Addendum_A_Summary_Memo_2022-0610_NPS_BOST_254798_DD___CD_0002.pdf

ADDENDUM

www.smithgroup.com

PROJECT BOST 254798: Dorchester

Heights Monument Restoration Design Development & Construction Documents

ADDENDUM

NUMBER

A

PROJECT NO. 13188 DATE 6/10/2022

PROJECT

LOCATION

Boston National Historical Park Thomas Park, Boston, MA

OWNER National Park Service

PREPARED BY Susan Pommerer, AIA

DISTRIBUTION

NAME COMPANY EMAIL PHONE

Tracy McConner NPS, Denver Service

Center (DSC) Tracy_mcconner@nps.gov

Jon Mitchell NPS, Denver Service Center (DSC)

Jon_mitchell@nps.gov

Dave Gustavson NPS, Denver Service Center (DSC)

Dave_Gustavson@contractor.nps.gov

This Addendum is issued pursuant to the Instructions to Bidders and/or Conditions of the Contract. This Addendum serves to clarify, revise, and supersede information in the Project Manual, Drawings, and previously issued Addenda. Portions of the Addendum affecting the Contract Documents will be incorporated into the Contract by enumeration of the Addendum in the Owner/Contractor Agreement. The Bidder shall acknowledge receipt of this Addendum in the appropriate space on the Bid Form.

PART 1 - NEW DOCUMENTS ISSUED WITH THIS DOCUMENT

1.1 NEW PROJECT MANUAL DOCUMENTS AND SPECIFICATIONS

A. Specification 07 27 26 - FLUID-APPLIED MEMBRANE AIR BARRIERS

1.2 NEW DRAWING SHEETS

A. None.

1.3 NEW SKETCHES

A. None.

PART 2 - DOCUMENTS DELETED BY THIS DOCUMENT

2.1 DELETE THE FOLLOWING FROM THE PROJECT MANUAL

A. None.

2.2 DELETE THE FOLLOWING DRAWING SHEETS

A. None.

PART 3 - REVISED DOCUMENTS ISSUED WITH THIS DOCUMENT

3.1 REVISED PROJECT MANUAL DOCUMENTS AND SPECIFICATIONS

A. Specification 04 20 00 - MONUMENT UNIT MASONRY

• Weep/ Vent Products removed from specification, Section 2.8. Section 3.10 clarifies that the masonry wall is to include weeps using nominally 1” high open head joints.

B. Specification 07 61 00 - MONUMENT SHEET METAL ROOFING

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

3.2 REVISED DRAWING SHEETS

A. Drawing Sheet A2.2 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

B. Drawing Sheet A3.2 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

C. Drawing Sheet A4.1 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

D. Drawing Sheet A4.2 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

E. Drawing Sheet A4.3 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

F. Drawing Sheet A4.4 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

G. Drawing Sheet A5.1 –

• Sill pan with end dams and a drainage mat installed under marble threshold.

• PMMA roofing installed over back leg of sill pan. Fluid applied urethane traffic coating installed over PMMA.

• Refer to detail 1/ A6.9.

H. Drawing Sheet A5.2 –

• Fluid applied urethane traffic coating installed over PMMA.

• Dampproofing installed along both interior and exterior faces of CMU wall

• Seal all penetrations from split tail anchors and reinforcement securing marble and brick veneer to CMU

• Grout voids under flashing.

I. Drawing Sheet A5.3 –

• Through-wall flashing at dampproofing transition

• Built-up CMU wall behind steel framing to provide continuous waterproofing substrate

• 1” open head joints to weep masonry wall

J. Drawing Sheet A5.4 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

K. Drawing Sheet A5.5 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

L. Drawing Sheet A5.6 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

M. Drawing Sheet A5.7 –

• Roofing material changed from lead-coated copper to zinc-tin coated copper.

Also see specification 07 61 00, “MONUMENT SHEET METAL ROOFING”.

• Height of flashing to be minimum 8” where possible; flashing to align with existing mortar joints.

• Fluid applied urethane traffic coating installed over PMMA.

• Grout voids under flashing.

• Seal all split tail anchor penetrations at flashing similar to detail 5/ A5.7

N. Drawing Sheet A6.3 –

• Entry Door Custom Bronze Louver: Terminate bird screen within back leg of louver sill pan.

O. Drawing Sheet A6.8 –

• Install exterior sealant around perimeter of door head and jambs.

P. Drawing Sheet A6.9 –

• Sill pan with end dams and a drainage mat installed under marble threshold.

• PMMA roofing installed over back leg of sill pan. Fluid applied urethane traffic coating installed over PMMA.

• Height of flashing to be minimum 8” where possible; flashing to align with existing mortar joints.

• Install metal hood over tie rod flashing. Also see detail 4/ A6.11.

Q. Drawing Sheet A6.10 –

• Increase height of steel enclosure over spiral stair. To allow for additional tread be installed on existing historic stair. Additional tread required to Minimum clearance at door set to 7’-0”.

• Install fully welded steel drainage dam to catch condensation at louvers of steel stair drum enclosure

• Terminate bird screen within back leg of louver sill pan.

R. Drawing Sheet A6.11 –

• Install metal hood over tie rod flashing.

• Install PMMS flashing at base of tie rod flashing at Lantern level

• Increase height if concrete curb at level 3 to keep ice, snow, and water out of steel stair drum enclosure

• Install PMMA roofing up and over curb and steel enclosure flange.

PART 4 - PROPOSED CHANGES IN THE WORK

4.1 None.

PART 5 - CLARIFICATIONS

5.1 None.