educational sheet using a harling trowel

1. EDUCATIONAL
SHEET
Using a Harling Trowel
NAMEOFTECHNIQUE
PRESENTATION OF THE MATERIAL / PRESENTATION OF THE TOOL
Harling is a term used to describe the application of a wet mortar to a surface to create a key or finish. A special
trowel is used for this purpose called a ‘Harling Trowel’. A specific technique is required to successfully distribute
the harled mortar. The consistancy of the mortar must allow it to sit on the trowel and allow the user to first turn
the trowel to face the wall and then with a sharp flick of the wrist ‘harl’ the mortar in arc. Good coverage is achieved
by being at the correct distance from the surface and then flicking the wrist enough to spread the arc as far as
possible. As you can tell, practice is essential !
ORGANIZATION BEFORE IMPLEMENTATION / BEFORE USE
The surface to be ‘harled’ has to be free of
dust and debris and is reasonably dry. If
the wall is dusty the harled mortar will not
stick. If the wall is too damp the wet
mortar will simple run off rather than
‘suck in’.
Take precautions to protect surrounding
areas as ‘harling’ is a messy process. Wear
protective glasses, lime is very aggressive
and can damage delicate tissue.

2. ORGANIZATION DURING IMPLEMENTATION / DURING USE
A good spread of
harled mortar is
desirable as it may go
on too thick if not
applied correctly. This
can lead to it
‘slumping’ off and
excessive amounts of
mortar used.
A well-
practiced
technique is vital.
You must clean all
areas of excess mortar
as you proceed as
lime mortar will dry
white and stain.
Always have
plenty of clean
water and a
brush to hand.
ORGANISATION AFTER IMPLEMENTATION /AFTER USE
Make sure that the
harled coat of mortar
is given enough time
to dry before applying
a troweled coat on
top.
If the harled
coat is not dry
you will not have
the key to the
background that
you require.
Once dry the harled
coat is an effective
key for the rest of
your plaster system,
whether internal or
external.
The harled
coat may require
damping down to
limit suction
depending on the
thickness of the
next coat.

3. USEOFAHARLINGTROWEL
IMPLEMENTATION / USE
ENSURE SURFACE TO BE ‘HARLED’ IS REASONABLY DRY AND FREE FROM
DUST AND LOOSE DEBRIS. ENSURE MORTAR IS OF A CONSISTENCY THAT WILL
FLOW FREELY OFF THE TROWEL BUT WILL SIT ON IT WHEN HELD FLAT.
BRUSH, WATER AND THE
HARLING TROWEL
PHOTOS
STANDING SIDE ON AT ABOUT 1M FROM THE SURFACE TO BE HARLED, AND
USING A WELL-PRACTISED FLICK OF THE WRIST APPLY THE MORTAR. YOU
SHOULD HEAR AN AUDIBLE ‘SLAP’ AS THE MORTAR HITS THE WALL. CLEAN
ALL EQUIPMENT AND SURROUNDING AREAS AS NECESSARY.
WET MORTAR (3 SAND TO 1
LIME PUTTY UNHAIRED) AND
YOUR HARLING TROWEL.
PLENTY OF CLEAN WATER
AND A BRUSH.
PHOTOS
ALLOW THE HARLED COAT TO FULLY DRY BEFORE APPLYING A TOP COAT.
DAMP DOWN IF NECESSARY
WATER. PHOTOS