Remodeling an Older Home in California

Planning guide · updated October 2026

Remodeling an older home in California is a different project from remodeling a newer one. The kitchen or the addition may be the reason for the job, but in a house built before the late 1970s, what is inside the walls often sets the plan: lead paint, materials that contain asbestos, wiring and pipes near the end of their life, a foundation that was never bolted down, and repairs nobody wrote down. This guide walks through what to test, what to expect when the walls come open, the upgrades a permit can bring, and the order of steps we follow on older homes across San Luis Obispo, Monterey and Santa Barbara counties.

Harrod Built remodels and adds on to homes across the Central Coast, from Paso Robles, Templeton and Atascadero to San Luis Obispo, Monterey and Santa Barbara. To talk through an older house, call 805-712-8993 or send the form at the end of this page.

Get a written estimate Call 805.712.8993

Beamed great room and dining area with a wood entry door and chandelier in a Tuscan Revival home built by Harrod Built in Paso Robles — Pictured: the great room in our Tuscan Revival home in Paso Robles. In an older house, finishes like these go in only after the walls, wiring, pipes and framing behind them have been opened, tested and made right.

The short answer

Test before you design. In a home built before 1978, anyone paid to disturb painted surfaces has to follow the EPA’s lead-safe rules. Asbestos has no cut-off year, so materials the remodel will disturb should be tested first, and the local air district sets the survey rules. Have an electrician look at the panel and wiring, camera the sewer line, and check the crawl space for rot, pests and how the house is attached to its foundation. Then plan for the code upgrades a permit can trigger, such as smoke and carbon monoxide alarms and water-conserving plumbing fixtures, and keep a clear process for anything found once the walls are open. Call 805-712-8993.

1. Why the age of the house matters

Each era leaves its own surprises

Most of the Central Coast’s older housing stock went up in waves: early homes near the old downtowns of Paso Robles, San Luis Obispo, Arroyo Grande and Pacific Grove, post-war neighborhoods, and the tracts and ranch houses of the 1960s and 1970s. Each wave was built with the materials and codes of its day, and most have been remodeled at least once since, not always with a permit. The table below is the pattern we see when we open up older homes for remodels and home additions.

When the house was built	What we often find	What we check before design is final
Older homes from before the Second World War	Plaster and lath walls, knob-and-tube wiring, galvanized or cast iron pipes, little or no insulation, a raised wood floor over a short crawl space, and layers of paint.	Lead paint, wiring condition, the foundation and how the house is tied to it, the sewer line, and dry rot.
Post-war homes through the mid 1960s	Original panels with few circuits, ungrounded two-prong outlets, galvanized supply lines, sheet flooring and textured ceilings, and slab or raised floors.	Lead paint, asbestos in flooring, ceilings and duct wrap, electrical capacity, water pressure and drains.
Homes from the mid 1960s to the late 1970s	Some homes and additions wired with aluminum branch circuits, popcorn ceilings, vinyl flooring with old adhesive, and early additions done without permits.	Aluminum wiring connections, asbestos testing, lead paint on anything painted before 1978, and the permit history.
Homes from the 1980s and early 1990s	Older plumbing fixtures that use more water than today’s, early windows, tired roofs and decks, and electrical service sized for a different way of living.	Plumbing fixtures under California’s water-conserving fixture law, electrical service for heat pumps or an EV charger, and moisture at windows and decks.

A general pattern from older homes we open up on the Central Coast, not a rule. Asbestos has no cut-off year, and every house has its own history of repairs and additions.

None of this means an older house is a bad candidate for a remodel. Many have good bones, mature lots and locations you cannot buy new. It does mean the first step is a careful look at what is already there, before the design is locked and before anyone prices the finishes. If the list of problems is long, our article on whole-home remodel vs new construction helps frame the bigger choice.

2. Lead paint

Homes built before 1978

The federal government banned lead-based paint for homes in 1978, and the EPA notes that many homes built before then still have some lead paint under later coats. Under the EPA Renovation, Repair and Painting (RRP) program, anyone paid to do work that disturbs painted surfaces in a home built before 1978 must be certified, and their crew must be trained in lead-safe work practices. The RRP rule page explains that firms must be EPA- or state-certified and use certified renovators. Before work starts, the contractor gives the owner the EPA’s Renovate Right pamphlet.

