How to Find the Original Blueprints and Building Permits for Your House

People look for original blueprints for practical reasons (a renovation, a restoration, a dispute over what was legally built) and for curiosity about how the house was first laid out. The honest starting point is that for most American single-family houses built before about 1950, no set of plans was ever filed with the government, and many that were filed have since been thrown away. What usually survives instead is a building permit: a short form or ledger entry naming the owner, builder, cost, and date. This guide shows you how to get the permit history for your address, where the rare surviving drawings are kept, and how to find a published plan that matches your house when the originals are gone.

1. The Honest Truth About Old Blueprints

Blueprints were working documents. The architect or builder kept them, the carpenters used them on site until they fell apart, and the owner might get a set. Cities that required permits generally kept the permit, not the drawings, for houses. The record shows how this plays out. Chicago's building permit ledgers from 1872 to 1954 survive and are online, but they contain no floor plans or blueprints. Seattle's permit microfilm reaches back to the 1890s, yet the city's single-family plans on file start only in 1974. In Washington, D.C., drawings filed with permits from 1877 to June 30, 1915 survive at the National Archives, but the District destroyed the drawings for permits issued from July 1, 1915 to September 7, 1949, and they do not exist in any form.

Many rural and small-town houses were built where no permit system existed at all. And many modest houses never had custom drawings: a builder worked from a plan book, a lumberyard plan service, a kit company's catalog, or simply experience. So the realistic goal is often not "the blueprints" but a combination of permit records, a published plan that matches, old photographs, and measurements of what stands today.

2. Request the Permit History From Your Building Department

Start with the city building department, or the county if you are in an unincorporated area. Ask for every permit on file for your address, plus any plans, plot plans, or certificates of occupancy. Bring or send the parcel number from your tax bill and any former addresses, since many older records are filed by historical address or by block and lot. An original permit typically gives the owner's name, the builder or architect, the estimated cost, and the date, which is often the single best evidence for when your house was built. Later permits record additions, porches enclosed, garages built, and conversions. Many departments charge copy or research fees, and copying plans for a building usually requires the owner's permission, and sometimes the original architect's.

Several large cities put their records online or offer a clear request route:

• New York City: the Department of Buildings' Buildings Information System (BIS) lets you search by borough and address to open a Property Profile with permits, filings, and scanned certificates of occupancy. Newer filings, including certificates of occupancy requested since March 1, 2021, are in DOB NOW. The department's building history page explains both.
• Los Angeles: LADBS's online building records include building permits from 1905 to the present, certificates of occupancy from 1940, plot plans, and some approved building plans. Copies of blueprints require a current grant deed and written authorization from the owner and, where applicable, the architect or engineer of record.
• San Francisco: the Department of Building Inspection's Records Management Division holds plans, permit applications, and job cards. Its 3R report (Report of Residential Building Record) lists a residential building's authorized use and building permit history; as of November 2026 it costs $379 and takes seven to ten business days. Plan copies need permission from the owner and the design professional.
• Seattle: the Seattle Department of Construction and Inspections keeps pre-2006 permits, plans, and land use files on microfilm indexed by address, with permits back to the 1890s but single-family plans only from 1974. The Seattle Municipal Archives' property history guide lists the sources, including King County assessor property cards with photographs of every building taken in the 1930s and 1940s, held at the Washington State Archives.
• Portland, Oregon: PortlandMaps shows building permits from 2000 to the present plus a Historic Plumbing section for older sewer and plumbing permits. For older building records and plan sets, the city's public records page explains how to request them.
• Chicago: the University of Illinois Chicago's Chicago Building Permits collection digitizes 90 permit ledgers covering 1872 to 1954, with an address card index you use first. According to UIC, permits from 2006 on are on the City of Chicago Data Portal.
• Washington, D.C.: the Department of Buildings' records page explains where every era of permits is held: 1877–1949 permits on microfilm at the National Archives, the surviving 1877–1915 drawings in the National Archives cartographic branch, and later records through the department's eRecords request.

If your city is not listed, search "[city] building permit records request" or "[county] permit history by address." Smaller departments often answer by email within a few days.

