10 Interior Design Mistakes That Cost The Most
Cheap mistakes are visible. Expensive mistakes are structural, electrical or dimensional and they get discovered after the joinery is installed.
The costliest interior design mistakes are starting work without a frozen layout, planning lighting after the ceiling is closed, buying furniture before checking circulation dimensions, under-specifying kitchen carcass material, and skipping bathroom waterproofing tests.
The ten, in order of what they cost to fix
1. Starting execution without a frozen layout. 2. Deciding lighting after the ceiling is closed. 3. Buying furniture before measuring circulation. 4. Ignoring storage volume until the end. 5. Choosing finishes under showroom lighting instead of on site.
6. Under-specifying the kitchen carcass to afford a better shutter. 7. Skipping the bathroom flood test before tiling. 8. Feature walls in trending colours on permanent surfaces. 9. Treating waterproofing and hardware as places to save. 10. Changing scope after fabrication has started.
Why layout errors dominate the list
Everything downstream depends on the layout: electrical points, ceiling design, joinery dimensions, furniture size. Changing a wall after the electrical first fix means redoing the ceiling, the wiring and the joinery around it. That is why designers push so hard for a signed layout it is the cheapest document in the project.
The sequencing rule that prevents most of them
Civil, then plumbing, then electrical, then ceiling, then flooring, then joinery, then paint, then furniture. Every mistake on the list above is some version of doing one of these before the one that should have come first.
