Building a small 6×8 playhouse on blocks is a smart way to practice real framing skills before moving on to a tiny house or cabin project. It is small enough to stay manageable, but large enough to teach the important things: how to prepare a site, how to build a level base, how to frame a floor properly, and how to make a structure square before you start standing walls.
For this build, the goal is not to create a code-perfect permanent dwelling. The goal is to build a solid, practical, well-framed practice structure using sound framing habits and a lot of the material you already have on hand. Since you want to reuse pallets and spare lumber, this is a great project for that. The trick is using reclaimed material in the right places. Structural members still need to be straight, sound, and predictable. Pallets are fine for non-structural cladding or trim later, but the floor system should be built from your best lumber.
This first part covers the entire lower stage of the project:
- choosing the site
- preparing the base
- setting the blocks
- laying out the floor platform
- framing the joists at 12 inches on center
- installing the subfloor
That is a full stage by itself. If this stage is sloppy, the rest of the build fights you. If this stage is square and level, the rest of the build becomes much easier.
Why build on blocks for a 6×8 playhouse?
For a full tiny house, blocks would not be my first recommendation. For a small 6×8 practice playhouse, though, they make sense.
A block-supported foundation keeps the project simple and affordable. It also lets you learn how floor systems work without forcing you into frost-depth footings, sonotubes, or trailer constraints. Since this is a small structure and not a full-time residence, a compacted gravel base with deck blocks or solid concrete support points is a reasonable approach.
The important distinction is this: do not just toss random concrete blocks on bare dirt and hope for the best. That is not a foundation plan. What you want is a leveled site, compacted base, deliberate block placement, and a floor platform that bears correctly.
Recommended floor system for this project
For this 6×8 build, I recommend:
- floor size: 6 feet x 8 feet
- support system: 6 deck blocks
- floor framing: 2×6 lumber
- joist spacing: 12 inches on center
- subfloor: 5/8-inch or 3/4-inch plywood/OSB
- exterior contact material: pressure-treated where needed
You mentioned using 12 inches on center instead of 16 inches on center for more sturdiness, and that is a good choice here. On a small build, the extra material is modest, but the floor feels tighter and more solid. Since this is also practice for a future tiny-house-style mindset, tighter spacing is a worthwhile habit.
Materials for Part 1
The exact list will depend on what you already have, but a typical material list for this stage looks like this:
Foundation and base
- 6 deck blocks or solid concrete support blocks
- gravel or crushed stone
- landscape fabric if wanted
- shims only for fine adjustment, not for fixing terrible layout
Floor framing
- pressure-treated skids or treated bearing members if used
- 2×6 lumber for floor joists and rim joists
- galvanized or coated structural screws / framing nails
- joist hangers if your layout uses them
- construction adhesive
Subfloor
- 2 sheets of 3/4-inch tongue-and-groove subfloor if you want a stiffer floor, or
- sheet goods sized to cover the platform with proper support under seams
Tools
- tape measure
- speed square
- framing square
- level
- string line
- shovel
- rake
- tamper
- circular saw
- drill/driver
- hammer or nail gun
- chalk line
If you already have lots of 2×6 material, that helps a lot. Just be ruthless about selecting the straight pieces for the platform.
Step 1: Choose the site carefully
Do not overcomplicate this. You want a reasonably flat area with decent drainage and enough room around the structure to work.
Look for:
- firm ground
- no standing water
- not the low point of the yard
- enough access to move lumber and sheet goods around
- enough open space to check your layout and keep things square
If you build in a wet dip in the yard, the project will punish you later. Even a small playhouse benefits from being slightly elevated and on a site that sheds water.
Step 2: Mark out the footprint
Once you pick the site, mark the 6×8 footprint.
Use stakes and string to outline the rectangle. Measure carefully and check both diagonals. If the two diagonal measurements match, your layout is square. If they do not match, adjust the lines until they do.
This matters more than beginners think. The temptation is to say, “close enough.” That decision is where sloppy structures begin.
A 6×8 rectangle should be clean, simple, and true. Treat it seriously. This is where you start learning real framing discipline.
Step 3: Clear and prepare the base
Remove grass, roots, loose organic material, and soft topsoil. You do not need to excavate like you are building a house, but you do want to get down to a more stable surface.
A good simple prep approach is:
- scrape off sod and organic material
- level the general area
- lay landscape fabric if desired
- add compacted gravel
- build a stable pad under the block locations
You are not pouring a slab. You are creating stable bearing points. The better you do this, the less shifting and twisting you will get later.
For a small build like this, you can usually use 6 support points:
- 3 supports along one long side
- 3 supports along the opposite long side
That creates two bearing lines running the 8-foot direction, with the floor spanning across the 6-foot width.
Step 4: Block layout
A simple and practical layout is:
- one block near each corner
- one intermediate block on each long side at the midpoint
That gives you 6 total support points.
Another approach is to use treated skids resting on blocks, then build the floor frame on top of the skids. That can work well too, especially for a small playhouse.
Simple support concept
Think of the supports like this:
- two parallel support lines
- one near each long edge of the floor system
- floor joists spanning between them or platform bearing arranged cleanly on them
Keep the support layout symmetrical and easy to understand. This is not the place to invent something weird.
Step 5: Get the blocks level
This step is where patience matters.