3. Get the Certificate of Occupancy

A certificate of occupancy (CO) states what a building is legally approved to be used for and, for multi-unit buildings, how many dwelling units it may contain. It is not a drawing, but it tells you whether a basement apartment or a converted attic is legal and when that status was granted. Coverage depends on the city: Los Angeles's online records include COs from 1940 on, while New York City says buildings constructed before 1938 generally do not need one unless later alterations changed their use, exits, or occupancy. If your house predates CO requirements, the absence of one is normal, not a red flag.

4. Identify the Architect, Then Find the Archive

If an architect designed your house, the best chance of finding original drawings is in that architect's office records, which sometimes ended up in a university library or historical society. First, get a name. The original permit may list it. So may newspaper building columns, which in many cities printed new permits with the owner, architect, and cost; search your address in our guide to free historical newspaper archives. A National Register nomination or local landmark survey for your area may also name the designer.

The free AIA Historical Directory of American Architects then tells you who the architect was. It lists national AIA members through 1978, includes the full text of the 1956, 1962, and 1970 American Architects Directory, holds digitized membership files, and links to other archives that hold architects' papers and drawings. As of October 2026 the AIA says scanning of member files on request has resumed; questions go to archives@aia.org.

Major repositories of architectural drawings include:

• Avery Drawings & Archives, Columbia University: one of the largest architectural archives in the country, organized by architect or firm, strong on New York but national in scope. Collections list; reading room by appointment booked at least seven days ahead.
• Ryerson & Burnham Art and Architecture Archives, Art Institute of Chicago: papers and drawings of Chicago architects and firms, including a 1950s project that microfilmed drawings borrowed from Chicago firms and building owners. Archive page; access by appointment.
• Athenaeum of Philadelphia: leads the Philadelphia Architects and Buildings database, which links biographies, buildings, and drawings from more than 25 Philadelphia-area repositories; guest access is free.
• Cal Poly Special Collections and Archives: home of the Julia Morgan Papers (architectural drawings, plans, and project files for the California architect) described in the Online Archive of California, which also searches architectural collections at other California institutions.

For local architects, the most likely home is the city or county historical society. Find yours in our directory of historical societies by state and ask whether it holds any architects' or builders' papers.

5. Check Kit House and Mail-Order Catalogs

Between about 1908 and 1940, mail-order companies sold complete house kits and plans by catalog. Sears, Roebuck is the best known, with sales commonly put at 70,000 to 75,000 houses, but there were several major competitors: Aladdin of Bay City, Michigan; Gordon-Van Tine of Davenport, Iowa, which also produced the houses Montgomery Ward sold as Wardway Homes; and others. If your house is one of them, the catalog page shows the floor plan and exterior as designed, room dimensions included.

The catalogs are free online. Central Michigan University's Clarke Historical Library has digitized Aladdin's annual catalogs from 1908 through 1954, with gaps for years when no new catalog was printed; the library also holds more than 15,000 post-World War II Aladdin architectural drawings. Sears' own corporate archives website is no longer online, but Sears catalogs are on the Internet Archive, for example a Sears Honor Bilt Modern Homes catalog, as is a c. 1930 Wardway Homes catalog. Our guide to whether your house is a Sears kit home explains how to confirm a match using stamped lumber, shipping labels, and hardware rather than looks alone, since many builders copied popular designs.

6. Search Pattern Books and Plan-Service Catalogs

Far more houses were built from published plans than from kits. From the late 1800s through the 1950s, builders and owners bought plans by mail from plan books, magazines, and lumberyard plan services, then built with local materials. The best free place to browse them is the Building Technology Heritage Library, a project of the Association for Preservation Technology hosted on the Internet Archive. It holds mostly pre-1964 trade literature, including roughly a thousand house plan catalogs. Search by company name, or browse catalogs from the decade your house was built and compare floor plans, window placement, and porch details. A match will not show the exact changes your builder made, but it gives you the intended layout and often the original room names and finishes.

7. Look for HABS Measured Drawings

The Historic American Buildings Survey, begun in 1933, and its companion engineering and landscape surveys (HAER and HALS) have produced measured drawings, large-format photographs, and written histories of more than 38,000 structures and sites, all free to view and download at the Library of Congress. Most documented buildings are notable or endangered, so your house is unlikely to be among them unless it is old or architecturally significant. A HABS drawing of a neighboring house by the same builder, or of the same plan type in your town, can still show you construction details and original layouts. Search by city and county.

