Mapei Topcem – Special Hydraulic Binder For Screed 20Kg Pallet Deals and Bulk Buy

Mapei Topcem extended information

Coverage: approx. 2-2.5 kg/m2 per cm of thickness.

Where to use

Formation of bonded, unbonded and floating or heated screeds on both existing and new concrete prior to the installation of wood, PVC, linoleum, ceramic tiles, natural stone, carpet or any other flooring where rapid drying is required for short installation times. Suitable for indoor and outdoor use.

Some application examples of Mapei Topcem

• Formation of screeds set to light foot traffic after 12 hours.
• Formation of screeds on which ceramic tiles can be laid after 24 hours.
• Formation of screeds on which natural stone can be laid after 2 days.
• Formation of screeds on which resilient flooring and wooden flooring can be laid after 4 days.
• Patching and repairing floor screeds where rapid restoration is required.
• Preparation of screeds incorporating underfloor heating systems without the need for polymer additives.

Mapei Topcem Technical Characteristics

Mapei Topcem is a special hydraulic binder which, when mixed with graded aggregates and water, can produce an early drying high strength screed ready to receive floor finishes between 24hrs and 4 days. Topcem is defined within BS 8204 -1 section 5.1.3 part f.

Mapei Topcem Uses

• High traffic areas such as airports, shopping centres, schools, hospitals etc.
• Fast track construction where the screed needs to be trafficked or overlaid early.
• Suitable for thin resin or cementitious systems such as Mapefloor or Ultratop.
• Suitable for underfloor heating systems.
• Suitable for use where BRE screed test category A or B is required.

Recommendations

• Do not mix Mapei Topcem with other cement, lime, gypsum or Mapei 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 to BS EN 13139 0/8.
• Do not mix Mapei Topcem with an excessive quantity of water.
• Do not add water and remix Topcem after it has started to set.

Unbonded Screeds (min 35 mm thick)

Preparing the mix

Carefully mix the Mapei Topcem with graded aggregates 0/8 mm in diameter and water, in a mixer or screed pump 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.
Topcem, aggregates and water can be mixed using:

• a forced action mixer;
• an ordinary concrete pan mixer
• a screw mixer
• an automatic pressurised screed pump.

Mixing manually with a shovel is not recommended as it does not permit good dispersion of the Mapei Topcem components resulting in the need to increase the quantity of water in order to obtain the right mix. Where it is not possible to use a mechanical mixer and for small areas that require mixing by hand, it is recommended to thoroughly dry mix the Mapei Topcem with the aggregates before adding the water in small amounts, turning the mix until a “damp earth” consistency is obtained.

Recommended Dosage

Topcem binder: 250 kg/m3

Recommended mix design:

0/8 mm aggregate: 1750 kg/m

Mapei Topcem binder: 250 kg/m3
Water: 100 kg/m3

Note: Water content may vary according to the moisture content of the aggregate.

Spreading the mix

The Mapei Topcem mix should be spread in the same way as a normal screed. A polyethylene isolating sheet (or other similar material) must be laid to create a separating layer between the screed and the supporting substrate.

This separating layer also provides the function of a vapour barrier, preventing damp rising from the substrate and also dehydration of the Topcem screed due to rapid absorption of water; the absorbed water, rising subsequently would retard the drying process.

Mapei Topcem screeds are prepared using the same techniques as for ordinary cement screeds, preparing levelling strips, laying the mix, carefully compacting it and then tamping for the required surface finish.
Where it is necessary to incorporate piping or sheathing in the Topcem screed the upper layer which must not be less than 25 mm thick, should be reinforced with galvanized steel mesh of not more than 30×30 mm.

Around the perimeter of the area and around columns etc., it is advisable to form an expansion joint about one centimetre wide between the wall and the screed with a flexible material (such as polyethylene, felt board, cork, polystyrene, etc.).

If the installation of the screed is interrupted away from a construction joint cut the day joint in the screed straight down and insert pieces of 3-6 mm diameter, steel rods 20-30 cm long.

They should be spaced 20-30 cm apart to ensure perfect bonding and to avoid cracks and differing levels when work is resumed.

On average there is more time available for laying and working with Topcem screeds compared to traditional cement screeds. However the ambient temperature influences the setting and drying times.

Bonded Screeds (Min 10mm thick)

Preparing the mix, proportions and spreading the mix are exactly the same as for unbonded screeds, but first apply a Planicrete bonding slurry onto the perfectly clean substrate.

Dosage of The Bonding Slurry

Planicrete: 1 part by weight
Water: 1 part by weight
Mapei Topcem: 3 parts by weight
To ensure adhesion, spread the slurry onto the surface to be covered immediately before the Mapei Topcem screed (fresh screed on fresh slurry).
Note: For thicker section bonded screeds over 50mm use Eporip Epoxy Bonding Agent.

Floating Screeds (min. 55 mm thick)

The screed mix is prepared and applied in the same way as an unbonded screed. Mapefibre NS12 may be added to the screed at 120 g/Bag of Mapei Topcem as an additional measure.

The insulation should have a high resistance to compression and not depress more then 3 mm under the anticipated final load.

Where underfloor heating pipes are incorporated, they should be located a minimum of 25 mm below the surface of the screed. Additionally reinforcing mesh if used, should be placed over the pipes. The underfloor heating may be commissioned after 4 days.

Note: For under floor heating systems the screed must contain either additional reinforcing mesh or Mapefibre NS12 fibres.

Measuring The Moisture Content

Because of the particular composition and character of Mapei Topcem, ordinary electric moisture meters do not give reliable values: residual moisture can only be recorded with a carbide hygrometer.

Cleaning

Tools can be cleaned with water.

Mapei Topcem Consumption

Consumption varies in relation to the thickness of the screed and the dosage of Mapei Topcem.
For doses of 200-250 kg of Topcem per m3 of aggregate consumption is 2-2.5 kg/m2/cm of thickness.

Packaging

20Kg bags

Mapei Topcem Technical Data

Consistency:	powder
Colour:	grey
Bulk density (kg/m3):	850
Dry solids content (%):	100
EMICODE:	EC1 R Plus - very low emission

Application Data (at 23oC – 50% RH)

Mixing ratio:	200-250 kg of Mapei Topcem with 1 m3 of aggregate (diameter from 0-8 mm) and 110-130 kg of water for dry aggregate
Density of the mix (kg/m3):	2100
Mixing time:	5-10 minutes
Working time of mix:	60 minutes
Application temperature:	from +5°C to +35°C
Set to light foot traffic:	after 12 hours
Ready for use:	4 days
Application of levelling compound:	after 1-4 days
Waiting time before installation:	24 hours for ceramic tiles 2 days for stone material 4 days for resilients and wood
Residual moisture after 4 days (%):	< 2.0
FINAL PERFORMANCE DATA
Resistance to alkalis:	excellent
Resistance to oils:	excellent (poor to vegetable oils)
Resistance to solvents:	excellent
Temperature when in use:	from -30°C to +90°C

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