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GEOTECHNICAL ENGINEERING INVESTIGATION
FRANTZ RESIDENCE
1711 COUNTY ROAD 331
A.K.A. DRY HOLLOW ROAD
GARFIELD COUNTY, COLORADO
Prepared for:
Andy Frantz
730 East 5t" Street
Rifle, CO 81650
CTLIT Project No. GS07096.000-120
April 30, 2026
CTL Thom son Inc.
Denver, Fort Collins, Colorado Springs, Glenwood Springs, Pueblo, Summit County — Colorado
Cheyenne, Wyoming and Bozeman, Montana
Is
Table of Contents
SCOPE.............................................
........... ....................... ......... ........................ 1
SITECONDITIONS......................................................
......... ......................... ._................................. 1
PROPOSED CONSTRUCTION .....................
........................................................................ 1
SITEGEOLOGY.................................................................................................
............... 2
SUBSURFACECONDITIONS ........ ................................
............. :........................... ......................... 2
SITEEARTHWORK.......................................................................................................
................. 3
..,.
Excavations ............................. ...........
...................................................................... 3
..... . ... .... ..... ....
StructuralFill ........... __ ................................................................................................................
3
FoundationWall Backfill...............................................................................................................
4
BUILDING FOUNDATION ............................
........... ,,........... ................................................. 4
SLAB -ON -GRADE CONSTRUCTION.....
....................:.....::...........................................................6
CRAWL SPACE CONSTRUCTION.................................................................................................
7
FOUNDATIONWALLS......................
............................................................................................. 7
SUBSURFACEDRAINAGE.......................................................................................:.;..;:...............
8
SURFACEDRAINAGE..... ..............
................................................... ................ ................... 9
CONCRETE...............................................
:........................... :.:::..:::..................... ..:....:._................. 10
CONSTRUCTION OBSERVATIONS ..........................
...................... .......................... I................. 11
GEOTECHNICAL RISK .....................
................ .............. ....................................... 11
LIMITATIONS.................................................................................................................................
12
FIGURE 1 —VICINITY MAP
FIGURE 2 — AERIAL PHOTOGRAPH
FIGURE 3 — SUMMARY LOG OF EXPLORATORY BORINGS
FIGURE 4 — SWELL -CONSOLIDATION TEST RESULTS
FIGURE 5 — FOUNDATION WALL DRAIN CONCEPT
TABLE I — SUMMARY OF LABORATORY TESTING
ANDY FRANTZ
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS0709.000-120
SCOPE
CTLIThompson, Inc. (CTLIT) has completed a geotechnical engineering investigation
regarding the Frantz Residence planned at 1711 County Road 331 (a.k.a. Dry Hollow Road),
Garfield County, Colorado. We conducted this investigation to evaluate subsurface conditions
on the subject lot and provide geotechnical engineering recommendations for the proposed
construction. The scope of our investigation was set forth in our Proposal No. GS 26-0042. Our
report was prepared from data developed from our field exploration, laboratory testing, engi-
neering analysis, and our experience with similar conditions. This report includes a description
of subsurface conditions found in our exploratory borings and provides geotechnical engineering
recommendations for design and construction of the residence on the lot. A summary of our
conclusions is below.
SITE CONDITIONS
A new residence is planned on the subject parcel located at 1711 County Road 331 (Dry
Hollow Road), Garfield County, Colorado. The parcel is approximately 45-acres in size and lo-
cated west of County Road 331. A vicinity map with the location of the site is shown on Figure 1.
The proposed residence is planned in the east -central portion of the parcel, at a location previ-
ously occupied by an 1,800 square -foot, single -level modular home that has been removed from
the property. Footings and stem walls from the previous modular home remain and will be par-
tially utilized by the new construction. The topography in the area of the proposed residence
consists of a relatively level area atop a northeast to southwest trending ridge, with scattered
shrubs, grasses, and weeds across the parcel. An aerial photograph of the site is provided on
Figure 2.
PROPOSED CONSTRUCTION
We reviewed factory plans, prepared by 520 Cavco-Goshen, dated December 3, 2025,
and structural plans, prepared by DB Structural Design, dated January 29, 2026, for the pro-
posed residence. The plans indicate the residence will be an approximate 2,300 square foot,
two -level modular style home with a structural floor over crawlspace in living areas and a slab -
on -grade floor for the attached garage. The new home will be partially supported on the existing
footings and stem walls at the site and partially supported on newly constructed footings. CTLIT
ANDY FRANTZ Page 1 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
should be provided with revised plans, if revisions occur, so we can provide geotechnical/geo-
structural engineering input.
