Jeffreyscottpen n

ARCHITECT

J E F F R E Y S C O T T P E N N

77 Worthington Road, Huntington, MA 01050

tel. [phone] fax. [phone]

[e-mail]
1 February 2017
Investigation and Evaluation of Roof for Estimating
Client:

Berkshire Trail Elementary School

2 Main Street

Cummington, MA 01026

General

Berkshire Trail Elementary School is a brick building constructed c. 1940 with additions including a major 1989 reconstruction. The building consists of three one story wings with the end sections hip-roofed connected by a center section with a flat roof. The pitched roof areas are degraded but functional with perhaps 10-15 years left of good seal. The flat area suffers from cupping and water retention and has exhibited some leakage. This EPDM/Rubber roofing is in need of attention.

Assessing the cupping

Roger Gunn, an assistant and I opened a section of the flat roof near the eave to determine the source of the cupping. We revealed the EPDM is installed on 2” brittle rigid insulation on homosote (or similar) press-board upon the deck. The deck was originally 2”x8 t&g douglas fir planking perpendicular to the steel trusses. Apparently at the 1989 renovation, the perimeter (at least 24” where checked) planking was removed and replaced with standard 2x6 nominal wood members without t&g. These boards are easily pushed (deflected) over an inch as shown in the photograph.

I calculated the required load on the planking (using 8'oc spacing for the steel trusses and noting the 50#/sf cummington snow load) and I determined that the replacement 2x6 material supports 46#/sf including dead load but the original 2”x6 planking supports 83#/sf. It is clear that the replacement material was not substantial enough and the deflection has allowed ice and water to build up on the surface.
Solutions for Estimate
1. restore flat roof. In order to restore the roof properly and stabilize the existing features, there are several tasks. See drawing Section A




Task
permit

Dumpster

ground cover/cleanup (tarps expected)

attic repair/cleanup (possible tarps building interior; remove construction debris from attic and top of drop ceiling)

demo roofing and insulation (7000sf)

demo planking (900sf perimeter 2x6's/7000sf entire 2”x6” as alternate c.)

new 2”x6 t&g #1 dougfir planking (900sf perimeter/7000sf entire as alternate c.)

securing method – code is 16d nails at each bearing (assume 2 @ 96”oc)

new insulation (4” rigid 7000sf tyvek tape joints) for R20 include radient reflector layer – also must spread (redistribute) existing loose blown in insulation into even 5 1/2” layer at attic joists

3/4” t&g cdx ply. (7000sf)

fasteners (6 3/4” Flat Lok or equal; 4”oc edges and 8”oc intermediate supports)

15# felt underlayment (7000sf)

EPDM (60 mil white) or approved equal roofing (7000sf)

scuppers (tin) assess existing for reuse (expected)

(picture at right)

assess penetrations (vent stacks, skylights, hatches)

ice and water shield by WR Grace (2 layers/min. 48” cover at eaves; 210 lin. ft. perimeter + one width at penetrations, hatches, 200 lin. ft. valleys)

flashing (tin 210 ft. perimeter Rake style + penetrations boots; bent at hatches)

chimney restoration (demolish to roofline, clean, reconstruct with (ASTM C 62) bricks and type N mortar) – chimney is 3'-6”x 3'-6” and extends 17' above roof

restore skylights (conditions to be determined) – see Alternate h. for skylight removal

remove/replace fascia with 2 layers Kleer lumber: 6” and 10” glued and secured

2. replace the sloped roof areas as is. See Section B

task
permit

Dumpster

ground cover/cleanup (tarps expected)

attic repair/cleanup (possible tarps building interior; remove construction debris from attic and top of drop ceiling)

demo roofing EPDM (3250sf South flat area) and asphalt shingles (footprint 9471sf South, 5318 sf North; 3/12 – 9763sf South, 5481sf North))

(assumption of good condition sheathing – carry alternate full sheathing replacement)

sister 3 rafters (2x10x20')

new insulation (R30 plastic batts secured in rafter bays; 18,500sf) and reinstall existing thin batts within ceiling joist bays

15# felt (18,500sf)

new 60 mil white EPDM or approved equal roofing (3250sf) for Flat area

new 30 yr asphalt architectural shingle roofing (15,300sf) and low profile ridge vent – see alternate i for 50 year roofing

drip edge/new fascia (850 lf perimeter – new kleer lumber 7 1/4”; Eave style drip)

ice and water shield WR Grace eaves (2 layers/min. 48” cover; 850 lin. ft. perimeter)

ice and water shield WR Grace hips/valleys (1 layer 30” 400lf + penetrations)

ice and water shield WR Grace edge EPDM (1 layer 30” 300lf)

assess penetrations (vent stacks, hatches)

flashing (penetrations; boots where possible)

remove, store and reinstall gutters

3. Alternates (a. add slope to top of South hip; b. metal roof; c. replace all flat roof sheathing; d. planking material change; e. replace sloped roof sheathing, f. additional rafter augmentation, g. ice and water shield entire roof, h. remove skylights, i. 50 year shingle roofing)
tasks
Alternate a. add slope to top of South Hip (3250sf):
demo EPDM

assess sheathing

new trusses at top of hip (South – picture right):

add trusses (3250sf) to be designed by manuf.

add securing/fasteners as determined by manuf. Tech dept

add 3/4” t&g CDX plywood (3350sf)

add 15# felt (3350sf)

additional roofing (+ 3350sf total)

extend vents

boot/seal/ice and water shield WR Grace penetrations

(deduct EPDM etc. from #2)
Alternate b. new metal roof (min. 26 ga enameled) (15,300sf + 3350sf):
after demo, verification of solid surface and installation of new trusses and plywood; install 18,650sf metal roof over 15# felt

(deduct other roofing from #2)

Alternate c. full flat roof sheathing replacement in addition to perimeter:
demo planking (7000sf entire as alternate)

new 2”x6 t&g planking (7000sf entire as alternate)

securing method – code is 16d nails at each bearing (assume 2 @ 96”oc)

(deduct perimeter planking replacement/securing from #1)

Alternate d. material change for planking
switch #1 Dougfir to #1 Hemfir and show difference per square foot
Alternate e. sloped roof sheathing replacement:
demo existing sheathing as determined degraded

new 3/4” t&g CDX plywood (18,650sf)

fasteners (16”oc rafters) 8d nails 4”oc edges and 8”oc intermediate supports for 3/4” plywood)
Alternate f. additional rafter augmentation
if rafters are determined degraded, provide a price per rafter for sistering new 2x10x20' #1 hemfir rafters
Alternate g. ice and water shield entire roof
add Ice and Water shield over entire roof (25,650sf total)

(deduct other sections)

Alternate h. remove skylights
remove 2 skylights

frame structural roof support (2x10's @ 16”oc)

install planking, insulation, plywood, 15# felt and EPDM roofing as part of main roof (square footage not deducted from main bid)

repair/complete interior ceiling (both locations drop acoustic tile panels)

Alternate i. 50 year roofing
new 50 yr asphalt architectural shingle roofing (15,300sf) and low profile ridge vent


4. other notes and tasks

a. building permit required, fee waived

b. proper staging and safety measures are required; protect existing features

c. Selectboard to determine all color and other choices

d. assess all other trim and brick for maintenance, repair or replacement recommendations

e. maintain clean work site and properly dispose of waste and demolition debris