8. Mid-Century Tract Houses and FHA-Era Records

If your house was part of a postwar subdivision, it was probably built from a small set of model plans used over and over. The developer's plans may survive with the city (as a master plan filed once for many permits), with the developer's successor company, or in a local historical society. Original sales brochures, which show the floor plan of each model, turn up in newspaper advertisements from the opening of the subdivision and in neighbors' files. Ask long-time owners on your street; someone often kept the brochure.

Many tract houses were financed with Federal Housing Administration insured mortgages, and the FHA set minimum standards that builders had to meet. The FHA's records at the National Archives (Record Group 31) include some architectural and engineering drawing series, but do not expect to find a file for your individual house; researchers report that individual loan case files were not kept permanently. Treat FHA records as context for how your house was designed, not as a source of its plans.

9. Ask Previous Owners and Check Old Listings

Original drawings are sometimes in the house itself: rolled up in the attic, tucked in a basement cabinet, or handed over at closing. Ask your seller or their agent, and trace earlier owners through your deed chain using our guide to tracing your property's deed history. Families of original owners occasionally kept the plans, the contract, and photographs of construction. Old real estate listings also help: multiple listing service records kept by local agents often include room dimensions and floor-plan sketches, and listing photos on real estate websites can show the house before a renovation. If the house was ever nominated to the National Register of Historic Places or surveyed for a local historic district, the nomination or survey form may include a sketch plan and a detailed description of the original layout.

10. When Nothing Survives: Commission As-Built Drawings

If no plans exist, you can have new ones made of the house as it stands, called as-built or measured drawings. An architect, a residential designer, or a drafting service measures every room, wall thickness, window, and door, and produces floor plans and often elevations; some use laser scanning. Cost varies with size, complexity, and the level of detail you need. Consumer cost guides commonly quote roughly $0.40 to $2.50 per square foot for basic residential as-builts, so get two or three local quotes and ask exactly what drawings and file formats are included. For a renovation, ask whether the drawings will be accurate enough for permit submission. For a history project, a careful hand-measured sketch plan of your own, with room dimensions, is a respectable record that the next owner will be glad to have.

Tips for Finding House Plans

• Ask for everything by address and by parcel. Old records may be filed under a former street number or a block and lot.
• Get the original permit first. The builder's or architect's name on it unlocks every other source in this guide.
• Compare plans, not just exteriors. Many houses look alike from the street; room layout and dimensions confirm a catalog match.
• Photograph what you find. If an archive lets you view drawings but not copy them, notes and permitted photos still capture the layout.
• Leave a copy with the house. Whatever you assemble, permits, catalog pages, or as-builts, will save the next owner the search.

Frequently Asked Questions

How do I find the original blueprints of my house?

Ask your city or county building department for all permits and plans on file for your address, then check with previous owners and the house itself. If the permit names an architect, look for that architect's papers at university archives and historical societies. For many older houses no blueprints were filed, so a matching kit or plan-book catalog page may be the closest substitute.

Can I look up building permit history by address online?

In many large cities, yes. New York, Los Angeles, Portland, and other cities have online permit lookups, and Chicago's 1872 to 1954 permit ledgers are digitized by the University of Illinois Chicago. Online records usually cover recent decades best; older permits may require an email or in-person request to the building department.

Why does the city not have plans for my house?

Most cities kept permits rather than drawings for single-family houses, many purged old plans, and many rural areas had no permit system when older houses were built. Seattle, for example, has single-family plans only from 1974, and Washington, D.C. destroyed drawings for permits issued from 1915 to 1949.

How do I find the floor plan of a Sears or kit house?

Identify the model, then find it in the company's catalog. Aladdin catalogs from 1908 to 1954 are free at Central Michigan University's Clarke Historical Library, and Sears, Wardway, and other catalogs are free on the Internet Archive, including in the Building Technology Heritage Library.

How much do as-built drawings of a house cost?

It varies with the size and complexity of the house and the detail required. Consumer cost guides commonly quote roughly $0.40 to $2.50 per square foot for basic residential as-built drawings. Get several local quotes and confirm which drawings and file formats are included.