The process
Approval is part of the product.
Window and door work on a landmarked townhouse is regulated at the level of profile, material and finish. We design to the Commission's standard from the first drawing, so most of our work qualifies for staff-level review rather than a public hearing.
01 · Six steps
From first call to close-out.(6)
- Step 1
Step 01
Initial call and document review
A conversation about the house, what you have noticed and what you hope to do. We look up the designation — individual landmark or historic district — and read any earlier LPC permits on file. If there is an architect involved, we include them from this call.
- You receive
- A plain account of what applies to your house and what a survey would cover
- We need from you
- The address, any photographs, earlier permits or correspondence
- Typical duration
- Typically within one week of first contact
- Step 2
Step 02
On-site survey
We measure every opening, take profiles of the sash, muntins and brickmold, and photograph inside and out. A written condition report records which elements can be repaired and which cannot, with the reason in each case.
- You receive
- Measured survey, profile drawings, photographs and a condition report
- We need from you
- Access to every room with a window or door in scope, about half a day
- Typical duration
- Typically 2–3 weeks to scheduled visit and report
- Step 3
Step 03
Proposal with LPC-ready drawings
A fixed proposal sets out the work opening by opening, with elevations, sections and a specification drawn to the standard the Commission expects. We note which filing route we expect and why, and where we see any risk of a hearing.
- You receive
- A fixed proposal, drawings and specification, and the expected filing route
- We need from you
- Your decisions on repair versus replacement where there is a choice
- Typical duration
- Typically 2–4 weeks after the survey
- Step 4
Step 04
Filing with the Landmarks Preservation Commission
We file the application and correspond with Commission staff on your behalf. Staff may ask for clarifications, a sample or a revised detail; we answer and keep you informed. We cannot promise an outcome, but we design for the route most likely to succeed.
- You receive
- Filing confirmation, copies of correspondence, a status note at each change
- We need from you
- Signed owner authorisation for the application
- Typical duration
- Typically 4–10 weeks of staff review, depending on the application
- Step 5
Step 05
Fabrication
Once a permit is issued we prepare shop drawings, make a sample of the key profile, and confirm finish and colour with you before production. Windows and doors are built in our workshop to the approved drawings.
- You receive
- Shop drawings, a profile sample and a finish sample for approval
- We need from you
- Approval of shop drawings and finish
- Typical duration
- Typically 10–16 weeks from shop-drawing approval
- Step 6
Step 06
Installation and close-out
Our own crews install, protect interiors and finishes, and leave each opening working. We complete any LPC sign-off required by the permit, and hand over warranty documents and plain maintenance notes for the windows and doors we have made or restored.
- You receive
- Installed work, permit sign-off where required, warranty and maintenance notes
- We need from you
- A clear installation window and access for the crew
- Typical duration
- Typically 1–3 weeks on site, depending on the number of openings
02 · Glossary
Terms, explained once.
- Sash
- The movable part of a window that holds the glass. A double-hung window has two sashes that slide past each other on weights or springs.
- Muntin
- The thin bar of wood or metal that divides the glass within a sash into smaller panes. Its width and profile set much of a window's character.
- True divided light
- Each pane is a separate piece of glass held by real muntins, as in historic windows — rather than a single pane with grilles applied on top.
- Brickmold
- The wood trim that frames a window or door where it meets the masonry. It covers the joint and gives the opening its outline from the street.
- Sightline
- How much frame and muntin is visible from the street. The Commission looks closely at whether new work keeps the original sightlines.
- Permit for Minor Work
- An LPC permit, issued by staff without a public hearing, for work that changes the building but is appropriate to its historic character.
- Certificate of No Effect
- An LPC permit, issued by staff, for work that does not affect the protected architectural features — often interior work or exact repairs.
- Staff-level review
- Review by the Commission's preservation staff, without a public hearing before the Commissioners. Most well-designed window replacements qualify.
- Historic district vs individual landmark
- An individual landmark is designated on its own; a district designates a group of buildings. In both, exterior work needs LPC approval.
03 · The standard
What the Commission looks for.
| Element | Historic configuration | What we do |
|---|---|---|
| Operation | How the window opened — double-hung, casement, pivot | Keep the original operation; we do not substitute casements for sash |
| Configuration | Pane pattern, e.g. six-over-six or two-over-two | Reproduce the pattern from the survey or period evidence |
| Material | Wood or steel, by period and house type | Build in the original material; no vinyl or clad substitutes |
| Profile & muntin width | The shape and size of the sash members | Draw profiles from the survey and hold muntin widths |
| Finish & colour | Paint colour appropriate to the style and district | Propose colours with period evidence; sample before production |
| Glass | Clear glass, often with slight distortion | Clear insulated or restoration glass; no tints or reflective coatings |
| Sightlines | How much frame shows from the street | Match the original sightlines in every new unit |
- Operation
- Historic configuration
- How the window opened — double-hung, casement, pivot
- What we do
- Keep the original operation; we do not substitute casements for sash
- Configuration
- Historic configuration
- Pane pattern, e.g. six-over-six or two-over-two
- What we do
- Reproduce the pattern from the survey or period evidence
- Material
- Historic configuration
- Wood or steel, by period and house type
- What we do
- Build in the original material; no vinyl or clad substitutes
- Profile & muntin width
- Historic configuration
- The shape and size of the sash members
- What we do
- Draw profiles from the survey and hold muntin widths
- Finish & colour
- Historic configuration
- Paint colour appropriate to the style and district
- What we do
- Propose colours with period evidence; sample before production
- Glass
- Historic configuration
- Clear glass, often with slight distortion
- What we do
- Clear insulated or restoration glass; no tints or reflective coatings
- Sightlines
- Historic configuration
- How much frame shows from the street
- What we do
- Match the original sightlines in every new unit
Summarised from the LPC Windows Fact Sheet and Rules §2-14. Always confirm against the current rules for your district.