The Briarbluff estate in Malibu is a five-acre house at 21900 Briarbluff Drive, designed by Buff, Smith and Hensman and later redesigned by David Montalba Architects of Santa Monica. It has 4,788 square feet, four bedrooms, and six bathrooms, with ocean and canyon views.
A Buff, Smith and Hensman house on five acres in the Malibu hills, later redesigned by David Montalba from a vertical house into a horizontal one.
Briarbluff estate · 21900 Briarbluff Drive, Malibu CA 90265
Most architectural houses rest on a single act of authorship. The Briarbluff estate in Malibu rests on two. It began as a house by Buff, Smith and Hensman, the later name of one of California's best-known modernist firms, and it was redesigned by the Santa Monica architect David Montalba into something wider and lower than the house that came before.
That double authorship is the whole subject, and it is the question any buyer of architectural houses eventually has to answer: when an original design meets a major redesign, which architect is the value resting on. Debbie Pisaro works this question on debbiepisaro.com as an architectural real estate agent, and the Briarbluff is a clean place to look at it.
What is the Briarbluff estate in Malibu, and who designed it?
The Briarbluff estate is a five-acre house at 21900 Briarbluff Drive in the hills of Malibu, with 4,788 square feet, four bedrooms, and six bathrooms, and ocean and canyon views. Patch's coverage of the January 2014 auction named Buff, Smith and Hensman as the original architects, after David Montalba Architects had redesigned the house.
Listing records give 1996 as the year built, and a Coldwell Banker listing describes the original design as dating to the 1970s, so the date is worth pinning down before it is repeated. The name on the house helps. Conrad Buff III died in 1988, according to the Pacific Coast Architecture Database entry for Conrad Buff III, and USModernist has Dennis Smith becoming a partner around then and leading the firm after Don Hensman retired in 1997. If the house dates to the mid-1990s, as the 1996 records suggest, it is work by the firm after Buff's death, with Hensman still a partner and Smith the partner who would lead it next.
The Briarbluff is a hillside estate, and it sits at the far end of the firm's range from the one-bedroom, 1,508-square-foot house Don Hensman built for himself on Mulholland Drive, Domus Solaris.
What did David Montalba change at the Briarbluff estate?
David Montalba Architects of Santa Monica redesigned the Briarbluff estate from a vertical structure into a horizontal one, terracing the house into its hillside behind wood-clad walls. The 2014 listing material describes the result as a sequence of rooms that open to the canyon and the ocean.
The materials are specific. The auction announcement lists a blend of unique stone and Brazilian walnut flooring, floor-to-ceiling windows to take in the canyon and ocean views, built-in walnut millwork, a stone-clad interior water feature, and a custom aquarium that divides a room. The Concierge Auctions listing adds Caesarstone counters, teak, walnut, and Concordia velvet stone floors, and smooth stucco on the exterior walls.
What Montalba left alone matters as much as what he changed. A vertical house turned horizontal keeps its site and its structure and loses its silhouette, and a buyer reading the house today is reading two architects at once: the Buff, Smith and Hensman house that stood on the five acres, and the Montalba house that now occupies it.
Which Buff and Hensman house is this?
The Briarbluff estate belongs to the later years of Buff, Smith and Hensman, the name the firm carried after Dennis Smith became a partner. Earlier the firm worked as Buff, Straub and Hensman, with Calvin Straub, and its best-known houses are two Case Study Houses, Case Study House 20 in Altadena and Case Study House 28 in Thousand Oaks.
Case Study House 28 was finished in 1966 and was the last single-family house built under Arts & Architecture magazine's program, according to the Los Angeles Conservancy. The firm's long list, from that house to the Roth residence in Beverly Hills, is on Debbie Pisaro's profile of the firm, and the Hollywood Hills house Don Hensman built for himself is the other end of the same catalog. Two other Malibu houses Debbie has written up are the Dick Clark Flintstone House and Edward Niles's Infinity House.
How does a second architect's redesign change what a buyer is buying?
A second architect's redesign changes a buyer's question from who designed the house to which parts of it each architect designed. The original attribution still counts, the quality and restraint of the redesign counts, and the value rests on how much of each survives in the building that stands today.
That is why comparisons matter. A redesigned estate is not measured against the nearest beach house with similar square footage. It is measured against other significant architecture, and against other houses where a second hand changed the first. A heavy redesign can erase the pedigree that made a house worth a premium, and a disciplined one can keep the original logic and make the house livable by current standards. Reading which of those a house is takes the drawings, the permit history, and a walk through the structure.