SITE GEOLOGY
As part of our geotechnical engineering investigation, we reviewed geologic mapping by
the U.S. Geological Survey (USGS) titled, "Geologic Map of the Silt Quadrangle, Garfield Coun-
ty, Colorado", by R. Shroba and R. Scott (dated 2001). The subject lot is in an area mapped as
Quaternary loess overlying older Quaternary terrace alluvium deposits. The sandy clay encoun-
tered in our exploratory borings is consistent with the description for loess.
SUBSURFACE CONDITIONS
Subsurface conditions were investigated by drilling two exploratory borings adjacent to
the location of the proposed residence on April 9, 2026. The borings were drilled at the approx-
imate locations shown on Figure 2 with a truck -mounted drill rig and 4-inch diameter, solid -stem
auger. Drilling operations were directed by our representative, who logged subsurface condi-
tions encountered and obtained representative samples of the soils. Graphic logs of subsurface
conditions found in our exploratory borings are included as Figure 3.
Our exploratory borings generally encountered natural sandy clay with gravel and scat-
tered cobbles to the maximum explored depth of 25 feet. A layer of clayey sand with gravel and
cobbles was encountered in TH-1, extending from a depth of about 6 to 11 feet. Groundwater
was not encountered in the borings at the time of drilling.
Samples of the soils obtained from our exploratory borings were returned to our labora-
tory for pertinent testing. Laboratory testing included swell -consolidation testing, Atterberg limits,
natural moisture content and density, percent passing the No. 200 sieve, and water-soluble sul-
fates. A sample of the sandy clay from TH-2 at 4 feet below the existing site grade exhibited a
liquid limit of 31 and a plasticity index of 19, contained 81 percent silt and clay -sized particles
(passing a No. 200 sieve) with a moisture content of 5.5 percent. The remaining samples con-
tained 38 to 76 percent silt and clay sized particles, with moisture contents ranging from 5.8
percent to 7.9 percent. Samples of the natural, sandy clay selected for one-dimensional, swell -
consolidation testing exhibited 0.9 to 1.5 percent collapse when wetted under a constant applied
ANDY FRANTZ Page 2 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
load of 1,000 (pounds per square foot) psf. The samples exhibited 2.9 percent to 4.9 percent
additional consolidation under an applied load of 3,000 psf with wetted conditions. Swell -
consolidation test results are included as Figure 4. Laboratory testing is summarized on Table I
SITE EARTHWORK
Excavations
A maximum foundation excavation depth of about 3 feet is likely to construct new foun-
dations. Our subsurface investigation indicates that excavations at the site can be accomplished
using conventional, heavy-duty excavating equipment. Sides of excavations need to be sloped
or retained to meet local, state, and federal safety regulations. The subsoils at the site will likely
classify as Type B soils based on OSHA standards governing excavations. From a "trench"
safety standpoint, temporary slopes deeper than 5 feet that are not retained should be no
steeper than 1 to 1 (horizontal to vertical) in Type B soils. Contractors are responsible for de-
termining the actual OSHA soil type when excavations are made and for maintaining safe exca-
vations. Contractors should identify the soils encountered in excavations and ensure that OSHA
standards are met.
We do not believe excavations to construct the new foundations will encounter a free
groundwater table. Excavations should be sloped to a gravity discharge or be directed to a tem-
porary sump where water from precipitation can be removed by pumping.
Structural Fill
Our experience indicates the natural, sandy clay soils at the site have the potential for
consolidation when wetted under building loads. Typically, sub -excavation and removal of a
depth of the natural soils below footings and replacement with properly compacted structural fill
could be used to mitigate a portion of the collapse potential of the natural soils. Based on the
planned re -use of the existing footings in the new construction, and the proximity of the new
footings to the existing footings, sub -excavation and removal of a depth of the natural soils and
replacement with properly compacted structural fill is not recommended.
ANDY FRANTZ Page 3 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
U
We recommend subexcavation of the natural soils below slab -on -grade floors to a depth
of at least 2 feet and replacement with densely -compacted, structural fill. The excavated soils
can be generally reused as structural fill, provided they are free of rocks larger than 4 inches in
diameter, organics and debris. If imported fill is needed, it should consist of an aggregate base
course or similar soil. A sample of the potential import soil for structural fill should be submitted
to CTLIT for approval prior to hauling to the site.
