Technical Characteristics

Topcem is a special hydraulic binder which, when mixed with graded aggregates and water, can produce mortars that can harden in approximately 24 hours, and dry in approximately 4 days.

Recomendations

• Do not mix Topcem with other cement, lime, gypsum or Mapecem etc.
• Do not leave Topcem dry-mixed with aggregates, immediately add the correct quantity of water to the mix.
• Do not mix Topcem just with fine sand, use aggregates graded from 0 to 8 mm (for screeds up to 5-6 cm thick).
• Do not mix Topcem with an excessive quantity of water.
• Do not add water and remix Topcem after it has started to set.

Application Procedure - Preparating the Substrate

All substrates are suitable for receiving a Topcem screed. Isolate the substrate with a sheet of polyethylene or similar; in the case of rising damp provide a suitable waterproof membrane. If the screed is not of the self-bearing type, and the old cementitious, stone or ceramic substrate needs to be dry, resistant to compression and tension, free from cracks, dust, loose material, oil, paint, wax and traces of gypsum. For other types of substrates consult MAPEI's Technical Service.

Unbonded Screeds (35 to 60mm thick) - Preparing the Mix

Carefully mix the Topcem with graded aggregates 0-8 mm in diameter and water, in a mixer or batcher for at least 5 minutes.

The mix must be spread, tamped and levelled in the shortest possible time and in any event not more than an hour after preparation. Particular care must be taken with the quantity of water which must be such as to obtain a mix with a "damp earth" consistency that under a float finish will compact to produce a closed and smooth surface without water bleed.