Item 4 - 1836 Pearl St Boulder - Structure Assessment Report1836 Pearl St. Boulder, CO P a g e | 1
Atkinson-Noland & Associates, Inc.
December 4, 2018
Ms. Marcy Cameron
Historic Preservation Planner II
1739 Broadway, P.O. Box 791
Boulder, CO 80306
(303) 441-3207
Re: Structural Observations - 1836 Pearl St. Boulder
Dear Ms. Cameron:
At the request of the City of Boulder, I conducted several site visits at the existing residence at 1836
Pearl St. Boulder, Colorado. Mr. Chris Hulse met me on site each time to facilitate entry into the
structure. The purpose of the site investigations were to look at the basic structural adequacy of the
residence and to report on the observed conditions.
The original residence is a single story, clay brick masonry house reportedly constructed before 1880.
The structure is approximately 29 ft. by 22 ft. in plan with the longer dimension running North to South.
There is an addition constructed at the southeast corner that encloses another approximately 320 sq. ft.
The addition is wood stud framed construction with wood floor joists and wood roof framing.
Foundation
The foundations are rubble stone masonry that is mortared. The foundation walls for the original
building transition to clay brick masonry approximately 30 inches above grade. The foundations for the
addition are also stone masonry. There is a cementitious parge coat on the exterior of all the
foundation walls.
Not all of the foundations could be observed. Portions of the foundations on the original structure could
be seen from the unfinished half basement (Figure 1). As the foundations have a parge coat on the
exterior, the conditions behind the coating could not be observed. Further, there was no practical
access to the crawl space under the addition to observe these foundations.
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Atkinson-Noland & Associates, Inc.
Figure 1. Image from the partial basement under the north
half of the original structure.
Floor System
The wood framed floors are not level on the interior and typically slope towards the middle of the floor
joist spans in the original building. The floor near the doorway to the front bedroom is nearly 3 inches
lower than the floor at the building perimeter. The floor joists are 2 x 6-inch members that need a
continuous support at mid-span to be structurally viable for the existing span. There is some support of
the floor joists near mid span however a number of joists have also been partially cut and compromised
when heating and plumbing were added (Figure 2).
The floor system will need to have a continuous structural support installed near mid-span and the cut
joists sistered with new joists. Identification of the wood species and grade of the floor framing could
result in the requirement that all joists be sistered.
The floor framing for the addition was not determined. It is likely that some strengthening/replacement
will be required.
Figure 2. Beam visible below heating duct is intended to act as a midspan support for the floor framing.
The vertical supports typically bear on earth or a loose stone. At right, a number of joists have been cut
and partially sistered with smaller framing members.
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Atkinson-Noland & Associates, Inc.
Ceiling
The ceiling is wood framed and supports what appears to be a plaster and lath ceiling. The framing is
undersized for the span length and will have to be strengthened by sistering with 2 x 6-inch members.
The ceiling framing in the addition was not observed.
Roof Framing
The roof framing is in good condition although the 2 x 4-inch rafters are undersized for the span (Figure
3). Some roof strengthening will be required including sistering the rafters with 2 x6 inch members and
installing collar ties at each rafter bay. The chimney bracing will have to be strengthened as well (Figure
4).
Figure 3. Images of the roof framing and gable ends. Left is a view to the south end of the house – right
to the north. Diagonal bracing is present at both gables and occasional collar ties are evident.
Figure 4. The clay brick masonry chimney enters the attic space to the West of the roof ridgeline (left)
and jogs to the East to align with the roof ridge (right). The bracing appears haphazard and constructed
with low-grade timber. The bracing is not structurally adequate for the eccentric loads of the inclined
chimney.
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Atkinson-Noland & Associates, Inc.
Exterior Walls
The exterior masonry walls appear to be in relatively good condition. The only major crack is in the
south elevation near the southwest corner and is through the wall. The exterior walls are generally
plumb with the exception of a portion of the east elevation where the wall is approximately 1/8 inch out
of plumb over the length of a 4’ level.
Figure 5. Through wall crack on south elevation.
The through-wall crack could be stitched with stainless steel helical reinforcing installed in the bed joints
on both sides of the wall. Mortar joints would be cut out to a depth of 1 inch, the reinforcing installed,
and mortar repointed to complete the repair. Plaster would need to be repaired on the interior as well.
The exterior stucco was installed sometime after the original construction of the main building. The
brick was scored to increase the bond with the stucco (Figure 6). Some of the stucco is missing – mainly
on the north elevation and there are adjacent areas where the stucco is debonded from the masonry
walls.
If it is deemed that the stucco is a desirable characteristic of the structure, the stucco can be sounded,
removed where delaminated, mortar joints repointed as necessary and a stucco coating reapplied. The
faux half-timbered work could also be rebuilt.
The exterior walls on the addition are horizontal wood siding with a mineral surfaced rolled asphalt
siding that is in poor condition. It is expected that the wood siding underneath the asphalt is in poor
condition as there are many cracks and patches in the asphalt siding that may have let in moisture for an
extended time.
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Atkinson-Noland & Associates, Inc.
Figure 6. Scored brick under stucco. Brick and mortar joints
appear to be in good condition behind stucco.
Windows
A detailed inspection of the windows was not done. However, it seems likely that all windows will need
some level of restoration.
Appendages
The front porch is in poor condition with a portion of the roof sheathing missing on the west side. The
stone masonry is in fair condition and will need cleaning, removal of inappropriate mortar and
repointing.
The shed roof over the rear entry should be rebuilt if original to the addition.
Roof
The roof on the original structure currently has asphalt shingles that are in poor condition. The roof on
the addition appears to have rolled roofing. This is likely in poor condition. All roofing should be
replaced.
The masonry portion of the chimney above the roof is in poor condition with weathered/recessed
mortar joints. Repointing will have to be done at a minimum but may include partial rebuilding of the
top several courses.
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Site and Drainage
Drainage away from the building is not positive as there is little perceptible slope to the site. This could
be slightly improved by creating small swales to carry moisture to the alley or Pearl St. (whichever is
lower).
There are two trees, one each on the east and west elevations and other vegetation close to the building
that should be removed before they cause damage the building.
Summary
The original structure is in fair condition overall, but will need significant work (as outlined above) to
make it compliant with the International Existing Building Code. The addition is in poor condition and
will require considerable work to make it code compliant as well.
Please don’t hesitate to contact our office if you have any questions or require further information on
the contents of this report.
Sincerely,
David B. Woodham, P.E.
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