The structural fill soil should be placed in loose lifts of 8 inches thick or less, moisture -
conditioned to within 2 percent of optimum moisture content and compacted to at least 98 per-
cent of standard Proctor (ASTM D 698) maximum dry density. Moisture content and density of
structural fill should be checked by CTLIT during placement. Observation of the compaction
procedure is necessary. Proposed structural fill import material should be reviewed by CTLIT to
judge its suitability for its proposed use.
Foundation Wall Backfill
Proper placement and compaction of foundation wall backfill soil is important to reduce
infiltration of surface water and settlement from consolidation of backfill. This is especially im-
portant for backfill areas that will support exterior concrete flatwork, such as driveways and pati-
os. The soils excavated from the site can be used as backfill, provided they are free of rocks
larger than 4-inches in diameter, organics, and debris.
Backfill soil should be placed in loose lifts of approximately 10 inches thick or less, mois-
ture -conditioned, and compacted. The backfill should be compacted to at least 95 percent of
standard Proctor (ASTM D 698) maximum dry density. Moisture content and density of the
backfill should be checked during placement by a representative of our firm. Observation of the
compaction procedure is recommended.
BUILDING FOUNDATION
The sandy clay encountered at the site at likely building foundation elevation has a col-
lapse potential when wetted. Typically, sub -excavation and removal of a depth of the natural
soils below footings and replacement with properly compacted structural fill could be used to
mitigate a portion of the collapse potential of the natural soils. Based on the planned re -use of
ANDY FRANTZ Page 4 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
the existing footings in the new construction, and the proximity of the new footings to the exist-
ing footings, sub -excavation and removal of a depth of the natural soils and replacement with
properly compacted structural fill is not feasible. As such, we judge the residence can be con-
structed on a footing foundation supported by the undisturbed, natural, sandy clay or densely
compacted, granular, structural fill, with low ground pressure footings and some risk of move-
ment. A representative of our firm should be called to observe soils in the foundation excavation
and check that conditions are suitable for support of the foundation, as designed. For portions of
the building supported on the existing footings, the existing footing sizes and structural integrity
should be verified by others prior to construction.
Differential settlement between portions of the structure supported on the existing foot-
ings and new footings should be considered in building design and construction. Differential set-
tlement of up to 1-inch or more, depending on the degree of wetting of the footing area subsoils,
should be anticipated. Proper surface and subsurface drainage design, as outlined in the Sub-
surface Drainage and Surface Drainage sections of this report, will be important to limit the po-
tential for differential settlement.
Recommended design and construction criteria for new footings are below. These crite-
ria were developed based on our analysis of field and laboratory data, as well as our engineer-
ing experience. If structural loads proposed for the new construction bearing on existing footings
will exceed the allowable bearing pressure recommended below, or if footing sizes and bearing
depth differ from the recommendations below, we should be contacted to review our recom-
mendations and provide alternatives, if warranted.
Footings should be supported by the undisturbed, natural, sandy clay or densely
compacted, granular, structural fill placed in accordance with recommendations
in the Structural Fill section.
2. Footings on the undisturbed, sandy clay or densely compacted, granular struc-
tural fill can be designed for a maximum net allowable soil bearing pressure of
1,200 psf. The weight of backfill soils above the footings can be neglected for
bearing pressure calculations.
3. A friction factor of 0.30 can be used to calculate resistance to sliding between
concrete footings and the sandy clay.
4. Continuous wall footings should have a minimum width of at least 16 inches.
Foundations for isolated columns should have minimum dimensions of 24 inches
by 24 inches. Larger sizes may be required, depending upon foundation loads.
ANDY FRANTZ Page 5 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
Grade beams and foundation walls should be well -reinforced. We recommend re-
inforcement that is sufficient to span an unsupported distance of at least 10 feet.
6. The soils under exterior footings should be protected from freezing. We recom-
mend the bottom of footings be constructed at least 36 inches below finished ex-
terior grades. The Garfield County building department should be consulted re-
garding required frost protection requirements.