In practice, lead-safe work means containing the work area with plastic sheeting, avoiding methods that create dust such as open-flame burning or uncontained power sanding, keeping dust out of the rest of the house, and cleaning and checking the area before it is reopened. Windows, doors, trim and exterior siding are the usual places old paint gets disturbed, because they rub, get scraped or get replaced.

The EPA notes that the rule generally does not apply to homeowners working on their own home, but it does apply if any part of the home is rented, used for child care, or bought to renovate and resell. California also certifies lead workers and supervisors for lead hazard work through the Department of Public Health’s Lead-Related Construction program. If young children or a pregnant family member live in the house, plan where they will stay while painted surfaces are being disturbed; the EPA’s tips for reducing lead exposure at home are a good starting point. We test painted surfaces the project will touch during design, so the plan and the schedule reflect what is there (we confirm per project).

3. Asbestos

No cut-off year, and three air districts

Unlike lead paint, asbestos has no cut-off date. The San Luis Obispo County Air Pollution Control District’s asbestos page notes that asbestos is not banned and may be present even in newer building materials. In older homes we most often see it suspected in textured or popcorn ceilings, sheet vinyl and floor tile and the adhesive under them, joint compound and wall texture, duct wrap and pipe insulation, and some siding and roofing. The EPA’s asbestos guidance for homeowners explains that material in good condition that will not be disturbed is generally safest left alone, and that fibers are released when the material is cut, sanded, drilled, scraped or torn out. Remodeling is exactly that kind of work.

What the air districts require

The asbestos rules for renovation and demolition are run locally by the air district: San Luis Obispo County APCD for SLO County, the Santa Barbara County Air Pollution Control District for Santa Barbara County, and the Monterey Bay Air Resources District for Monterey, San Benito and Santa Cruz counties. Each one explains which buildings its asbestos rules cover. The SLO district describes a single-family home as generally exempt from the federal asbestos rule, with listed exceptions, such as a project that includes two or more houses, a house that was once used commercially, or a house torn down for a commercial or public project. The Santa Barbara district describes its rules as covering institutional, commercial and industrial buildings, not private homes and apartment buildings with four or fewer units. The Monterey Bay district publishes a flowchart for whether a property is regulated and requires a survey by a certified consultant before work on regulated properties. The rules differ by district and by project, so we confirm the survey and notice requirements with the district before demolition (we confirm per project).

Even where a single-family remodel is exempt from district notice, worker-safety rules still apply. Cal/OSHA requires registration for contractors who remove larger amounts of asbestos-containing material, and certification for consultants who sample it. Our practice on older homes is simple: test the materials the remodel will disturb, during design, and let a certified abatement contractor remove anything that tests positive before the rest of demolition begins. That keeps the house and the crew safe and keeps tear-out from stopping halfway through.

4. Old wiring

Knob-and-tube, aluminum circuits and tired panels

Electrical systems age quietly. The wiring we find in older Central Coast homes falls into a few groups:

Knob-and-tube wiring. Found in the oldest homes. It has no ground wire, the insulation on the conductors can become brittle, and it was designed to shed heat into open air, which is a problem where insulation has since been blown into walls and attics. It is also easy to damage when walls are opened.
Aluminum branch circuits. The U.S. Consumer Product Safety Commission’s publication on repairing aluminum wiring explains that aluminum wire was used for general outlet and lighting circuits in many homes and additions built between the mid 1960s and mid 1970s, and that its connections can overheat over time, sometimes without warning signs. The CPSC advises having a qualified electrician evaluate and repair it rather than doing it yourself.
Ungrounded outlets and too few circuits. Two-prong outlets, a few circuits feeding a whole kitchen, and extension cords doing the work of wiring are common in post-war homes.
The panel and service. Some older panels have known problems, many have no room for new circuits, and the service size may not support a heat pump, an induction range, an EV charger or a new addition.

An electrician’s walk-through during design tells us whether the remodel can tie into what is there or whether the house needs a new panel, a service upgrade or a rewire. New circuits and panel work need a permit; our remodel permit guide covers which electrical work does. When walls are open for a kitchen or bathroom remodel is the most practical time to replace old wiring in those rooms, and often the rooms around them.

