Design class: BudgetValidation status: Data validated

Plywood Economy Cat

Exterior plywood, 30 mm XPS and an interior lining. For two cats that get along, without the framing and hardware of the engineered models.

A warm shelter that gets damp can be worse than a simpler one that stays dry.

“Data validated” means only the data and calculations are checked; the model has not been built or tested physically.

Capacity2–3
Outside size800 × 600
BuildBeginner
Time (estimate)4 h–7 h
model v1.0.0compiler P1.0.0plan c7b09a00597d99e4Panel boxWinter · Rain · Wind
800 mm

This model has no 3D view; the drawing and dimensions below fully describe the construction.

Who this is for
  • For beginners with basic tools and a small budget.
  • For 2 cats (up to 3), including community cats.
When not to use it
  • For young, old, sick or unacclimated animals without extra protection and supervision.
Tools and calculations
Required tools
Hand saw, Jigsaw +1
Budget class
Medium
Location
Exposed outdoor spot
Supported calculations
Geometry, Bill of materials, Cut list, Sheet nesting, Thermal estimate, Cost estimate, Drawing, Build guide
Build time is a planning estimate, not a promise.
Geometry

Dimensions

Front, side and top views. Outside size 800 × 600 mm, front height 540 mm, rear 480 mm.A · FRONT VIEWB · SIDE VIEWC · PLAN800 mm590 mmwater runs off to the rear →600 mm530 mm800 mminside 708 × 508 × 418 mm
Text equivalent of the drawing
Outside size (W × D)800 × 600 mm
Height front / rear540 / 480 mm
Raised off the ground50 mm
Interior708 × 508 × 418 mm
Entrance1 × 150 × 180 mm, sill 80 mm
Chambers1
Geometry typederived from canonical dimensions
Bill of materials · compiler output

What you have and what to obtain

Quantities come from the model geometry; items marked as assumptions are planning allowances. Reused material must pass the checklist.

Fill in “My workshop” to see what you still need to buy.

My workshop
MaterialNeededOwnedStatus
Exterior plywood2 sheets–Buy
Interior plywood lining2 sheets–Buy
XPS foam board5 sheets–Buy
Solid softwood (battens, studs)3.46 m–Buy
Roofing felt0.73 m²–Buy
Sealant1 pack–Buy
Wood or foam adhesive1 pack–Buy
Wood screws1 pack–Buy
Straw1 bale–Buy
  • Exterior plywood2 sheetssheet nesting · 2 × 2500 × 1250 mm (planning format; check with your supplier).
  • Interior plywood lining2 sheetssheet nesting · 2 × 2500 × 1250 mm (planning format; check with your supplier).
  • XPS foam board5 sheetssheet nesting · 5 × 1250 × 600 mm (planning format; check with your supplier).
  • Solid softwood (battens, studs)3.46 mfrom geometry · Total length from the cut list + 10% allowance.
  • Roofing felt0.73 m²assumption · Roof area + 15% for overlaps and edges; match overlaps and slope to the product instructions.
  • Sealant1 packassumption · Sealing exterior edges and joints.
  • Wood or foam adhesive1 packassumption · Insulation-compatible adhesive.
  • Wood screws1 packassumption · Exterior screws; shorter than the wall build-up so they do not protrude inside.
  • Straw1 baleassumption · Loosely to a quarter or half of the height; keep the rest dry for refills.
Cut list

Parts to cut

IDPartDimensionsQty
shell-floorFloor · Exterior plywood800 × 600 × 12 mm1
shell-frontFront wall · Exterior plywood800 × 516 × 12 mm1
shell-rearRear wall · Exterior plywood800 × 456 × 12 mm1
shell-sideSide wall · Exterior plywoodsloped top edge576 × 515/457 × 12 mm2
shell-roofRoof · Exterior plywood900 × 703 × 12 mm1
ins-floorFloor insulation · XPS foam board776 × 576 × 30 mm1
ins-frontFront wall insulation · XPS foam board776 × 482 × 30 mm1
ins-rearRear wall insulation · XPS foam board776 × 422 × 30 mm1
ins-sideSide wall insulation · XPS foam boardsloped top edge516 × 478/426 × 30 mm2
ins-roofRoof insulation · XPS foam board708 × 511 × 30 mm1
lin-floorFloor lining · Interior plywood lining776 × 576 × 4 mm1
lin-frontFront wall lining · Interior plywood lining716 × 482 × 4 mm1
lin-rearRear wall lining · Interior plywood lining716 × 422 × 4 mm1
lin-sideSide wall lining · Interior plywood liningsloped top edge508 × 477/427 × 4 mm2
lin-roofRoof lining · Interior plywood lining708 × 511 × 4 mm1
corner-batten-frontFront corner batten38 × 38 mm · 516 mm2
corner-batten-rearRear corner batten38 × 38 mm · 456 mm2
raise-battenRaising batten45 × 50 mm · 600 mm2
Sheet nesting

Parts on sheets

Sheet formats are planning assumptions; check your supplier's format. Sloped parts occupy their rectangular envelope.

