the tensile resistance that the concrete needs to withstand the load placed on it. Control joints will later be used to control any cracking that may occur on the top of the concrete slab from the weight placed on it. The placement of the WWF will also prevent interference when the control joints are set 1″ deep in the concrete floor, as will be further explained in the subsequent section. Additionally, placing the remesh near the center of the slab height will provide enough clear cover from the edges of the concrete to prevent the remesh from corroding due to potential water near the edges of the slab. In reinforced concrete design, the term “clear cover” refers to the distance between the nearest reinforcement and the outer concrete surface. It’s an important parameter to be cognizant of because this distance protects the performance of the reinforcement by protecting against corrosion and extreme heat, such as fire. To place the WWF, use small stones to elevate the WWF to the 1 ¾â€ height above the vapor barrier and set it on top of the stones, ensuring that it is level.
One Community’s Video Is Coming: Vapor Barrier Install
6. POUR CONCRETE, SCREED, AND SET CONTROL JOINTS
Once the WWF is in place, the concrete floor can be poured. It is advised to have a team member on site who is experienced in working with concrete to assist in the pouring, screeding (the process of removing excess wet concrete to bring the top of the slab to the proper grade and smoothness), and finishing of the concrete. Professional expertise is required to guide the process once the concrete is delivered to the site by a truck with a concrete chute.
In terms of the desired concrete mix ratio, the concrete should be low slump (meaning that it does not contain a copious amount of water) and a strength of 3000 PSI. It is not necessary to include an air-entraining admixture into the concrete because the floor will be protected from the elements by the walls of the dome. If freezing of the concrete was of concern, as it will be for the Earthbag Village patios, an air-entraining admixture would be required. Air-entrained concrete is concrete that has a system of microscopic air bubbles in it to increase its resistance to freezing and thawing, thus, improving its workability. Water will freeze and expand inside the air bubbles, as opposed to inside of the concrete where the stress can lead to cracking of the concrete.
Experience with concrete is required to finish the concrete pour. This entails using an instrument to screed the concrete and setting control joints. Screeding the concrete pour will create a smooth and level floor. A straight edge instrument, such as a bull float, or reuseable forms is used to screed the concrete by employing a side-to-side motion while simultaneously pulling the instrument in a circular motion around the pour. As the concrete settles, it may require another round of screeding. To avoid leaving footprints in the concrete a two phase pour may be necessary. If doing a two phase pour, the first pour should either be 1/3rd or 2/3rd’s of the pour to leave a rough surface, otherwise known as a “cold joint” where the control joints will be, as shown in Figure AA.
Control joints are placed into the concrete to control random cracking. They are continuous vertical joints that weaken the concrete in a straight line to predispose the concrete to crack in a predominantly straight line, as shown in Figures A1 and A2. The control joints encourage and control cracking from the shrinking of concrete over time. They are created by using a groover tool, as shown in Figures A3 and A4, and should be placed every 4-5′ at 1″ deep for the 4″ concrete floor pour, acordingly to this site. The control joints are cut to 1/4th of the concrete slab depth. Figure AA presents an example of a 5’x5′ grid pattern of control joints on the dome floor. It is important to cut the control joints into the slab within 6-12 hours after the concrete is screeded. After cutting the control joints, saw them within 6-18 hours. The joints should be sawed as soon the concrete can withstand the energy of sawing without particles becoming dislodged.
For the patio, it may also be necessary to include expansion joints. Expansion joints are continuous vertical or horizontal joints that are left free of mortar but are filled with an elastomeric sealant to prevent the entry of water, as shown in Figure A5 which shows the difference between the joints in plan and section view. They are necessary to deal with differential movement and settlement at a larger scale and tend to be used at 20′ intervals; they are not necessary for the concrete floor of each dome.
Figure AA. Plan View of Grid-Pattern Control Joints
Figure A1. Concrete Control Joints – Click here to open “Rules for Designing Contraction Joints” Article
Figure A2. Minimum Depth of Control Joints – Click here to open “Placing Joints in Concrete Flatwork- Why, How, and When” Article
Figure A3. Hand Groover Tool – Click see thisitem on Lowes.com store
Figure A4. Groover with Extension Handles
Figure A5. Control Joint vs. Expansion Joint – Note: Top diagram is in plan view and bottom diagrams are section cuts.
