Small cracks on a rooftop can explain the appearance of moisture spots on the ceiling of rooms just below. Before intervening, the tightness must be thoroughly checked and all localized infiltration areas.
Begin by cleaning the terrace at high pressure and then remove the non-adhering parts from the watertightness.
Carefully brush the surface.
Apply a layer of resin and hardener at the level of the leaks.
Then affix a piece of glass mat to reinforce the tightness.
Cover the mat with glass again with resin and hardener until the set becomes transparent.
After drying (4 hours minimum), sand lightly and then prepare the gel-coat sealant mixture in a jar for the top coat.
Spread the putty over the glass mat and roll it evenly. There are tinted products that unify the color of the roof.
On a heavily damaged roof, do not hesitate to renew the gel-coat by treating the vertical surveys well to ensure the final waterproofing.