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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
Although the principles contained within the Code are still
sound, after nearly twenty years, BS 8102:1990 Code of Practice for
Protection of Structures against Water from the Ground was overdue
for revision. First of all, the Code is now called BS 8102:2009
Code of Practice for Protection of Below Ground StructuresBS
8102:2009 Code of Practice for Protection of Below Ground
StructuresBS 8102:2009 Code of Practice for Protection of Below
Ground StructuresBS 8102:2009 Code of Practice for Protection of
Below Ground Structures against Water from the Ground. Relevant
ChangesRelevant ChangesRelevant ChangesRelevant Changes Although
the original BS 8102 principles are maintained, there are several
changes and additional points in the revised code which
significantly enhance the original. Of these, the following are
most pertinent: 1. Design team to include a waterproofing
specialist. 2. Assume water pressure to the full height of the
basement. 3. Meaning of the term “defects”. 4. Grade 4 environment
has been removed. 5. Type C now includes cavity drainage membrane.
1) Waterproofing Specialist1) Waterproofing Specialist1)
Waterproofing Specialist1) Waterproofing Specialist In section 4.2,
The Design Team, the code recommends “A waterproofing specialist
should be included as part of the design team so that an integrated
waterproofing solution is created. The waterproofing specialist
should:
• be suitably experienced;be suitably experienced;be suitably
experienced;be suitably experienced; • be capable of devising
solutions that accommodate the various project restraints be
capable of devising solutions that accommodate the various project
restraints be capable of devising solutions that accommodate the
various project restraints be capable of devising solutions that
accommodate the various project restraints and needs;and needs;and
needs;and needs; • provide the team with information and guidance
that assists and influences the provide the team with information
and guidance that assists and influences the provide the team with
information and guidance that assists and influences the provide
the team with information and guidance that assists and influences
the design, installation and future maintenance of the waterproofed
structure.”design, installation and future maintenance of the
waterproofed structure.”design, installation and future maintenance
of the waterproofed structure.”design, installation and future
maintenance of the waterproofed structure.” It goes on to say “…The
waterproofing specialist could be a manufacturer or material
supplier, provided that the manufacturer/supplier has the relevant
expertise”
The new revision of BS 8102 and how it may affect The new
revision of BS 8102 and how it may affect The new revision of BS
8102 and how it may affect The new revision of BS 8102 and how it
may affect your waterproofing designyour waterproofing designyour
waterproofing designyour waterproofing design
Meet “The Expert” “The Expert” “The Expert” “The Expert” This
man of mystery is an experienced waterproofing expert with a wealth
of knowledge to share. In this article we look at BS 8102:2009 BS
8102:2009 BS 8102:2009 BS 8102:2009 and how the changes affect
waterproofing design.
© Timberwise (UK) Ltd 2010
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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
The code is not specific about what the qualifications of the
Waterproofing Specialist, which is why the Property Care
Association (with the approval of the BS 8102 committee, as well as
the Basement Information Centre) is putting together a
Waterproofing Design Consultant qualification. Once there are
sufficient Design Consultants, design teams will be able to call on
these Consultants to assist in the waterproofing element of the
design. 2) Water Pressure2) Water Pressure2) Water Pressure2) Water
Pressure It is in this area that BS 8102 has the most significant
change. Whereas it used to say that you had to anticipate a head of
water of ¾ the depth of the basement, or 1m (whichever is the
greater), it now separates groundwater into two categories:
Hydrostatic head Saturated ground The hydrostatic head (from a
water table, whether natural or perched) is there for the purpose
of the structural engineer, who has to design the structure to
resist this water pressure. The code gives more latitude to the
engineer to interpret the maximum head he needs to design for, and
gives guidance on these matters. From the waterproofing point of
view, the code is now quite clear: regardless of the decision made
by the structural engineer as to the position of the water table,
the waterproofing specialist has to allow for some water pressure
(from saturated ground) to the full height of the basement.
The code does not specify the source of the water. The most
obvious is heavy and persistent rainfall, but it could just as
easily be burst water mains, damaged drains or rainwater goods,
etc.
© Timberwise (UK) Ltd 2010
Diagram showing water pressure
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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
3) Defects3) Defects3) Defects3) Defects The term “defects” has
long been a contentious issue, as the common perception of
“defects” is “poor workmanship”. However, the code now recognises
that there are two types of defect: Defects owing to poor
workmanship or inappropriate use of materials; Defects owing to the
specific properties of the materials being used. Whilst defects
owing to poor workmanship can be avoided by proper design, planning
and supervision, and the use of skilled workmen, the code now
recognises that the defects inherent in the system because of the
properties of the materials being used can not necessarily be
avoided. Consideration must be given, at design stage, to the
effects of defects, and how they can be overcome should they result
in an unacceptable situation. From this point of view, there is no
difference between the new and old codes, but the issue is now
described in a much clearer and unambiguous manner.
