Sealing pipes and joints on the roof

If you do not seal the joint

When removing the chimney, a hole is made in the roof. The gap between the coating and the walls of the chimney is sealed with special aprons, collars and seals. You can buy them at any hardware store. These protective elements are easy to make with your own hands.

If you do not seal the seams on the roof in time, the following consequences are possible:

1. Increased wear on the roofing material. Water entering the gap enters the inner surface of the roof, which causes deformation of the coating.
2. Reduced service life of the building frame. Water, which is poured into the gap between the pipe and the roofing, promotes the gradual rotting of the wood. This is fraught with deformation and destruction of the rafters.
3. Insulation loses its effectiveness. The heat-insulating materials with which the roof is equipped can quickly lose their properties when wet. If hard heaters are not very susceptible to moisture, then soft ones quickly begin to rot.
4. Increased humidity in the attic. Increased dampness causes stale, heavy air. This can negatively affect the interior decoration of the attic.

The way to eliminate the gap between the pipe and the roof depends on its size and type of coating. Also take into account the shape of the chimney. At a distance of less than 5 mm, a heat-resistant sealant is used. If the gap width of 1 cm is exceeded, cement mortar, an apron or a special sealant are used.

It is necessary to close the gap between the pipe and the roof in order to:

• ensuring the isolation of the attic from atmospheric moisture;
• to improve the efficiency of thermal and waterproofing;
• increasing the service life of the rafter system and the entire roofing structure;
• exclusion of cold bridges.

Sealing the chimney on the roof avoids the destruction of the roof itself.

The better to close the chimney

In the house, ventilation and chimneys are brought out to the roof. Each species requires its own protection.

Smoke head protection

So, for stove and fireplace heads of the Ministry of Emergency Situations and SNiP norms, it is forbidden to use any elements that prevent the direct exit of smoke. But if the Ministry of Emergency Situations insists on this categorically and does not accept houses with improper chimney protection, then in the SNiP it makes a reservation: caps and other elements can be provided that there are no obstacles to the exit of smoke. And how to do it right - the norms do not specify.

In winter, icicles can form on the canopies due to strong condensation.

Experts on construction forums claim that wind vans and deflectors were created as a lifeline for solving the problem of weak thrust. During the construction of chimneys in many houses, the norms for the output of the pipe, its place on the roof, are violated, which leads to poor-quality combustion. Only if it is impossible to "reanimate" the mine itself, they begin to correct errors by installing additional elements that improve traction. Therefore, in houses with a normal chimney, such elements are not used.

Inexperienced owners often put umbrellas for no apparent reason in order to protect the mine from precipitation and birds. But they do not take into account that the metal umbrella is located in an open space, blown by all the winds. When the stove or boiler is working, combustion products, including water vapor, go out onto the roof and fall directly on the inside of the cold umbrella. Condensation forms, which gradually flows down, and freezes in icicles in the frost. Frost will begin to block the free exit of smoke, and it will partially return to the room, poisoning the air with carbon monoxide.

As can be seen in the drawing, the wings of the hood (it is shown in black) do not cover the interior space, but only provide protection from precipitation to the brickwork

The deflector also tends to form condensation, but in addition, its design accelerates pipe clogging. From below, the deflector begins with a piece of bare pipe (about 20 cm), inside which condensate mixes with soot and forms a dense substance, cleaner than glue. It gradually clogs the interior space, like a cork, blocking the free exit of smoke.

The problem of the weather vane is that it can jam if the owners periodically do not clean the metal from soot, rust, etc. And an incorrectly rotated vane repeats the above disadvantages of the umbrella and deflector.

Thus, the best option for protecting the chimney pipe would be an ordinary hood, the drawing of which can be seen in the picture above.

If the chimney is made of a metal insulated round pipe, then an apron cap is used for it. It is pulled through the pipe to the roof and sealed, thus protecting the chimney outlet from precipitation.

The apron-cap protects the roof from leaks

Ventilation protection

On ventilation pipes, you can put hoods with any "bells and whistles" - umbrellas, protective grilles, etc. This is required by SNiP. Birds and debris often get into the ventilation, and it is difficult to get them out of there. A conventional cover cap is not suitable in this case. A visor must be installed to protect the ventilation shaft.

Regardless of which protective element you install on the pipes, you need to inspect the system once a year, and in severe frosts - 2 times a month, and promptly remove soot, ice and debris. This is the only way to ensure complete safety for yourself and your loved ones.

