STATE OF CALIFORNIA - NATURAL RESOURCES AGENCY GAVIN NEWSOM, GOVERNOR

CALIFORNIA COASTAL COMMISSION South Coast District Office 301 E Ocean Blvd., Suite 300 Long Beach, CA 90802-4302 (562) 590-5071

Th19d5-20-0142 (316 24TH STREET HOLDINGS, LLC)

September 10, 2020

CORRESPONDENCE

1. Nicole Ellis2. Bud Gottesman

8/19/2020 Mail - Seifert, Chloe@Coastal - Outlook

RE: Clarification on Duplex at 316 24th St

Nicole Ellis <nellis@hermosabeach.gov>Wed 8/5/2020 10:29 AMTo: Seifert, Chloe@Coastal <chloe.seifert@coastal.ca.gov>

Good morning Chloe and thank you for reaching out!

The site contains an exis�ng leg al non-conforming duplex as indicated in the City’s permit records and through theLA County Assessor. A property owner cannot declare a use or density as terminated or ended. There must be aformal review/ consent from the City such as through a permit/plans.

Our City is preparing a memorandum to address replacement units, ADUs and JADUs and SB330. In themean�me, an ADU is c onsidered a dwelling unit under state law. Government Code 65852.2(j)(1) states:

(1) “Accessory dwelling unit” means an a� ached or a detached residen�al dw elling unit that providescomplete independent living facili�es f or one or more persons and is located on a lot with a proposed orexis�ng primar y residence. It shall include permanent provisions for living, sleeping, ea�ng , cooking, andsanita�on on the same par cel as the single-family or mul�f amily dwelling is or will be situated. Anaccessory dwelling unit also includes the following:

(A) An efficiency unit.(B) A manufactured home, as defined in Sec�on 18007 of the Health and Sa fety Code.

Thus, the proposed single-family residence with ADU at 316 24th Street would replace the same numberof exis�ng dw elling units.

Please let me know if you have any addi�onal ques �ons.

Thanks again Chloe!

Nicole EllisAssociate PlannerCity of Hermosa Beach | Community Development Department1315 Valley Drive | Hermosa Beach | CA 90254(310) 318-0244 | www.hermosabeach.gov

Please consider the environment before prin�ng

1

California Coastal Commission South Coast District Office 301 Ocean Blvd. #300 Long Beach, CA 90802

RE: Application for residential construction at 316 24th St, Hermosa Beach CA 90254/Permit 5-20-0142

August 13, 2020

Dear CCC Panel:

We are writing to express our concern over the development of a single-family home at 316 24th St, Hermosa Beach, on the adjacent lot to the downhill/west side of our home at 322 24th St, Hermosa Beach. The development is scheduled to be discussed by your panel on Wednesday, Sept. 9, 2020.

Our concerns focus primarily on the proposed two-level subterranean basement (“double basement”) outlined in the plans for the new home. As proposed, each level of the underground double basement spans approx. 1,400 square feet and would require excavation of a depth of anywhere from 16 to 24 feet, along with the requisite shoring and protective retaining walls.

While the applicant engaged NorCal Engineering to examine the site, the soils and the suitability of the site for such development, we similarly engaged an independent soil engineering firm, Hamilton & Assoc. based in Torrance, to also conduct a thorough examination of the site.

The findings of Hamilton & Assoc. are contained in the attached document, including the identification of loose-running sandy soils that show indication of caving when disturbed. Of course, this is not a surprise since the proposed site sits atop a very steep former sand dune on what is now one of the steepest streets in Hermosa Beach (see attached, fig. 1-3).

Because our property sits just 3 feet uphill from the proposed construction, (see attached, fig. 4 & 5), we have legitimate concerns about not only the integrity of our home, including its foundation, but for our own safety in the event of sliding or movement of our residence during the excavation and shoring process.

In fact, both NorCal and Hamilton & Associates distinctly forewarn of the danger to neighboring structures, including (but not limited to) ours.

From NorCal: “Shoring members should not be vibrated or driven due to the potential for damage to neighboring structures” (page 8, section 8.2).

From Hamilton & Associates: “Baseline-, during- and post-construction monitoring should be performed on the site improvements and the shoring systems, including off-site improvements and structures, not limited to your residence at 322 24th Street” (page 3, second to last paragraph).

Although we personally believe that new construction calling for the deep excavation of up to 24 feet in loose-running sandy soil that may cave and can potentially damage nearby homes may be problematic, we realize that people have the right to build the house they want to build.

2

That said, we would join in supporting the requirement (outlined by both by NorCal and by Hamilton & Associates) for the construction to be fully and completely monitored daily by an on-site, third-party soils engineering professional during the precarious excavation and shoring period.

In addition, we would request:

• A thorough Q-A plan that outlines exactly how the excavation, shoring and workmanship will be monitored and supervised by a professional engineer each day on site, and by whom.

• The filing of daily reports that track the excavation/shoring and immediately note any evidence of caving or sliding issues. It is critical that the contractor be continually reminded about and aware of the extreme instability of the soil, and its apparent inability to maintain a steep slope when excavated.