One Community’s Video Is Coming: Concrete Pour, Screeding, and Setting of Control Joints
7. BROOM FINISH, CURE, AND SEAL
The final part of finishing the concrete floor includes a broom finish, ensuring proper curing conditions, and applying a sealant. A broom finish will create a non-slip surface. This is done by using a wide, rectangular and stiff broom with bristles that are hard enough to leave noticeable marks. When applied, the concrete should be soft enough to be shaped by the bristles but also hard enough to retain them by not sinking back together. Begin by dipping the broom into a bucket of water and shaking off the water, not onto the concrete. Gently drag the broom over the concrete in segments, overlapping the previous segment to ensure full coverage.
Next, cure the concrete. This is the drying process of the concrete, which takes several weeks. Curing at the correct rate will minimize the chance of damage during the floor’s service life. Follow a simple curing process by wetting the concrete’s surface and covering it with plastic sheeting. This will protect the concrete from unnecessary moisture entering the slab and will keep it clean as it hardens and gains its strength.
Allow the concrete to cure for 30 days then apply a water-based sealant. This will act as a decorative and protective topcoat to the concrete slab floor. Before applying the sealant, ensure that the surface is clean and free of debris. Apply two coats of sealant with the second coat running perpendicular to the first, and applied about two hours after the initial coat. The final coat will take 3-6 hours to dry, depending on the time of application and the relative humidity.
One Community’s Video Is Coming: Broom Finish, Curing, and Sealing Application
8. INSTALL METAL SHEET FLASHING
The final step in finishing the floor is inserting metal sheet flashing around the interior perimeter of the floor. This is important because as shown above in Figure X, the vertical insulation and vapor barrier from the foundation is not covered by the concrete floor slab. This means that they are exposed and susceptible to puncture or damage if a large point load is placed above them, such as the leg of a table or desk. The metal sheets will protect the insulation and vapor barrier, as well as create an aesthetic finish to the interior perimeter of the dome.
It is recommended to use 8×12″ metal sheets because their smaller size will better match the curvature of the circumference. As shown in Figure BB, the sheets will be placed every 5° around the dome. In a 15′ diameter dome, this translates to having the interior 8″ side of each sheet being placed 7″ O.C. away from the next sheet. This placement will require 72 sheets per dome. Place the sheets with the 12″ side perpendicular to the wall with 2″ of the sheet extending under the first wall layer and 4″ of the sheet extending beyond the insulation (represented by the dashed line in Figure BB), towards the center of the dome floor. This will allow the 6″ length of the insulation to be entirely covered.
The sheets will be held in place by the wall and with the use of mechanical fasteners. The 2″ portion of the sheet that is under the wall will be held in place by the weight of the wall. This can be achieved by marking a line 2″ from the short edge of the sheet and sliding it under the wall until the marked line aligns with the interior edge of the wall. The other edge of the sheets, which extends toward the center of the floor, will be held in place with 3/16″ diameter x 1-¾â€ long Steel Flat Head Tapcon Concrete Screws. Use a drill to position the screws in the 1″ overlap between each metal sheet. Drill the screws straight into the concrete until the heads are as flush as possible without going through the metal flashing. This will secure each sheet on both interior corners.
Figure BB1. Placement of Metal Sheet Flashing – Click here to open full image
Figure BB2. Placement of Metal Sheet Flashing – Click here to open full image
Figure B1. Placement of Metal Sheet Flashing – Click here to open full image
One Community’s Video Is Coming: Metal Flashing Instalation
THESE PAGES ARE SIGNIFICANTLY DEVELOPED OR DONE
CHECK OUT OUR OTHER OPEN SOURCE HUBS ALSO
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IF YOU'D LIKE TO HELP, CONSIDER THESE OPTIONS
SUGGESTIONS | CONSULTING | MEMBERSHIP | OTHER OPTIONS
JOIN OUR TEAM
One Community is specifically seeking to further build our team with additional Members, Consultants, and Partners with the following skill sets:
CLICK IMAGES FOR COMPLETE JOB DESCRIPTION PAGES
We are also seeking any other sustainability-related skilled professionals, quality writers and researchers to help finish our People's Agenda 21 website, and anyone with other skills they feel would benefit our open source creative process. The people who join our team as either volunteers/consultants or members typically fit one or more of the following descriptions:
- A person wanting to live sustainably and change the world (Pioneers!)
- A person looking to gain experience and share new skills (students, recent graduates, etc.)
- A person seeking to share experience and build their business (entrepreneurs and business owners)
- A person seeking humanitarian and/or philanthropic contributions (world-change professionals)
| Click Here for the Pioneer Application | Click Here for Satellite Member Application | Click Here for our General Application |
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