Note on English translation / Hinweise zur englischen Fassung
This is a translation of the technical data sheet valid in Germany.
All stated details and properties are in compliance with the regulations of the German standards
and building regulations. They are only applicable for the specified products, system components,
application rules, and construction details in connection with the specifications of the respective certificates and approvals.
Knauf Gips KG denies any liability for applications outside of Germany as this requires changes
acc. to the respective national standards and building regulations.
F321.de
Floor Systems
Knauf Floor Screed FE 25
Fast-setting self-levelling calcium sulphate floor screed CAF-C30-F6
Product description
Fields of application
Properties
Knauf Floor Screed FE 25 A tempo is a factorymixed dry mortar, calcium sulphate-based, to be
mixed with water. It consists of special gypsum,
liquefier and aggregates (0 to 4 mm).
Quality classification
according to EN 13813: CA-C30-F6
Knauf Floor Screed FE 25 A tempo is applied as
self-levelling bonded floor screed, floor screed on
separating layer, on insulation layer or as heating
floor screed with high compressive strength > 30
N/mm²) and tensile strength (> 6 N/mm²).
Knauf Floor Screed FE 25 A tempo can be dried
immediately after application (immediate heating
up of heating floor screed).
The short drying time allows for early floor covering and fast usability of rooms. Knauf Floor
Screed FE 25 A tempo is the ideal screed for
deadline sites (fast readiness for floor covering)
and for floors with high strength requirements (e.
g. schools, commercial buildings).
■ Calcium sulphate based
Order information
40 kg bag
Silo (bulk)
Storage: (dry)
Material no. 00005349
Material no. 00005527
up to 6 months
Quality
In compliance with EN 13813 the product is CE
marked and subject to initial type testing and
continuous factory production control.
■ Ideal for underfloor heating
■ High thermal conductivity
■ Self-levelling
■ Low shrinkage and expansion
■ Can be loaded quickly
■ Short drying time as heating screed
■ No formation of sinter layers
■ Creates even surfaces
■ Areas with low number of joints
■ Machine application is possible
■ Controlled, constant quality
2012-08
F321.de Knauf Floor Screed FE 25
Fast-setting self-leveling calcium sulfate floor screed CAF-C30-F6
Application
Technical data
For 40 kg of dry mortar (1 bag) approx. 7 l of water are required.
Mix Knauf Floor Screed FE 25 A tempo with
clean water and pump on prepared surface using a mixing pump (e.g. FErro 100, PFT G4/ G5,
or similar).
The recommended flow test diameter is 45 cm,
determined with Flow Test Box 1.3 l on an even,
non-absorbent surface.
While spreading no water should separate from
the screed.
Reaction to fire:
A1fl - non-combustible EN 13501-1
Density
dry:
wet:
approx. 1.9 kg/l
approx. 2.1 kg/l
Bulk density of dry material:
approx. 1.5 kg/l
EN 13813
Compressive strength:
> 30 N/mm²
EN 13813
Bending tensile strength:
> 6 N/mm²
Free expansion during setting:
approx. 0.5 mm/m
Reaction of mortar:
alkaline
Elastic modulus:
approx. 17,000 N/mm2
Can be trafficked:
after approx. 3 h
Can be loaded:
after approx. 8 h
Yield from 100 kg dry mortar:
approx. 54 l mortar
Thermal conductivity:
λZ= 1.4 W/(m•K)
Thermal expansion coefficient:
approx. 0,011 mm/(m∙K)
Application time
Apply mixed mortar within approx. 40 minutes
and level applied screed within approx. 10 minutes. In case of machine application, empty and
clean machine and hoses within 30 minutes after
final machine stop.
Application temperature/climate
Do not apply screed at room or substrate temperatures of less than +5 °C / 41 °F.
Can be trafficked:
(depending on thickness and temperature) after
approx. 3 hours.
Can be loaded:
After approx. 8 hours.
