Hi
have read a lot of mention of using SLC over UFH mat/cable. Is it essential or can I just use tile adhesive in place of SLC? ie cover the mat with adhesive before then applying the adhesive bed that will take the tiles?
Cheers
Jon

You can do, as long as you dont go over the recommended thickness of that adhesive. I find it easier to use a SLC then tile over the top, it reduces the chance of damaging the mat.

yeah. It would seem slc would be better. I assume it will fill the gaps in the mat more easily and be easier to spread to an even finish.
Downside I guess is that it has to cure before the tiling starts whereas just using adhesive means I can put the mat down and start tiling. Mat is 5mm by the way so within the recommended adhesive thickness

Its really down to preference. I lay the heating mats and SLC one the first day then come back to tile the floor with a brand new flat/level screed. Others use adhsive that can be used thick enough to tile straight over the mats, like Mapei Adesilex P4 or BAL PTB.My only problem with this method is that Id be worried about damaging the wires.

Why dont you try each method out and see which one suits?

Partly depends on how good the floor level is & weather you want to build up your bed. The bottle & bag latex will go off in about an hour, as long as you leave enough time before grouting to allow drying to take place, no good reason not to latex, (slc) if it makes the job easier & you have the time ..I've done both & prefer to latex first.

Originally Posted by Tecnik2000

Partly depends on how good the floor level is & weather you want to build up your bed. The bottle & bag latex will go off in about an hour, as long as you leave enough time before grouting to allow drying to take place, no good reason not to latex, (slc) if it makes the job easier & you have the time ..I've done both & prefer to latex first.

What latex are you using?
Iv not come across any SLC ready to tile in an hour

A min of 12 hours for the Mapei SLC Iv used.

Originally Posted by Dylante

What latex are you using?
Iv not come across any SLC ready to tile in an hour

A min of 12 hours for the Mapei SLC Iv used.

