Waterproofing of chimney

In houses with stove heating or decorative fireplaces, an important stage in the performance of a quality roof is the waterproofing of the chimney. The place where the pipe comes out is subject to increased stresses: temperature changes, mechanical stresses and high humidity, so the waterproofing of the chimney should be given special attention.

Principle of waterproofing

In the place of passage of pipes through the roof, gaps are necessarily obtained, and their usual waterproofing with mastics and sealants is not sufficient measure for reliable protection from leaks. Therefore, when laying the roofing, it is necessary to perform a number of activities:

• The pipe should be positioned as close as possible to the roof ridge, this will help to prevent snow accumulation at the point of its exit outwards;
• A moisture removal system, a protective membrane and so-called "aprons" and "tie" are placed under the roof covering. Their shape depends on the shape of the pipe;
• The pipe exit points must be waterproofed with a special sealant, resistant to temperature changes;
• An additional decorative apron is placed on the roof covering. Its purpose is to drain rainwater from the pipe.

Furnace pipes are known to have different shapes, so the design of waterproofing elements for them is somewhat different.

Waterproofing of a rectangular section of a chimney

Such pipes are often made of bricks. Inside the brick box, an asbestos-cement or metal pipe can pass, or a chimney can be made using brickwork. The brick has good thermal insulation characteristics, so a sharp temperature drop in such a pipe, as a rule, does not occur.

For the implementation of gas isolation pipes are needed:

• Diffusion membrane;
• Waterproofing mastic;
• Sheet metal or finished metal aprons and ties in the size of the pipe;
• Heat-resistant sealant.

Waterproofing technology:

1. It is necessary to start the waterproofing immediately after laying the waterproofing under the roofing. The edges of the diffusion film are bent onto the tube with an overlap and are glued with polymer-bitumen mastic.
   

   Edges are smeared with bitumen mastic

2. A layer of mastic is also applied over the bent and firmly pressed edges of the diffusion membrane film.
   

   Sample of waterproofing at the base

3. Carry out a crate under the inner aprons at a distance of 5-10 cm from the pipe. Wooden blocks can be treated with additional bio-protective compound for additional protection.
   

   The process of creating a crate

4. Install aprons, also starting from the bottom. Aprons should be 10-15 cm above the roofing and cover the roof on all sides by 20-30 cm. If the roof slope is less than 20 degrees, the lower apron can be made up to the overhang, this will improve the waterproofing properties of the roof.
   

   The process of installing the apron on the

5. pipe The joints between the aprons and the pipe are smeared with heat-resistant pipe sealant.
   

   The process of spreading with heat-resistant sealant

6. Attach the apron to the pipe using dowel-nails, clogging them at a distance of 15-20 cm into the pre-drilled holes.
   

   Fastening the apron to the pipe

7. After installing the aprons proceed to laying the roof covering: it is laid on top of the apron level with the pipe, trying to make the gaps minimum.
   

   The process of laying the roofing

8. Over the roof covering an additional waterproofing apron is made of metal or adhesive materials such as Waakflex.
   

   Installation of additional waterproofing apron

9. For additional waterproofing, it is possible to make a drainage tie from the very ridge of the roof.
   

   Installation of additional water repellent tie

Material laying technology Wakaflex

Wakaflex is a self-adhesive plastic waterproofing tape. Wakaflex has an internal reinforcement with aluminum, due to which it can take the shape of the roofing profile, while being adjacent to the pipe. Mounting Vacaklex is simple, it can be performed by one person.

1. The tape is glued on the bottom edge of the pipe. Cut it along the length of the wall with a margin of three to five cm on each side. Bend along in half, remove the top half of the protective layer and glue the tape to the pipe, rolling it with a solid roller. Then remove the lower protective film and glue to the roof covering, carefully rolling with a roller until a full fit is achieved. The corners of the tape are gently pruned, bent to the side walls of the tube and glued.
   

   Laying process Waqflex

2. Similarly, glue the sides of the pipe. Corners gently lead to the lower and upper edge of the pipe, and their corners are rounded with scissors for better fit and wind protection.
   

   Material laying technology Wafer( step 2)

3. The top wall of the pipe is pasted in the last place, its corners are wrapped on the side surfaces. For better hydroprotection, it is allowed to glue another strip of tape onto the roof covering above the pipe, all joints must be laid so that the top layer is higher in the direction of water flow.
   

   Pipe waterproofing( Step 3)

A Waka bar is attached to the pipe over the waterproofing tape, eliminating the water flow along the pipe surface.

Waterproofing of the circular pipe section

Recently, round sandwich-pipes have been installed more often for flue gas removal. They are easy to install and are cheaper, besides they are fireproof and do not create an unnecessary load on the foundation of the furnace. The waterproofing of such pipes is quite simple. This requires special pipe penetrations. They are an aluminum or steel frame made of thin sheet metal with a flexible apron made of polymer material. The aisles are produced in a variety of colors, allowing it to be selected for the color of the roof.

Technology of waterproofing the round pipe:

1. Before laying the roofing, try on the penetration and if necessary make an additional crate next to the pipe to which the penetration will be fixed.
2. Lay the roof covering. Sheets are more convenient to cut so that the joint was just on the pipe.
3. Cut a hole in the hole with the required diameter, put a hole on the pipe, lay it on the roof covering and give the base a shape of the coating profile.
4. Joints are coated with high-temperature pipe sealant.
5. Fasten the base of the penetration on the roof using self-tapping screws.
6. Self-tapping screws are fastened to a prefabricated crate in steps of 7-10 cm.

round waterproofing process The correctly executed waterproofing not only reliably protects the roof from leaks, but also extends the service life of roofing materials, crates and the chimney itself.