5. Pipes, drains and fixtures

Galvanized lines, cast iron, sewer laterals and the fixture law

Older homes often have galvanized steel water lines, which rust from the inside and slowly lose pressure, and cast iron or clay drain and sewer lines that crack, corrode or let roots in. Neither problem shows from the room you are remodeling. Two simple checks help: a look at the supply pipe where it enters the house, and a camera run down the main sewer line to the street or septic tank. If the main line is in poor shape, it is far easier to replace it before new floors and landscaping go in. On rural lots, the septic system deserves the same look, especially if the remodel adds bedrooms or bathrooms.

Water-conserving fixtures

California’s water-conserving fixture law applies to many older homes. Under Civil Code section 1101.4, for a single-family home built on or before January 1, 1994, a permitted building alteration or improvement generally requires noncompliant plumbing fixtures, such as older toilets, showerheads and faucets, to be replaced with water-conserving ones as a condition of final permit approval. That can include fixtures in rooms the remodel does not touch. The law lists exceptions, including some historic properties and cases where a licensed plumber certifies replacement is not technically feasible (we confirm per project). We plan the fixture count during design so it does not surprise anyone at final inspection.

Gas lines and water heaters get a look too. Old flexible gas connectors, water heaters without proper seismic strapping, and gas appliances being swapped for electric ones all change the plumbing and electrical scope.

6. Structure

Foundations, cripple walls, rot and termites

Many older raised-floor homes on the Central Coast sit on short wood walls in the crawl space, called cripple walls, and some were never bolted to their foundations. The Earthquake Brace + Bolt program, run through the California Residential Mitigation Program, describes bolting the house to its foundation and bracing cripple walls with plywood as a way to help keep a house from sliding or falling off its foundation in an earthquake, and focuses on wood-framed homes built before 1980 with a raised foundation. A remodel that already has the crawl space open is a natural time to add that work; we check whether the program is open in your area when we plan it (we confirm per project).

Older foundations can also be unreinforced, cracked or undersized for a new addition or a second story. Our second story guide covers what building up asks of the structure below. In parts of North County, expansive clay adds its own movement; our guide to expansive clay soils explains how it shows up in older slabs and footings.

Rot, pests and moisture

Dry rot at sills, around old windows and doors, under bathrooms and at deck ledgers is one of the most common finds once walls are open. Termites and other wood destroying organisms are another. Inspections for them are done by companies licensed by the state Structural Pest Control Board, and a recent report is a useful planning tool before a remodel. Where there has been a leak, the EPA’s guide to mold and moisture is clear that the key is fixing the moisture source, not just the stain; we plan for flashing, drainage and ventilation fixes alongside the finish work.

7. Upgrades a permit can trigger

What the inspector will ask for

A permit for a remodel or addition covers the new work, but in an older house it can also pull parts of the existing house up to current rules. The common ones:

Smoke and carbon monoxide alarms. Health and Safety Code section 17926 already requires carbon monoxide devices in existing single-family homes with a fuel-burning heater or appliance, a fireplace or an attached garage. When a permit is issued for an alteration or addition, the California Residential Code generally requires the home’s smoke and carbon monoxide alarms to meet the rules for new construction, with some exceptions (we confirm per project).
Water-conserving fixtures for homes built on or before January 1, 1994, as described above.
Energy rules. Under the 2025 Energy Code, which applies to permits applied for on or after January 1, 2026, altered parts of an existing home, such as new windows, an added room, a replaced heating system or new lighting, must meet the energy rules for alterations. Our Title 24 overview explains the basics.
Fire hazard zones. In a mapped fire hazard severity zone, additions and many exterior replacements follow Chapter 7A materials rules; see our guide to building in a fire hazard severity zone.
Unpermitted past work. An enclosed porch, a garage converted to a bedroom, or a bathroom added without a permit can come up during plan check or inspection. Sometimes it can be legalized with drawings and inspection; sometimes it has to change. Our guide to remodel permits in SLO County walks through how that works.
Coastal and design review. Exterior changes in the coastal zone or in towns with design review can need planning approval first; see our coastal development permit guide and, for the City of Santa Barbara, our Single Family Design Board guide.