Hi Dylante, thinking of it I guess I meant walking on ... the arditex is usually fine after an hour, though it does say in the literature longer, & coverings maybe 6 hrs. Have done it in less,no probs.Site conditions were favourable..ARDITEX RS
Latex-Based Sub-Floor
Smoothing Compound
JANUARY 2007
PRODUCT DATA SHEET
Features
Cost effective solution for smoothing concrete and
cement/sand screeds
Unaffected by moisture, can be used under a damp
proof membrane
Simply mixed, pre-gauged 2-part pack
Excellent flow characteristics
Feather edge to 6mm in one application
Apply from 6mm to 12mm incorporating ARDEX Aggregate
Ideal for use with ARDEX floorcovering adhesives
(43) Pr3
CI/SfB
Reg No. FM 1207
ARDEX UK LIMITED
Homefield Road, Haverhill, Suffolk CB9 8QP UK.
Telephone: +44 (0)1440 714939
Fax: +44 (0)1440 716660
Technical Services Fax: +44 (0)1440 716640
Email: technical.services@ardex.co.uk
ARDEX online: Tiling and Flooring products from ARDEX UK
DESCRIPTION
ARDITEX RS, a cost effective, partially
self-smoothing latex screed with excellent
properties of adhesion and water resistance,
is designed for use on rigid and absorbent
sub-floors such as concrete, cement and
sand screeds, etc. ARDITEX RS can be
laid from a feather edge up to 6mm and
to greater thicknesses by incorporating
ARDEX Aggregate.
Concrete and cement/sand screeds can be
smoothed with ARDITEX RS prior to the
application of a suitable surface damp proof
membrane, such as ARDEX DPM.
USE
For smoothing rigid and absorbent sub-floors
prior to the application of floorcoverings.
PREPARATION
The surface of the sub-floor must be clean,
firm and free of dust, dirt, grease, oil,
adhesive residues etc., or loosely adhered
materials e.g. plaster or paint residues.
On highly porous or absorbent sub-floors,
damp down the surface with water without
leaving puddles. An alternative is to prime
the surface with ARDITEX RS latex diluted
1 part to 4 parts water and allow to dry,
prior to applying the ARDITEX RS mortar.
MIXING
Mix one 25kg bag of ARDITEX RS powder
into 5 litres of ARDITEX RS latex.
(Approximately 3 volumes of powder into
one volume of latex). The emulsion should
be shaken, poured into a clean mixing
container and the powder added gradually
with continuous stirring. The use of an
ARDEX mixing paddle with a 10mm chuck
slow speed electric drill makes light work
of mixing. The mixed mortar has a working
time of approximately 30 minutes at 20°C.
APPLICATION
The mixed material is poured on to the
prepared sub-floor and spread with a trowel
to the required thickness in one operation.
ARDITEX RS is partially self-smoothing,
but should any trowel marks remain, the
surface may be smoothed with a wet trowel
once the material is “finger tight”, i.e. not
fully hardened. This can usually be done
after approximately 60 minutes at normal
temperatures. Alternatively any trowel
marks can be lightly rubbed down with a
carborundum stone once the ARDITEX RS
is hard enough to walk on.
Apply at temperatures above 5°C.
THICKNESS
ARDITEX RS is suitable for thicknesses from
a feather edge up to 6mm. For thicknesses
from 6mm to 12mm incorporate up to a
third volume of ARDEX Aggregate.
DRYING AND HARDENING
At normal temperatures a 3mm layer
of ARDITEX RS is walkable after
approximately 2 hours and is ready to
receive most floorcoverings after 6 hours.
The setting, hardening and drying times
will be extended at low temperatures
and shortened at high temperatures.
Thicker applications will require a longer
time to dry.
CLEANING OF EQUIPMENT
All tools and mixing containers should be
washed and cleaned in water immediately
after use before the material hardens.
COVERAGE
Approximately 1.9kg mortar/m2/mm, e.g.
one unit will cover approximately 5m2 at
3mm thickness.
PACKAGING
ARDITEX RS powder is packed in paper
sacks incorporating a polyethylene liner -
net weight 25kg.
ARDITEX RS latex is in white polyethylene
containers - contents 5 litres.
STORAGE AND SHELF LIFE
ARDITEX RS powder contains a reducing
agent to control the level of Chromium VI
when mixed prior to use. ARDITEX RS
powder must be stored in unopened
packaging, clear of the ground in cool dry
conditions and protected from excessive
draught. If stored correctly, as detailed
above, and used within 12 months of the
date shown on the packaging, the activity
of the reducing agent (added to control the
level of soluble Chromium VI) will be
maintained and this product will contain,
when mixed with water, no more than
0.0002% (2ppm) soluble Chromium VI of
the total dry weight of the cement content
of this product. ARDITEX RS must not be
used after the end of the declared
storage period.
ARDITEX RS latex has a storage life of not
less than 6 months in a sealed container if
stored in frost free conditions, out of direct
sunlight.
PRECAUTIONS
Wash off any mortar or latex on the skin
before it dries. During mixing and application
ensure adequate ventilation since the latex
component contains ammonia which is
released and may cause eye watering in
confined spaces. Avoid generation of
airborne dust during mixing.
ARDITEX RS powder contains more than
20% Portland cement and, therefore, in
line with current legislation, is classified as
irritating to eyes and skin. For this reason
the following precautions should be
observed:-
Avoid contact with skin and eyes; in case
of contact with the eyes, rinse immediately
with plenty of water and seek medical
advice; wear suitable gloves and keep the
product out of the reach of children.
For further information, consult the relevant
health and safety data sheet.
TECHNICAL DATA
Bulk density
of powder approximately 1.5kg/litre
Weight of
fresh mortar approximately 1.9kg/litre
Initial Set (Vicat)
DIN 1164 approximately 1/2 hour
Final Set (Vicat)
DIN 1164 approximately 2 hours
Compressive Strength (DIN 1164)
After 28 days 17.0 N/mm2
Tensile Bending Strength (DIN 1164)
After 28 days 5.5 N/mm2
Ball Pressure Hardness (Brinell)
After 1 day 19.0 N/mm2
After 3 days 42.0 N/mm2
After 7 days 51.0 N/mm2
NOTE: The information supplied in our literature or given
by our employees is based upon extensive experience and,
together with that supplied by our agents or distributors,
is given in good faith in order to help you. Our Company
policy is one of continuous Research and Development; we
therefore reserve the right to update this information at any
time without prior notice. We also guarantee the consistent
high quality of our products; however, as we have no control
over site conditions or the execution of the work, we accept
no liability for any loss or damage which may arise as a
result thereof.
Country specific recommendations, depending on local standards,
codes of practice, building regulations or industry guidelines,
may affect specific installation recommendations

Wow, thats a long winded reply
I thought you meant dry to tile onto in an hour.
Havnt used the ardex gear,as Im a Mapei man, is it any good?

Originally Posted by Dylante

Wow, thats a long winded reply
I thought you meant dry to tile onto in an hour.
Havnt used the ardex gear,as Im a Mapei man, is it any good?

I thought he did as well... especially with this remark about grout drying..???

The bottle & bag latex will go off in about an hour, as long as you leave enough time before grouting to allow drying to take place,

That did make me make this face

It's just another specialist product ...Not tied to tiling. I like the abilities for all situations, vinyl etc, even carpets where the floor is naff.. I have come across it during shopfitting where floors need to be improved & other contractors recommend it for their needs.. BTW it was a cut & paste. Didn't mean to mislead...... I only wish to share, & it's really good gear. They do a vermiculite type product too ( dry beads) which will fill 20- 30 mm & goes off like a rocket...

I used to use Arditex all the time but now prefer Mapei fibre plan or PCI HSP34..both fibre enhanced and go thick bed... but HSP goes thicker.. 60mm in one bite if needed.

if you slc it all, there's less chance of getting air voids tht can expand when heated and pop your tiles. Also it acts like bricks in a storage heater, distributing the heat evenly

there are some good fibre modified SLC that are great for this type of application, all the major players make one and also some smaller players like Tile Master, I've just tried a new one from weber called floor flex which was pretty good.