© Timberwise (UK) Ltd 2010
A failure in concrete waterproofing
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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
4) Internal Environments4) Internal Environments4) Internal
Environments4) Internal Environments Table 1 of the old code has
been replaced with Table 2. Table 2 Grades of waterproofing
protectionTable 2 Grades of waterproofing protectionTable 2 Grades
of waterproofing protectionTable 2 Grades of waterproofing
protection
This table is similar, in that Grade 1 still permits some
seepage as long as the area remains fit for purpose, but no seepage
is permissible for Grades 2 or 3. Table 2 also omits Grade 4, as it
is simply Grade 3 with enhanced ventilation, air condition or
dehumidification.
GradeGradeGradeGrade Examples of use of structure (a)Examples of
use of structure (a)Examples of use of structure (a)Examples of use
of structure (a) Performance levelPerformance levelPerformance
levelPerformance level
1111 Car parking; plant rooms (excluding electrical equipment);
workshops.
Some seepage and damp areas tolerable, dependent on the intended
use. (b) Local drainage might be necessary to deal with
seepage.
2222 Plant rooms and workshops requiring a drier environment
(than grade 1); storage areas.
No water penetration acceptable. Damp areas tolerable;
ventilation might be required.
3333 Ventilated residential and commercial areas, including
offices, restaurants etc; leisure centres.
No water penetration acceptable. Ventilation, dehumidification
or air conditioning necessary, appropriate to the intended use.
(a)(a)(a)(a) The previous edition of this standard referred to
Grade 4 environments. However, this grade has not been retained as
its only difference from Grade 3 is the performance level related
to ventilation, dehumidification or air conditioning
(b)(b)(b)(b) Seepage and damp areas for some forms of
construction can be quantified by reference to industry standards
such as the ICE’s Specification for piling and embedded retaining
walls.
© Timberwise (UK) Ltd 2010
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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
Type CType CType CType C The original code recognised Type C as
the most reliable system, but it did not include the currently used
cavity drainage membrane systems. The new code recognises the place
that membranes have in Type C, and includes a great deal more
detail on their installation, as well as accentuating the
importance for ongoing maintenance. The three different types of
system quoted in BS 8102 are : • Type A: Barrier ProtectionType A:
Barrier ProtectionType A: Barrier ProtectionType A: Barrier
Protection • Type B: Structurally Integral ProtectionType B:
Structurally Integral ProtectionType B: Structurally Integral
ProtectionType B: Structurally Integral Protection • Type C:
Drained ProtectionType C: Drained ProtectionType C: Drained
ProtectionType C: Drained Protection
© Timberwise (UK) Ltd 2010
Cavity Drainage Membrane System
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The new revision of BS 8102 and how it may affect your
waterproofing designThe new revision of BS 8102 and how it may
affect your waterproofing designThe new revision of BS 8102 and how
it may affect your waterproofing designThe new revision of BS 8102
and how it may affect your waterproofing design
Conclusions Conclusions Conclusions Conclusions Once architects
have taken on board the need for a waterproofing specialist on the
design team, defective designs should be reduced. Furthermore,
where unacceptable leakage occurs as a result of defects, it should
be possible to undertake remedial work without having to completely
strip out the basement, as is often the case at the moment.
Furthermore, it should be much easier for waterproofing specialists
to comply with the code, as it is clearer, less ambiguous, and more
flexible in terms of what can and cannot be done. Finally, it is
worth noting that it is not a statutory requirement to comply with
this (or any) BSI code. However, when things go wrong and law suits
start flying, the first thing the courts look at is compliance with
relevant codes. If a design does not comply with the appropriate
code, the designer will need to justify why it does not comply. In
short, it is easier to comply with the relevant codes in the first
place and, with this new code, it should be easier.
For Further information on Basement Waterproofing and the
solutions available For Further information on Basement
Waterproofing and the solutions available For Further information
on Basement Waterproofing and the solutions available For Further
information on Basement Waterproofing and the solutions available
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Timberwise are Experts in Rising Damp, Damp Proofing, Basement
Waterproofing, Condensation Control, Dry Rot, Timberwise are
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