Quick answer: For a kitten and an adult cat in a sunroom, build the IKEA hack with two routes: low cork-topped steps 25 to 30 cm apart for the kitten, and wider jumps up to the top shelf for the adult. Give each cat its own resting platform, shade the top level from midday sun and anchor the unit to a stud.
A mixed-age household creates a design problem. The kitten wants to climb everything and does not yet judge distance well; the adult cat wants a high, quiet spot that the kitten cannot easily invade. One cat tree can serve both if it is laid out with two routes and enough resting places.
A sunroom adds its own conditions: bright light, heat on hard surfaces and windows that fascinate both cats. Cork tiles suit the platforms here because they stay cooler than bare wood in the sun and give soft paws a sure grip. Our IKEA hack cat tree that looks like real furniture covers the basic shelf conversion this build starts from.
What a Kitten Needs From a Cat Tree
Kittens under six months are agile but poor at judging landings. They also climb higher than they can comfortably get down. Steps 25 to 30 cm apart, deep enough to land on with all four feet, let them practise without long drops. A rug or play mat under the tree softens any falls.
Avoid dangling toys on long cords at kitten height; they can tangle a small cat. Attach toys with short loops instead. Our guide to stopping a kitten scratching furniture explains how a well-placed tree also cuts down on damage elsewhere in the house.
What the Adult Cat Needs
An adult cat sharing space with a kitten wants an escape route and a lookout. The top shelf should be reachable by a jump of 45 to 60 cm from the level below, which the adult manages easily and the kitten will not attempt for months. That gives the older cat a guaranteed retreat.
Provide a second resting spot elsewhere in the room, such as a window perch, so the adult has choices. International Cat Care on multi-cat households stresses separate resources for each cat to reduce tension, and resting places count as resources.
Laying Out Two Routes on One Shelf Unit
Start with a tall pine shelf unit anchored to the wall. On one side, fix three small cork-topped steps at 25 cm, 50 cm and 75 cm from the floor, each about 25 by 30 cm. These form the kitten route to a mid-height shelf.
On the other side, leave a clear vertical jump from that mid shelf to the top shelf for the adult. The adult can also reach the top via a wall shelf placed 50 cm to the side. The kitten route deliberately ends below the top level.
| Level | Height from floor | Used by | Size |
|---|---|---|---|
| Step 1 | 25 cm | Kitten | 25 x 30 cm |
| Step 2 | 50 cm | Kitten | 25 x 30 cm |
| Step 3 | 75 cm | Kitten | 25 x 30 cm |
| Mid shelf | 100 cm | Both | Full shelf width |
| Top shelf | 150 cm | Adult | Full shelf width, shaded |
With the steps 25 cm apart, the kitten never faces a vertical jump of more than 25 cm, and the adult's jump from the mid shelf to the top is 50 cm.
Fitting Cork Tiles to the Platforms
Use plain, unfinished cork tiles around 6 mm thick. Cut them to the platform size with a sharp utility knife against a straightedge. Fix them with a water-based, low-odour adhesive and press them flat under weight overnight.
Choose an adhesive labelled low in volatile organic compounds, and let the tiles air out for a few days before the cats use them. EPA on VOCs and indoor air explains why that matters in a closed, sunny room where heat can increase off-gassing.
Round the cork corners slightly so small paws do not catch on a sharp edge, and sand the plywood edge beneath to match.
Managing Heat and Glare in a Sunroom
Glass rooms can get hot by early afternoon. Wood and especially dark surfaces absorb heat; cork stays more comfortable to the touch, but even cork warms up under direct sun. Position the tree so the top shelf is in partial shade at midday, or fit a simple fabric awning to the shelf above it.
Keep a water bowl in the sunroom and watch both cats on hot days. Kittens are less good at moving out of the heat by themselves. If the room routinely gets very warm, move the tree to the cooler wall and use a window perch for sunbathing instead.
Anchoring for Two Cats at Once
Two cats landing at the same time put more force on a tree than one. Fix the shelf unit to a wall stud with a metal strap near the top, and add a second strap if the unit is more than 150 cm tall. Test it by pulling the top toward you firmly before either cat climbs.
Sunrooms often have glass or thin walls on three sides. Use the one solid wall for the tree, or anchor to the floor with angle brackets if no stud is available. Our apartment anchoring checklist for tall cat towers covers both methods.
Introducing the Tree to Both Cats
Let the adult explore the tree first while the kitten is in another room. Put a few treats on the top shelf so the adult claims it as its own. The next day, let the kitten explore with the adult present and lure it up the low steps with a wand toy.
Expect some chasing. That is normal play between a kitten and a tolerant adult. If the adult hisses repeatedly or stops using the tree, add another high resting place elsewhere. International Cat Care on play suggests separate play sessions for each cat to burn off energy.
Growing the Tree With the Kitten
By around nine to twelve months, the kitten will be an adult in size and skill. At that point you can remove one of the low steps and widen the gap to 35 cm, giving the younger cat a more challenging climb. Keep the top shelf reserved for the older cat as long as it uses it.
If the two cats become firm friends, they may share the top. If not, add a second high perch on another wall so each has a lookout. Our non-wobbly cat tree stability test is worth repeating after any change to the layout.
Cleaning Cork and Plywood
Wipe cork with a barely damp cloth and dry it quickly; soaking it can lift the tiles. Vacuum fur from the platforms weekly. Plywood edges benefit from a light coat of water-based clear finish, applied before the cork goes on so it does not soak into the tiles.
For more layout ideas that work with two cats of different ages, our DIY cat tree hub collects tower, condo and wall-shelf builds in one place.
Replace any tile that starts to lift at a corner, since a kitten will pick at a loose edge until it comes away. Keep a spare tile or two from the original pack for this. Our compact cat tree under 2 sq ft is a useful follow-up if you need a second, smaller tree elsewhere.
Kitten and Adult Cat Tree Questions
How far apart should cat tree steps be for a kitten?
Keep steps about 25 to 30 cm apart for a kitten under six months, and make each step deep enough to land on with all four feet. That limits falls and lets the kitten build confidence. Widen the gaps gradually as it grows and its landings improve.
How do I stop a kitten taking over the adult cat's spot?
Make the top shelf reachable only by a jump the kitten cannot manage yet, such as 50 cm from the level below. Add a second high resting place elsewhere in the room so the adult has options. Give treats on the top shelf to the adult first.
Are cork tiles safe for cat tree platforms?
Plain, unfinished cork is safe and grippy. Fix it with a low-VOC, water-based adhesive and let it air for a few days before use. Avoid cork with a glossy finish or printed surface, which can be slippery and may contain coatings that cats lick.
Does a sunroom get too hot for a cat tree?
It can by early afternoon in summer. Put the top shelf in partial shade or fit a fabric awning, keep fresh water in the room and watch kittens closely on warm days. If the room is routinely very hot, move the tree to a cooler wall.
When can I change the tree as the kitten grows?
Around nine to twelve months, when the young cat is close to adult size, you can remove one of the low steps and widen the gaps to 35 cm. Retest the anchoring after every change, and keep the adult's top shelf as its own space.