SLAB -ON -GRADE CONSTRUCTION
We understand a slab -on -grade floor will be used for the garage. Exterior slabs, such as
driveways and patios, are also normally constructed as slabs -on -grade. The fine-grained, sandy
clay, soils encountered at the site possess potential for frost -heave as well as consolidation
when wetted under building loads, Frost -heave potential is dependent on soil type and the
amount of moisture present in the subsurface soils, as well as the potential for freezing tem-
peratures in slab areas. Slabs -on -grade at the site should be feasible provided the soils below
the slabs are subexcavated to a depth of at least 2 feet below bottom of garage slab elevation
or 18 inches below bottom of exterior concrete slabs -on -grade, such as driveways and patios,
and replaced with properly compacted structural fill. Recommendations in the Structural Fill sec-
tion of this report should be followed.
Based on our analysis of field and laboratory data, as well as our engineering experi-
ence, we recommend the following precautions for slab -on -grade construction at this site.
Slabs should be separated from footings and columns pads with slip joints which
allow free vertical movement of the slabs.
2. Underslab plumbing should be pressure tested for leaks before the slabs are
constructed. Plumbing and utilities which pass through slabs should be isolated
from the slabs with sleeves and provided with flexible couplings to slab supported
appliances.
3. Exterior concrete slabs, such as the driveway and patios, should be isolated from
the building. These slabs should be well -reinforced to function as independent
units.
4. Frequent control joints should be provided, in accordance with American Con-
crete Institute (ACI) recommendations, to reduce problems associated with
shrinkage and curling.
5. The International Building Code (IBC) may require a vapor retarder be placed be-
tween the base course or subgrade soils and concrete slab -on -grade floors. The
ANDY FRANTZ Page 6 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
merits of installation of a vapor retarder below floor slabs depend on the sensitivi-
ty of floor coverings and the building to moisture. A properly installed vapor re-
tarder (10 mil minimum) is more beneficial below concrete slab -on -grade floors
where floor coverings will be sensitive to moisture. The vapor retarder is most ef-
fective when concrete is placed directly on top of it. A sand or gravel leveling
course should not be placed between the vapor retarder and the floor slab.
CRAWL SPACE CONSTRUCTION
Crawl space areas will be constructed in living areas of the building. The required crawl
space height depends on the materials used to construct the floor system above the crawl
space. Building codes normally require a clear space of at least 18 inches between exposed
earth and untreated wood components of the structural floor.
Utility connections, including water, gas, air duct, and exhaust stack connections to ap-
pliances on structural floors should be capable of absorbing some deflection of the floor. Plumb-
ing that passes through the floor should ideally be hung from the underside of the structural floor
and not laid on the bottom of the excavation.
Control of humidity in crawl spaces is important for indoor air quality and performance of
wood floor systems. We believe the best current practice to control humidity involves the use of
a vapor retarder or vapor barrier (10 mil minimum) placed on the soils below accessible subfloor
areas. The vapor retarder/barrier should be sealed at joints and attached to concrete foundation
elements. It may be appropriate to install a ventilation system that is controlled by a humidistat.
FOUNDATION WALLS
Foundation walls that extend below -grade should be designed for lateral earth pressures
where backfill is not present to about the same extent on both sides of the wall, such as below -
grade spaces like crawlspace. Many factors affect the values of the design lateral earth pres-
sure. These factors include, but are not limited to, the type, compaction, slope, and drainage of
the backfill, and the rigidity of the wall against rotation and deflection.
For a very rigid wall where negligible or very little deflection will occur, an "at -rest" lateral
earth pressure should be used in design. For walls that can deflect or rotate 0.5 to 1 percent of
wall height (depending upon the backfill types), design for a lower "active" lateral earth pressure
ANDY FRANTZ Page 7 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
may be appropriate. Our experience indicates typical below -grade walls in residences deflect or
rotate slightly under normal design loads, and that this deflection results in satisfactory wall per-
formance. Thus, the earth pressures on the walls will likely be between the "active" and "at -rest'
conditions.
For backfill soils conforming with recommendations in the Foundation Wall Backfill sec-
tion that are not saturated, we recommend design of below -grade walls at this site using an
equivalent fluid density of at least 50 pcf. This value assumes deflection; some minor cracking
of walls may occur. If very little wall deflection is desired, a higher design value for the "at -rest'
condition is appropriate using an equivalent fluid pressure of 60 pcf. We should be provided with
construction plans, when available, so we can confirm these recommendations.
