31B-255 60 State engineering! RYAN S. HELLWIG, PE ! STRUCTURAL ENGINEER !
September 2, 2011
Thomas M. Growhoski, Attorney at Law
Doherty Wallace Pillsbury & Murphy, P.C.
60 State Street
Northampton, MA
Re:Tree Damage to Roof Structure
60 State Street
Mr. Growhoski,
The following is a summary report of the inspection that I made today of the above-mentioned roof.
This roof is approximately 22'-6" wide, with a pitch of roughly 7 vertical to 12 horizontal. The bottoms
of the rafters are tied together with existing ceiling joists at the eave level. Several rafters as well as
some of the roof sheathing must be replaced due to the impact of the tree.
The proposed repair consists of #1/#2 2x8 Spruce-Pine-Fir rafters spaced at 16" on center. Because of
difficulties with fitting a new rafter into the existing structure, a kneewall was built about four feet from
the front exterior wall, and the new rafters on that side were spliced over this wall. The rafters on the
back side of the roof are full-length from ridge to eave.
In order to avoid overloading the existing ceiling joists with the roof load carried by this kneewall, the
wall will be reinforced. Since the wall is 12 feet long, the reinforcement should consist of a single full-
length piece of 1¾" x 14" LVL (laminated veneer lumber) or a double 1¾" x 11f" LVL. The LVL
should be attached to the kneewall studs with two TimberLOK or TrussLOK screws at 16" on center.
The existing rafters that were not damaged are “grandfathered” by the Code, as existing construction
predating the first building code in Massachusetts. However, the new work must meet the snow load
grequirements of the current Code, 8 Edition. For Northampton the ground snow load p is 55 psf. Thisth
stranslates to a sloped roof snow load p of 39 psf, which is the value that I used in my analysis. This
t eincludes values of 1.0 for the temperature factor C , exposure factor C , importance factor I and the slope
sfactor C .
After the emergency work is complete, restoring the roof to a proper weather-tight condition, the walls
below the ends of the kneewall should be checked to ensure that they have a continuous supporting load
path down to the ground. Additional work may be necessary.
Respectfully,
Ryan S. Hellwig, PE
Massachusetts Professional Engineer #37300 - STRUCTURAL
Copy to:Bill Gillen (Architect) & Charles Miller (Assistant Building Commissioner)
! 28 ALDRICH STREET ! NORTHAMPTON, MA 01060 !
! Voice = 413-584-HLWG (4594) ! Fax = 413-584-HLWFax (4593) ! Email = rshpe@crocker.com !