To the chimneys brought out through the pitched roof, certain requirements are imposed by both engineers working with fireplace and boiler equipment, and roofing specialists.
In this article, we will look at how the pipe is connected to the roof, at which point on the roof it is best to place the chimney, how high it should be, and how to properly equip the place where the pipe passes through the pie and the roof covering.
Connection location
According to SNiP 41-01-2003, which includes the regulatory framework for chimneys, there is no clear regulation of the location of the chimney.
There is a clear definition only for its height:
- The height should be at least 50 centimeters above the ridge, if the pipe is located no more than 1.5 m from it;
- Should be equal to or higher than the ridge if located at a distance of 1.5 to 3 m;
- When located further than 3 meters from the ridge, the pipe should be located at the same level or above the line conventionally drawn down from the ridge at an angle of 10 ° relative to the horizon.
When solving other issues related to the location of chimneys and the arrangement of such elements as the adjoining of the roof to the chimney, one has to rely only on the opinion of specialists.
Condensation can occur both inside the pipe and at its end or on an umbrella that serves to protect it from precipitation. The main danger of condensate is that in the cold it forms ice, which significantly worsens the draft in the boiler or fireplace..
Moreover, the dripping of condensate along the outer surfaces of the chimney worsens the appearance and reduces the life of both the pipe and the material. house roofs.
Chimney outlet to roof It is best to equip in the area of \u200b\u200bthe ridge for two reasons:
- Here it is easier to connect the roof to the chimney;
- No snow pockets, minimizing the risk of leaks.
Chimney and pie roof
Quite often, the question is raised of how to arrange the connection of the roof to the chimney pipe in the case of an insulated roof, which is a pie of several layers (thermal, steam and waterproofing).
In this case, the protection of the insulation (most often glass wool or basalt wool) from external moisture and water vapor is provided by layers of hydro and vapor barrier that are continuous over the entire roof area.
At the same time, according to SNiP, fire safety is ensured when the distance between the outer surfaces of the chimneys and roof elements made of flammable materials should be at least 13-25 cm (depending on the type of pipe used).
The optimal solution is to separate the area adjacent to the chimney from the rest of the roof:
- With the help of rafter legs on the sides of the chimney;
- Fastening the transverse beams to the rafters - below and above the pipe.
Thus, a separate box is created for passing the pipe through the roof, and the distance from the beams and rafters is chosen in accordance with the requirements of SNiP. The roof around the pipe is filled with non-combustible heat-insulating material (usually dense stone wool).
This insulation is less susceptible to moisture than conventional insulation in a roof pie, which often has an average density. Due to this, it is not necessary to lay hydro- and vapor barrier around the chimney pipe.
Adjacency of films to this box is carried out in the usual way:
- The canvases are cut in the form of an envelope;
- Bring the canvas to the edge of the transverse beams or rafters;
- Attach to them with staples or nails;
- Press the waterproofing with bars battens and counter-lattices;
- The vapor barrier is pressed with the help of a frame - the base for the attic finishing material.
Important: maximum protection of the insulation from moisture is achieved by hermetically sealing the junction points of the films to the wooden element of the box using special tapes or adhesives.
There is also an opinion that the temperature of the outer surface of the chimney at the point of passage through the roof does not reach 60 °, which is not dangerous for the films. Thanks to this, it is possible to bring the films directly to the pipe with gluing the joints with adhesive tape.
In addition, a drainage gutter should be made in the waterproofing layer above the pipe to drain water from it, penetrating under the roof.
Chimney and roofing material
The nodes for the passage of pipes through the roof are distinguished by the shape that the cross section of the chimney has (round, square and rectangular), as well as by the type of roofing material. The basic rules are the same for all factors.
When leading the pipe through the coating, it is necessary to ensure that the water flowing down the slopes and along the walls of this pipe is drained, for which an apron is arranged around the chimney. If the outer walls of the pipe are made of concrete or brick, and the cross section is square or rectangular, the apron is made from components for the roofing material.
For example, a set of some materials has an elastic tape with an adhesive coating on the back.
Important: plastering of chimneys is recommended to be done before the roofing material is laid, in order to avoid its staining and damage;
This tape is glued with one edge to the roof, the other - to the pipe. Its upper part is pressed with a metal curved bar, which is attached directly to the chimney or to the strobe made on it in advance with dowels. The flanging of the strip is covered with a roofing sealant, which completely excludes the penetration of water under the tape.
The junction for a roof made of flexible tiles is similarly performed, the difference is that instead of a tape, a valley carpet or an ordinary tile is used, wound up on the chimney. For metal tiles, the difference lies in the fact that for the manufacture of an apron, smooth sheets are used, the color of which matches the color of the roofing material.
Important: in the case when the width of the chimney is more than 80 cm, a slope is made from the side of the roof ridge, which is a small gable roof that drains snow and rainwater from the top of the chimney.
For its manufacture, the same material is used as for the roof itself.
It should be borne in mind that the creation of layers of vapor, hydro and thermal insulation, as well as the provision of ventilation of the wooden base and insulation in this design is difficult.
It should also be noted that a wide chimney prevents ventilation of the insulated roof. In this regard, additional ventilation elements (aerators, ventilation tiles, etc.) are installed on the slopes.
Modern round chimneys are usually thermally insulated three-layer structures, equipped with a stainless steel outer pipe. Their connection to the roof is equipped with the help of finished products, such as roof passages in the form of a base - a steel flat sheet that is attached to an apron-cap, inside which the chimney itself passes.
The roof passage can also be made independently and from a metal flat sheet.In both cases, it should be rigidly fixed only to the roof structure; rigid fastening to the chimney is not allowed in order to avoid damage to the elements during shrinkage of the roof and during thermal expansion and contraction of the pipe.
At the junction of the apron and the pipe, a steel collar (skirt) is put on the chimney, sometimes with a heat-resistant elastic gasket that prevents precipitation from penetrating under the apron.
The arrangement of the correct connection is required both for the safety of the home and to ensure its reliability, comfort and durability. When arranging such a connection, the main thing is to comply with the requirements of SNiP and take into account the opinions of specialists on emerging issues.
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