Plastering & Replastering using AcryLatex

TUTORIAL 23:

PLASTERING AND RE-PLASTERING USING ACRYLATEX FOR WATERPROOF PLASTER

Download PDF

Determining your product requirement:

• Measure area to which paint is to be
• Depending on surface to which the product is to be applied, determine which products are needed. (Refer to Product Specifier Tool)
• Check the Theoretical Spread Rates (TSR) on each of the specified products and see how many coats of each are recommended, then calculate what quantities of each product you will require.
• Check out the specifications on all the top coat choices (referring to the relevant data sheets) and decide which is right for

BEFORE PLASTERING

Surface Preparation

1. It is essential that all surfaces are free from friable matter or other unsound substances. Dusty patches, old paint and contaminants such as oil and grease must be removed prior to application of AcryLatex modified Cement substrates should be dampened with water prior to application. Old walls and floors may require mechanical scarifying (chipping) prior to application while new smooth surfaces like power

floated screeds may require etching using hydrochloric acid. Always ensure thorough washing to remove all traces of acid. Water damaged/crumbly plaster should be removed back to brick or a sound surface and to DPC (damp proof course) level, and then repaired as per no. 4 below.

2. Applications of AcryLatex modified plaster mortars should be restricted to no more than 10mm per coat. Greater thickness may tend to sag or even fall off. Several coats may however be applied in fairly rapid The time required between coats will vary according to conditions, but reaction time for the mortar is typically 15 to 30 minutes.

Application Method

1. Primer (Bitumen surfaces, walls and floors) Priming is normally required to obtain maximum adhesion of the subsequent renderings or coatings. The primer is prepared by mixing one part Portland cement with one-part AcryLatex. The slurry is them brushed onto the required surface ensuring that all the brush strokes end in the same direction g. Vertical. Apply a second slurry coat at right angles to the first coat

e.g. horizontal. Allow half to one hour drying time between applications. Allow 48 hours drying time before over coating.

2. General-purpose wall plasters and floor screeds. Plaster Sand / River Sand: 150 kg

Ordinary Portland Cement:                50 kg

Acrylatex:                                                  10 litres

Water:                                                        As required for consistency

It is recommended that all wall and floor surfaces be primed as described in 1 above and that the plaster or screed mortars be applied whilst the priming coat is still sticky. Mortars can be laid to any thickness, down to a featheredge if necessary. However, a sufficiently fine grade of sand should be used and no ultra-fine clay- like materials must be present in the sand.

3. Concrete and heavy duty flooring

River Sand:                                                150 kg

Crushed Granite Stone:                       150 kg

Ordinary Portland Cement:                100 kg

AcryLatex:                                                 20 Litres

Water:                                                        As required for consistency.

It is recommended that all existing floors be prepared as described above, followed by priming as described in 1 above.

4. Water and moisture resistant mortars. (Plaster) It will be required that surfaces be prepared as described above, followed by priming as described in 1 above. The primer coat must be left to dry for at least 48 hours after Ensure the entire area is completely sealed after each

application of the primer coat. Before application of the plaster mortar a tack coat of PlasterBond should be applied and the plaster mortar applied, as soon as the PlasterBond has dried, in the following proportions:

Plaster Sand:                                            150 kg

Ordinary Portland Cement:                50 kg

AcryLatex:                                                 15 – 20 Litres

Water:                                                        As required for consistency.

The amount of AcryLatex required in the mortar composition depends upon the degree of water resistance required and the conditions prevailing. Where high hydrostatic pressures are anticipated, the level of AcryLatex could be increased to levels where no water is required in the composition of the mortar.

Relevant Product Information