Paint affects a cat twice over: through the air she breathes in a room full of fumes, and through her coat and paws, because anything that settles on her fur will be groomed off and swallowed. That is why the safe sequence is exclusion first, ventilation second, and readmission last, judged by the paint maker's guidance and by a smell test done with a fresh nose rather than by the clock.
Out of the Room From the Start of Painting
Close the door on her before the work begins, not once the fumes build. A cat present during painting can brush against wet walls, step in a tray or a spill, and breathe the strongest concentration of fumes the room will ever hold. Set her up beforehand in another room with her bed, litter tray, water, food and something to scratch, so the shut door reads as a change of base rather than a punishment. Tell everyone in the house that the painted room stays shut, and keep it shut during drying as well as during the work itself, because wet paint remains tacky and transferable long after the brushes are washed. Paint, solvents, brush cleaner and sanding dust all stay stored securely behind that closed door or in a cupboard she cannot reach, never on the floor of a room she might slip into.
Ventilating by the Paint Maker's Guidance
Open the room's windows and follow the paint maker's own guidance on ventilation and drying, since different paints give off fumes at different rates and the maker's instructions are written for the product actually on your walls. There is no universal fixed number of hours that fits every paint, room and season, so treat any single figure with suspicion and work from the tin and the room itself. A through-draught, with air moving in one opening and out another, clears a room far better than one cracked window, and keeping the airflow going while the room stands empty costs nothing. Close the windows only once the room is aired; while they stand open, the door to the rest of the house stays shut so fumes clear outward instead of drifting through her living space.
Judging When the Smell Has Genuinely Gone
Your nose adapts to a smell within minutes, so a room that seems fine to someone who has been decorating all day may still be strong to a fresh arrival, and a cat's sense of smell is keener than yours besides. Step outside for a while, then walk back in and judge the room on that first breath: she returns only when the smell has genuinely gone, not merely faded to a level you have stopped noticing. Check the surfaces too, running a fingertip over skirting and sills, because a room can smell clear while low edges and sheltered corners are still tacky enough to mark a coat. Soft furnishings and her bedding go back in only after that check, washed or aired if they stood in the room during the work.
If She Walks Through Wet Paint
Act promptly rather than waiting to see. Keep her off carpets and furniture, and wash her paws with lukewarm water and a mild soap, rinsing well, before she can groom the paint off and swallow it. Do not use solvents or white spirit on her skin, however tempting, since those can harm her in their own right. Phone your vet for advice the same day, telling them what the paint was and how much she may have taken in, and follow what they say about watching her. Relatives you select may instead view that profile once you share it through KinsLe Family Sharing.