One Sheet. So Many Possibilities: Why Thick XPS Foam Can Be Your Base, Landscape and Creative Foundation
When people first look at a sheet of pale green XPS foam, they may see just that — a sheet of foam.
But for a modeller, student, hobbyist, terrain builder, artist or creative maker, a thicker piece of XPS can be much more.
It can be:
- a strong, lightweight base
- the landscape itself
- a hill, mountain or mound
- a carved riverbed or lake
- a surface into which you can add and secure scenery
- a foundation for models, miniatures and structures
- and finally, a fully painted and finished part of the project
That is the real advantage of using thicker XPS foam.
Instead of starting with a separate wooden board, cardboard base, scenery material and then additional layers to create height, you can often begin with one substantial piece of XPS foam and build directly into it.
At Hobby Foam Supplies, our Australian-made XPS foam is available in a range of thicknesses, including 40mm, 50mm and 75mm options in selected sheet sizes. These thicker sheets are particularly useful when you want the material to do more than simply sit underneath your project.
Think of Your XPS Foam as a Blank 3D Canvas
A thin material gives you a surface.
A thicker piece of XPS foam gives you a surface plus depth.
That depth is where the creative possibilities really begin.
Imagine starting with a flat 50mm or 75mm thick sheet. Before you have added a single tree, building, miniature, train track or craft decoration, you already have a substantial three-dimensional foundation.
You can leave some areas completely flat.
You can cut other areas lower.
You can carve into the surface.
You can build up additional sections.
You can create gentle slopes or dramatic cliffs.
You can turn one piece of foam into a complete landscape.
The important idea is this:
The foam does not have to be hidden underneath the project. The foam can become part of the project.
That means a single sheet can perform several jobs at once.
Application 1: Start With a Strong, Lightweight Base
The first job of thicker XPS foam is simple:
Use it as the base itself.
For many hobby and display projects, the XPS sheet can provide the main foundation without needing to immediately attach it to another board.
This is especially useful for:
- tabletop gaming terrain
- model railway modules
- school geography projects
- dioramas
- miniature landscapes
- architectural models
- display bases
- cosplay and prop components
- exhibition models
- creative craft projects
Hobby Foam Supplies' existing project gallery already shows XPS foam being used as substantial terrain and model bases, including a 100 × 60 × 40mm foam base, large geography projects and wargaming terrain.
Why use the foam itself as the foundation?
Because you immediately gain:
Height – your project is already elevated above the table.
Depth – you have material available to carve into.
Light weight – compared with many solid timber or plaster alternatives, foam is easier to move and handle.
Easy shaping – you can cut the outline of the base into something more interesting than a simple rectangle.
Creative flexibility – you can change the design as you go.
For example, instead of starting with:
Wooden board → glue foam on top → add scenery → paint
you may be able to start with:
Thick XPS foam → carve directly into it → add scenery → paint
That can simplify the construction of many hobby projects.
Application 2: The Same Base Can Become the Landscape
This is where thicker XPS foam becomes particularly useful.
Once your foam is acting as the foundation, you can begin to transform the same piece of material into scenery.
Want a river?
Carve down into the surface.
Want a lake?
Create a shallow depression.
Want a road cutting through a hill?
Lower the road area and leave the surrounding terrain higher.
Want a mountain?
Start with the thickness you already have and add more foam only where additional height is required.
Want rolling countryside?
Sand or carve gradual transitions directly into the foam.
Want a battlefield?
Create trenches, shell craters, embankments, ruined roads and raised defensive positions.
The material underneath is no longer just a hidden support.
It has become the terrain.
Hobby Foam Supplies' own geography and model railway guides demonstrate the use of XPS for features such as rivers, elevations, embankments and multi-level landscapes.
Application 3: Carve a River Bed Directly Into the Foam
A river is one of the easiest examples of why a thicker base can be so useful.
Imagine beginning with a 50mm thick piece of pale green XPS foam.
The top surface is your landscape.
Now mark out a winding river.
Instead of building the river on top of the base, you can cut or carve down into the foam.
The surrounding material automatically becomes the riverbank.
From there you can shape:
- shallow edges
- steep banks
- gentle curves
- deep channels
- waterfalls
- rocky sections
- rapids
- bridges
- culverts
The deeper the starting foam, the more freedom you have to create changes in elevation.
The geography project guide on the Hobby Foam Supplies website uses this same basic principle, describing how a river or lake can be created by working directly into the XPS surface before painting and finishing the landscape.