Materials (edit)

The seam between the pipe and the roof can be sealed with silicone, acrylic, polyurethane and bitumen sealants. Special sealing tapes are also successfully used. Each of these types has its own advantages and areas of application.

Silicone sealant has become a kind of versatile material in construction. It is used both for working with the roof and for sealing window openings. Silicone sealant is often used when working with glass and wood. They are often treated with a gap around the chimney of a pipe on the roof. The material does not lose its properties with prolonged exposure to ultraviolet radiation and high temperatures. To seal the joints of roofing material, there is a special subspecies of it - roofing sealant.

Acrylic sealant is most commonly used to seal crevices in walls and floors. Also, acrylic compounds are used to repair windows. For outdoor work, it is rarely used - it is not elastic enough.

Polyurethane, unlike acrylic, is used almost everywhere for outdoor work. They are glued to metal, concrete, wood, stone. For minor repairs, the roof is ideal.

Bituminous mortars are ideally combined with roofing work. They are resistant to precipitation, temperature extremes, and chemical solvents. The only drawback of such a sealant is its toxicity. For this reason, no internal work is carried out with him. They are ideal for sealing a roof chimney.

The main advantages of bitumen:

• super-durability;
• low cost;
• elasticity;
• the possibility of staining;
• high moisture resistance;
• high level of adhesion to dry and wet surfaces.

There are several subspecies of bituminous mixtures that are specially designed for roofing. They are able to ensure complete tightness of the gap to be treated between the pipe and the roof covering.

Pipe protection elements

• Cap

In construction guides, a cap is a tin plate that closes the pipe section and protects it from precipitation. In this case, the chimney channel is not blocked in any way. The hood is laid flat on top of the head to protect the brickwork from rain and snow. Its width is greater than the width of the masonry, so the brick does not get wet.

The main purpose of the hood is to protect the brick from precipitation and sun.

• Umbrella

To protect metal pipes, a cap with an additional structure above it is used. It can be an umbrella or a weather vane. The umbrella is so named for its conical shape, similar to a mushroom cap. It creates protection against the ingress of precipitation into the mine and at the same time provides a 360 degree release of combustion products. The umbrella, as it were, hovers over the chimney cap, connecting with it by 3-4 racks. In another way, it is called a visor.

An umbrella is installed only if the stove is rarely heated, for example, in the country

• Weather vane

A weather vane differs from an umbrella in that it serves not only to protect against precipitation, but also to regulate traction. She, like a weather vane, is able to rotate under gusts of wind, preventing reverse thrust. The smoke from the weather vane comes out only along the axis, and not 360 degrees. Such structures are usually placed on complex roofs, where there is a high probability of counter air flows coming from the opposite slope.

A weather vane protects the ventilation duct from reverse draft and oncoming air flows

• Deflector

Another "representative" from this group is the deflector. Its task is to improve the weak draft in the furnace caused by poor placement, installation errors or climatic conditions of the terrain. However, it also serves as a barrier to precipitation, debris and birds.

Deflectors stabilize the draft, but in some cases the stoves start to smoke heavily

As you can see, the hood is the simplest of the existing elements, the task of which is to protect the chimney from external factors. Unfortunately, all of the above designs are sold on the network under this name, which misleads the owners of private houses.

And the last term is chimney. It was named so because the element is installed on the heads of the chimneys and serves to protect them. Thus, a cap, a windproof umbrella, a weather vane, and a deflector can be called a chimney.

Tape sealant

Tape sealant is a hard material. Many builders consider it to be the most beneficial option for roof sealing. Material Features:

• it is based on butyl rubber;
• the sealant tape is highly resistant to ultraviolet and high temperatures;
• it has high adhesiveness, due to which it is easy to install;
• ideal for sealing joints between chimney and roofing.

The tape has an aluminum coating, which increases the life of the sealant for outdoor use. The tape is easy to install and operate. The average service life of the product is 10 years. Due to its wide range of colors, the tape can be used for sealing various roofing coverings. The sealant has excellent adhesion to a variety of surfaces. The tape is used when it is necessary to seal wooden, plastic, metal surfaces. The tape is also successfully used for sealing translucent roofs.

How is it applied

The pipe and roof surface to which the tape is glued must be cleaned and dried. It is important that the area to be treated is level. To apply the tape, you need to cut a piece of a certain length, then remove the protective film and press the product tightly to the joint (gap). At temperatures below +5, the tape is first kept indoors at a temperature of 15 degrees for 12 hours.

The use of the tape in subzero temperatures involves heating the surface to be treated. The tape is not used for surfaces with a working temperature above 80 degrees or when the roof slope is more than 55 degrees.