DIN 52612-1
The stated technical data were evaluated acc. to the respective test standards. Deviations under site
conditions are possible.
Material consumption / efficiency
Floor Screed FE 25
A tempo
per 1 cm
Consumption
kg/m2
approx. 19 kg/m2
All stated values are approximate values and may deviate depending on the substrate conditions. The
exact consumption can only be determined on the individual object.
Movement joints
Drying , floor covering
Knauf Floor Screed FE 25 A tempo expands
slightly during hardening. Separate all adjacent
vertical components from screed using min.
8 mm thick edge strips. Provide joints in door
openings and if the diagonal length of the area
is over 10 m.
Structural settlement joints should be transferred
in full width at the same position into the floor
screed. Construction joints depending on work
progress, machine performance and size of the
object are allowed.
For further information see Code of Practice “Fugen in Calciumsulfatfließestrichen” of the IGE.
As heating floor screed, FE 25 A tempo
should be heated until dry before covering!
Knauf Floor Screed FE 25 A tempo • 35 mm
Knauf Schrenzlage
Knauf L Profile 50/30
e.g. fixed with adhesive tape
Knauf Movement
Joint tape,
self-adhesive
Dry heating immediately after application
■ Switch floor heating to maximum temperature
(max. 55 °C / 131 °F) immediately after application of the screed . Values of orientation
for drying: For 35 mm screed thickness (construction type B) approx. 5 days, for 55 mm
screed thickness (construction type A) approx.
10 days, if screed thickness is ≥ 60 mm dry
heating period must be increased.
Dry heating of the hardened screed
■ If the screed cannot be dry heated immediately
after application, start with 25 °C / 77 °F heating temperature for one day, then switch to
max. heating temperature (max. 55°C / 131°F).
In general
Keep maximum heating temperature without
lowering overnight until screed is dry.
Testing of residual moisture
Testing of residual moisture with applied foil or
CM measurement.
FE 25 A tempo as heating floor screed is ready
to be covered after reaching a residual moisture
of ≤ 0.3 CM-% for all kind of covers.
(Please request detailed heating up rules with
heating up report from Knauf).
2
Knauf FE 25 A tempo without underfloor heating
is ready to be covered after reaching a residual moisture of
≤ 1.0 CM-% for covers open to vapour or
≤ 1.0 CM-% for vapour-retardant covers, e.g.
tiles,
≤ 0.5 CM-% for vapour-proof covers and parquet
(CM measurement).
The drying time for a screed thickness of 35 mm
can be estimated approx. 8 to 14 days depending on the drying conditions.
Note:
Drying time depends, beside the screed thickness, mainly on temperature, humidity, and air
speed. Continuous ventilation is required for
quick drying. Additional heating (no gas burner)
and the use of Knauf Dry Heating Cable shorten
the drying process.
Further notes
For further details, fields of application and building physical properties as floor screed system,
see Knauf broschure F20.de “Konstruktion und
Verarbeitungstechnik”. For environmental product declarations see www.knauf.de/nachhaltigkeit (EPD calcium sulphate screeds).
F321.de Knauf Floor Screed FE 25
Fast-setting self-leveling calcium sulfate floor screed CAF-C30-F6
Bonded Floor Screed, nominal thickness ≥ 25 mm
■ The substrate should be sufficiently solid,
rough, dry and free of grease and cracks..
Apply an appropriate primer before screed application:
■ Prime absorbent surfaces such as raw concrete with diluted Knauf Estrichgrund (volume
ratio: 1 part of Estrichgrund + 1 part of water).
■ Prime non-absorbent mineral surfaces with
suitable special primers (e. g. Knauf Spezialhaftgrund).
■ Use a bonding floor sealant (e.g. Knauf FE-Abdichtung) if rising humidity is likely to occur.
prime if necessary
(if surface is absorbent)
or edge insulation strip
Knauf Floor Screed
FE 25 A tempo • 25 mm
Knauf Estrichgrund screed primer
Bonded floor screed
Floor Screed on Separating Layer, nominal thickness ≥ 30 mm
■ Apply a layer of Knauf Schrenzlage on the prepared substrate with a sheeting overlap of at
least 8 cm.
