IMI after renovation: how much will your property tax actually go up?
By Kellogg Fairbank · Co-founder of remodel.pt · Last updated August 2026
What's in this guide
- Structural renovations requiring a building permit (licenciamento) typically trigger an automatic VPT reassessment within the same tax year
- The 2026 base construction value rose to €712.50 per square metre, up from €665, pushing new and reassessed VPTs higher nationwide
- A kitchen refit from €28,000 rarely changes VPT on its own, but a full renovation from €85,000 that adds a bathroom or extends floor area usually does
- Municipal IMI rates range from 0.3% to 0.45% of VPT, so identical renovations produce different tax increases in Cascais versus Lisboa
- Owners can request a VPT reassessment only once every three years, and the request can raise the value as easily as lower it
Does renovating actually change your IMI bill?
Foreign owners often assume any visible improvement will show up on the caderneta predial and increase their bill the following year. That is not how the system works, and it is one of the more common sources of confusion for owners managing a project remotely. The caderneta predial does not update on its own when a contractor finishes a job. It updates when a legal trigger, usually a building permit application or a licença de utilização change, sets off a reassessment.
That gap matters for budgeting. An owner who paid €12,000 for a bathroom rebuild and sees no IMI change the following year has not been overlooked. The works probably did not touch the elements the VPT formula measures: gross area, use classification, or quality and comfort features that carry their own coefficient. An owner who added a bedroom by converting an attic, on the other hand, changed the gross private area (Aa) that feeds directly into the formula, and a reassessment is close to certain.
How is VPT calculated, and what part do renovations affect?
The formula, set out in the Código do IMI, is:
Renovation touches two of these six variables directly: area (A), if you extend or convert space, and quality and comfort (Cq), if you add features the Cq table rewards, such as a second bathroom, double glazing, or central heating. A kitchen refit that keeps the same footprint and the same number of bathrooms rarely moves either variable. A full renovation that adds a bathroom, closes in a balcony, or converts unused storage into habitable space moves both.
Age (Cv) does not reset because you renovated. It only resets if the works were significant enough to require a new licença de utilização, effectively restarting the property's fiscal age from the date of that new licence.
Which renovations trigger a reassessment?
In practice, foreign owners planning a project through remodel.pt fall into one of three groups:
Repainting, refinishing floors, replacing cabinetry or appliances within the same footprint, bathroom updates without moving plumbing runs.
- Electrical rewiring from €5,000
- Plumbing overhaul from €8,000
Adding a bathroom, converting an attic, garage, or storage room to habitable space, closing in a balcony (marquise).
- Full renovation from €85,000 with any area change
Structural changes under RJUE, façade alterations, use reclassification, any project producing a new licença de utilização.
- Permit application itself often starts the clock
How much could your IMI rise, by project type?
To illustrate the mechanics, take a 90m² apartment with an existing VPT of €180,000, taxed at a municipal rate of 0.35% (an IMI bill of €630 before renovation):
| Project | Reassessment likely? | VPT change | Annual IMI change |
|---|---|---|---|
Kitchen refit (from €28,000) Cabinetry, appliances, same footprint | Rarely | €0 | €0 |
Bathroom rebuild (from €12,000) Fixtures, tiling, no area change | Rarely | €0 | €0 |
Electrical rewiring (from €5,000) Code-compliant rewire | No | €0 | €0 |
Full renovation + bathroom (from €85,000) New bathroom, upgraded finishes, area unchanged | Likely | €8,000–€15,000 | €28–€53 |
Full renovation + attic conversion (from €85,000) New habitable area, new bathroom | Certain | €25,000–€45,000 | €88–€158 |
Structural renovation, new licença Load-bearing changes, façade work, reclassification | Certain | Full recalculation at €712.50/m² | €500–€800+ |
These figures are illustrative, not a quote. Actual VPT changes depend on your property's specific location coefficient, existing quality classification, and the câmara municipal's current rate, which owners should confirm on their caderneta predial before budgeting a project.
How does remodel.pt help you plan for the increase?
The scoping stage of the four-step process, before quotes go out to alvará-verified contractors, flags whether the intended work involves a licenciamento application, a change in gross area, or a use reclassification. That flag goes into the written project brief alongside the quote comparison, so a foreign owner deciding between a bathroom rebuild and a full renovation with an attic conversion can weigh the IMI consequence alongside the contractor's price.
Note: Because payments are staged and released only after independent inspection sign-off, owners also get a documented record of what was actually built, useful if the Finanças later requests supporting detail during reassessment.
Frequently asked questions
Conclusion
The mechanism is narrower than most foreign owners expect: IMI moves when a renovation changes registered area, use, or triggers a building permit, not simply because money was spent on the property. A kitchen refit or bathroom rebuild that stays within the existing footprint rarely shows up on next year's bill. A full renovation that adds habitable space almost always does, and the 2026 rise in the base construction value to €712.50 per square metre means any reassessment now lands on a higher starting point than it would have two years ago.
Related reading: IMT, IMI and renovation tax · AL rental law and renovation · Do you need a permit to renovate? · Full renovation cost by category
Kellogg is a former payments executive turned entrepreneur, with a family background in real estate. He has spent the past year bringing that experience to the Portuguese property market, and co-founded remodel.pt to apply the same rigor to how contractors are vetted.