The collar beam in the Polish broken roof has three horizontal beams:
• the lower purlin between the columns for the rafters of the lower slope,
• top plate bracing the columns on which the floor beams are based,
• upper purlin which supports the rafters of the upper roof.
The Polish mansard roof is a two-story roof with separated roof slopes of the same slope.
Polish roof construction:
• The lower rafters are based on wall boards and lower purlins, supported by poles with swords.
• A cap beam is placed on the columns stiffened with swords.
• Ceiling beams rest on the cap, dividing the roof into two storeys.
• The rafters of the upper part of the roof are based on the upper purlin fastened above the ceiling beams and connected at the top with a collar.
A variation of the Polish mansard roof is the so-called. Krakow roof, in which, thanks to the use of higher columns, a partition wall is made between the lower and upper roof slope.