Exterior plywood · 12 mm2 × 2500 × 1250 mm

shell-roofshell-floorshell-frontshell-rear
Sheet 1 · 60% used
shell-sideshell-side
Sheet 2 · 18% used

Interior plywood lining · 4 mm2 × 2500 × 1250 mm

lin-floorlin-frontlin-rearlin-roof
Sheet 1 · 46% used
lin-sidelin-side
Sheet 2 · 15% used

XPS foam board · 30 mm5 × 1250 × 600 mm

ins-floor
Sheet 1 · 60% used
ins-front
Sheet 2 · 47% used
ins-rear
Sheet 3 · 44% used
ins-roofins-side
Sheet 4 · 79% used
ins-side
Sheet 5 · 31% used
Layers and thermal

Known and unknown layers

Complete estimate: every layer has a sourced thermal conductivity.

Wall

  • Exterior plywood · 12 mmR 0.07
  • XPS foam board · 30 mmR 0.91
  • Interior plywood lining · 4 mmR 0.02

Known-layer resistance: 1.00 m²K/W · U 0.85 W/m²K

Floor

  • Exterior plywood · 12 mmR 0.07
  • XPS foam board · 30 mmR 0.91
  • Interior plywood lining · 4 mmR 0.02

Known-layer resistance: 1.00 m²K/W · U 0.82 W/m²K

Roof

  • Exterior plywood · 12 mmR 0.07
  • XPS foam board · 30 mmR 0.91
  • Interior plywood lining · 4 mmR 0.02

Known-layer resistance: 1.00 m²K/W · U 0.87 W/m²K

Not included
  • Air leakage through the entrance and joints
  • Thermal bridges through battens, edges and fasteners
  • Moisture, condensation and property changes of damp material
  • Heat produced by the animal
  • Wind and transient temperature changes
Assumptions
  • Thin layers without a sourced λ (roof covering, film, mat) are not counted.

The estimate is not a temperature guarantee and does not claim the shelter is safe to any temperature.

Water and moisture

Weather exposure

A warm shelter that gets damp can be worse than a simpler one that stays dry. This is an explanation, not a condensation calculation.

  • Ground contactRaised about 50 mm off the ground.
  • Rain splashRain splash from the ground can reach the floor and lower edges; protect the edges.
  • Roof drainageThe roof falls from the entrance to the rear, so water runs off away from the entrance.
  • Rain at the entranceThe entrance sill is 80 mm above the floor.
  • DryingWithout a service opening drying and cleaning are harder; change bedding through the entrance.
  • Absorbent materialInterior surfaces do not absorb much moisture.
  • Maintenance accessLeave room around the house for checks and cleaning.
Local price profile

Cost estimate

Quantities come from the model. Prices are not fabricated: enter what you actually pay locally and the estimate stays in your browser.

Prices entered: 0 / 9
Exterior plywood2 × 2500 × 1250 mm (planning format; check with your supplier).
2 sheetsRSD 0
Interior plywood lining2 × 2500 × 1250 mm (planning format; check with your supplier).
2 sheetsRSD 0
XPS foam board5 × 1250 × 600 mm (planning format; check with your supplier).
5 sheetsRSD 0
Solid softwood (battens, studs)Total length from the cut list + 10% allowance.
3.46 mRSD 0
Roofing feltRoof area + 15% for overlaps and edges; match overlaps and slope to the product instructions.
0.73 m²RSD 0
SealantSealing exterior edges and joints.
1 itemRSD 0
Wood or foam adhesiveInsulation-compatible adhesive.
1 itemRSD 0
Wood screwsExterior screws; shorter than the wall build-up so they do not protrude inside.
1 itemRSD 0
StrawLoosely to a quarter or half of the height; keep the rest dry for refills.
1 itemRSD 0
Estimate from entered pricesRSD 0

Sheet, XPS, framing and hardware quantities come from the compiler. The estimate still excludes delivery, tools, labor, local taxes and unforeseen losses beyond the stated allowances. PROVISIONAL and product-specific items remain explicitly labeled.

Placement

Check the spot

Tick what applies to the chosen spot
No obvious issue detected

This is not a safety certificate for the spot: it only means none of the listed questions is ticked.

Bedding

What goes inside

Maintenance

Inspection schedule

  • WeeklyCheck that the straw is dry and loose; replace it when damp or compacted.
  • WeeklyCheck for water or dampness on the floor and walls, especially under the entrance.
  • After stormsAfter rain or snow check the interior and the ground under the shelter.
  • MonthlyCheck the roof covering, overlaps and that water runs off at the rear, away from the entrance.
  • MonthlyCheck that screws and nails are tight and no tip protrudes.
  • MonthlyCheck edges: no splinters, cracks or swollen areas.
  • After stormsClear snow from entrances and exits so the animal cannot be snowed in.
  • Each seasonClean the interior; service access must allow cleaning without dismantling.
Upgrade path

Where to go next

Each step states what you add, what you gain and what stays limited. A new model has a new plan ID; changing an existing build has no canonical plan.