• The prohibition of unsupported temporary excavations adjacent to our property to the east (uphill), which currently includes existing walls and pavement immediately abutting the property line.

• A thorough review by the City of Hermosa Beach building department (or third-party expert) focused on the geotechnical challenges of this lot, and the merit of its structural and shoring design. This local review is extremely important prior to approval of the building permit, as it is the city’s responsibility to protect the life and safety of its residents.

• Complete sets of structural and shoring plans applicable to development for third-party review prior to demolition. These documents have yet to be made available.

Finally, we would like to sincerely thank you for your panel’s commitment to the integrity of our coastal zone in California. We have lived in Hermosa Beach for more than 60 years, raised our family here, and have always appreciated the work you do on behalf of coastal residents and in the best interest of our beach communities.

Thank you and we look forward to your consideration,

Bud and Joanne Gottesman 322 24th St. Hermosa Beach CA 90254 310-376-9541 310-780-0511

CC: Bob Rollins, Building/Code Enforcement Official, City of Hermosa Beach

Updated July 31, 2020 Project No. 20-2751

Mr. Bud Gottesman 322 24th Street Hermosa Beach, CA 90754 Subject: Geotechnical Consultation Letter Update, Proposed Subterranean

Construction at 316-318 24th Street Hermosa Beach, Hermosa Beach, California.

References: 1. Geotechnical Engineering Investigation, Proposed Single Family

Residence, 316 24th Street, Hermosa Beach, California, NorCal Engineering, Project No 21210-20, Dated January 14, 2020

2. SDG Design & Development, Inc. Select Provided Pictures of Proposed

Project, Proposed Multi-Family Residence over a Basement, 316-318 24th Street, Hermosa Beach, dated unknown.

3. Civil Engineering Plans, Proposed Residence, 316 24th Street, Hermosa

Beach, California, B.A. Sims, Project No. 20017 R2, Building Permit No. B20-00027, Dated April 20, 2020

4. Geotechnical Consultation Letter, Proposed Subterranean Construction

at 316-318 24th Street Hermosa Beach, Hermosa Beach, California, Hamilton & Associates, Inc., Project No. 20-2751, Dated June 10, 2020

Dear Mr. Gottesman: In accordance with your request, this letter has been updated to include review of two additional references provided by the City after we issued our initial review letter dated June 10, 2020 (Reference No. 4). A public records request was submitted to the City of Hermosa Beach on May 11, 2020 requesting available geotechnical documents for the adjacent site. On June 15, 2020, the City replied back and provided H&A with the geotechnical report and Civil plans for the subject project. Proposed Plans

The Civil plans provided to H&A were prepared by B.A. Sims and are dated April 20, 2020. Based on review of the Civil plans the following has been noted. For the proposed project, the existing rear alley street grade and front street grade are roughly 296 and

Gottesman Consultation Updated July 31, 2020 20-2751 Page 2

302, respectively, 6-feet +-. The proposed basement elevation is roughly 283 and will be under the entire footprint of the proposed residence. Temporary excavation for a mat slab or footings would be deeper. Surface grades vary along the sidewalk of the Gottesman property and the Civil plan shows a few spot elevations on the order of 297 to 305, therefore their proposed basement may include temporary excavations on the order of 16- to 24-feet below the Gottesman property grades. Civil Plan Sheet C-3.0 shows the approximate location of the proposed temporary shoring to be used in the construction of the basement. The shoring is provided by a separate permit. No further information about shoring was obtained from this plan set. An exterior wall is proposed immediately against the property line and the existing Gottesman wall. It is not clear if the porposed wall is only a screen wall (like a fence) or will retain soil or require temporary excavation immediately adjacent to the Gottesman wall. Select pictures of architectural plans prepared by SDG Design and Development were provided to this firm. Based on our review of the provided plans the proposed residence appears to include a 1,425 ft2 subterranean basement level, 445 ft2 partial subterranean first floor, 530 ft2 partial subterranean first floor ADU, 408 ft2 partial subterranean Garage, 925 ft2 second floor and 1323 ft2 third floor. The design possibly includes perimeter property line retaining walls in lieu of portions of residence first and second floor retaining walls. Plans indicate on the order of 10- to 20-feet (however, Civil plans indicate 16- to 24-feet) of temporary excavation to achieve proposed subterranean foundation grades. Plans indicate that a separate shoring plan was also submitted. Neither the structural plans nor shoring plans were provided to this firm for review. Geotechnical Report

A soils report for the subject site was prepared by Norcal Engineering and is dated January 14, 2020. Review of the report indicates that the proposed residence will be supported by conventional slab on grade foundations with perimeter spread footings and interior footings. According to the Norcal report, grading will include cuts on the order of 10 to 20 feet. (However, the Civil plans indicate possibly up to 24-feet of temporary excavation relative to the Gottesman property grades) Field exploration by Norcal consisted of three borings via hand operated auger to depths of 2-feet to 24-feet below the ground surface. Encountered fill material was classified as a silty sand with an approximate depth of 1- to 1.5-feet. Underlying the fill material was native silty sand. No groundwater was encountered but some caving occur at depth. NorCal provided geotechnical recommendations for shoring and recommended that any drilled caissons be cased and that shoring members not be vibrated or driven due to

