Introduction

At the request of Ms. Angela Lomanto, Director of Development, Massachusetts Horticultural Society, Ms. Andrea Mones performed an on-site visual inspection of the Gardener’s Cottage and its surrounding site on Sunday, August 27, 2006 to determine reasons for the basement’s extreme damp.  During the investigation, a heavy rain occurred, which assisted in the evaluation.  All inspection occurred from the ground and within the building’s basement.  Ms. Mones was unable to inspect the condition of the roofing materials, eaves, and gutters.  Basement wall integrity (even, level, settling, buckling, cracking) was not determined.  Ms. Mones was not involved in the restoration/renovation of the cottage and has no knowledge of the structure’s prior condition, quality of materials, or the 2006 project’s design.  Her recommendations are based on this visual investigation only.

The entire site of Elm Bank was placed on the National Register of Historic Places in 1987 because of the significance of the buildings and the site.  The Commonwealth of Massachusetts currently owns the property.  In April of 1996, the Massachusetts Horticultural Society signed a lease with the Commonwealth and pledged to bring
Elm Bank back to life for generations to come.

Prior to the present 2006 restoration/renovation, the Gardener’s Cottage was in a state of severe deterioration, as described to Ms. Mones by a site visitor on August 27, 2006.  Earlier alterations are unknown.  Extensive exterior restoration and interior renovation is now visibly apparent.  New heating, ventilation, and air conditioning, as well as plumbing, have been added during this project.  The building is now functioning as a visitor and retail center for the Massachusetts Horticultural Society. 

1. Roofing, eaves, valleys, and flashing
2. Gutters
3. Downspouts fitted on spacers and splash blocks
4. Landscaping
   • (Height and slope of the land adjacent to the foundation, directing water away from the foundation)
   • Proximity and type of vegetation adjacent to the foundation
   
5. Walkways:  surface materials and slopes
6. Soil erosion prevention program

In addition, waterproofing foundation walls below grade and installation of a concrete floor at the basement level will alleviate rising damp from ground water.

On August 27, 2006, water was noted streaming over the gutters and hitting the bare earth adjacent to the Gardener’s Cottage during the severest period of a rain shower.  The dirt surrounding the Cottage was saturated and large puddles in the dirt were visible.  The porch remained dry beneath the overhanging roof.  The basement’s dirt floor was wet mud to a depth of one inch.  The basement’s interior stone walls were moist to the touch. 

Evaluation

Observed conditions: 

1. The water pattern spilling over the gutters may indicate that the gutters are undersized or that the gutters must be cleaned of debris 
2. No hosing or piping was connected to the base of the downspouts to direct the water away from the cottage foundation 
3. The building site’s exterior surrounding surfaces are bare dirt, dirt mounds, and construction debris 
4. The basement floor is dirt
5. No water leaks were visible through the new window sash and frames at the basement level
6. No frass or sawdust was visible on the basement floor (indications of carpenter ants or drywood termites).  However, the structural members were encased in sheet rock and, if made of timber, have unknown conditions
7. No interior plaster water staining was visible

Both ground water and water infiltration through the foundation walls are probable causes of the water infiltration and the subsequent problem of a damp/wet basement. 

Work Recommendations

1. Immediate Actions:

• Install electronic monitoring devices to characterize the interior environment for both relative humidity and temperature.  This will enable staff to verify effectiveness of moisture mitigation program
• Re-configure exterior roof drainage systems, ensuring gutters are properly sized and there are a sufficient number of downspouts
• Install an “industrial” variety dehumidifier with internal condensate pumps in the basement space to dry it out

2. Intermediate Actions:

• Execute a complete drainage system, addressing all the elements cited under the section titled “Summary of Findings”, using the enclosed historic restoration resources for guidance and SMACNA (Sheet Metal and Air Conditioning Contractors National Association) Architectural Sheet Metal Manual for sizing downspouts and gutters
• Install a finish floor at the basement level
• Waterproof the foundation walls below grade
• Establish a maintenance plan, with established dates, for work such as
  gutter cleaning, removal of vegetation intruding on the building foundation, and cleaning of a french drain adjacent to the Gardener’s Cottage

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Brereton, Chistopher.  The Repair of Historic Buildings:  Advice on Principles and Methods.  London, England: English Heritage, 1991.

Fram, Mark.  Well Preserved: The Ontario Heritage Foundation’s Manual of Principles and Practice for Architectural Conservation.  Ontario:  The Boston Mills Press, 1988.

London, Mark and Dinu Bumbaru.  Traditional Masonry: Maintenance/Repair/Replacement.  Montreal:  Heritage Montreal, 1986.

Ramsey, Charles George and Harold Reeve Sleeper.  Architectural Graphic Standards:  Third Edition.  New York: John Wiley and Sons, Inc., 1950.