Many country houses and cottages during construction are equipped with stove heating, a fireplace or a solid fuel stove for cooking. One of the important tasks that must be solved when installing a fireplace or stove is the insulation of the chimney on the roof.
This task, in fact, is divided into two:
- Make a pass chimney on the roof through combustible materials roofing cake and fireproof ceilings.
- Make a good waterproofing of the pipe outlet itself, that is, protect the premises from the flow of water from rain or snow through a hole in the roof.
To your attention! First you need to carefully choose the place where the pipe exits from the roof. A good place for a chimney outlet is directly through the roof ridge.
There are several reasons for this:
- installation through a ridge is much easier than through a roof slope;
- snow pockets do not form on the ridge, therefore, the likelihood of precipitation is reduced.
So, how to fix a pipe on a roof. The method of mounting the pipe through the ridge has a serious drawback. In order not to violate the strength of the roof frame, the rafter system must be mounted without a ridge beam.
If a ridge beam is needed, then two of them will have to be installed, and additional supports for the rafters will have to be installed at the place where the chimney passes from both sides.
Tip! Therefore, most often the chimney is passed through the roof next to the ridge, but on the roof slope. In no case should a chimney be installed in a roof valley, where multidirectional roof slopes are connected to each other at an internal angle. Water and snow often accumulate in this place, therefore, a leak will appear over time.
If your fireplace or stove is located so that the pipe from them does not exit where it needs to be led through the roof, then an additional chimney elbow can solve this problem.
Fireproof pipe outlet through the roofing pie
Cutting the pipe on the roof is an important task when leading the chimney through the roof, since the safety of your family depends a lot on its correct implementation.
According to fire regulations, the temperature at the points of contact of the chimney with combustible materials should not exceed 50ºС. Cutting for the most popular brick chimneys is solved by increasing the thickness of the walls of the pipe itself at the point of passage through the ceiling or roof.
For a brick pipe, cutting is recommended to be brought up to 380 mm. With such a thickness of brickwork, sufficient thermal insulation is guaranteed.
What are the main points when cutting you need to know?
- The distance between the roof and the rafters (25-30 cm) should be observed with any roof covering. For combustible roofing materials (roofing, wood, roofing material) - 15-30 cm. For non-combustible roofing materials - 10-25 cm.
- Difficult in the device is the option of passing the chimney through the "roofing pie". "Roofing pie" is a complex roof structure that includes layers of vapor barrier, waterproofing and a layer of insulation. It is impossible to violate the integrity of the cake, as moisture can get inside and break the thermal insulation of the roof.
In addition, the insulating films inside the roofing cake are made of combustible materials. Therefore, a gap is required between the chimney and the roofing cake.
In this case, you need to make a separate box that separates the pipe from the roof. The box is made of wooden rafters and a cross beam. The distance between the duct and the chimney is 14-16 cm, it must be filled with non-combustible thermal insulation (for example, stone wool, which is not afraid of moisture).
The insulating films of the roofing cake in the opened places are cut with an “envelope”, pulled up to the rafters and the transverse beam and fixed with nails.
The waterproofing in the cake is pressed with a crate, the vapor barrier is fixed with frames made for finishing.For absolute peace of mind, the joints of the insulating films and the box can be wrapped with special tapes.
Chimney waterproofing
In most cases, water leakage from the roof next to the chimney is due to poor sealing of the roof groove. It flows from above if the cutting is above the roof and flows from below if the cutting is under the deck.
Properly organized chimney waterproofing ensures the protection of the interior from water and melted snow ingress in all weather conditions.
Roof chimney waterproofing produced by installing insulating aprons on the pipe.
It is carried out in several stages:
- Above the chimney, in the waterproofing layer, it is necessary to lay a drainage gutter. It is most often made from stainless steel. A drainage gutter is needed to drain water from the chimney.
- Proper installation of the inner apron ensures the sealing of the junction of the roofing material to the pipe.
- After installing the inner apron, proceed to the installation of the "tie". This is a sheet of waterproofing material that is laid under the bottom of the inner apron. It should reach the edge of the roof. If you have a roof made of metal or slate, then you can bring the edge of the tie to the surface of the roof between the bottom sheets. Be sure to make bumpers along the edge of the tie, they can be done with simple pliers. Simple sides will not allow water to spread over the entire surface of the roof, but will direct it down the roof slope.
- Roofing material can now be laid around the pipe.
- An external decorative apron is installed on top of the roofing material.The installation of the outer apron is carried out in the same way as the inner one, with the difference that its upper edge is attached directly to the pipe wall.
Tip! In addition to the independent manufacture of insulating aprons, you can purchase factory options. For wiring round pipes through the roof, finished products are offered on the market - roof passages.
These passages are constructed from a flat steel base sheet, which is connected to a cap-shaped apron. Inside this cap, a chimney pipe is passed.
To your attention! There is one more small nuance that many people forget about. Any roof shrinks over time. At the same time, the integrity of the roof itself is preserved, but at the junction of the roof with pipes, when the apron is rigidly attached, either the apron or the roof can be damaged.
Thermal expansion of the chimney pipe can lead to the same result. To avoid this, it is recommended not to make a rigid fastening of the apron, but to install a steel collar-skirt at the junction and fasten it to the pipe with a heat-resistant elastic gasket.
If, when building your house, you think over and properly organize the insulation of the chimney from combustible roof materials and take care of the organization of waterproofing, then living in a house with a stove or fireplace will be comfortable and safe.
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