EPDM Roofs in Kensington, MD
One Kensington building has its low roofs written down: the Mizell Building at 10500 St. Paul Street, where flat wings from 1911 sit behind a parapet between metal-clad gables. It is a useful test of when a rubber membrane is even the right question.
The record
What does a Maryland inventory form say about the roofs at 10500 St. Paul Street?
The form describes the two side wings as flat roofs "with a low pitch concealed by a low parapet wall", now covered with "a rolled roofing material". The gabled roofs beside them are clad with standing seam metal.
Maryland Inventory of Historic Properties, St. Paul Street Survey District, No. M: 31-6, prepared by EHT Traceries, April 2022. Opened October 15, 2026.
The survey district is part of Kensington's locally designated historic district but sits outside the National Register district, according to the same form. It lists 10500 and 10520 St. Paul Street as contributing resources.
The form is silent where an owner most needs an answer
It was written in April 2022 and describes how the building looks. It does not say what the wings have on them today, how they drain or whether the parapet is sound. The Town and county pages we read name no roofing membrane either, so none is welcomed or ruled out. Neighbouring pages cover the Howard Avenue flat roofs and the rented-roof question.
Building biography
How did a general store come to carry flat wings between its gables?
- About 1902
William Mannakee builds a general store after a fire destroys the earlier one. The front-gabled main block dates from this build.
- 1911
Arthur Williams adds side wings. These are the roofs the form calls flat with a low pitch.
- 1923 to 1924
A service station is attached by a frame hyphen, shown on the 1924 Sanborn map, and a cross-gabled rear addition is dated 1924.
- 1931 to 2016
Russell Mizel buys the property at auction and runs his lumber company there until 2016.
- 2021
A senior living complex is built on the lot to the west and joined to both historic buildings by a one-story hyphen.
Our reading: every addition is a place where one roof meets another wall. The form does not describe the roof of either hyphen, so we make no claim about them.
Two roofs, two questions
Which of this building's roofs could ever be an EPDM candidate?
| Roof | Recorded as | Slope question | EPDM candidate? |
|---|---|---|---|
| The 1911 wings | Flat, low pitch, hidden by a parapet, rolled roofing. | The model building code sets a minimum design slope of 1/4 in 12 for single-ply sheets, so a low pitch must be measured, not assumed. | Only after someone checks slope and drainage from the roof itself. |
| The metal gables | Gabled, standing seam metal. | Far steeper than any sheet membrane is designed for. | No. Read the Kensington metal roof page instead. |
The parapet
Where does a rubber sheet stop and start on a wing hidden by a parapet?
- Membrane across the roof surface
- Cant strip at the corner
- Termination bar and counterflashing
- Coping on top of the wall
On a wing like this the parapet is where a membrane meets masonry or wood, which is why the edge parts matter as much as the field. The model building code says rusted or damaged metal edgings and counterflashings are not reinstalled on a reroof, and it asks for metal edge systems on low-slope membrane roofs to be tested to a named standard, ANSI/SPRI ES-1. Both belong in the scope.
Before anyone proposes EPDM
Which five checks come first on a flat wing between two pitched roofs?
- Name what is on it now.This building's record says rolled roofing. A sheet's colour does not tell you which membrane it is, so ask for the data sheet or open a corner.
- Find where the water leaves.A roof edge that rises above the roof can hold water in. Our reading: ask where the wing drains before asking what covers it.
- Learn what sits under the covering.Before covering over existing insulation, core cuts show whether it is wet and whether it can dry.
- Ask how seams will be made and checked.EPDM sheets are joined with adhesive or tape, and a trade library item from 1991 lists seams among the problems studied on EPDM roofs. It is old, so put it to a bidder as a question.
- Ask the county which review applies.Montgomery Planning treats matching roof repairs as work outside the Historic Preservation Commission. Whether rolled roofing becoming a sheet counts as matching is a question for the Historic Preservation Office, 301-563-3400.
FAQ
Flat wings, parapets and rubber sheets in Kensington
Why does an EPDM page cite the Mizell Building?
It is the Kensington building whose flat roofs we could read about in an official record. It is a worked example, not a King's job.
Does the form say 10500 St. Paul Street has an EPDM roof?
No. It says the wings are covered with rolled roofing and the gables with standing seam metal.
Can a rubber sheet cover a steep gabled roof?
The model code gives single-ply a minimum design slope for drainage, and gables are steeper than that. Gabled roofs are a shingle or metal question.
Is St. Paul Street inside the National Register district?
The form says the survey district belongs to the locally designated historic district but lies outside the National Register one.
Does a parapet change what a membrane needs?
It adds a wall to turn the sheet up and finish at the top, so flashing, termination and capping join the scope alongside the sheet itself.
Does a connecting building next door change a roof question?
It adds a joint where two roofs meet. The form does not describe the 2021 hyphen's roof, so ask who maintains that junction before work starts.
How often should a low wing be looked at?
The Single Ply Roofing Industry association says low-slope roofs should be inspected at least twice per year and after any major storm.
Keep reading
Where can a Kensington owner read more before calling?
Start with the Kensington roofing page for the Town and county order of approval, then the flat roof guide for how membranes are built. Nearby EPDM pages: Bethesda and Silver Spring.
Official pages used
Checked October 15, 2026: Maryland Inventory of Historic Properties, M: 31-6, Historic Area Work Permits, 2021 International Building Code, Chapter 15 and Single Ply Roofing Industry FAQ.
Roof material guides for Kensington: metal roofs in Kensington, TPO roofs in Kensington, PVC roofs in Kensington.
Talk through the next step
Tell us what covers the low roof today
Give us the street, which part of the building is flat and what you think is on it now. A short phone call comes first, and we will help you sort out whom to ask before any sheet is ordered.
9220 Topaz St, Fairfax, VA 22031
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