Attachment - VA 541-23-202 Statement of Work.pdf

Statement of Work

SOW

GENERAL SCOPE

The general scope of this project is to provide design and provide engineering services together with a VA format driven construction contract package for the replacement of the roof on the Learning Exchange Building. The final construction drawings and investigative deliverable of this project will be a comprehensive condition survey of the roofs including a description of existing conditions, recommendations, and a preliminary construction cost estimate. The final deliverable of this project will be a complete, stamped construction package including drawings, specifications, project narrative, and a construction cost estimate. The design package will incorporate the findings and recommendations detailed throughout the investigation narratives within this report.

SITE SAFETY

The roof is only accessible by a roof hatch from a second-floor fixed ladder. This hatch is equipped with guardrails and a gate at the ladder side. When the hatch guardrails are removed for construction temporary guardrails need to be installed during that time. The high corner roof at the south corner can only be accessible by a ladder. The approximate height change from the main roof to the high roof is four feet.

There is an equipment screen around the mechanical equipment which serves two purposes. This screen conceals the equipment and provides roof edge protection during equipment maintenance.

The proposed staging plan shows the location of the dumpster, and temporary fencing around the building area. Access to the sidewalk needs to be always maintained between the fence and the curb. When materials are to be loaded up onto the adjacent roof safety precautions are to be put in place as to protect vehicle and pedestrian traffic.

The trees along both streets will need to be protected during construction.

The building roof south of the site is to be used as a staging area. The contractor shall protect the roof during construction, provide fencing at the perimeter. The contractor is also responsible for providing a loading capacity diagram of this roof and the location of the materials need to be shown on the plan. The contractor will also have to coordinate with the COR regarding the hours it can be used deeding on the eradicated noise levels that will be generated.

EXISTING CONDITIONS

General Roof Conditions The general roof conditions indicate the roof have been previously patched and maintained. There are four (4) roof drains on the main roof which are located in two pairs which collects the water from the center area of the roof with a main cricket to direct the water to the drains. Within the two pairs there are low drains which are the primary drains.

The overflow drains are slightly higher and are adjacent to the primary drains. The high corner roof drains onto the main roof by a scupper.

The owner stated that the roof perimeter gravel stops are leaking, and the roof drains may be plugged. There are areas where roof leakage is evident, and overall deterioration is evident on the roof.

The EPDM membrane is failing as it is billowing, cupping, and stretching. This will lead to the material tearing and allowing water into the building.

Building Roof The building roof composition is .060 EPDM membrane, 3” polyisocyanurate roof insulation over a 1-1/2” metal roof deck.

The main roof structure has a high point at the permitter and slopes down to a central area at column line B. The water is then directed to the roof drains by sloped crickets which are located at the center of the building, running north-south

The high roof at the south and the roof at the north end of the building slopes to a scupper east side and deposits water directly onto the roof below. At the main roof the structure slopes 8 inches from the high points which are roughly 1/4 inch to a foot slope.

There are no parapets as the edge of the roof is only slightly higher than the main roof elevation.

Roof Drain Investigation It appears that the four (4) main roof drains may be slightly clogged as there are roof stains showing ponding water at the drains. This is an unsafe condition as the ponding water can leak into the building causing damage, and mold. The standing water also deteriorates the roofing membrane and adds to the dead load to the roof.

Rooftop Equipment The roof equipment is located in the screened area at the west side of the building. The flashing and conduit and pipe support look to be in good shape. There are also some small roof fans at the north and south end of the building that look newer and have held up well.

There are a fair number of pipes and conduits and wires on the roof and in the equipment screened area. These supports temporary support during construction and then be supported when the work is complete.

This process of working around many obstacles will increase the construction costs as it will require more labor.

Lightning Protection The existing lightning protection was installed in 2017 and is in very good condition, although there may be a few couplings that may need to be replaced.

The air terminals are located at the perimeter of the main roof and on top of some of the roof fans, and on the four corner columns at the mechanical screen wall. There are also air terminals on the high roof terminals at the southeast corner of the building. The building is also grounded at the mechanical equipment and waste pipes.

