Platon Plaster Base - Tanking Membrane (5mm Stud)

Preparation:

Platon Plaster Base can be applied to retained sound renders, brickwork, blockwork, stone or concrete. The quality and appearance of the applied finishes will be a direct reflection of the underlying substrate.

All surfaces must be of a sound, firm nature and any loose areas should be removed prior to application. Uneven, loose, or soft brick/stonework may need to be dubbed out to level off and stabilise the background. Retaining sound cement render can be a good option if the substrate underneath is known to be in poor condition.

Gypsum based plaster, wallpaper and any buried timber must be removed as these materials can deteriorate over time and in the presence of moisture.  Where necessary a fungicide wash should be applied to the wall surface. Platon Plaster Base should not be used on floors.

Remove loose and soft plaster / render, wallpaper and embedded timbers. Dub out voids, hollows and loose areas of masonry using a cement mortar. Offer up the membrane, hollow studs facing into the room, and fix in place using sealed Plaster Plugs (Sealed using Platinum Waterseal Rope).

Application Method:

Pull the membrane as tightly as possible against the structure to minimise hollow areas behind as these can interfere with the application of plaster or plasterboard.

Use a minimum of 13 fixings per square metre, spaced out in a regular ‘diamond’ pattern no more than 250mm apart. Drill through the membrane in the centre of a 4 stud cluster, rather than through the stud itself. In some cases, additional fixings may be required in order to produce a stable and tight membrane layer.

Fit the membrane tightly into and around corners to avoid damage when applying finishes.

Platon Plaster Base is joined by overlapping adjacent sheets by a minimum of 2 studs. Fix the Fixing Plugs as close as possible to the edge of the membrane. Fixings should be made at 150mm centres along the joint. Once all fixings are in place, clean the membrane surface thoroughly and ensure it is dry and free from dust.

Apply a Mesh Tape along the joint with equal overlaps onto each sheet of membrane and press firmly into place. If for some reason the membrane edges are in tension or are likely to try and pull apart, reinforce the joint with Corner Strip before applying the Mesh Tape.

Finishing:

Most common Lightweight and Renovating Plasters (Tarmac Whitewall) or sand / cement renders can be applied to Platon Plaster Base. (The use of British Gypsum Hardwall or Tuff Coat is not recommended). When using sand / cement renders, mixes of 1 part cement to 6 parts washed plastering sand, incorporating either SBR or Hydrated Lime should be used. NB Grade ‘M’; medium sharp sand should be used. Do not use soft or building sand.

All renders / plasters should be applied in a minimum of two coats, allowing the 1st coat of 7mm - 10mm to be trowelled firmly into the membrane studs and then scratched to provide a key for subsequent coats to be applied. The first scratch coat should be left to cure and harden. Ideally this should be 7 - 10 days depending on site & atmospheric conditions.

Do not allow the plaster or render to dry out too quickly or cracking may occur. The minimum plaster thickness should be 15mm and the maximum thickness (sand / cement 30mm) (lightweight plasters 40mm).

Plasterboard can be bonded using regular ‘dab’ adhesive or Low Expansion PU Foam Adhesive. Apply the adhesive over the heads of the fixing plugs and ensure that 50% of the membrane area is also covered. This ensures that direct ‘through’ contact is made between the plasterboard and the masonry substrate.

Plasterboard fixed in this way can be skimmed the next day and painted or wallpapered a few days after that. Drying times are very much reduced when compared to ‘wet’ systems.

Technical Data Sheet

System Platon Installation Manual

BBA Certificate