Private house roof: Sudeikin roofs

Recommendation points

• Who is Sudeikin
• Snap to building shape
• Mauerlat and rafter system
• Strapping and crate
• Insulation system
• Used roofing materials

It is always difficult to choose the optimal roof configuration: you want it to be beautiful, not too difficult to install, and not very expensive in terms of materials. However, sometimes the question of aesthetics is put at the forefront, in such cases solutions of old-school engineers come to the rescue, for example, Sudeikin’s roof.

Who is Sudeikin

Grigory Mikhailovich Sudeikin was a Russian engineer and architect who lived and worked in Tsarist Russia. The master became famous for the publication of a technical album, which included forty house projects, illustrated with more than 250 drawings and sketches, accompanied by estimate documentation. According to the author himself, his album includes small and medium-sized projects intended for private developers who are not specialists in construction, but who need a finished project with a detailed description of the technology for performing work.

For the most part, the houses proposed by Sudeikin are of little note in terms of the architecture of that era. However, the album contains a group of five projects, which use a completely atypical roof structure, which is the author’s invention. A characteristic feature of these roofs is the presence of four gables and the streamlined shape of the slopes, converging with two sloping planes. This configuration is beneficial not only in terms of appearance, it also has greater resistance to wind loads and contributes to the accumulation of less snow..

Snap to building shape

One of the main disadvantages of the Sudeikin roof is the possibility of its installation only on houses, the shape of which is close to square in plan. At least, such a flaw is presented as an argument in disputes between private developers and roofers..

However, in the album of Grigory Mikhailovich’s projects itself there are samples of houses of rectangular and irregular shape. In the simplest case, to cover a building whose shape is far from square, one of the gables protrudes from the main structure to form a classic gable roof. There is also a much more interesting solution: in one of the projects, a rectangular house is covered with two roofs of an original design, in which adjacent gables are combined.

Obviously, the shape of the building is not a limitation for the installation of a roof of this configuration. Even without removing the gables, the rafter system can be scaled to a rectangular shape within a fairly wide range, the qualities of the supporting system will not suffer from this..

Mauerlat and rafter system

The Sudeikin roof structure is notable for the fact that it does not have a classic Mauerlat. Instead, four posts of the same height are used, installed at the corners of the building and tied with horizontal beams to form a kind of parapet. There is an important nuance here: initially, such a structure was designed for use in wooden houses made of rounded beams, at the corners of which there were cuttings with an increased bearing capacity. Brick houses were also able to withstand concentrated loads due to the significant thickness of the walls. Modern projects cannot boast of the massiveness of the bearing layer of the enclosing structures, therefore, they require a Mauerlat device with a continuous contour and the strengthening of the racks on both sides with braces forming right-angled triangles.

Roof rafter system Sudeikin

In the central part of each pediment, high racks are installed, which are connected to the horizontal beams of the strapping with a reclining lock with a cut in 1/3 of the section of the bar. From the top of the high racks to the corners, inclined beams are laid. In the classical version, it was supposed to link the inclined beams with oblique rafter locks, which in the lower nodes were protected from shear by longitudinal dowels. In the modern version, nail plates can be used instead of carpentry joints. The bearing capacity of the rafter system can be increased by increasing the cross-section of the used timber or by adding additional vertical racks to the frame of the gables.

Strapping and crate

The assembly pattern described above forms a frame with four prefabricated gables, but the roof slopes are still not formed. Initially, it was supposed to lay four bars from the tops of the high posts, which converge in the center, forming the ridge of the upper slopes, and protrude above the high posts to the required length of the wind overhang. However, this required the installation of a center pillar to support the upper superstructure. In the modern version, this element can be avoided by using two trusses instead of inclined beams, intersecting in the central axis of the roof..

The conjugation of the slopes is formed by ties in the form of horizontal bars fixed between the tops of high racks. The knot for joining the elements of the rafter system in this place is the most difficult. It is required not only to cut the ends of the beams at the desired angle, but also select the grooves in them for the spike connection device. It is also imperative to ensure that the edges of the harness beams do not protrude beyond the plane of the slopes formed by inclined rafters..

The lathing for such a rafter system should be selected for the type of roofing used. For slate, profiled sheet, standing seam roofing and other large-format materials, a flooring made of edged boards 20-25 mm thick, laid with gaps of 30-40 mm, is well suited. If a continuous sheathing is required for bituminous shingles, the planes of the slopes are covered with OSB or moisture-resistant plywood. The joints between the sheets should be reinforced with a lining of a wide board and be sure to leave temperature gaps of 8-10 mm, which are subsequently filled with non-hardening mastic.

Insulation system

One of the most important requirements in modern construction is the low thermal conductivity of the building envelope. Provided that the attic is operated in cold mode, the described roof configuration does not require modifications. However, this design is well suited for the device of a warm attic, so it will not be superfluous to discuss insulation options.

Sudeikin in his projects proposed this option: to hem the rafter system from the inside with a tongue-and-groove board and fill the space under the roof with free-flowing filler in the form of moss, sawdust or crushed peat. In the current realities, this option is not particularly convenient: developers are too much accustomed to mineral wool.

First of all, it is necessary to solve the problem with cold bridges: massive wooden elements with high thermal conductivity are involved in the supporting structure, this gap in thermal protection must be eliminated. The simplest option is to use paired boards instead of timber, placed on the edge parallel to the planes of the enclosing surfaces. A similar technique is used in the Finnish frame housing construction, where LVL with thermal break is used..

The space under the roof can be insulated with mineral wool slabs without additional efforts. To do this, it is necessary to provide the rafter system with a counter-lattice, ensuring a sufficient width of the insulation. The plates can be fastened through cotton wool to the outer lathing of the roof with self-tapping screws with a wide plastic washer, plastic mesh or fishing line extensions. Ultimately, the insulation will be reliably fixed by the slats of the frame of the inner lining, but before that, a continuous vapor barrier should be provided.

Used roofing materials

In conclusion, a few words about which type of roofing to choose. Sudeikin roofs can be covered with any material, however, due to the complex configuration and a large number of junctions, it is optimal to use roofing coverings of a small format, such as bituminous tiles, flake roofing or flat roofing iron, avoiding a large number of illiquid diagonal scraps.

If preference is given to sheet large-format materials, the upper slopes should hang over the lower ones. In places of abutments, protection against leaks is carried out by an overlay on the lower slope of a wind bar with a wide upper shelf. It is advisable to calculate the geometry of the roof in advance so that the angles of convergence of the slopes are the same: this will allow the use of diagonal cuts on other parts of the roof.