8 Signs that your roof is needing to be rehabilitated



Roofs serve as the primary defense for buildings, yet determining the optimal time for renovations poses a significant dilemma.


With the demands of everyday life, it’s common to neglect this important regular check. It is easy to forget that it is necessary to regularly inspect and be alert to possible damages and anomalies.


Keep reading to discover the main internal and external signs to pay close attention to.





Focus on prevention is key

Being one of the most important elements of buildings and being the most exposed to climatic actions, roofs tend to be the beginning of their deterioration and devaluation, since the problems that may emerge represent a great risk to the whole building surroundings.


Even before reaching the end of its useful life, it is natural for a roof to face failures and anomalies due to numerous conditions. It may only look aged and worn out, but it is necessary to be very attentive to the signs that, at first sight, go unnoticed. This is the only way to properly maintain and rehabilitate it at the right time, avoiding major problems down the road.


It is very important to do this inspection at least twice a year and to maintain the proper functioning of the roof. This includes cleaning, periodic inspections, and minor repairs. Doing this in advance can save a lot of work and money in the long run.









Internal Signals

First of all, surveying and observing the signs should be done internally, which means inspecting the interior of the building, especially on the top floors, near the roof.

You should be aware of the following signs:


  1. Mold and moisture: when observed on ceilings and walls, this can be one of the first signs that the roof waterproofing system has ceased to perform its function.
  2. Corrosion and degradation: this can be a serious sign that further rehabilitation is needed, as it indicates structural problems in the building. It is often the result of poorly executed maintenance, poor quality materials, and problems that have persisted for a long time.
  3. Water infiltrations: Water infiltrations indicate that their origin may lie in serious and larger defects in the roof waterproofing system.
  4. Light from outside: in this case, “a light at the end of the tunnel” is not a good sign! If this happens it means that your safety is compromised and that there is severe damage to the structure that has caused holes or cracks, letting light in.


External signs

Pathologies on the outside may explain some of the problems on the inside, but they can also expose new problems not noticed if you only do an interior review.

Signs to look out for include:


  1. Damage to the structure and the waterproofing system: we can observe waterproofing damage such as rips, detached joints, or water pouches underneath the membranes. Pointed areas with small plants or mosses can also indicate failures in the waterproofing system. It is also important to make sure that the structural elements adjacent to the waterproofing system do not present damage such as cracks or peeling, and take care to check the condition of components such as trim profiles, skylights, or frames.
  2. Poor conception: not dedicating enough time to the development of a waterproofing project can result in errors in the execution of finishes in critical areas of the roofs, causing losses of water tightness of the system itself.  The details of waterproofing are very important and can jeopardize the efficiency of the entire system. Therefore, we advise a careful analysis of the trimmings to sills and walls, rainwater drainage, trimmings to fixed elements, or those that cross the roof, such as antennas and air conditioning pipes, among others.
  3. No form layer with adequate slopes: first of all it is important to clarify that flat roofs are not really flat. They should have a small slope to help the water drain properly. Since this is a slight slope, around 2%, it is normal that it is imperceptible. This failure generates water puddling that encourages the accumulation of detritus and the proliferation of microorganisms that can seriously affect the materials of the waterproofing systems. In addition, it causes discomfort when using roofs and can create excessive weight in certain areas of the roof structure.
  4. Useful lifetime:  it is important to know about the waterproofing solution applied to the roof. The warranty on systems normally varies between 5 and 15 years, and can be up to 25 years in exceptional cases, depending on the solution, the quality of the materials, and the company that applied them. From the end of the warranty period, the attention paid to analyzing any problems must be redoubled.



If you suspect that your roof has one of these pathologies, consider having it rehabilitated or having minor repairs done urgently. To be sure, make sure you regularly check both the inside and the outside of your roof.





KOSTER Solution: Quality, Durability, and Performance

With a warranty of 15 to 25 years and a lifespan exceeding 40 years, KÖSTER TPO membranes are the right choice for any flat roof rehabilitation project.


By choosing a KOSTER TPO membrane, you’re opting for proven quality! KOSTER is one of the oldest TPO manufacturers globally, with nearly 30 years of experience in producing single-ply and double-ply thermoplastic membranes. It produces PE-based TPO, offering an even more durable and efficient solution.


Additionally, the membranes feature a unique characteristic: the top and bottom layers are made from the same high-quality material, ensuring UV stability throughout the thickness and perfect welding.


As exclusive brand representatives and implementers in Portugal, our dedication lies in delivering bespoke solutions tailored to meet the demands of every project!




Obra da Prudêncio
Prudêncio’s Work – Rehabilitation of Roof, Amélia Madaíl Nursing Home – Aveiro



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For all these reasons, it is essential to work with experienced professionals with a deep knowledge of different solutions available in the market.


Our solutions are specialized and adjusted to the needs of each client.

Contact us and schedule a commitment-free meeting.


Find out more about the advantages of the KÖSTER solution for flat roofs in this article.

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