No upgrade path is defined for this model yet.

Don't have this material?

Exterior plywood · 12 mm
  • OSB/3 boardThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
  • OSB/4 boardThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
Interior plywood lining · 4 mm
  • Exterior plywoodThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
  • OSB/3 boardThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
  • Vinyl protective floor surfaceThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
XPS foam board · 30 mm
  • EPS foam boardabout the same layer resistance at 35 mm (conservatively 35 mm); thermal equivalence is not structural
  • PIR / polyiso boardabout the same layer resistance at 22 mm; thermal equivalence is not structural
  • Cork boardPossible substitute requiring redesign: at least one material has no sourced thermal conductivity, so an equivalent thickness cannot be calculated.
Roofing felt
  • Bituminous membraneThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
  • EPDM membraneThe substitute changes the construction (thickness, strength or water protection); parts and joints must be re-planned.
All substitutes and material limits
Build sequence

Build steps

Progress is stored in this browser against the exact plan ID; it works offline once the page has been opened.

0 / 10steps completed
  1. Cut the outer panels

    Following the cut list, cut the floor, walls and roof from 12 mm exterior plywood. Side walls are sloped: 540 mm overall at the front and 480 mm at the rear, so the roof falls to the rear.

  2. Cut the entrance

    Cut a 150 mm × 180 mm opening through the front wall and every inner layer, with the sill 80 mm above the floor so rain and snow stay out. Face the entrance away from the prevailing wind. Cover or sand sharp edges.

  3. Assemble the box

    Front and rear walls run the full width and the sides fit between them. Join the walls on the floor with corner battens, glue and screws shorter than the wall build-up.

  4. Fit the insulation

    Fit xps foam board boards to the walls, floor and under the roof. Insulation must not stay exposed to the animal.

  5. Interior lining

    Cover the insulation with interior plywood lining. Close the edges around the entrance so no foam is visible.

  6. Roof

    Fix the roof. Fit the roof covering per the product instructions, with overlaps and protected edges.

  7. Protect the outside

    Coat outside faces and edges with a wood protection finish and let it fully cure before use.

  8. Raise the shelter off the ground

    Set the shelter on two battens, about 50 mm above the ground, so the floor does not touch cold, wet ground. Check that it does not rock.

  9. Add straw, not hay

    Loosely fill straw to a quarter or half of the interior height. Do not use hay, towels or blankets in an outdoor winter shelter: they absorb moisture and chill.

  10. Choose the spot and secure it

    Set it against a wall or fence, out of the wind, away from roof runoff and roaming dogs. Weight or secure lightweight shelters. Check the spot with the placement checklist.

Provenance

Sources and verification status

A source supports a guideline or material value, but it does not confirm this specific model. Container sizes are assumptions and build time is a planning estimate.

  1. Data validatedcurrent
  2. Geometry validatednot confirmed
  3. Engineering reviewnot confirmed
  4. Physical prototypenot confirmed
  5. Field validationnot confirmed
ASPCApro · Tier 1Winter Shelters for Community Cats: FAQs and Cold Weather TipsSupports small insulated shelters, cat-sized entrances, elevation from wet ground, straw bedding and predator-aware entrance decisions.Alley Cat Allies · Tier 1Providing ShelterDescribes a community-cat shelter of about 2 ft × 3 ft and at least 18 in high for three to five cats, a doorway about 6-8 in wide, an entrance away from prevailing wind or a flap/L-shaped entry, straw rather than hay or blankets, pallets for elevation and scrap lumber from building supply stores or contractors.FIBRAN · Tier 1FIBRANxps 300 Technical Data SheetDeclares 1250 × 600 mm board dimensions and λD 0.033 W/mK for thicknesses up to 60 mm.ISO · Tier 1ISO 10456:2007 - Hygrothermal properties - Declared and design thermal valuesCurrent published edition, confirmed in 2023; provides procedures for declared/design thermal values and conversion for temperature and moisture conditions.Nord Compensati · Tier 2Technical Specifications of Birch Marine PlywoodManufacturer technical specification lists thermal conductivity of 0.17 W/mK for birch marine plywood.USDA Forest Products Laboratory · Tier 1Wood Handbook: Wood as an Engineering Material, Chapter 4Documents that wood thermal conductivity varies materially with species, density, moisture content and grain direction.U.S. DOE Building America Solution Center (PNNL) · Tier 1Typical R-Values and Vapor Retarder Classifications of Common Insulation MaterialsTypical R-value per inch: EPS 3.8-4.4, XPS 5, polyiso approx. 6, fiberglass batt or board 2.5-4, mineral wool board 3-4. Šapice converts these to planning λ ranges (λ = 0.0254 m / (R_IP × 0.1761)); a product datasheet always takes precedence.