The cables primarily run along the perimeter of another roof but also run in and around the mechanical screen wall area. These cables are attached to the membrane roof with adhesive and an attachment device.

PROPOSED DESIGN

Building Roof The new roof will consist of a Cold Adhesive (SBS) Modified Bituminous Membrane roof system over new ¼” cover board over the existing insulation. This roof system will include a base sheet, and a top granule coated top sheet.

The wood fascia blocking at the perimeter of the building will be removed including the aluminum fascia. The roof insulation along the perimeter will also need to be removed the width of the new wood blocking. The height of the permitter blocking will be increased to accommodate a new cant strip. All the new wood blocking shall be pressure treated material. In reviewing the code, fire retardant material is not required for this type of building which is listed as Type 1B. There will be a flat gravel stop along the edge of the roof which will flashed into the roof.

The wood blocking and the roof equipment such as the roof fans, HVAC equipment, flues, roof hatch, etc. will remain in place.

The mechanical supports will remain connected to the conduits and pipes and will be lifted off the roof surface during construction. The roof equipment, including HAVC, roof will remain in place and flashed into the new roof. The roof fans, roof hatch, and electrical roof box covers will have to be removed to install the curb flashing.

The roof crickets will be removed and replaced with new material to divert water into the low areas and into the roof drains. The roof drain and skimmers will be removed and replaced in kind with new materials and be connected to the existing pipping in the building.

New walk pads will be provided from the roof hatch to the screen mechanical area and will continue around the mechanical equipment.

The perimeter gravel stop and fascia will be removed including the scupper at the high roof. As the scupper and gravel stop are one piece it will be removed and replaced with a scupper and downspout to the roof below. A downspout will now be provided to prevent the damage of the roof below. Depositing water directly onto a roof even a short distance will damage it over time. There will be elbow at the bottom of the downspout into the splash block. We are showing a concrete splash block to divert the water directly onto the roof.

The roofing at the intersections between the walls and the roof shall be flashed into the wall using a termination bar, sealant, and counterflashing, like the existing conditions.

Lightning Protection The overall lightning protection system seems to be in good condition as it was installed in 2017.

Remove and reinstall the air terminals and cables. Replace air terminal bases or cable supports as necessary, such that the reinstalled lightning protection system will match the existing and pass inspection. Any equipment damaged during construction shall be replaced in kind. For lightning protection system design, drawings, and calculations see the refer to Project Number 541-17-510 performed by others.

Roof Drains The two (2) current 4” roof drains have been running slow with the result of water ponding on the low portion of the main roof. There are two (2) additional 4” overflow drains adjacent to the main drain about 3 feet away but the water still seems to be ponding. I referred to the International Building Code (IBC) regarding the drainpipe size requirements for a flat roof in Cleveland, Ohio. According to (IBC) Plumbing code section 1106, two (2) 4-inch drains would be required for the main roof based on 4 inches of rain per hour. The current two main drawings are 4 inches which are sized correctly but they will need to be checked for flow as they may have been clogged with debris over the years.

This will require working from below to connect it to the deck from the bolts at the roof level.

Fall Protection Anchors We are proposing four (4) steel pipe anchoring devices for the center portion of the roof, to access the portions of the roof outside of the screened walls. Although most of the mechanical work is inside the screen walls a person is protected in this area by the permanent screens, although the tie downs can be utilized for all portions of the roof.

These anchoring devices will be bolted to the steel deck below and fastened by a square steel plate. We are specifying a factory manufactured post with a steel plate with holes for bolting the unit onto the roof. This unit would be manufactured of high strength steel, with a tensile strength of 5,000 lbs.

This will require working from below to connect it to the deck as through bolts and plates are required for the installation.

PROJECT PHASING AND IMPACTS ON MEDICAL CENTER

This is a preliminary discussion on project phasing. Project phasing will be updated in the specifications, project narrative, and construction drawings as the project progresses. It is recommended that roof replacement phasing should take place by wings and buildings. Preliminary phasing includes:

• Phase 1 – Column line 4 (center of the building east-west) to the north

• Phase 2 – Column line 4 (center of the building east-west) to the south including the high roof