NBS Source
Newton 801-M Mastic Sealant


  • To seal fixing plugs to System 800 membranes, including Newton 803, Newton 803 Newtonite, and Newton 805 Newlath.
  • For sealing around service penetrations and protrusions through the substrate/ membrane.
  • As a general, high performance and multipurpose sealant in the building industry.


A multipurpose silicone sealant primarily used with the Newton 805 Newlath and 803 Newtonite membranes – applied to the plug before fixing into the membrane, 801-M seals the penetration and prevents bridging between the damp substrate and new internal surface.

Applied to the fixing plugs before they are fitted, the product serves 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 high adhesive strength, without primer, on the majority of materials used in the building and engineering industries.

Features and benefits:

  • 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, anodized steel, treated wood, and polyvinyl chloride (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.

General information


Flexible, smooth, white sealant




Silicone sealing mastic


Flexible white silicone


25 cartridges of 310 ml per box

Uniclass 2015

Pr_30_31_76_77 Silicone construction joint sealantsPrimary


J40/290 High density polyethylene/ polypropylene studded cavity drain membrane

J40/47 High density polyethylene/ polypropylene studded cavity drain membrane

Product range

Damp Proofing Systems

Specification data - Silicone construction joint sealants Enhanced data


EN 15651-1:2012.

Product Reference

801-M Mastic Sealant

Fire resistance

Class E - EN 13501-1:2007.

Skin forming time (23°C at 50% relative humidity)

25 minutes.

Vulcanisation rate (23°C at 50% relative humidity)

2.5–3 mm every 24 hours.


1.36 g/ml.

Installation temperature

+5°C to +40°C.

Hardness (shore A)

20 ISO 868.

Elastic recovery

> 90% ISO 7389.

Deformation capability


Modulus at 100% elongation

0.32 N/mm² ISO 8339.

Elongation at break

350% ISO 8339.

Volatile organic compounds

<100 g/L.

Temperature resistance

-50°C to +150°C.

Environmental information

Country of material origin

United Kingdom

Country of product manufacture

United Kingdom