Acceptable heights of single-draught chimneys elevated above roof – H:

Flue dimeter [cm] External measurements [cm] Chimney height [m] Walled 12 cm Plastered 2 cm
14-20 36×36 < 8m 2,10 1,55
8 – 20m 1,80 1,05
22 40×40 < 8m 2,35 1,95
8 – 20m 2,00 1,25
25 48×48 < 8m 3,05 2,35
8 – 20m 2,60 1,55
30 55×55 < 8m 3,05 2,75
8 – 20m 2,70 1,80


Acceptable heights of single-draught chimneys with ventilation flue elevated above roof – H:

Flue dimeter [cm] External measurements [cm] Chimney height [m] Walled 12 cm Plastered 2 cm
14-20 36×50 < 8m 2,45 1,50
8 – 20m 1,90 1,00
22 40×56 < 8m 2,60 1,75
8 – 20m 2,10 1,15
25 48×62 < 8m 3,35 2,30
8 – 20m 2,75 1,50
30 55×71 < 8m 3,45 2,75
8 – 20m 3,00 1,80

The data can be used while supporting chimney in roof construction

Improving stability of chimney shaft
For chimneys elevated higher above roof than in the box special reinforcement can be used. It ought to be made of ribbed bars Φ12 based on caps available in our offer and placed in channels in the corners of hollow bricks. The reinforcement should be twice as long as the part of the chimney elevated above roof. Upper tips of the bars should be 25cm form the covering board and lower minimum 75cm lower than side support e.g. in the ceiling structure. After putting bars into the channel they should be damped and filled with thin cement mortar.
Rys._13 Rys._13a

Steel supporting frame should be made of angle plates 50x50x5 joined with flat bars 80×6 every 1 m. Chimney must be supported in two places – at the level of ceiling structure (lower support) and at the level of rafter framing (upper support).
Rys._14 Rys._14a


Stability of the construction depends on the following data:

Flue dimeter [cm] Hmax [m]
hk≤2 [m] hk=2-2,5 [m]
14-20 4,45 2,75
14-20+W 4,20 2,70


While placing chimney by the bearing wall steel bands can be used to provide its stability. The bands can be attached to the wall with expansion bolts. Bands should be mount in the area of tie beams. Gap between the bolts should be 3m. While placing chimney next to the bearing wall bands made of angle plates or channel bars can be used.

Rys._15 Rys._15a

The height of the chimney above the roof should be chosen accordingly to the box in picture no.10.

Chimney shaft should go through rafter framing accordingly to the scheme.


Steel pieces of supporting structure should be protected against corrosion.