Historic homes

Some older homes are listed on a local historic register or sit in a historic district, and those can carry their own design review for exterior changes. California’s Historical Building Code, Part 8 of the California Building Standards Code, gives qualified historical buildings alternative ways to meet code so their character can be kept. The Office of Historic Preservation notes that for properties on the California Register of Historical Resources, the local building inspector must allow the alternatives in the State Historical Building Code. Whether a house qualifies is a question for the local planning department, early (we confirm per project).

8. Planning for what you cannot see

Discovery, contracts and living through it

No amount of testing sees everything. The goal is to find the expensive surprises before design is final and to have a fair, written way to handle the rest. On older homes we do four things:

Look before we price. Attic, crawl space, panel, sewer camera, lead and asbestos testing, and small inspection openings where the owner agrees, so the estimate is based on the house, not on guesses.
Name the unknowns. The written estimate lists the conditions we could not see and how they would be handled if found, rather than hiding a cushion in the total.
Agree on changes in writing. California sets out what a home improvement contract and change orders must contain; the Contractors State License Board’s guidance on hiring a licensed contractor is worth reading. Before hiring anyone, see how to check a CSLB license, and if you are weighing doing it yourself, our owner-builder vs licensed contractor guide.
Plan how you will live. Lead-safe and asbestos work, water and power shutoffs, and a kitchen or the only bathroom being out of service all shape whether a family stays in the house. We plan the sequence with you so the time without a working kitchen or bath is as short as the scope allows.

For how long the most common rooms take, see our kitchen remodel timeline and bathroom remodel timeline.

9. Planning the schedule

A realistic order of steps

Step	What happens	What usually sets the pace
Walk-through and history	We walk the house, attic and crawl space, ask what has been repaired or added, and pull the permit history.	How much is known about past work.
Testing and inspections	Lead and asbestos testing of the materials the remodel will disturb, a sewer line camera, an electrician’s review of the panel and wiring, and a wood destroying organism inspection where it makes sense.	Consultant and lab scheduling.
Design with real conditions	Drawings that account for what the tests found, the structure, the electrical service and the code upgrades the permit will trigger.	Decisions on scope, and whether to rewire or replumb while walls are open.
Permit	Plan check with the city or county, plus any planning, coastal or historic review.	Plan check corrections and any design review.
Abatement and demolition	Certified crews handle asbestos and lead-safe work first, then careful demolition with the work area contained.	What the survey found and how much of it has to come out.
Open-wall review	With framing exposed, we check for rot, pests, past fire or water damage and hidden structural changes, and agree on any changes in writing.	What is behind the walls.
Rough-in, inspections and finish	New wiring, plumbing, framing repairs, insulation and the inspections that go with them, then finishes and final.	Inspections and long-lead materials.

The order we plan a remodel of an older home in. A small project may combine steps; a whole-house remodel or an addition can add more.

The older-home remodels that go most smoothly put the testing and inspections at the front, while design can still respond to what they find. For the permit path in general, see our SLO County permits guide.

10. Before you design

12 questions to answer about an older house

When was the house built, and when were any additions built?
Do the permits on file match what is built today?
Which painted surfaces will the remodel disturb, and have they been tested for lead?
Which materials will be cut or removed, and have they been tested for asbestos?
What kind of wiring does the house have, and is there room in the panel and service for the new work?
Are the water lines galvanized, and what does a camera show in the sewer line or septic system?
Is the house bolted to its foundation, and are there cripple walls in the crawl space?
Is there dry rot, termite damage or a history of leaks?
Which plumbing fixtures will need to change at final inspection?
Are the smoke and carbon monoxide alarms where current rules want them?
Is the house historic, in the coastal zone, in a fire hazard zone or in a design review area?
Will you live in the house during the work, and who in the family needs extra protection from dust?

If you have an architect already, we work from their drawings. If not, Harrod Drafting & Design can draw the remodel, the addition and the permit set.