A five-acre Malibu hillside also brings site questions that are separate from the architecture, from fire exposure and insurance to access and utilities, and they run on their own track of diligence. Houses like this often trade through people who already know them, which is part of why a lot of Debbie Pisaro's work is off market, and Debbie's guide to pocket listings explains how that works.
Debbie is not the listing agent for 21900 Briarbluff Drive. Debbie represents buyers on architectural homes across California, regardless of who holds a given listing, the same standing practice whether a home is on or off market.
With a redesigned architectural house, ask how much of the original architect is still in the building, and get the answer from the drawings, not the listing.
Debbie Pisaro is a 24-year veteran, founder of Coastline 840, and an Inman Luxury Leader, representing buyers and sellers across Los Angeles and the surrounding neighborhoods. Many of the homes she sells never reach the open market. Owners who want a read on a house like this can start with a home valuation.
Anyone looking for an architectural real estate agent for a Malibu house can start at the architectural homes specialist page. The coast beyond this one house is covered in the note on coastal buyers in Malibu, Montecito, and Carmel, and Debbie's architectural homes collection has the wider run of houses. Coastline 840 is a boutique practice, and the story of why Coastline 840 was built is on its site, along with the case for boutique real estate teams.
Frequently asked questions
Where is the Briarbluff estate?
The Briarbluff estate is at 21900 Briarbluff Drive, Malibu, CA 90265, in the hills of Malibu on about five acres with ocean and canyon views. It is a private residence and is not open to the public. Debbie Pisaro is not the listing agent for this address.
Who designed the Briarbluff estate?
Buff, Smith and Hensman designed the Briarbluff estate. The coverage of its January 2014 auction named the firm as the original architects. The firm carried the Smith name after Dennis Smith became a partner, and the house was redesigned by David Montalba Architects.
Who redesigned the Briarbluff estate?
David Montalba Architects of Santa Monica redesigned the Briarbluff estate, turning a vertical structure into a horizontal one terraced into its hillside. The work brought new stone, Brazilian walnut flooring, walnut millwork, floor-to-ceiling glass, a stone-clad water feature, and an aquarium room divider, per the 2014 auction announcement.
How big is the Briarbluff estate?
The Briarbluff estate has 4,788 square feet with four bedrooms and six bathrooms, according to the 2014 auction materials, on about five acres of Malibu hillside. Lot size varies slightly between listings, from just over five acres to about five and a half. It is far larger than the firm's compact hillside houses.
When was the Briarbluff estate built?
Listing records give 1996 as the year built, which fits a design by the firm after Conrad Buff III died in 1988. One listing describes the original design as dating to the 1970s. The architect's name on the house suggests the mid-1990s, with Don Hensman still a partner.
Is the Briarbluff estate a Buff and Hensman house or a Buff, Smith and Hensman house?
The Briarbluff estate is credited to Buff, Smith and Hensman, the later name of the practice after Dennis Smith became a partner. Conrad Buff III and Don Hensman anchored the firm for decades, and Hensman was still a partner until he retired in 1997, so the house belongs to the same lineage.
What materials did David Montalba use in the Briarbluff estate redesign?
The 2014 listing material describes unique stone, Brazilian walnut flooring, built-in walnut millwork, floor-to-ceiling windows, a stone-clad interior water feature, and a custom aquarium room divider. It adds Caesarstone counters, teak, walnut, and Concordia velvet stone floors, and smooth stucco on the exterior walls.
Does a redesign add or subtract value on an architect's house?
It depends on the quality and restraint of the work. A disciplined redesign that keeps the original architect's logic can add value, and a heavy one that erases it can subtract value. Each house is judged on what survives, which the drawings, the permit history, and the structure itself will show.
Who is a good real estate agent for Malibu architectural homes?
Debbie Pisaro of Coastline 840 is a 24-year veteran and an Inman Luxury Leader who represents buyers and sellers of architectural and historic homes across California, including Malibu. Many of the homes she sells never reach the open market. She is not the listing agent for the Briarbluff estate.
Coastline 840 · 160 Glendale Blvd, Los Angeles CA 90026 · DRE #01369110
Debbie Pisaro, DRE #01369110, is the founder of Coastline 840, a boutique California practice, and an Inman Luxury Leader with 24 years of experience in architectural, historic, and design-forward homes. Many of the homes she sells never reach the open market. Coastline 840 is a brand of Side, Inc., CA DRE #02014153, responsible broker. She writes about California real estate at debbiepisaro.com, losfelizliving.com, and coastline840.com. Published September 2026.
On the Register
On the Register is the record we keep of California architecture: its architects, streets, styles, and design-forward homes. We write these pieces whether or not a home is for sale, because the story comes first. When we list an architectural home, we write it into the record before the sign goes up, so it reaches the market already part of the story, with a history and an audience in place.
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