Sitework
Setting out
General principles
Plan for laying to start from an outfall at the lowest point of
the system. This ensures self-draining if wet weather occurs during
installation.
Use level pins and string lines to ensure correct level and
alignment.
HydroKerb:
Excavate trench large enough to allow for concrete bed and
haunching, min. 460 mm wide, depth will vary on choice of HydroKerb
base unit.
Units should be set out such that the top of kerb is at required
level, correct horizontal alignment, radii etc. as shown on setting
out drawing (provided by the Engineer), using string lines and pins
as appropriate. If radii required is larger than available kerb
radius, then use the next size up.
Starting at the outfall, the HydroKerb base units should be laid
on a min. 150 mm thick fresh concrete foundation ST4min.
or, alternatively, on a 25 mm thick mortar bed on a previously laid
foundation of 150 mm thick concrete. Haunching should be to front
and rear of HydroKerb base units 150 mm wide.
Place HydroKerb top unit onto base unit, ensuring that all
seatings are clear of concrete and debris to allow for proper
location, complete haunchings as required and compact.
Place inspection units at required intervals as work proceeds.
This would normally be at the head of the run and at 30 m intervals
unless it would coincide with an outlet. Surfacing can be rolled up
to units but inlets should be examined afterwards and any surfacing
removed from holes.
System should be flushed through after completion.
For optimum laying speed lay a run of base units before laying top
units.
Clearway/Safeticurb:
The surface of these systems’ drainage units should be 3-6 mm
below the level of the surrounding pavement surface.
After completing base foundations, lay units onto a Class 1
mortar (1:3 cement: sand) bed, adjusting to line and level using a
pavior’s maul.
Leave 1mm gap between units to allow for thermal expansion.
If a watertight joint is required, a gun-applied sealant may be
applied to the end of each unit.
Clearway grid units
Grid fixing bolts should be tightened to a torque of 20 Nm after
installation and whenever grids have been removed for
maintenance.
Safeticurb DBA and DBJ slot
units
Protect slots from stones during construction. Slot units without
iron inserts can be damaged when stones are impacted by vehicle
traffic.
Safeticurb DBG and DBJ grid
units
Grid fixing bolts should be tightened a minimum of 5 turns after
clamping plate has made contact with the soffit of the bore.
Highway/Mini Highway/Highway Ultra
(including Porous Asphalt units):
Specially designed lifting tools available to enable units to be
placed accurately in position.
Lay units onto a fresh concrete base (see installation design),
adjusting to line and level using a pavior’s maul.
Apply gun-applied (see note, below) sealant to the ends of the base
outlet unit prior to laying.
Note: Suitable product would be Evo-Stik roof
and gutter sealant. Alternatively a trowel applied mastic sealant
can be used, e.g. Denso.
Apply gun-applied sealant to the sealant recess in the end of
the first standard base unit – lay the unit against the base outlet
unit with the sealant recess away from the outlet. Lay subsequent
base units, applying sealant to the sealant recess in each,
preferably before laying each unit in position.
When a crossfall is required across the top of Highway units,
the base units should be laid to this crossfall. Do NOT rely on
varying the thickness of mortar in the joints between top and base
units.
Use Class 1 mortar (1:3 cement:sand) to fill joints between top
and base units. The joint reduces from 20 mm outside to 15 mm
inside the unit to ensure complete filling and compaction inside
the bore and to avoid cavitation from the water flow.
While laying, the vertical joints between top and bases are
unlikely to be maintained over the full length of the run because
of minor manufacturing and jointing tolerances. A full top unit cut
to suit may be required to complete the run.
Use the specially designed lifting tool to place top units in
position, ensuring that the inlet holes at the ends of each unit
are correctly aligned. Adjust using a pavior’s maul.
Remove excess mortar from inside bore as
each unit is laid.
Seal the pipe bore at each end of the run, either by extending the
base and haunch concrete (of the Highway units or any adjacent
kerbline), or with engineering bricks surrounded with concrete or
by using the Highway base stop end units.
Handling equipment
For appropriate handling and lifting equipment, contact Probst
Haldning Equipment on 01939 235325.