How we help

Remodeling older homes with Harrod Built

An early look at the house. Harrod Built is a family general contractor based in Paso Robles, CSLB #986950. We walk older homes with owners and architects, line up the testing and trade reviews, and give a written estimate with the unknowns named. You can confirm our license on the state license lookup.
The right specialists, in the right order. Certified asbestos consultants and abatement contractors, lead-safe certified work, electricians, plumbers and structural engineers, scheduled so findings shape the design instead of stopping the job.
Whole-house thinking. interior remodeling, kitchen and bathroom remodels, exterior remodeling, home additions and structural upgrades, planned so the wiring, plumbing and framing are fixed once, while the walls are open.
Design support. Harrod Drafting & Design, our drafting studio, draws remodels, additions and permit sets, and we also build from plans by outside architects.
Outside the house. Paso Robles Landscaping can rebuild the yard after a sewer line, foundation or addition project, with water-efficient planting.

We remodel in Paso Robles, Templeton, Atascadero, San Luis Obispo, Arroyo Grande, Monterey and Pacific Grove, and across San Luis Obispo, Monterey and Santa Barbara counties, with general contracting, design-build and remodeling services; our process page explains how a job runs.

Planning a remodel of an older home? We can walk the house with you or your architect, line up the testing and inspections before design is final, and give you a written estimate with the unknowns spelled out. Call 805-712-8993 or contact us.

Sources: U.S. EPA: Lead Renovation, Repair and Painting program and rules pages, Renovate Right pamphlet, reducing lead exposure at home, asbestos guidance for homeowners, and A Brief Guide to Mold, Moisture and Your Home. California Department of Public Health Lead-Related Construction program. San Luis Obispo County Air Pollution Control District asbestos page; Santa Barbara County Air Pollution Control District asbestos page; Monterey Bay Air Resources District asbestos renovation and demolition page. Cal/OSHA asbestos page. U.S. Consumer Product Safety Commission Publication 516, Repairing Aluminum Wiring. California Residential Mitigation Program, Earthquake Brace + Bolt retrofit page. Structural Pest Control Board consumer information. California Building Standards Commission codes page; California Energy Commission 2025 Building Energy Efficiency Standards; California Health and Safety Code section 17926 and Civil Code section 1101.4; California Office of Historic Preservation, California Register of Historical Resources. Contractors State License Board guidance on hiring a contractor. All checked October 24, 2026. This guide is general information, not legal, engineering, environmental or code advice; your city or county building department, air district and licensed specialists have the final word on a given house.

FAQ

Common questions

Something else on your mind? Call Michael at 805.712.8993.

Do I need to test for lead paint before remodeling an older home?

If the home was built before 1978, the EPA Renovation, Repair and Painting rule requires anyone paid to disturb painted surfaces to be certified and to use lead-safe work practices, and to give the owner the Renovate Right pamphlet. Testing the surfaces the project will disturb tells everyone what to plan for before work starts.

Is asbestos only a concern in very old houses?

No. Asbestos has no cut-off year, and the San Luis Obispo County Air Pollution Control District notes it is not banned and can appear even in newer materials. Test materials the remodel will cut or remove, such as ceiling texture, flooring and adhesive, joint compound and duct wrap. Survey and notice rules are set by the local air district.

Should I replace knob-and-tube or aluminum wiring during a remodel?

Have a licensed electrician evaluate it during design. Knob-and-tube wiring has no ground and was not designed to be buried in insulation, and the Consumer Product Safety Commission warns that aluminum branch-circuit connections can overheat over time. Replacing wiring is most practical while walls are open.

What code upgrades can a remodel permit trigger in California?

Common ones are smoke and carbon monoxide alarms that meet current rules, water-conserving plumbing fixtures in homes built on or before January 1, 1994, energy code rules for the parts being altered, and fire-zone materials rules for exterior work in mapped hazard zones. Unpermitted past work can also come up during plan check.

How do you handle surprises once the walls are open?

We test and inspect before design is final, list the conditions we could not see in the written estimate, and handle anything found with a written change order before the work changes, as California home improvement contract rules require.

Planning guides

Remodeling an older home? Tell us about your project.

A few details help us call you back with useful answers about budget, schedule and permits.

805.712.8993

michael@harrodbuilt.com
1345 Riverside Ave, Paso Robles, CA 93446
CSLB License #986950

Remodeling an Older Central Coast Home: Lead Paint, Asbestos, Old Wiring and What Hides in the Walls

Each era leaves its own surprises

Homes built before 1978