How to seal a pipe on a roof made of corrugated board - important points for sealing a roof

The use of roofing sheeting is a fairly popular solution for the design of private and country houses, which is explained by its reliability, practicality and resistance to external aggressive influences. When laying overlapping material, special attention should be paid to sealing the joints of the roof and other elements (pipes, communications, etc.).

Sealing the gap

The traditional method of sealing the gap between the pipe and the roof involves an apron. For its construction, you will need abutment strips. They are placed at the bottom of the chimney pipe. They are applied to the pipe and marks are made on the top.

The grinder is used to perform the strobe. Subsequently, the remaining parts of the apron are overlapped around the pipe. The edges of the strip inserted into the groove must be covered with a heat-resistant sealant. The lower parts of the plank are trimmed and fastened with self-tapping screws. The gap between the pipe and the roof is sealed in such a way that water flows into the gutters.

A roofing part is mounted on top of the laid elements, and an external tie is constructed around the pipe. When setting it, it is important to take into account the inner tie pattern. The upper strips are not inserted into the groove, they are simply adjacent to the pipe.

If the pipe has a round shape, a special nozzle can be used. It is also used to seal antennas and ventilation outlets. It looks like a stepped pyramid. If the nozzle is rubber, it can be used in a temperature range from -50 to +130 degrees. Silicone models have a wider range - from -70 to +250 degrees.

There should be a distance of 25 cm from the chimney to the structures protected from fire. In the case of unprotected elements, it should not be less than 35 cm. The ideal option is to create an air gap. However, such a solution causes a large heat loss, which is disadvantageous from the point of view of thermal insulation.

Where to remove the pipe on the roof from the corrugated board

In order for the roof to be reliable and moisture-proof, it is important to choose the correct outlet for the chimney or ventilation shaft. This will save time as much as possible, since in this case it will be much easier to seal the pipe on the roof made of corrugated board.

The following sections are considered the most optimal places for organizing the passage:

• On a skate... This is the most practical place to get the pipe out. By making the passage of the chimney through the roof of the corrugated board in this place, snow pockets, condensation will not form and the risk of leaks will be minimized as much as possible. At the same time, it is important to take into account that such a placement of the passage will lead to a violation of the solidity of the ridge beam. In this case, silicone sealant is used to fill the formed joint. To preserve the external aesthetics, a decorative apron is used.
• Not far from the ridge (50-7- cm). Also a good option is how to make a pipe on the roof from corrugated board. If you remove the chimney at a specified distance from the ridge, this will not violate the integrity of the rafter system. Joint protection is carried out with elastic gaskets and special additional elements.

There is a rule that with a decrease in the level of location on the roof of the outlet for the pipe, the complexity of its sealing increases.

Is the roof leaking or the chimney leaking?

Before starting work, it is important identify the nature of the leak:

• The roof leaks near the chimney. The pipe passage assembly is leaking, but the chimney is free from defects. Needed repair of the problematic area of ​​the roof.

• The chimney is flowing. The cause of the leak is the destruction of the pipe and damage to the weather vane.The situation is typical for brick chimneys. Required pipe restoration, masonry and plastering works. If the masonry is made of low grade bricks, it is recommended to insulate and sheathe the chimney to protect it from the effects of the environment.

Related article: Do-it-yourself insulation of a pitched roof from the inside

How to seal a roof joint with an oval and round pipe

To organize the passage of the pipe through the roof of the corrugated board, a galvanized steel pipe with a round section can be used. In this case, the sealing of the abutment joints is not very difficult. It is for these purposes that elastic funnel-type penetrations are intended. The materials for their manufacture are usually latex and synthetic rubber. They are usually included with pitched and flat roofs.

The process of sealing a joint using elastic penetration looks like this:

• Selection of flexible penetration suitable for the size.
• Cutting off the narrow section to ensure a tight grip on the pipe.
• Removing the protective umbrella and deflector from the pipe, followed by careful tightening of the elastic penetration. The product must cover the entire pipe section.
• Fixing the base of the penetration to the roof surface is facilitated by the presence of a self-adhesive backing. You can also use silicone sealant or roofing screws.
• At the final stage, a decorative apron is mounted. It looks like a cap and is tinted to match the color of the roof. The apron is designed to protect elastic penetration from solar radiation and mechanical stress.

Elastic penetration sizing is key to ensuring a reliable joint seal. When the product lies loosely on the pipe, it is necessary to additionally use a sealant and a steel clamp. Small diameter passages can break when trying to fit over the chimney.