Maple Street Chapel Preservation Society

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THE MAPLE STREET CHAPEL

Basement Waterproofing

Background

The majority of the chapel's basement is crawl space, which is of very little value, except for some storage potential. What we really would like to do is a complete excavation of the basement (tending to structural needs as it is done), including adding a sewer system to the building, allowing for restrooms. But this project would cost hundreds of thousands of dollars, so let's get real.

The parts of the basement that are full-depth usable areas have a serious issue with water. This makes those areas essentially unusable for storage or as a facility, and presents a hazard to the heating & air conditioning plant.

This problem is two-fold:

1) The main/north area (under the sanctuary) floods due to a floor that pitches
away from the sump pit & pump.

2) Water “fountains” in through the foundation walls in the boiler room (under
the Reade Room).

At first glance, it would appear that the main/north area would not have a problem with flooding, because it is 2’ shallower than the boiler room, which is where the sump pit & pump are located. The problem that arises is that the floor pitches down to the north, with the north end approximately 6” lower than the south end. This drawing illustrates this condition (with north being to the left).....

.....which results in 6” of water at the north end of the main/north (under sanctuary) area.

The boiler room does not flood per se, but water actually “fountains” in during a rainstorm. This water flows across the floor to the sump pit where it is pumped away. But this condition makes the room unavailable for practical use, and in the location shown below, the water sprays against the side of a boiler.

The Solution

This is a description of the basics of the generally-used solution to water in an existing basement. There are subtle variations according to the individual site conditions, which this report will not attempt to define. We would leave such details up to the contractor we have chosen as best-qualified.

1) Severe leaks, such as the places that are currently “fountaining” water
through the wall should be repaired on the inner surface of the wall.

2) A trench is made around the perimeter on the inside of the walls by breaking
away approximately 12” of floor and digging.

3) A thin, tough barrier is applied to the insides of the walls beginning at a
    height equivalent to ground level outside, going down into the perimeter
    trench. This forces any water that gets through the wall to go into the trench
    rather than into the basement working area.

4) A pipe or “French drain” is placed in the trench which routes the water to
the sump pit & pump.

5) Concrete is installed on the top of the trench to re-establish a continuous
floor.

In the above drawing, the barrier is referred to as “DRY-COVE”.

It should run up to ground level, higher than shown in the drawing.

The pipe or “French drain” is referred to

as “PERMA-DRAIN” in the drawing.

This is a rough idea of what it would look like with the barrier and perimeter trench completed, before pouring the concrete to re-level the floor.

Cost and Financing

We are obtaining multiple bids, but it seems as if the overall budget for this project will be about $10,000.

The current situation is not a crisis, so we are not going to rush out and do the project until we have the funds to cover it, whether these come from a grant or we gradually save the money.

Job Goals

With elimination of the water problem, the basement could be fixed up further, including better lighting, heating, and a general facelift. This would be of some considerable value:

1) Storage space is currently at a premium, and storage of much of the
    day-to-day materials detracts from the historic appearance of the main areas
    of the chapel. This non-historic-looking storage could safely be moved to
    the basement.

2) Due to the absence of plumbing for restrooms, the chapel itself is not a
    practical place for changing rooms, “bride’s room”, etc. These activities are
    done in the First Church building next door. But in case of inclement
    weather, an area for cleanup and “final touchup” in the basement would be
    invaluable.