Question: What is the difference between a rowhouse and a townhouse?
Answer: About three zeros.

The above may point out a truth about the power of perception and marketing, but also can suggest it perhaps is
time to take a new look at the humble rowhouse. With two existing warm walls, insulation on the roof, insulation
front and rear, reconditioned windows, heat recovery ventilation (HRV), and renewed plaster, a row house can be
an energy efficient structure at modest cost. The Healthy Rowhouse Project estimates that for the minimum of the
$300,000 it takes to build a new affordable house in Philadelphia, between 14 and 30 homes can be improved.
Preserving rowhouse blocks builds on architecturally significant assets. Preserving existing resources is
environmentally sustainable. The most sustainable home is the one that already exists.

The first step is to evaluate building and components for structural integrity from foundation to roof. What repairs
are needed? What is the condition of existing components? joists? walls? windows, etc. How many layers on roof?
What is the scope, sequence and critical path of work?

A flat roof on a row house may present an opportunity to cover the roof with light weight insulation such as 6”
Polyiso panels (about $30 each at Home Depot) which then can be covered by EPDM ($350 for 10' x 50' roll). A
15 x 25 roof (375 sq') would then take about 12 panels ($320) and could be done with one roll of EPDM . The
condition of roof and number of existing layers will guide planning. (estimate $2,000)

Heat Recovery Ventilation is a way to warm incoming air coming into the house which reduces heating load (not
having to raise incoming 30 degree air so far to a comfortable level)
Heat recovery ventilation  Can an air intake
at the top of the house gather heated, stale air and then send fresh, warmed air to the basement where it will
rise? Can triangular tubing where the wall meets the ceiling be decorative AND functional? Can heat be
exhausted in the summer so that only fresh, cool air is circulated?
Yes. (Est $3,500)

Wooden windows are good windows. Historic windows, particularly those made before the 1940’s, are from old
growth wood which is denser and stronger than modern equivalents and are built with components (stile, mutton,
etc) that can be repaired or replaced…..
This means less waste going to a landfill with equivalent efficiency, better
cost savings, and better aesthetic appeal. Design and proportions matter. Windows are the eyes of a house, and
eyes are the windows to the soul. (Est $1,500 )

Diathonite is a rediscovery of an ancient method and is a type of insulating plaster made from diatomaceous
earth, hydraulic lime, cork and clay which breathes and has excellent dehumidification and sound absorption
qualities. Non-toxic, it can be used for interior or exterior applications and can be sprayed on. It is rated 3.2 R
Diathonite Evolution      Video of application   (Est $2,000)

Plaster is in virtually every building built before 1940 but people trained in the skill of plastering are rare,
so quality work may be prohibitively expensive.
The basic techniques of flat plaster can be learned (mastery takes
Tearing out plaster instead of repair results in more expense (labor/disposal/tipping fees in disposal of
plaster and lath
), with a less aesthetic, fire-resistant, sound absorbing result. The best way to learn is through
hands on training under experienced supervision. The Academy offers an opportunity to learn, and upon
completion of the module, to train newer students. (Est $1,000)  

(Total estimated $10,000 for sustainable shell)
Proposal for Conservation of Rowhouses
Academy of Building Conservation
(Draft - 2/23/16)