FLOOD03449

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Basin: Statewide
• Title: Colorado Flood Proofing Manual
• Date: 10/1/1983
• Prepared For: State of Colorado
• Prepared By: CWCB
• Floodplain - Doc Type: Educational/Technical/Reference Information

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PROTECT MEMBRANE

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GRADE

MEMBRANE WATERPROOFING

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Figure 7.13. Membrane waterproofing. (Reference 8)

Structural requirements and concerns regarding coiltinuous internal membrane lining are
very similar to those for external membranes, I n ge~eral, water leaks can form more easily
with internal linings. This is because water pressure 'helps keep exterior linings tight against
the wall or slab. With internal linings, the water i" allowed to penetrate to the inner part of
the wall or slab to where the membrane is attacheq. Deflection is more important when
internal linings are used, and it should be limited to 1/500 of the length of the shorter span
of the wall or slab.

The third method of waterproofing involves additiqn of the waterproofing agent to the con-
crete mixture, This method, like the other two, reqyires that slabs and walls act together
monolithically, Deflection of any wallar slab should be limited to 1/500 of its shorter span,

I ntegrally waterproofed concrete should have a ,e\fen day compressive strength of 3,000 psi
and a 28 day compressive strength of 4,000 psi. i\p!)roved admixtures should not reduce the
compressive strength of the concrete. They should act as a densifier and increase workability,

For existing structures which are considered for ,'erf'odeling or rehabilitiation, waterproofing
can be achieved through the use of special buildin~ materials and fill when it is not feasible
to elevate a structure by raising the foundation. The! use of treated framing and sheathing
materials must be considered if backfill material is rjlaced against the structure (Table 10.2),
Figure 7.14 illustrates the concept of using treated ~uilding materials for protection against
the deterioration of structural members while the filii material provides protection from flood-
water inundation. This flood proofing practice should be considered for flood inundation
depths generally less then two feet.