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Diagnosis before any quote
Every detail point inspected, flood test by zones and inspection holes at the junctions to find the real entry point.
Leaks · BarcelonaFree site visit
Roof and terrace waterproofing
A leak is not fixed with a product. It is fixed by finding where the water gets in, which is almost never where the stain appears.
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- How we work
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Short answer
Why the leak came back after it was repaired
Because the repair was made where the stain was, not where the water enters. Water crosses the floor slab following its fall and emerges metres away from the point of entry, so the visible damp patch is evidence of a route, not of a location. A proper diagnosis means inspecting every detail point, flood testing zone by zone and opening inspection holes at the junctions. That takes a day or two; renewing the build-up runs from €95/m², or from €130/m² where roof insulation goes in under the same membrane. The works themselves run four to eight weeks on a building roof, and the quote is fixed in writing within 48 hours of the diagnosis.
This is the single most repeated waste of money in Barcelona buildings: three cheap repairs to the wrong spot, and then the whole terrace rebuilt anyway because nobody looked properly the first time.
| Where it fails | What you see inside | Fix |
|---|---|---|
| Upstand at the parapet too low | Damp along one wall of the top flat | Raise and re-form the upstand |
| Blocked or badly connected outlet | Ponding after rain, damp below | Rebuild the outlet and its reinforcement |
| Unresolved movement joint | A crack line reappearing every year | Form the joint properly through all layers |
| Balustrade fixings piercing the membrane | Isolated patches near the edge | Reseal and reinforce each penetration |
| Badly welded membrane laps | Damp with no obvious pattern | Strip and relay the affected area |
Execution
The layers that make waterproofing last
It is not a product applied over the top. It is a build-up, and the order of the layers does not tolerate shortcuts.
The sequence
- Remove the paving and existing layers down to the structural slab
- Form falls to the outlet: 1.5 % minimum, with no flat zones
- Prime the substrate according to the membrane specified
- Membrane with welded laps and vertical upstands at parapets
- Specific reinforcement at outlets, corners and every penetration
- Flood test for 24 hours before anything goes on top
- Separating layer, insulation where appropriate, and paving with movement joints
The flood test
We flood the surface and wait a full day before laying a single tile. If there is a defect it shows then, when repairing it costs almost nothing. That is one day of programme against rebuilding the whole terrace a year later, and it is the line most cheap quotes leave out.
Insulate while it is open
If the paving has to come up anyway, adding thermal insulation over the roof costs relatively little and transforms comfort in the top-floor flat, in August as much as in January. It is the one moment when doing it is cheap, and skipping it means never doing it.
For non-resident owners
Who pays, and how it runs while you are away
On a Barcelona building the leak usually appears in the top-floor flat, and the first question is not technical. It is whose bill it is.
What has to be settled first
- Whether the roof is communal or for private use, and what the statutes say
- Whether the leak comes from structural waterproofing or from how the surface is used
- The real scope: a single detail point, or the whole build-up renewed
- Whether to add insulation while the paving is up
Comunidad or owner
Structural waterproofing of a communal roof is the comunidad’s responsibility and is funded by a derrama voted at the junta. Where a terrace is for the private use of one flat, the statutes govern: as a general rule day-to-day upkeep falls to whoever uses it and the waterproofing itself to the comunidad. Getting that line drawn in a written condition report, before the junta meets, is what stops a leak turning into two years of argument.
Evidence you can read from anywhere
You receive the diagnosis with photographs of each detail point, the flood test documented before and after, and the layers photographed as they go down — because once the paving is back nothing is verifiable. For a non-resident owner that record is also what you hand to the administrador, and to a buyer’s surveyor years later.
How we work
From first contact to handover
02
Written condition report
Cause identified, scope defined and the comunidad-versus-owner line stated, in a form that can be taken to a junta.
03
Strip out and form falls
Down to the slab, then falls of 1.5 % minimum to the outlets, with no flat areas left.
04
Membrane and reinforcement
Welded laps, upstands at parapets and specific reinforcement at every outlet, corner and penetration.
05
Flood test, then finish
24-hour test documented with photographs before the separating layer, insulation and paving go on.
Frequently asked
What clients ask most
Almost always because the repair was made where the stain showed rather than where the water enters. Water travels across the slab and emerges metres from the entry point, so the patch is evidence of a route, not a location.
Flooding the surface and waiting 24 hours before the paving goes back. Any defect shows then, when repairing it costs very little. It is one day of programme that avoids rebuilding the terrace a year later.
Not necessarily. Sometimes a single outlet or parapet junction is the entire problem. That is exactly why the diagnosis comes before the quote — it is what decides between a detail repair and renewing the build-up.
The comunidad, through a derrama voted at the junta, since the roof is a communal element. On terraces for private use the statutes decide: usually day-to-day upkeep falls to the user and the waterproofing to the comunidad.
Very much. If the paving is coming up anyway, adding thermal insulation costs relatively little and changes comfort in the top-floor flat completely, in summer and in winter. It is the only moment when it is cheap to do.
Next step
Shall we talk about your project?
Free site visit in Barcelona and the metropolitan area. Fixed written quote within 48 hours, no obligation.
Before you decide
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Real prices, permits and how a project runs when you live abroad. So you can compare quotes knowing what you are looking at.
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Blog
What we learn on site
Real housing problems in Barcelona, explained by the people who fix them.
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The cheapest trade with the biggest visual return — and the one where the quote hides the most, because everything that matters happens before the roller touches the wall.
Clients
What clients say after their renovation
Rated 5.0 from 14 Google reviews. All real, from real projects.
★★★★★
“Doy un 10 la verdad con el servicio que me han prestado en una reforma de un piso en Barcelona capital, gente muy seria y responsable, gracias.”
Araks SahakyanJuly 2026
★★★★★
“Quedé encantada con la atención y la calidad del trabajo. Se nota que cuidan los detalles y cumplen con lo que prometen.”
Ana RiveraApril 2026
★★★★★
“Servicio muy profesional. Me explicaron todo con claridad y el trabajo quedó perfecto.”
Ana AlemanMarch 2026
★★★★★
“Si estas buscando profesionales responsables para hacer tu reforma, es el lugar indicado. Especializados en reformas integrales con la mejor atención personalizada. 100% recomendados.”
Daniel GarganoFebruary 2026
★★★★★
“Muy buen trabajo, ha realizado un trabajo muy profesional, ha cumplido en plazo y en calidad.”
Francisco PiñeirosAugust 2025
★★★★★
“Muy buenos profesionales, con excelente resultado.”
Esther DiezJune 2026
Shall we talk about your project?
Free technical visit in Barcelona and the metropolitan area. Fixed written quote within 48 hours.
+34 615 78 93 41· Carrer de la Diputació, 189, Local 2 · 08011 Barcelona