Set your blocks and use a straightedge, long level, string line, or laser if you have one to make sure they are level relative to one another. They do not need to be perfect to the thousandth of an inch, but they do need to be good.
Aim for:
- same elevation across matching supports
- no major rocking
- full bearing under each block
- no blocks sitting on loose junk fill
If a block is wrong, fix the base under it. Do not stack random scraps under it and call it done.
Step 6: Build the floor frame
For a 6×8 floor, a straightforward platform is the best choice.
Example floor frame concept
- rim joists at the 8-foot sides
- end joists at the 6-foot sides
- interior 2×6 joists running the 6-foot direction
- joists spaced at 12 inches on center
Since this is a small span, 2×6 floor joists are a strong choice. Your notes show that 2x6s can handle spans beyond what this playhouse needs, so you are comfortably in range for a stiff little floor. That is good. You want this thing to feel solid underfoot.
Why 12 inches on center?
Because it gives you:
- stiffer floor
- better support for sheet goods
- stronger feel
- good practice for careful layout work
Yes, 16 inches on center could work for a small structure like this. But since you want sturdiness and you already mentioned 12 inches on center, I agree with that call.
Step 7: Lay out joists properly
Mark your joist layout on the rim joists before assembly. Hook your tape from one end and mark at 12-inch on-center intervals.
Be consistent. Label your marks clearly. Put an X on the side of the line where the joist goes. That little habit prevents dumb mistakes.
A clean layout now saves frustration later.
You do not need to get fancy. Just be accurate and deliberate.
Step 8: Assemble the floor platform
Build the rectangular outer frame first. Check it for square before locking everything in.
Then install the interior joists.
Use:
- framing nails or structural screws
- joist hangers if your configuration calls for them
- construction adhesive where helpful
- full bearing wherever possible
Your framing references show minimum bearing concepts and support logic. For this simple build, the principle is the same: members should sit and bear properly, not just float on fasteners.
Once the joists are in, check the platform again for square. Do not assume it stayed square just because it looked fine five minutes ago.
Step 9: Consider blocking
For a small 6×8 floor, full blocking is not always necessary if the joists are well restrained by the rim and the subfloor goes on quickly. But a line of blocking can add stiffness and help keep things aligned during assembly.
If you have the material and want the practice, add blocking neatly. Just do not turn a simple floor into a cluttered mess of unnecessary pieces.
The lesson here is not “more wood equals better.” The lesson is “clean structure wins.”
Step 10: Set the platform on the blocks
Once the floor frame is built, set it onto the prepared supports. Make sure bearing is correct and the load path makes sense.
You want:
- support under the main bearing points
- no major gaps
- no twist in the frame
- frame sitting stable without wobble
Recheck level. Recheck square. This is where small errors become obvious.
A floor frame can look nice on the ground and still sit badly once it goes onto its supports. Fix issues now, not after the walls are up.
Step 11: Install the subfloor
Once the platform is square, level, and solid, install the subfloor.
For this project, I would lean toward 3/4-inch subfloor if you have it. That gives a stronger feel and a better working surface. If you are using material you already own, choose the best sheet goods you have, as long as they are sound and appropriate.
When installing subfloor:
- stagger seams if applicable
- make sure seams land on framing
- leave proper small expansion gaps if required by the panel manufacturer
- use adhesive on joists if desired
- fasten thoroughly and evenly
Your framing references note that panel subflooring ties the joists together and improves overall floor stiffness. That is exactly what you want here. Once the subfloor is on, the platform starts behaving like a unit rather than a loose collection of members.
Where pallets fit in this stage
This is important.
For Part 1, pallets are not your main structural answer. Use your best dimensional lumber for the floor system. Use pallets later for:
- siding
- trim
- decorative cladding
- shelving
- bench material
- interior finish accents
Could you salvage individual pallet boards for odds and ends? Sure. But the floor system needs straight, reliable members. This is one place to stop being romantic about “free wood” and be practical.
Common mistakes to avoid
A lot of beginner frustration comes from a few predictable mistakes:
1. Building on a bad site
If the ground is wet, soft, or sloppy, the structure will reflect that.
2. Not checking square
If the floor is out of square, wall framing becomes more annoying immediately.
3. Using twisted junk for the floor
Save ugly reclaimed material for non-structural use.
4. Trusting the eye instead of measurements
A structure can look okay and still be wrong.
5. Rushing block setup
If your support points are bad, nothing above them really gets better.
What success looks like after Part 1
At the end of this stage, you should have:
- a cleared, stable site
- 6 properly placed support blocks
- a square 6×8 floor platform
- 2×6 joists at 12 inches on center
- a solid subfloor installed
- a flat, stiff base ready for wall framing
That is a real milestone. Once you have that, you are no longer “thinking about building a playhouse.” You are building one.
Final practical notes
This tutorial is based on sound framing principles for a small practice structure, but local code, frost conditions, and specific use matter. If you later evolve this into a more permanent shed or occupied structure, your foundation requirements may change. For this practice build, the point is to learn layout, level, load path, and clean floor framing.
And that is worth doing right.
A small, square, solid 6×8 platform teaches more real carpentry than a pile of half-finished pallet experiments ever will. Build this first stage cleanly, and the walls will go up with far less pain.