Flat-deck roof structure and making

Construction&installation works on flat-deck roof making include the works conducted in compliance with the design or estimate documents on a specific roof.

The main stages on flat-deck roof making stipulate for the following:

  • acceptance, preparation or organization of the support;
  • vapor sealing organization;
  • heat insulation organization;
  • slope organization;
  • organizing upstands, balustrades, projection, etc.;
  • installing the components of active and/or passive ventilation (if necessary);
  • organizing the support structure under (if necessary);
  • waterproofing with the Abrin materials;
  • water discharge organization;
  • organizing a safetysystem (in case of necessity).

The support for a flat-deck roof can be provided by plain surfaces:

  • surfaces made from assembled bearing plates the seams between which are filled with a grout made of a dry cement universal mix М-150 (under GOST 28013);
  • monolithic reinforced-concrete roof slabs;
  • wooden surfaces (supports made of moisture-proof, oriented strand board, etc.);
  • flooring from metal smooth or corrugated sheets. 

The prepared support should be hard, regular, without damage of integrity, clean - without dust, corrosion or layer stripping.

Vapor sealing is made from bitumen, polymer&bitumen materials “Abrin”. When choosing the vapor sealing installation technology, one should take into account the type of a bearing support and the object intended use.

Vapor sealing is recommended to be layered immediately before heat insulation application. Vapor sealing should be continuous and waterproof.

In the spots of roof and wall contact, roof and lamp wall contact, the connection joints with vent stacks and equipment passing through the roof, vapor sealing must be higher than the top elevation of a heat insulating layer and be fixed there. Vapor sealing from polymer films at the spots of connection to vertical components is glued with a special adhesive (or adhesive tape). It is allowed mechanically fixing vapor sealing on the walls (clamping bar on a sealer) but in such a way that a waterproofing layer closes the connection area.

All the joints of separate vapor sealing plates should be connected in the overlap and leak-tight manner. The adhesion of lateral overlapping of vapor insulation film on the corrugated sheet support should be conducted on the upper edge plane or by means of providing temporary lining in the form of a rigid support, for example, OSB plywood. It is not allowed making the adhesion of lateral overlaps of vapor insulation in suspension.

During the installation of vapor insulation film one should avoid the film mechanical damages.

After vapor sealing finishing, the certificate on hidden work acceptance should be made.

The organization of a vapor sealing layer should be conducted in compliance with the manufacturer’s instructions and design documents.

The thickness of heat insulation is determined in compliance with thermal design on the basis of existing regulatory documents, in particular, in compliance with Construction Directives and Rules 23-02.

The heat insulation material is applied layer-by-layer on the support. Empty spaces and gaps more than 2mm are not allowed inside a heat insulation layer.

Heat insulation consisting of the slabs shall have similar thickness in each layer, except for slope forming plates. When the thermal insulation is applied in several layers, the slab joints should be staggered, with overlapping of at least 150 mm in any direction.

In case of applying a cement&sand lining above the insulation, one should use a heat insulator with the characteristics sufficient for preserving its operation characteristics at conducting the works on cement&sand lining installation.

Slabby insulation application on corrugated sheets without any additional levelling layers is possible in case the layer thickness is equal to more than a half of distance between corrugated sheet ridges.

All the nipples, vent stacks and other engineering equipment, passing through the roof of residential housing to the street, should go through special sleeve pipes installed inside a heat insulation layer. The sleeve pipes should hang at least by 500 mm over the roof.

After heat insulation finishing, the certificate on hidden work acceptance should be made.

Roof sloping shall be conducted in compliance with design documents.

To provide the maximum service life of the roofing, the roof slope should make up at least 1.5%. The roofs with a slope of at least 1% require special measures to be taken for waterproofing reliability.

The roof slope can be set by the slope of the bearing support or with the help of insulant tapered plates. The requirements towards roof sloping are provided in the Code of Practice 17.13330.

The works on waterproofing of connection joints, balustrades and overhangs and other roof structural components should be conducted in compliance with the project and requirements of the manufacturers of waterproofing materials.

The installation of passive and active ventilation should be conducted in compliance with the project and manufacturer’s requirements.

The support under waterproofing is made in compliance with the design solution. The support for a waterproofing layer can be generally provided by the surfaces, enumerated in cl. 5.6 of the Code of Practice 17.13330.

The waterproofing with the Abrin materials is made in compliance with the waterproofing manufacturer’s instructions and fire safety requirements.

At making up a multi-layer waterproofing from rolled roof materials, one should make up the hidden works acceptance certificates during lower layers arrangement (the certificate should be drawn up for each layer).

The draining from flat-deck roofs should be made with the account of inside water drainage peculiarities.

A local decrease of the roof surface in the places of installing the inside water draining funnel should be equal to 15-20 mm in the radius of 0.5-1 m due to the reduction of the thickness of the insulation layer or due to the decrease of the support for waterproofing cover.

Rainwater funnels, located alongside the balustrades and other projections, should be situated at the distance of at least 600 mm from such parts. It is not allowed to install rainwater pipes inside walls.

Water diversion elements should not change its position at the support deformation in relation to the roof waterproofing. The bowls of roof drains should be fixed to the bearing roof support and connected with the stacks through compensators.

The attic roofs and the roofs with ventilated air gaps the inlets of roof drains and cooled sections of drainage lines should have heat insulation. It is allowed stipulating for the roof drain inlets and stacks heating within the area of cooled sections.

The spot of roof adhesion to the flanges of a rainwater funnel (roof drain) bowls should be reinforced with an additional layer of the melting material while using bituminous melting materials.


ИНН 7430022739, КПП 745301001, ОГРН 1157430000640, ОКПО 34549080
Р/С 40702810904000009845 УРАЛЬСКИЙ ФИЛИАЛ АО "РАЙФФАЙЗЕНБАНКА" Г. ЕКАТЕРИНБУРГ, К/С 30101810100000000906, БИК 046577906
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