Roof and Gutter Waterproofer


Cemix Roof and Gutter is a non-toxic solvent free water based high performance polyurethane based elastomeric and flexible exterior grade brushable waterpoofer with long term UV and weather resistance to exposed and permanently immersed areas. This versatile durable and tough weatherproof coating is able to withstand extreme weather conditions (hot & cold). It is a very user friendly product that can be brush applied and has excellent adhesion to a wide range of substrates like concrete and wood.

Typical Applications & Uses:

  • Exterior protective coating for roofs, gutters, decks, steel, aluminium, concrete, bricks, plywood, timber, fibre cement sheets, vertical wall facades and general surfaces exposed to the weather


  • Water based, non toxic and non flammable
  • Can where potable water is involved
  • One pack – safe & easy to apply by brush or roller
  • Fast drying
  • Very durable and highly flexible to withstand movement
  • Resistant to mould growth
  • Excellent adhesion to a wide variety of substrates
  • UV Stable

2L, 4L and 10L

Substrate Preparation:

All substrates should be structurally sound. Properly brush clean the surface ensuring that it is rust free, clean and free from loose material. Rough surfaces and protrusions should be evened out and leveled out appropriately.


Before applying mix the product in the container with a stirrer.


Fully remove any existing coatings, grease or any other surface contaminants. If there are holes or honeycombing in concrete substrates, fill it with quick patch repair mortar and allow to cure fully before brush applying the waterproofer. Apply proper flexible silicone sealant to fully seal all joints and corners prior to application of this product. Apply it generously with a brush or a roller. Apply a minimum of two coats at right angles to each other with a total dry film thickness of 1.5mm. Let the first coat dry (3-4 hours) before you apply the second coat. For heavy duty applications apply three coats. Allow it to fully cure for 7 days and then do a ponding test to ensure that the waterproofer has been effectively applied. Contact Cemix technical support if you intend to use this product on large commercial jobs.


Normal concrete curing practises should be adopted.

Technical Data:

Appearance - Cementitious powder

Yield / Coverage - 0.5m2 per litre – with a minimum thickness of 1.5mm. Two coats at right angles to each other are recommended to achieve this. This is consistent wording with How to brochure

Packaging - 2L, 4L and 10L pails

Potable Water – Suitable.

Hydrostatic Pressure Use – Suitable

Fresh Concrete Temperature - >5ºC

The data shown above reflects typical results based on laboratory testing under controlled conditions. Reasonable variations may occur on site.


  • Do not apply if temperatures are below 10oC or if humidity is over 85% or if rain is imminent.
  • Substrate should be surface dry and there should be no rising or migratory damp. The coating will delaminate if there is rising damp underneath the applied waterproofing membrane.
  • Not recommended on glazed shiny surfaces, like glass etc.

See datasheet at for more information on this product, watch the YouTube video and contact Cemix technical if you are not clear about anything. Follow all safety instructions on the pack wear gloves, mask and especially eye protection. Avoid contact with skin.


Clean all tools with water & brush immediately after use.


Do not apply second or third coats until previous coats are dry. This will lead to delamination


Store in a cool dry area and use within six (6) months.