Flooring Options

Part of Permanent Shelter

A bare dirt floor is the first thing that makes a shelter feel like a cave. It generates dust in dry weather, turns to mud in wet weather, harbors insects, and loses heat into the ground. Every civilization independently developed floor finishing techniques — because the improvement in daily life is enormous and the materials are free.

Comparative Overview

Before choosing a flooring method, understand the tradeoffs:

Factor	Tamped Earth	Stone Flags	Plank Floor
Material cost	Free	Free (gathered)	Moderate (trees)
Labor intensity	Low	High	Medium-High
Build time (12 m2)	1-2 days	3-5 days	2-4 days
Durability	5-15 years	50+ years	20-40 years
Warmth underfoot	Medium	Cold	Warm
Moisture resistance	Poor (without sealer)	Excellent	Moderate
Repairability	Easy — patch and re-tamp	Replace individual stones	Replace individual planks
Best climate	Dry to moderate	Any	Cold climates

Option 1: Tamped Earth Floor

The simplest effective floor. A well-made tamped earth floor is smooth, dust-free, and surprisingly durable. It was the standard floor in most of the world’s buildings until the 19th century.

Preparation

1. Excavate the floor area to 15-20 cm depth. Remove all organic material — roots, leaves, grass. Organic matter decays under the floor and creates soft spots.

2. Level the subgrade. Use a straight board and a water level to check that the surface is flat. Fill low spots, remove high spots. Compact the subgrade by tamping — a heavy flat stone or a log section (20-30 cm diameter, 40-50 cm long) on a handle works well.

3. Add a gravel drainage layer (optional but strongly recommended in wet climates). Spread 5-10 cm of gravel or crushed stone and tamp level. This prevents ground moisture from wicking up into the floor.

Building the Floor

4. Mix the floor material. The ideal mix:

   • 70% subsoil (sandy clay — not topsoil, which contains organic matter)
   • 20% sharp sand
   • 10% chopped straw or dried grass (fiber binder)
   • Water — enough to make the mix damp but not wet. Squeeze a handful: it should hold together without dripping.

5. Lay the first layer — 5-8 cm thick, spread evenly across the floor area.

6. Tamp thoroughly. This is the critical step. Tamp every square centimeter with a flat tamper (a 15 x 15 cm flat stone or board lashed to a stick). The surface should feel solid and resistant, with no give when you press hard with your thumb.

7. Let dry for 24 hours, then apply a second layer of 3-5 cm. Tamp again. Two layers are minimum. Three layers, each tamped and dried, produce a very hard floor.

8. Smooth the final surface with a flat stone or wet board, working in overlapping passes. The finished surface should be as smooth as you can make it — a smoother surface sheds water and resists abrasion better.

Hardening Treatments

A raw tamped earth floor dusts underfoot and softens when water is spilled. These traditional treatments dramatically improve durability:

Treatment	Method	Effect	Availability
Ox blood	Mix fresh blood into the top layer before final tamping	Creates a polymer-like binder; very hard, water-resistant surface	Requires slaughter
Linseed oil	Apply 2-3 coats, letting each soak in for 24 hours	Seals surface, prevents dust, moderate water resistance	Requires flax crop
Beeswax	Melt and rub into the dry surface, then buff with a cloth	Smooth, water-resistant, beautiful finish	Requires beekeeping
Lime water	Mix slaked lime into water (thin, milky), mop onto surface	Hardens and stabilizes the top layer	Requires lime production
Cow dung wash	Mix fresh cow dung with water (1:3), mop onto surface weekly	Antimicrobial, binds dust, traditional across Africa and India	Requires cattle

The Ox Blood Floor

This is not folklore. Blood contains albumin proteins that, when mixed into earth and dried, create a binding matrix similar to a weak polymer. The result is a floor that can last 15+ years with minimal maintenance. The blood smell disappears entirely after drying and does not attract animals.

Maintenance

Sweep daily. Re-apply sealer (oil, wax, or dung wash) every 3-6 months. Patch damaged areas by dampening the edges, pressing in fresh mix, and tamping. A well-maintained tamped earth floor improves with age as the surface compresses and hardens.

Option 2: Stone Flag Floor

Stone flag floors are the most durable floor you can build by hand. They are waterproof, fireproof, pest-proof, and will outlast the building. The downside: they are cold underfoot and labor-intensive to lay.

Selecting Stones

You need flat stones — 3-8 cm thick, with at least one smooth face. Irregular shapes are fine; you will fit them together like a puzzle.

• Best: Slate, flagstone, flat limestone, flat sandstone
• Acceptable: Split granite, flat field stones
• Avoid: Rounded stones (unstable, uncomfortable to walk on)

Gather more than you think you need. Sorting through a large pile to find the right fit for each spot is much faster than stopping to quarry more.

Laying the Floor

1. Prepare the subgrade exactly as for a tamped earth floor — excavate, remove organic material, level, compact.

2. Lay a sand bed — 3-5 cm of sand or fine gravel, leveled and tamped lightly. This bed allows you to adjust individual stones for level.

3. Start from a corner. Place your largest, flattest stones first. Work outward, fitting stones together with the smallest gaps possible.

