How to stop infiltrations

Infiltrations in the walls

Problem
Infiltration and water leakage, in general, cause mold, dark spots and bad smell on the walls. If they are on top of them, the cause is probably in the ceiling or gutter. If it’s at the bottom, the floor is to blame. Infiltrations also generate cracks and fall of plaster.

Solution
Locate the infiltration or leak point on the ceiling or floor. Then, after removing the plaster from the wall, apply waterproofing. Then, apply new plaster (mixture of cement, sand and water). In this mass, add a little waterproofing agent. Over it goes a nylon screen and, on top of the screen, a layer of waterproofing type Vedalaje® (18 kg costs about R$ 166*) or similar. Finally, apply spackle and paint. Prefer acrylic and glossy wall paint (about R$ 22* for 900 ml), more resistant to humidity.

Infiltrations in the ceiling

Problem
Some dark spots usually appear on the living room or bedroom ceiling after the rains. This is infiltration. The same can happen on the walls, causing the plaster to fall, for example.

Solution
First, find the point that originates the infiltration to correct it. Then, with the ceiling completely dry, do a scraping to clean the wall, sanding the dark parts. Then apply spackle (the 18-liter pot costs around R$50*), sand to leave the wall smooth and paint with acrylic ceiling paint (about R$21* for 900 ml).

Infiltration through the tiles

Problem
Because of heavy rain, tiles can break and move out of place. “This causes the water circuit to be diverted, causing infiltrations”, says César Pasquini Simão, architect at Telhanorte. The useful life of a roof is about 50 years. If the construction is older, be careful: old tiles tend to become porous by “absorbing” water and thus become more fragile.

Solution
On a hot day, check that the tiles are fitted and intact. Climb up a ladder supported on the roof or enter the trapdoor. Shift some tiles and preview the coverage. To waterproof them, wash the roof and apply acrylic resin (900 ml costs around R$ 11). ”The resident can make the application himself, but he must take into account the height of the roof. NEVER step on the middle of the tile, but on the joints to avoid breakage”, says Simão. It is also good to assess whether there are cracks in the wood that supports the structure.

slab without roof
To avoid problems, it must fit correctly. This will cause the water to flow into the gutters, preventing the formation of infiltrations. The application of waterproofing (19 kg for R$ 73*) on the slab is also important!

Infiltrations through the gutters

Problem
Excessive rain often leads to leaks in the house due to holes in the gutters. Also, over time, dirt and leaves clog the conductor. This causes the water to overflow in the house.

Solution
On a clear day, remove dirt from the gutters with a cloth and brush. Cleaning should be done every three months. Install a nylon screen (R$ 180 for 50 m2) close to the gutter to block the entry of leaves and hail, preventing clogging. Don’t forget to also check the gutter for cracks and holes. If small, soldering helps to resolve the situation. Otherwise, you must replace the affected snippet.

leaks down the drain

Problem
The water can “come back” through the drains, flooding the house. “This happens because the piping cannot withstand the intense volume, and the water emerges”, explains Simão.

Solution
Make sure the bathroom and backyard pipes are interconnected to drain the water in the sewer together. If so, you need to separate them. But if the drains are clogged, the correct thing is to remove the grids and place a connected hose inside the pipe. The force of the water will cause the dirt (leaves, threads, dust, etc.) to drain, unclogging the drain.

secure structure

Take great care when waterproofing the areas where the floor and wall meet!

Problem
The lack of adequate trim means that, when it rains, the water does not drain directly into the drain. “A floor like this facilitates the accumulation of water and infiltration”, says Luiz Sérgio Coelho, professor of engineering at FEI. Water can dampen walls, darkening the underside of the wall. If the house has an unfinished floor, built on beaten cement, it is more prone to infiltrations, as it becomes porous over time.

Solution
First, remove the old coating and then level it with cement (25 kg bag for R$ 10) so that the water flow goes directly to the drain. The grout also deserves attention! If you notice that it has already lost its seal, you can reapply it (1 kg costs about R$ 3.50). Just follow the instructions on the product’s packaging: “In the case of floors on cement, waterproofing with flexible material, such as an asphalt blanket (which costs around R$ 95 for 10 m2) is recommended”, observes Coelho. If it has cracks and holes, cover them with cement and waterproof.

Who fixes?

You can do some minor repairs yourself at home. Always bear in mind that, depending on the level of degradation caused by rain and the degree of difficulty of the repair, only a professional (mason, plumber or electrician) will be able to perform the service. If you want to get your hands dirty, follow the safety rules and manufacturers’ instructions.

When you need to renovate

Burst pipes or uneven outdoor floors can cause serious leaks. There’s no way out: the help of a professional is essential to put an end to the torment! The architect and safety engineer Regina Maia Galvão, from Guaratinguetá (SP), explains some techniques used to solve such problems.

Infiltration caused by uneven floors

Inside the house: the common thing is to scrape the walls until you reach the plaster. Then apply a good layer of waterproofing.

Outside: usually, an external trench is opened next to the affected wall. The gap is completed with stones and sand, which absorb the water.

Infiltration in the ceiling caused by the slab

A generous layer of asphaltic or waterproofing layer is applied over the plaster and before installing the floors.