Complete Ferrocement Water Tank Construction: From Wire to Water Storage
⟁ cover painted for this edition — the source module carried no illustrations
Complete Ferrocement Water Tank Construction: From Wire to Water Storage
Ferrocement tanks provide affordable, durable water storage that can be built with basic materials. This campaign covers design, armature construction, plastering, curing, and waterproofing.
Chapter 1: Design Principles
Tank Shape
Capacity
Structural Efficiency
Difficulty
Best For
Cylindrical
500-10,000+ gallons
Excellent (hoop stress)
Moderate
Most applications
Rectangular
200-2,000 gallons
Moderate (needs reinforcement)
Moderate
Tight spaces
Dome/spherical
500-5,000 gallons
Excellent
High
Underground
Jar (olla) shape
100-1,000 gallons
Very good
Moderate
Above ground, traditional
Sizing: 1) 1 cubic foot = 7.48 gallons. 2) Cylindrical tank: Volume = pi x radius squared x height. 3) Example: 4-foot radius x 4-foot height = 201 cubic feet = 1,503 gallons. 4) Wall thickness: 1-2 inches (ferrocement is thin-shell construction). 5) Foundation: flat, level, compacted surface or concrete pad. 6) Overflow: pipe at maximum water level. 7) Outlet: pipe near bottom (with valve). 8) Access: manhole or removable lid for cleaning. 9) Vent: screened opening prevents vacuum during draining.
Chapter 2: Armature Construction
Component
Material
Function
Specification
Skeleton
Rebar (3/8 inch) or welded wire mesh
Primary structure
Vertical and horizontal rings
Mesh layer 1
Chicken wire (1 inch hex)
Mortar support
Wrapped around skeleton
Mesh layer 2
Hardware cloth (1/2 inch)
Fine mortar support
Over chicken wire
Tie wire
Galvanized wire (18-20 gauge)
Connect all layers
Every 6-8 inches
Cylindrical tank armature: 1) Set vertical rebar rods in foundation (every 8-12 inches around circumference). 2) Bend horizontal rebar rings to match tank diameter. 3) Tie horizontal rings to verticals at every intersection. 4) Wrap chicken wire around entire frame (inside and outside). 5) Overlap chicken wire by 2 inches at all seams. 6) Tie chicken wire to rebar at every 6 inches. 7) Optional: add hardware cloth layer for smoother finish. 8) Armature should be rigid (no flexing when pushed). 9) All wire ends must be tucked in (no protrusions). 10) Leave openings for inlet, outlet, overflow, and access.
Chapter 3: Plastering
Mortar Mix
Cement
Sand
Water
Strength
Use
Standard
1 part
2-3 parts
As needed
Good
General walls
Rich mix
1 part
1.5-2 parts
As needed
Very good
First coat, waterproofing
Waterproof mix
1 part + waterproofer
2 parts
As needed
Very good
Final interior coat
Plastering process: 1) Mix mortar to thick, workable consistency (not runny). 2) Wet armature thoroughly before plastering. 3) Apply first coat from inside (push mortar through mesh). 4) Work from bottom up. 5) First coat: fill mesh completely (1/2 inch thick). 6) Let first coat set but not dry completely (24 hours). 7) Apply second coat from outside (covers all mesh). 8) Total wall thickness: 1-1.5 inches. 9) Smooth interior surface (water contact side). 10) Apply waterproof coat to interior (cement + waterproofing additive). 11) Keep moist during curing (cover with wet cloth or plastic). 12) Cure for minimum 7 days (28 days for full strength).
Chapter 4: Waterproofing
Method
Cost
Effectiveness
Durability
Food Safe
Cement + waterproofing additive
Low
Very good
Very good
Yes (most brands)
Bituminous coating
Low
Excellent
Good
No (exterior only)
Epoxy coating
Moderate
Excellent
Excellent
Yes (food-grade)
Lime plaster (interior)
Very low
Good
Good
Yes
Silicone sealer
Low
Good
Moderate
Varies
Chapter 5: Testing and Commissioning
Test
Method
Pass Criteria
Action if Fail
Visual inspection
Examine all surfaces
No cracks, holes, or exposed wire
Patch with mortar
Fill test
Fill with water, mark level
No drop in 48 hours
Find and seal leak
Tap test
Tap walls with hammer
Solid sound (no hollow spots)
Replaster hollow areas
Pressure test
Fill to overflow
No bulging or cracking
Reinforce weak areas
Reference Card
Cylindrical is strongest (the cylinder distributes water pressure evenly as hoop stress; it is the most efficient shape for water tanks). 2. Multiple mesh layers are key (ferrocement strength comes from multiple thin layers of mesh embedded in mortar; more layers equals more strength). 3. Tie everything together (every intersection of rebar and mesh must be tied with wire; loose connections create weak points). 4. Plaster from inside first (pushing mortar through the mesh from inside ensures complete penetration and eliminates voids). 5. Cure for 28 days (cement reaches full strength at 28 days; keep the tank moist during curing by covering with wet cloth). 6. Waterproof the inside (the interior surface must be sealed to prevent water from seeping through; use cement with waterproofing additive). 7. Ferrocement is cheaper than any alternative (a DIY ferrocement tank costs a fraction of a commercial plastic or concrete tank of the same size). 8. One tank changes everything (reliable water storage transforms a homestead; build the largest tank you can afford and maintain).