A simple workflow
Step 1: Draw the river path.
Step 2: Cut or score the outline.
Step 3: Remove or compress material to create the channel.
Step 4: Shape the banks so they rise naturally from the water.
Step 5: Add texture using appropriate carving or sculpting tools.
Step 6: Paint the riverbed.
Step 7: Add scenery around it.
The result is much more integrated because the river and landscape come from the same original base.
Application 4: Turn the Base Into Hills, Mounds and Elevated Terrain
A flat sheet does not have to stay flat.
With 40mm, 50mm or 75mm XPS foam, you already have a significant amount of material to work with.
You can remove foam from selected areas while leaving other areas untouched.
That instantly creates relative height differences.
For example:
Leave an area untouched
It becomes a plateau or raised area.
Carve around it
It starts to become a hill.
Round the edges
It becomes a natural mound.
Cut sharp angles
It can become a rocky cliff.
Layer extra foam on top
It can grow into a mountain.
This approach gives you tremendous flexibility.
You are not simply adding scenery onto a base.
You are sculpting the base itself.
This is particularly useful for:
- model railways
- wargaming boards
- fantasy landscapes
- historical battlefields
- geography projects
- architectural landscaping
- miniature villages
- garden and park models
XPS is already featured by Hobby Foam Supplies for applications including wargaming, model terrain and model railways, where carving and elevation changes are central to the build.
Application 5: Create a Hill Without Building a Hill
Traditionally, a hobbyist might create a hill by stacking cardboard, adding paper, covering it with plaster or applying other scenic materials.
With thicker XPS, you can often begin with the hill already partly there.
A 75mm sheet, for example, gives you a substantial starting depth.
You can:
- Mark the outline.
- Cut away the surrounding material.
- Round and shape the edges.
- Add additional layers only if you want more height.
- Carve rock faces or erosion lines.
- Paint and texture the finished surface.
Suddenly, one sheet is doing multiple jobs:
Base + elevation + landscape + carving material.
That is the core idea behind using a thicker XPS sheet creatively.
Application 6: Build Structures Directly Into the Landscape
Once you have created the basic terrain, the foam can also support the next stage of the project.
You can create areas for:
- houses
- castles
- bridges
- miniature trees
- fences
- signs
- railway scenery
- gaming buildings
- rock formations
- volcanoes
- decorative craft pieces
For lightweight components, the foam can provide a convenient surface for appropriate pins, skewers, toothpicks or other supports, while foam-compatible glue can be used where suitable.
This means the same sheet can act as a practical anchoring surface for the scenery above it.
For example, imagine a model village.
You could:
- carve the river directly into the foam
- shape the hills from the foam
- cut a road into the surface
- create flat areas for houses
- add miniature trees
- add fences
- glue lightweight scenery into place
- paint the entire landscape
All from one main XPS foundation.
Application 7: Pin, Glue and Build Into the Foam
One of the enjoyable aspects of working with XPS for lightweight hobby scenery is that the material is easy to customise.
Small decorative items can be positioned using suitable pins or inserted supports, while foam-safe adhesives can be used to attach compatible scenery and details.
Depending on the project, you might add:
- miniature trees
- signposts
- fences
- telegraph poles
- flags
- small figures
- rocks
- model buildings
- decorative plants
- school project labels
The existing Hobby Foam Supplies geography project guide, for example, describes adding miniature trees, toy animals and other decorative details to an XPS landscape.
Important: choose your adhesive carefully
Not every glue, solvent or aerosol product is suitable for polystyrene foam.
For hobby projects, use products specifically labelled as foam-safe, and test unfamiliar paints, adhesives or coatings on an off-cut first.
Foam-safe PVA and other compatible craft adhesives are commonly used in XPS modelling projects, while your choice should depend on the weight and purpose of the item being attached.
Application 8: Carve Texture Directly Into the Surface
The creative potential does not stop with the overall shape.
You can also add surface detail.
Depending on your tools and technique, XPS can be shaped to suggest:
- stone
- brickwork
- rock faces
- cracked earth
- timber planks
- paving
- cobblestones
- cliff layers
- erosion channels
- rough ground
This is particularly valuable for model makers because the material can serve as both the structural form and the textured surface.
Hobby Foam Supplies' XPS terrain product information highlights the ability to carve fine details and use hobby knives, hot-wire tools and sanding techniques for modelling and terrain work.