4. Level each stone by adding or removing sand beneath it. Check with a straight edge laid across multiple stones — the surface should be flat enough that the edge does not rock.

5. Tap stones into place with a wooden mallet or a block of wood struck with a stone. Do not hit the stone directly with metal or hard stone — it chips.

6. Fill gaps between stones with smaller wedge stones driven in from above, or with a sand/clay mix packed in tightly. Grouting with lime mortar (1 part lime putty, 3 parts sand) produces the most durable and cleanest result.

Drainage Under Stone Floors

Stone floors laid directly on clay soil trap moisture underneath. In wet climates, always lay a 5-10 cm gravel drainage layer beneath the sand bed. Without drainage, the floor stays perpetually damp, grows mold on the underside, and makes the room feel cold and clammy.

Maintenance

Stone floors need almost no maintenance. Sweep regularly. Re-grout joints when mortar cracks or washes out (typically every 5-10 years). If a stone cracks, pry it out, level the sand bed, and replace it.

Option 3: Plank Floor

A plank floor is the warmest option and the most comfortable to live on. It requires more materials (timber) and skills (splitting or sawing planks, building a joist structure) but provides excellent insulation from ground cold.

Making Planks

Without a sawmill, you have two methods:

Splitting (riving): Select straight-grained logs (oak, ash, cedar, pine). Drive wooden or stone wedges along the grain to split the log into halves, then quarters, then thin slabs 3-5 cm thick. Trim with an axe or adze. Riven planks are stronger than sawn planks because they follow the wood grain.

Pit sawing: Position a log over a pit or raised platform. One person stands on top, one below. Using a long two-handled saw, cut the log into planks by ripping along its length. This produces more uniform planks but is extremely labor-intensive — expect 3-5 planks per day from two people.

Building the Substructure

1. Prepare the subgrade — excavate, level, and compact as for other floors. Lay a gravel drainage layer.

2. Set stone piers or low walls to support the joists. Space piers 60-90 cm apart in both directions. Each pier should be a flat stone or stacked stones, 10-20 cm above ground level.

3. Lay floor joists — straight poles or squared timbers, 8-12 cm in diameter/width. Space joists 40-60 cm apart, resting on the piers. Level each joist by shimming with thin stone wedges on the piers.

4. The air gap between the ground and the joist bottoms is intentional — it prevents moisture from wicking into the wood. Leave ventilation openings in the foundation walls to allow air circulation under the floor.

Laying Planks

5. Lay planks perpendicular to the joists. Each plank should span at least two joists. Stagger the end joints so they never align on adjacent planks.

6. Fasten planks to joists with wooden pegs (drill holes with a bow drill and drive in hardwood pegs) or hand-forged nails if available. At minimum, two fasteners per plank-joist intersection.

7. Fit planks tightly. Gaps between planks let cold air rise from below and drop crumbs and dirt into the crawl space. If planks are not perfectly straight, plane or scrape the mating edges with a drawknife or stone scraper until they fit snugly.

8. Finish the surface. Sand or scrape smooth. Apply linseed oil, beeswax, or rendered fat to seal the surface against moisture and make cleaning easier.

Moisture Barriers

The plank floor’s enemy is rot from below. Protect against it:

• Gravel under the crawl space prevents moisture from pooling
• Ventilation openings in foundation walls allow air movement (two openings on opposite sides, each at least 10 x 15 cm)
• Never lay planks directly on the ground — even on a gravel bed. The air gap between joists and ground is essential.
• Treat joist ends and undersides with charring (lightly burn the surface with a torch) or tar/pine resin. Charred wood resists rot and insects far better than raw wood.

Charring for Preservation

Pass a burning torch slowly over the wood surface until it blackens to 1-2 mm depth. This technique, called “shou sugi ban” in Japanese tradition, carbonizes the outer layer. Carbon does not rot, does not feed insects, and does not absorb water. Apply to all joist ends, plank undersides, and any wood near the ground.

Choosing the Right Floor

Choose tamped earth when you need a floor quickly, have limited tools, or are in a dry climate. It is the fastest to build and easiest to repair.

Choose stone flags when durability is the priority, you have access to flat stone, and you are willing to invest the labor. Best for kitchens, workshops, and wet-climate shelters.

Choose plank flooring when warmth underfoot matters most — cold climates, sleeping areas, and living spaces where people sit on the floor. The air gap provides natural insulation.

Combining types is common and practical: stone flags in the cooking area (fireproof, easy to clean), tamped earth in storage areas, and plank flooring in sleeping and living areas.

Key Takeaways

• Tamped earth is the fastest floor — excavate, mix, tamp, seal. Hardening treatments (blood, oil, lime) transform it from adequate to excellent.
• Stone flag floors last centuries — flat stones on a sand bed with lime mortar grouting. Always include gravel drainage beneath.
• Plank floors are the warmest — the air gap below is both insulation and rot prevention. Never lay wood directly on the ground.
• Gravel drainage layers under all floor types prevent moisture problems — the most common cause of floor failure.
• Char wood surfaces near the ground with a torch to prevent rot and insect damage.
• Combine floor types in a single building — stone near the fire, planks in the sleeping area, earth in storage.
• Maintenance is simple — sweep daily, re-seal earth floors seasonally, re-grout stone floors when needed.