Gottesman Consultation Updated July 31, 2020 20-2751 Page 3

potential damage. NorCal states that unshored cuts may have a maximum 3 foot of exposure unless soil is cohesionless. (However, unshored excavations should not be performed adjacent to the Gottesman Property) Comments

The proposed development will cover the majority of the property. Based on our recent review of the Civil Plans the proposed basement will require on the order of 16- to 24-feet of vertical temporary excavation below the existing Gottesman grades, adjacent to the property line. The design and construction team are required to meet California Building Code (CBC), City of Hermosa Beach building department and performance standards and the standard of practice. Hermosa Beach Municipal Code details requirements for the protection of private property during construction, including but not limited to Section 15.04.070. Norcal classified subsurface soils as loose to medium dense silty sands with water content on the order of 2% to 4%. This relatively dry sand material is also referred to as a running sand due to its instability to maintain a steep slope when excavated. It is imperative that the contractor for the site beware of this condition and consider appropriate construction techniques for the installation and performance of shoring, as needed. The NorCal geotechnical report states that unshored cuts may have a maximum 3 foot of exposure unless soil is cohesionless. However, no unsupported temporary excavations should be allowed adjacent to the Gottesman property, which includes existing walls and pavement immediately adjacent to the property line. Shoring design, construction techniques and workmanship should meet the standard of practice. The general contractor and their subcontractors’ workmanship are imperative to successful implementation and performance. Baseline-, during- and post-construction monitoring should be performed on the site improvements and shoring systems, including off-site improvements and structures, not limited to your residence at 322 24th Street. Installation of the shoring should be monitored by a full-time deputy soils inspector, under subcontract to Norcal, the Geotechnical Engineering Firm of Record. It is not the responsibility nor within the authority of Mr. Gottesman or Hamilton & Associates, Inc. to review or approve the geotechnical report by Norcal. The Norcal report should be reviewed and approved by the City as part of the Building Department Plan Check process. If the City does not have in-house specialty to review and approve the geotechnical report, then the City should contract a qualified third-party Geotechnical Firm to perform review of the geotechnical report by Norcal, until it is approved. The reviewing

Gottesman Consultation Updated July 31, 2020 20-2751 Page 4

geotechnical firm should be reputable and regularly provide geotechnical building department reviews for Cities, such as GMU Geotechnical, or another qualified firm.

CLOSURE

This letter was made in accordance with generally accepted engineering procedures and included such observation and document review considered necessary in the circumstances. In the opinion of the undersigned, the accompanying report is in conformity with generally accepted engineering principles and presents fairly the information requested. No other warranty, expressed or implied, is made as to the professional advice included in this report. Respectfully submitted, HAMILTON & ASSOCIATES, INC. David T. Hamilton, PE, GE President/ Principal Geotechnical Engineer Distribution: (1) Addressee

lo

Figure 1: Sandy lot at 322 26th Street, HB shows similar loose sand characteristics

Figure 2: 300 block of 24th Street

Figure 3: 400 block of 24th Street

Figure 5: 322 and 316 24th Street from front (24th Street)

Figure 6: 322 and 316 24th Street from back (Loma Drive)

8/19/2020 Mail - Seifert, Chloe@Coastal - Outlook

https://outlook.office365.com/mail/search/id/AAMkADBjOGQ0ZTIwLTBmODctNDgyNy1hM2YwLTc0MzE1NjY0ZDBlMgBGAAAAAAC10kBwZvnrSaeVe… 1/1

Addendum to Gottesman correspondence

Bud Gottesman <bud.gottesman@gmail.com>Fri 8/14/2020 3:38 PMTo: Seifert, Chloe@Coastal <chloe.seifert@coastal.ca.gov>Cc: Bud Gottesman <bud.gottesman@gmail.com>

1 attachments (2 MB)GuestHouse24thSt.jpg;

Dear Chloe:

In reading the August agenda items, we noted a postponed Hermosa Beach residen� al permit request that wasvery similar to the request next door to us at 316-318 24th St. (permit 5-20-0142).

As an addendum to our le� er dated August 13, we would simply emphasize that the structure in ques� on at 316-318 24th St. is a zoned R-2 duplex that has long offered housing to two dis� nct family units with a pa� o/open spacebetween them.

The “back house” at 318 24th St has consistently been rented to a range of neighbors, from single parents withschool-age children to young couples just star� ng out, and the “front house” has also been home to a wide rangeof tenants.

A� ached is a photo of the guest house, which shows a dis� nct and separate unit that surely reflects the originalspirit of the ADU/JADU required by the Coastal Commission.

Best,

Bud and Joanne Go� esman322 24th StHermosa Beach, CA 90254

“Attached is a photo of the guest house, which shows a distinct and separate unit that surely reflects the original spirit of the ADU/JADU required by the Coastal Commission.” -Bud Gottesman