Imagine creating a castle scene.
The base can become:
- the ground
- the hill
- the moat
- the road
- the rocky cliff
Then additional pieces of XPS can become:
- castle walls
- towers
- stone ruins
- dungeon entrances
One material.
Multiple functions.
Application 9: Paint the Foam and Make the Material Disappear
This is perhaps the most satisfying stage.
At the beginning, everything is pale green XPS foam.
At the end, nobody should necessarily be thinking:
"That looks like foam."
Instead, they might see:
- a rocky mountain
- a muddy battlefield
- an ancient ruin
- a river valley
- a volcanic landscape
- a miniature forest
- a castle on a hill
- a realistic railway scene
Painting is what brings the entire project together.
Hobby Foam Supplies' existing project tutorials use acrylic paints, washes, layered colours and surface treatments to transform the raw foam into finished scenery.
A simple painting approach
1. Base colour
Apply the main colour of the object.
For example:
- dark grey for rock
- brown for soil
- green for grass areas
- blue tones for water
- black or charcoal for volcanic rock
2. Dark wash
A darker, thinner colour can help define recesses, cracks and carved texture.
3. Mid-tone
Bring back the main colour across the larger surfaces.
4. Highlights
Use a lighter shade on raised areas.
This can make carved rocks, cliffs and textures stand out dramatically.
5. Add scenery
Once the paint is dry, add appropriate:
- static grass
- flock
- moss effects
- miniature rocks
- trees
- bushes
- sand
- pathways
- buildings
The Hobby Foam Supplies moss and algae guide demonstrates how paint, texture materials and optional scenic additions can be layered to create more realistic finishes.
Which Thickness Should You Choose?
There is no single "best" thickness.
It depends on what you want the foam to do.
40mm XPS Foam — A Great All-Round Starting Point
40mm is a useful thickness when you want a solid base but don't need extremely deep carving.
It can work well for:
- smaller dioramas
- tabletop gaming terrain
- school projects
- moderate hills
- roads and rivers
- display bases
- craft projects
- architectural and landscape models
You still have enough depth to create noticeable changes in elevation while keeping the project relatively compact.
Think of 40mm as:
Base + shallow terrain + moderate carving depth.
50mm XPS Foam — More Depth, More Freedom
50mm gives you extra material to work with.
That additional depth can be particularly useful for:
- deeper riverbeds
- more substantial hills
- railway embankments
- volcano bases
- larger dioramas
- wargaming terrain
- multi-level scenery
The 50mm thickness is also a practical middle ground.
It is substantial enough to feel like a real three-dimensional foundation while remaining easy to incorporate into many hobby projects.
Think of 50mm as:
Base + terrain + deeper carving + greater visual impact.
Hobby Foam Supplies currently lists 5cm variants across selected XPS product sizes.
75mm XPS Foam — When You Want Serious Depth
75mm gives you the greatest starting depth of the three.
This is where you can really begin to think in three dimensions.
You can create:
- deeper valleys
- dramatic hills
- larger cliffs
- sunken roads
- river gorges
- substantial embankments
- large gaming terrain
- major landscape features
- architectural elevations
- impressive display bases
And the best part is that you can start with the height already built into the material.
Instead of gluing together several thin layers before you even begin shaping, you can begin with a substantial block and sculpt directly into it.
Think of 75mm as:
Base + major elevation + deep carving + large-scale creative freedom.
The Hobby Foam Supplies range includes 7.5cm options in selected hobby and large-format XPS sheets, including examples featured in the customer project gallery.
One Project, Four Jobs for the Same Foam
Let's look at a simple example.
Imagine you are building a miniature countryside scene.
You start with one 50mm or 75mm XPS sheet.
Job 1 — The Base
The entire piece becomes the foundation of the project.
No immediate need to create the landscape on a separate sheet of cardboard.
Job 2 — The Terrain
Carve away material to create a river running through the middle.
Leave some sections high.
Lower other sections.
Now you have a valley.
Job 3 — The Support
Create flat areas where lightweight buildings, trees, fences and other scenery can be attached.
Use appropriate pins or foam-compatible adhesive where suitable.
Job 4 — The Finished Surface
Paint the exposed foam.
Add texture.
Add grass.
Add rocks.
Add water effects.
Now the original foam is still there — but visually, it has become an entire landscape.
That is why thicker XPS foam can be such a versatile starting material.
