LT-1K building joint mastic

LT-1K building joint mastic

LT-1K building joint mastic is a paste-like material based on a polysulfide polymer (thiokol), fillers and plasticizers. The mastic is two-component, consists of the main paste and the hardening pastes. After curing, LT-1K thiokol mastic turns into an elastic rubber-like material without shrinkage (it does not contain solvents). Recommended for application on both vertical and horizontal surfaces.

It has good adhesion to the main building materials: concrete, metal, brick, wood.

LT-1K mastic highly resistant to thermal and shrinkage deformations, highly resistant to various aggressive media (acids, alkalis); UV resistant; high water resistance; excellent weather and ozone resistance; moisture and air impermeability; high resistance to vibrations; excellent resistance to thermal aging. Due to the presence of thiokol as the main component, the mastic has low gas permeability. Application temperature range is from +5 °С to +30 °С. Working temperature range is from -50 °C to +70 °C.


LT-1K building joint mastic is used in construction and repair of residential, industrial buildings and structures for: sealing of joints of elements of enclosing external walls (interpanel, interblock, etc.) and foundations, protectiong of building structure junctions from atmospheric corrosion, sealing metal junctions brick walls, roofs and attics, sealing seams on tray style roofing and balconets; waterproofing, noise, heat insulation, etc. Sealing work on joints of elements of external walls are carried out during installation or after its completion, as and during repair and restoration sealing.


Mastic LT-1K can be used for maintenance and repair of joints, while mastics can be applied on the existing layer of thiokol and thiokol-containing sealants.


Specification 5772-058-05766764-2003


  1. excellent adhesion to all building materials (concrete, wood, plaster, metal, brick, asphalt);
  2. thixotropic density for treatment of any surfaces;
  3. high resistance to various aggressive media (solutions of acids, alkalis, fuel);
  4. high resistance to vibration (therefore, it is used on buildings of airports, railway stations, elevators, multistorey car parks, garages, for installation of machines, mechanisms and other equipment, etc.);
  5. high water resistance, as well as the ability to work for a long time in aqueous and hydrocarbon environments;
  6. excellent weather and ozone resistance, gas impermeability;
  7. excellent resistance to heat aging; moisture and water permeability;
  8. the ability to work for a long time under conditions of dielectric properties;
  9. high resistance to thermal and shrinkage deformations under the combined effects of heat and frost, oxygen, ozone, light, ultraviolet and infrared radiation, precipitation, water, etc.;
  10. it can perform in the temperature range from -50°С to +70°С;
  11. ability to turn into an elastic rubber-like material without shrinkage after curing;
  12. has small consumption and is easy to use;
  13. does not shrink, does not lose shape throughout the service life;
  14. guaranteed service life of the mastic joint is at least 10 years, the estimated service life is 15-20 years.

Technical characteristics

Mastic type




Pot life, hours, within the range of


Yield strength, mm, maximum


Nominal tensile strength at seam failure, MPa, minimum


Water absorption, %, maximum


Failure type



Steel barrels, metal cans or any metal wide-mouthed, hermetically sealed containers with pastes pre-packing in plastic bags.

Guaranteed shelf life:

6 months


The product is manufactured according to the Specification. The product meets the stated information within the shelf life and subject to storage conditions.