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PLATON PLASTER BASE MEMBRANE APPLICATION
(internal applications in below ground structures)

	PLATON PLASTER BASE MEMBRANE APPLICATION
	Platon Plaster Base can be applied onto existing solid wall finishes. All surfaces must be of a sound, firm nature and any loose areas should be removed prior to application. Any voids or hollow areas should be filled or dubbed out prior to application. Where necessary a fungicide wash should be applied to the wall surface. Platon Plaster Base is for internal use only on walls and curved soffits and is compatible with other Platon membranes. Platon Plaster Base is not recommended for external application and should not be used on floors.
	Platon Plaster Base membrane is fixed to walls with the Platon plaster plug. The plaster plugs should be prepared for use before fixing by wrapping Platon sealing rope around the neck of plug just under the head. This will form a seal with the membrane when the plug is driven home into the substrate.
	If the ceiling height is constant, measure and cut drops of the membrane to completely cover the wall areas to be treated. Place the membrane against the wall as level as possible by eyesight. In the top right or left hand corner (depending on which way around the room the membrane is being taken) drill a hole, 3 studs in from the edge through the centre spacing between 4 studs, not through the stud itself. Using an 8mm drill bit and insert the plaster plug and hammer home the plug till it finishes flush with the membrane. (See fig 46)
	Using a spirit level, level out the membrane and pull taut, then drill and fix another plaster plug in the same manner at the other top edge of the sheet. Offer up the next length of membrane and position the membrane so that this sheet overlaps by a minimum of (2) studs over the first sheet and fix with 2 plaster plugs at high level as previously described. Continue on in this manner, ensuring the membrane stays as level as possible until all the walls are covered. These independent membrane drops will relax after a while and hang flatter to the wall. The drops are now ready for the next step.
	Down the overlap joint, fix Platon plaster plugs through the studs as close as possible to the edge of the overlapping membrane. Fixings should be made at 150mm centres along this joint. Continue fixing the plaster plugs in a diamond pattern through the centre spacing between the 4 studs until sufficient fixings have been installed, ‘minimum 13/m²’. The membrane must fit tight against the structure with no voids or hollow areas left between the wall and the membrane, as this could cause bonding problems between the membrane and the plaster/render. Care should also be taken at corners to ensure the membrane is fitted tightly into the corner so to avoid snagging or tearing with a trowel. (See fig 47,48 & 49)
	Once all fixings are in place, clean the membrane surface thoroughly along the overlap joint and ensure it is dry and free from dust. Apply Platon fleece-back overtape along the joint with equal overlaps onto each sheet of membrane and press firmly into place. Platon floor membrane can now be laid over the completed drainage system. Wall/floor junction, corner strip or a creased upstand is always placed in front of the Plaster base membrane and sealed on the perimeter with Platon sealing tape or rope as the case may be. If the plaster finish is required to extend down to the finished floor and therefore over the wall/floor junction or corner strip or upstand, Platon fleece back overtape will need to be applied to provide a key for plastering. (See fig 50 & 51)

	FINISHES (top)
	Most common lightweight and renovating plasters (Tilcon 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 render, mixes of 1 part cement to 6 parts washed plastering sand, incorporating either PAM SBR or hydrated lime should be used. NB Grade ‘M’; medium sharp sand should be used. Do not use soft or building sand.
	All render/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. The minimum plaster thickness should be 15mm and the maximum thickness (sand/cement 30mm) (lightweight plasters 40mm). Plasterboard can also be dot & dabbed onto the plasterbase as a fast track system, using board adhesive.

	FIXING THROUGH PLASTER BASE AFTER PLASTERING OR RENDERING (top)
	On occasions where a fixing is required through the membrane, any one of the three fixing methods set out below can be used to achieve this:
-	By using a Platon brick plug with Platon rope seal. First mark out on the plaster surface where the fixing is required and then place the head of the brick plug over the mark and draw a pencil line around the circumference of the head. Drill a 10mm hole through the centre and carefully scrape/scratch out the plaster within the pencil line back to expose the membrane. Blow out the debris, insert the brick plug and hammer the plug home so that the head of the plug sits flush with the membrane surface. (See Fig 62)
-	By using a rawl plug. Simply drill a hole through the plaster and membrane and clean debris from the hole. Fill the hole with PAM epoxy resin, allowing the resin to ooze out slightly onto the plaster surface and insert the rawl plug and allow to harden. (See fig 63)
-	By using contact adhesive and timber batten. As before, mark out where fixing is required and remove any setting coat plaster. Apply PAM epoxy resin to the surface area and to the timber batten and press the batten into position. Some temporary support may be required until the timber has fully bonded. (See fig 64)

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