If basic floors have contact with soil (in basements) a humidity sealing is necessary according to DIN 18195-4 or equivalent, e.g. Knauf
Sealing Membrane Katja Sprint. Apply a layer of
Knauf Schrenzlage on the sealing.
Knauf Edge Insulation Strip FE 8/100
with foil clad
Knauf Floor Screed
FE 25 A tempo • 30 mm
Knauf Schrenzlage
synthetic coated kraft paper
Floor screed on separating layer
Floor Screed on Insulation Layer, nominal thickness ≥ 35 mm
■ See detail drawings for various insulation constructions.
■ Cover insulation with Knauf Schrenzlage or
equivalent.
■ For basic floors without a basement below apply a humidity sealing (acc. to DIN 18195-4 or
equivalent, e.g. Knauf Abdichtungsbahn Katja
Sprint).
Knauf Edge Insulation Strip FE 8/100
with foil clad
Knauf Floor Screed FE 25 • 35 mm
Knauf Schrenzlage
Thermal insulation or
footfall insulation EPS
Floor screed on insulation layer, solid ceiling
Knauf Edge Insulation Strip FE 8/100
with foil clad
Knauf Floor Screed FE 25 • 35 mm
Knauf Schrenzlage
load distribution
• 9.5 mm Knauf Board
mineral wool footfall insulation
or dry bulk leveller
Floor screed on insulation layer, wood joist ceiling
Heating Floor Screed, nominal thickness ≥ 35 mm
■ Construction type A: nominal thickness ≥ 35
mm above tube;
■ Apply heating screed (construction type A) in
2 layers if necessary;
Knauf Floor Screed FE 25 A tempo
• 35 mm above tube
Knauf Schrenzlage
insulation layer / mounting board
Knauf Floor Screed FE 25 • 35 mm
Knauf Schrenzlage
heat distribution sheet
insulation panel with
precast grooves
Secure heating elements against buoying. If this
is not done, apply screed in two layers.
Heating floor screed (type A)
Heating floor screed (type B)
Construction in domestic moist rooms, e.g. kitchens and bathrooms
In domestic moist rooms the screed construction
should be sealed with a water-proof sealant, e.g.
Knauf Flächendicht with Flächendichtband, to
protect it against effects of moisture.
edge sealing,
Knauf Flächendichtband (sealing tape)
filling material made of foam plastic
Knauf Sanitär Silicon
(sanitary silicone)
Knauf Flächendicht (sealing primer)
Knauf Floor Screed FE 25 A tempo
3
F321.de Knauf Floor Screed FE 25
Fast-setting self-leveling calcium sulfate floor screed CAF-C30-F6
Heating up report for ready-for-flooring heating
□ FE 50 Largo
□ FE 80 Allegro
□ FE 25 A tempo
□ FE Fortissimo
□ Alphadur 430
□ Levelling Screed 425
□ Thin-layer Screed 325
Fill in every change of flow temperature (warm
water heating) or floor thermostat (electrical heating) during heating up process and during reduction of temperature exactly to 5 K*.
Every drying test should be reported.
Client:
Installer of the heating:
Building site:
Site manager:
Heating system:
Average screed thickness:
Date of screed application:
Thickness of heating pipe covering:
min.:
mm
max:
mm
mm
Heating up (ready-for-flooring heating):
Date
Flow temperature
in °C / °F
Signature
Drying test (foil test)**:
Date
Dry
yes / no
Signature
Lowering of flow temperature:
Date
Flow temperature
in °C / °F
Signature
Ready-for-flooring heating finished:
* K = Kelvin; is the scientific unit of temperature. A
temperature increase of 5 K is commonly an increase of 5°C.
Date
Outdoor air temperature
in °C / °F
Signature
** Does not replace CM measurement before covering.
Please retain report
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