Colour Scratch Plaster

Description

A blend of Colorcem, OPC and aggregate for the creation of an 18 to 20mm coloured plaster.

Purpose

To provide a tough, coloured, economical plaster directly onto flush-jointed brickwork. The surface should first be waterproofed with a single coat of Cemcrete StippleCrete.

Applications

Recommended for both interior and exterior walls where an earthy appearance and low maintenance is required.

Specifying

"Cemcrete Coloured Scratch Plaster of an approved colour applied in one coat over a single coat of Cemcrete StippleCrete in accordance with the manufacturer's instructions."

Note

Coloured plaster finishes are susceptible to non-uniformity of colour unless precautions are taken to create surfaces with even suction. The colour of the aggregate will affect the colour of the final finish.

Specimen finish

A trial area should be treated on-site for the architect's approval.

Site Work

Storage

Colorcem can be stored in a dry shed off the floor on wooden slats for 3 months.

Weather

Do not apply to exterior surfaces if rain is expected or if there is a risk of frost.

Suitable surfaces

Drystack brickwork, breeze blocks, stock and face bricks, rough concrete, hard, clean bagwash, scratch plaster, etc..

Masking

For best results all windows, doors and adjacent surfaces should be masked using masking tape and brown paper. All masking material must be removed at the end of the day's work.

Surface preparation

All brick surfaces to be clean and mortar joints flushjointed, properly cured and hard. Apply one good coat of Cemcrete StippleCrete as per its data sheet. Cure all completed StippleCrete the day after application by damping down with clean water three times during the day. Apply Coloured Scratch Plaster no later than the following day.

Mixing

Using a cement mixer, combine one volume of Cemcrete Colorcem and two volumes of OPC. Mix thoroughly in the dry form. Remove and re-bag.

Application

Mix 1 volume of the Colorcem/OPC mix, 3 volumes clean plaster sand and 1 volume clean river sand. Mix dry before adding enough clean water to create a thick plaster consistency. To avoid cracking plaster should be applied no thicker than 18 to 20mm. Work from architectural feature to architectural feature to prevent unsightly joints. Wait for plaster to be biscuit-hard and scrape back using a straight edge or a steel trowel held at 900 to the wall. Care must be taken to scrape all areas evenly to ensure uniformity.

Curing

Cure by wetting with clean water 3 times during the day following the day of application.

Acid-washing

Ensure that all adjacent areas are properly masked. Dilute 1 volume of hydrochloric acid with 3 volumes water. Wet plaster and then apply the diluted acid using a blockbrush. Always start at the bottom and work upwards to prevent streak marks. Allow the acid to react for at least 10 minutes and then rinse with plenty of clean water.

Sealing

Once properly dry (minimum 28 days), surfaces can be sealed using Cemcrete Siliconseal as per its data sheet.

Packaging

Colorcem is supplied in 5kg and 25kg non-returnable drums.