Liquid Apply Membrane for waterproofing in wet areas

Liquid Applied Membrane for Wet AreaScope: Sikalastic 450 is a one part, specially formulated polyurethane based, elastic, crack bridging membrane. It cures to form a highly elastic, waterproof coating with excellent crack bridging properties. It can be applied on concrete, brickwork, roof tiles, roofing felt etc.


Crack Bridging
Excellent adhesion
Economic and easy to apply
Highly Elastic

1. Product type: Sikalastic 450, high performance, elastic polyurethane liquid membrane

2. Preparation

All concrete surfaces to which Sikalastic 450 will be applied including elevations, joints and upstands etc, must be clean, dry and free of any major defects or contaminants. Before liquid membrane application, all 90° corners must be chamfered with a mortar and Sika Latex. Inside corners must be chamfered by applying a fillet bead of cementitious mortar based on Sika Latex. The fillet must be allowed to dry or cure before application.

3. Membrane application

Waterproofing built up:

Primer: 1 x Sikalastic 450 + 15 wt.-% Thinner C (~ 0.25 – 0.35kg / m²)
Coating: 2 x Sikalastic 450 – (~ 0.45 kg / m² / layer)

The system will be semi-reinforced with Sika Reemat or Polyester fabric. (120 gr / m2 for 1.5 mm thk system). The total dry film thickness of the cured membrane must be ~ 1.5mm thick (included Sika Reemat).

The Sika Reemat or Polyester fabric reinforcing must be embedded into the first wet membrane layer around all perimeter joints, floor waste pipes, wall and floor joints to a width of 300 mm on both sides of all joints and protrusions. In shower trays the entire floor area will be reinforced with Sika Reemat or Polyester fabric.

All vertical sections must be treated with membrane to a height at least 300 mm above the floor. All vertical corners and joints must be waterproofed to a height of 1.8 m. Broadcasted sand can be done on the waterproofing top layer to reinforce the screed adhesion for the vertical areas.

4. Cement Based Screed

A cement based topping screed having a thickness of 20 – 50 mm is applied directly over the membrane. Tiles may be embedded directly into the cement screed or bonded to the top of the screed using a suitable tile adhesive.

5. Installation

For detailed installation advice contact your nearest Sika branch.