Newton® 801-M Mastic Sealant

Newton® 801-M Mastic Sealant

John Newton & Co. Ltd | Damp Proof Membrane Ancillaries

Damp Proof Membrane Membrane Tapes & Sealing Products

Newton® 801-M Mastic Sealant is a non-toxic, solvent-free, multi-purpose and single component silicone sealant, primarily used in conjunction with Damp Proofing Membranes.

Applied to the fixing plugs before they are fitted, Newton® 801-M Mastic Sealant serves so as to seal the penetration and stop the occurrence of a ‘bridge’ between the damp or stained substrate and the new internal surface.

Newton® 801-M Mastic Sealant has a high resistance to both ageing and extremes of temperature, as well as achieving a high adhesive strength, without primer, on the majority of materials used in the building and engineering industries.

Typical Applications:

  • To seal fixing plugs to Damp Proof Membranes.
  • For sealing around service penetrations and protrusions through the substrate / membrane.
  • As a general, high performance and multipurpose sealant in the building industry.

Newton® 801-M Mastic Sealant

  • Prevents efflorescent salts and staining to the finished surface

  • Seals the fixing plug to the membrane

  • Obtains a high adhesive strength without a primer

  • Applicable to most materials used in the building and engineering industries, including, but not limited to laminated and double glass, aluminium, steel, stainless steel, anodised steel, treated wood, and PVC

  • Also compatible with alkali substrates such as concrete and brick

  • Applicable in temperatures as high as 150°C and as low as -50°C

  • High resistance to ageing

  • Non-toxic

  • Solvent-free


All surfaces should be dry, clean and free from dust or grease. Where necessary, de-grease the surface with MEK, alcohol or ethanol.

For general use, it is recommended to carry out preliminary tests in order to determine the suitability of the product for the surface to which it will be applied.


Fixing Plugs:

After drilling the pilot holes in preparation for the fixing plugs to be fitted to the membrane and substrate, cut the supplied nozzle to the required bead-size.

Using a cartridge gun, apply the Newton® 801-M Mastic Sealant in a ring around the pilot hole which, when the fixing plug is inserted, will form an effective waterproof gasket between the head of the fixing plug and the membrane.

Use Newton® 801-M Mastic Sealant only in well ventilated rooms, and ensure good ventilation whilst curing.

General Sealing:

Cut the supplied cartridge nozzle to the required bead-size and use a cartridge gun to apply the Newton® 801-M Mastic Sealant directly into the recess, joint or penetration. Avoid applying thin layers of sealant, ensuring that any recesses are fully sealed with the product, and that you pay attention to the shape of joints and penetrations in order to achieve a good seal.

Where necessary, use a stopping knife to smooth the surface of the mastic in order to achieve the desired finish.

Use Newton® 801-M Mastic Sealant only in well ventilated rooms, and ensure good ventilation whilst curing.


Do not expose to thermal, mechanical or chemical influences until curing is fully completed.

Not suitable for use on structural glazing, mirrors, polyacrylate, polycarbonate, or on sanitary applications

Not suitable if the cured sealant is to be used as part of a painted surface finish.

Data Sheets

Technical Data Sheet

Safety Data Sheet

Newton 'System 800' Installation Instructions

Declaration of Performance (DoP)

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