SPECIFICATION SHEET | NBS CLAUSE | TECHNICAL DRAWING
NEWTON SPECIFICATION SHEET
External Waterproofing of Concrete Raft & Walls
Rev 1.0 - 15 June 2015
Specification Sheet - A43-1
A concrete box formed of reinforced concrete walls supported from a reinforced concrete raft foundation is the most
common and preferred design where some or all of the structure is earth retained.
If not waterproofed, the concrete structure is at risk of allowing water ingress where the concrete “isn’t”, through fine
cracks, the construction joints/day work joints or through poorly compacted concrete. The use of an external, fully
bonded membrane completely surrounding the structure can be a very effective means of preventing water ingress
through joints and minor defects within the concrete.
B
D
C
A
D
A - Newton 403 HydroBond
B - Newton 108 HydroBond-LM
C - Newton 312 BentoProof
D - Newton 303 PolyProof
Occurance
Issue
Result
Cracks within the concrete that
are greater than the designed
crack widths due to poor concrete
compaction or insufficient steel
reinforcing.
Cracks of 0.3mm and above are not
deemed to be self-healing and the
structure could suffer from slight water
seepage.
Water seepage to the inner
surface of the structure
that may not be acceptable
for the required habitable
grade.
Joints.
Construction joints within the concrete due
to raft size or complexity.
Water seepage that could
pressurise the internal
finishes leading to severe
impact on the internal
habitable space.
Horizontal joint at the base of walls where
supported by the raft, either with or
without kicker.
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Newton House, 17-19 Sovereign Way, Tonbridge, Kent, TN9 1RH
T: +44 (0)1732 360 095 W: www.newtonwaterproofing.co.uk E: info@newtonwaterproofing.co.uk
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E X T E R N A L WAT E R P R O O F I N G S O L U T I O N S
OVERVIEW
NEWTON SPECIFICATION SHEET
External Waterproofing of Concrete Raft & Walls
Newton 403 HydroBond is a high performance composite sheet membrane that features a locking fleece to one side
and a polymer hydrophilic coating to the other. When placed below the new raft, and to permanent formwork, the
fibres of the fleece inner core are encapsulated into the concrete, forming a close and intimate bond. The membrane
has excellent peel adhesion qualities and thus prevents water from tracking and the membrane from dropping away
from the underside of the slab due to settlement. Newton 403 HydroBond has the ability to self-heal small holes due
to the hydrophilic coating which expands when in contact with water.
Where the formwork is removed, the walls are sprayed with Newton 108 HydroBond-LM a very flexible rubber
membrane, overlapping the 403 HydroBond by 150mm at the toe and terminating to the DPC detailing at ground
level, to fully envelop the structure with a continuous membrane, isolating the structure from ground water.
Where it is not possible to spray Newton 108 HydroBond-LM due to space or other constraints, Newton 109-LM should
be applied by brush or roller.
This is a Type A Waterproofing System to BS 8102:2009.
SOLUTION - WATERPROOFING THE CONSTRUCTION JOINTS
Where construction joints to the concrete raft and concrete walls are unavoidable, Newton 303 PolyProof hydrophilic
waterbar is placed midway within the joint and expands when in contact with water to seal joints against water ingress.
The high polymer content of Newton 303 PolyProof ensures that the waterbar remains stable even when resisting high
heads of water pressure over many cycles of use.
At the compressed horizontal kicker joint, Newton 312 BentoProof waterbar is placed midway within the joint and
expands when in contact with water to seal joints against water ingress. The bentonite rubber slightly emulsifies to
seal further into the joint and into any surface inconsistencies between the two concrete faces to further seal against
water ingress.
At kicker-less horizontal joints, Newton 301 EasyProof, a metal waterbar, is fixed within the steel reinforcement and
becomes buried equidistantly within the concrete of the walls and raft as a permanent barrier to water passing through
the joint. Its textured surface bonds to the concrete to further emphasise the already torturous path to water.
This is a Type B Waterproofing Solution to BS 8102:2009.
RESULT
The Newton HydroBondTM System fully isolates the concrete structure from ground water, preventing water ingress
through non-structural cracks, minor defects and planned construction joints. Used in conjunction with Newton 303
PolyProof, Newton 312 BentoProof and Newton 301 EasyProof waterbars to further waterproof the joints, the most
likely places for water ingress, the result is an effective, resilient and coordinated strategy that seals the structure
against ground water. The above specification is accepted by the NHBC and fully conforms to NHBC Chapter 5.4 as
Type A and Type B waterproofing.
COMMENTS
Depending on the end use and habitable grade of the structure, the designer may decide that two or even three forms
of waterproofing are required.
A further form of waterproofing can be added to the design with the inclusion of Newton System 500, an internal cavity
drain membrane system. Please see Newton Specification Sheet AC135 (for a Type C solution).
If the structure was correctly designed and formed of reinforced concrete to BS EN 1992 (Eurocode 2) and of sufficient
mass and quality to resist heads of water pressure as required by BS 8102: 2009, and the construction joints are correctly
waterproofed as indicated above, the structure itself is recognised as being a Type B, integrally waterproof structure.
Links: Newton 403 HydroBond
Newton 108 HydroBond-LM
Newton 301 EasyProof
Newton 312 BentoProof
Newton 109-LM
Newton 303 PolyProof
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E X T E R N A L WAT E R P R O O F I N G S O L U T I O N S
SOLUTION - FULLY ISOLATING THE CONCRETE STRUCTURE FROM GROUND WATER
Newton Waterproofing Systems Is A Trading Name Of
© John Newton & Co. Ltd.
Newton House, 17-19 Sovereign Way, Tonbridge, Kent, TN9 1RH
T: +44 (0)1732 360 095 W: www.newtonwaterproofing.co.uk E: info@newtonwaterproofing.co.uk