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Infiltration and influx (I & I) of water through concrete or ‘block'
surfaces located below grade is a common problem. Home owners with cellars, city managers with manholes, and businesses
with sumps and collection pits frequently have problems with seepage or leakage. Such problems can be solved thanks
to several new products now on the market. These products will work on moisture saturated surfaces and on the ‘inside'
negative pressure surface (the inside wall of a leaking basement as opposed to the outside surface where the water
presses the coatings into the concrete instead of away from the concrete).
The ease and cost of fixing this problem is largely determined by the extent of the leakage and the composition/density
of the wall material. Concrete or ‘cinder' block is a common basement wall material. The density, porosity and
void space size vary greatly from manufacturer to manufacturer. Some cinder blocks do a reasonable job of holding
back water while others seem more characteristic of a window screen. A less dense building block will require more
dramatic measures to stop its leaking.
Concrete density and porosity can also vary, particularly as the concrete deteriorates due to slightly acidic ground
water, or due to the initial mix of cement and sand. Simply put, each case is unique and the contractor/applicator
must decide which solution will work for the least cost.
The simplest solution is to use a concrete fortifier/sealer such as Bio-Vee from Progressive Epoxy
Polymers (http://www.epoxyproducts.com). This water like product soaks completely into the concrete, reacts with
the cement grains to form new crystal grains between the existing cement particles. With less air filled void spaces,
water migration through the concrete is stopped or greatly reduced. There is still enough pore space, however,
to allow the block to breathe. A single application by brush or roller is generally all that is required. It's
effectiveness on cinder block varies. It works well on the denser blocks, less well on the coarser blocks.
The next level of sealing involves applying a coat of thin, solvent-free,
water displacing epoxy over the surface. These special epoxies (also available from Progressive Epoxy Polymers)
can actually be applied to a damp, saturated, or completely submerged surfaces and will form a tough, non-porous
surface coating. Problems can result if the surface is dirty, greasy, weak, or dusty and the epoxy cannot get a
good bond to the surface. Another possible concern, primarily with the more porous cinder blocks, is that the thin
epoxy cannot completely fill the larger voids and spaces in one application. In such situations a thicker water
displacing epoxy is recommended.
The best protection against water seepage is to apply a thickened, thixotropic, water displacing epoxy. Often fiber
thickened (frequently with Kevlar (tm) microfibers) these products can be applied by plastic edger (or ‘float')
to the surface. Application literally pushes the thick epoxy into surface spaces and the thick gelled epoxy resists
air or water expulsion while it cures to an extremely hard, durable and even attractive surface. As with the thinner
versions of these 100% solid epoxies, surface preparation and surface condition are critical for a firm bond.
For commercial applications, such as manhole repair and restoration, a two coat system consisting of water displacing
epoxies of contrasting colors is often specified. The different colors helps to visually insure uniform and complete
coverage, compensating for thick or thin zones during the application of each coating. An even better system would
include using Bio-Vee sealer before applying the one or two coats of the epoxy. The Bio-Vee would by itself, help
resist the influx of water. The Bio-Vee densified concrete will also better resist chemical deterioration when
and if the epoxy surface coating integrity is breeched. The Bio-Vee will also reduce the possibility of pinholing
through the coating by reducing the volume of air spaces in the surface of the concrete.
Material costs for the above treatments varies from about $0.40 per square foot to $3.00 per square foot.
Current thinking (10-02)
seal around the 'leak' with Bio Vee Seal then patch crack or damaged
area with a coat of our Corro
Coat FC 2100 epoxy with Kelvar and Ceramic. The Bio Vee Seal
will keep the water from migrating through the concrete and around the epoxy after you've sealed the crack. Note
that the Bio Vee Seal does not work on cracks or sealed (or painted) surfaces. It also is less effective on 'cinder'
blocks.
--- both these products are non-hazmat, solvent free and can be applied
to wet surfaces ---
Knowledge is Power - We like informed consumers!
Learn the basics of epoxy at our educational EPOXY 101 page -
Click Here.
Finally, email us back with your questions or comments before
you buy - EMAIL HERE
For specific product application (i.e. leaking basements) hints/directions - CLICK HERE
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