The "One Sheet, Many Uses" Workflow
Here is the concept in its simplest form:
STEP 1: START WITH ONE SHEET
Choose your thickness based on the depth and scale of your project.
40mm for a substantial all-round base.
50mm for more carving and terrain depth.
75mm for dramatic landscapes and larger elevation changes.
STEP 2: USE IT AS YOUR FOUNDATION
Decide on the overall size and shape.
Trim the foam if required.
Round corners, create irregular coastlines or create a custom-shaped display base.
STEP 3: DRAW YOUR LANDSCAPE
Sketch directly onto the surface.
Mark:
- rivers
- lakes
- roads
- hills
- building locations
- railway lines
- forests
- battle zones
- mountains
This gives you a simple plan before you start carving.
STEP 4: CARVE THE BIG FEATURES
Start with the largest changes first.
Cut down for:
- rivers
- valleys
- roads
- trenches
Leave material behind for:
- hills
- raised ground
- plateaus
- cliffs
STEP 5: ADD FINE DETAIL
Once the overall shape looks right, add:
- rock texture
- erosion
- cracks
- stone
- brick patterns
- pathways
- small terrain changes
STEP 6: BUILD INTO THE FOAM
Add your structures and scenery.
Use suitable supports and foam-compatible adhesives for the materials you are attaching.
At this stage, the project starts coming alive.
STEP 7: PAINT THE ENTIRE SCENE
Cover the raw foam with your chosen colours and scenic effects.
Use darker colours in recesses and lighter highlights on raised surfaces.
The goal is to visually transform the XPS into whatever you imagined.
Beyond Terrain: Other Ways Thick XPS Can Do More Than One Job
The "one piece, multiple functions" idea is not limited to landscapes.
School Projects
A thick XPS sheet can become:
- the presentation base
- the landscape
- the ocean floor
- a volcano foundation
- mountains
- landforms
- a place to attach labels and lightweight features
Hobby Foam Supplies already features XPS tutorials for volcano and geography projects built around carving, shaping and painting the material.
Model Railways
The foam can become:
- the layout base
- raised terrain
- embankments
- cuttings
- tunnels
- riverbeds
- scenery foundations
The model railway guide on the Hobby Foam Supplies website specifically highlights XPS for lightweight layouts, carving and creating elevations and scenery.
Wargaming Terrain
The same material can form:
- the gaming board
- trenches
- hills
- ruined roads
- rocky ground
- defensive positions
- scenery foundations
The existing XPS range is marketed for applications including wargaming terrain, modular gaming boards and detailed model scenery.
Dioramas
One foam base can become:
- the display foundation
- the floor
- the terrain
- the walls
- rocks
- ruins
- environmental details
The Hobby Foam Supplies project gallery includes examples of XPS being used for detailed dioramas and scenery work.
Architectural and Display Models
Thicker XPS can also be used to create:
- stepped display bases
- landscape contours
- building elevations
- prototype forms
- exhibition models
The large-format XPS product range specifically positions the material for larger models and architectural prototyping applications.
Why Buy a Base When Your Material Can Become the Base?
This is the question at the heart of the whole idea.
When you choose a thicker XPS foam sheet, you are not necessarily buying just enough material to place underneath your creation.
You are buying material that can potentially become:
The foundation.
The landscape.
The height.
The carved detail.
The support for lightweight scenery.
The painted surface.
The finished project.
That is why a thicker sheet can offer so much creative value.
The more creatively you look at the depth of the material, the more possibilities you discover.
Final Thoughts: Start With a Block. End With a World.
A 40mm, 50mm or 75mm piece of pale green XPS foam can start life as something very simple.
A rectangular sheet.
But with a few cuts, some carving, suitable glue, a little paint and a bit of imagination, that same piece can become almost anything.
A winding river.
A mountain.
A battlefield.
A railway landscape.
A volcanic island.
A fantasy kingdom.
A school geography project.
A miniature world.
One piece of foam can perform multiple roles from the very beginning of the project right through to the finished display.
So next time you're planning a project, don't just ask:
"What can I make from XPS foam?"
Ask:
"How many jobs can this one piece of XPS foam do?"
Because the answer might be:
Your base. Your scenery. Your structure. Your support. And your finished canvas.
One Sheet. So Many Uses.
Explore the range of Australian-made XPS foam at Hobby Foam Supplies and see available hobby and large-format sheets in thicknesses including 40mm, 50mm and 75mm on selected products.