SUBSURFACE DRAINAGE
Our experience in similar geology and topography in the area indicates the upper soils
could become saturated during snowmelt in spring and early summer months. Frozen ground
during spring runoff can also create a perched condition. Additionally, water from precipitation,
snowmelt, and irrigation frequently flows through relatively permeable backfill placed adjacent to
a residence and collects on the surface of less permeable soils at the bottom of foundation ex-
cavations. These sources of water can cause wet or moist conditions in below -grade areas after
construction. To reduce the likelihood water pressure will develop outside foundation walls, we
recommend provision of a foundation wall drain around the perimeter of the structure.
The foundation wall drain should consist of 4-inch diameter, slotted PVC pipe encased in
free -draining gravel. A prefabricated drainage composite should be placed adjacent to founda-
tion wall exteriors. Care should be taken during backfill operations to prevent damage to drain-
age composites. The drain should lead to a sump pit where water can be removed by pumping.
The outlet should not be susceptible to clogging or freezing. We recommend installation of a
clean -out along the drainpipe. A representative of our firm should be present to observe the
drain is constructed properly prior to backfilling. A foundation wall drain concept is shown on
Figure 5.
ANDY FRANTZ Page 8 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
SURFACE DRAINAGE
Surface drainage is critical to the performance of foundations, floor slabs, and concrete
flatwork. Site grading should be designed and constructed to rapidly convey surface water away
from the building. Proper surface drainage and irrigation practices can help control the amount
of surface water that penetrates to foundation levels and contributes to settlement of founda-
tions. Positive drainage away from the foundations and avoidance of irrigation near foundations
also help to avoid excessive wetting of backfill soils, which can lead to increased backfill settle-
ment and possibly to higher lateral earth pressures, due to increased weight and reduced
strength of the backfill. Recommendations in this report are based on effective drainage for the
life of the structure and cannot be relied upon if effective drainage is not maintained. We rec-
ommend the following precautions be observed during construction and maintained at all times
after construction is completed.
The ground surface surrounding the exterior of the building should be sloped to
rapidly convey surface water away from the building in all directions. We recom-
mend a constructed slope of at least 12 inches in the first 10 feet (10 percent) in
landscaped areas around the building.
2. Backfill around the foundation walls should be moisture -treated and compacted
pursuant to recommendations in the Foundation Wall Backfill section. Increases
in the moisture content of the backfill soils after placement often results in settle-
ment. Re-establishing proper slopes (owner maintenance) away from the building
may be necessary.
3. We recommend that the building be provided with roof gutters and downspouts.
The downspouts should discharge well beyond the limits of all backfill. Splash
blocks and/or extensions should be provided at all downspouts so water dis-
charges onto the ground beyond the backfill. We generally recommend against
burial of downspout discharge pipes.
4. Landscaping should be carefully designed and maintained to minimize irrigation.
Plants placed close to foundation walls should be limited to those with low mois-
ture requirements. Irrigated grass should not be located within 5 feet of the foun-
dations. Sprinklers should not discharge within 5 feet of foundations. Plastic
sheeting should not be placed beneath landscaped areas adjacent to foundation
walls. Geotextile fabric will inhibit weed growth and allow some evaporation to
occur.
ANDY FRANTZ Page 9 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. G807096.000-120
CONCRETE
Concrete that is in contact with soil can be subject to sulfate attack. We measured a wa-
ter-soluble sulfate concentration of 0.62 percent in a sample of the soils from the site (see Table
A-1). Pursuant to ACI 332-20, these concentrations correspond to a sulfate exposure class of
Severe (RS2) as indicated on the table below.
SULFATE EXPOSURE CLASSES PER ACI 332-20
Water -Soluble Sulfate (SO4)
Exposure Classes in Soil A
Not Applicable RSO < 0.10
Moderate
Severe
Very Severe
Y—
RS1
RS2
RS3
A) Percent sulfate by mass in soil determined by ASTM C1580
0.10 to 0.20
0.20 to 2.00
> 2.00
For these levels of sulfate concentration, ACI 332-20, "Code Requirements for Residen-
tial Concrete", indicates special cement type requirements for sulfate resistance as indicated on
the table below.
CONCRETE DESIGN REQUIREMENTS FOR SULFATE EXPOSURE PER ACI 332-20
Cementitious
Maximum
Material Types
B
Minimum
Calcium
Exposure Water/ Compressive ASTM
ASTM
I ASTM
Chloride ;i
Class Cement Strength A C150/
C595/
C1157/
Admixtures
Ratio (psi) C150M
C595M
C1157M
RSO N/A 2500 No Type
No Type
No Type
No
Restrictions
Restrictions
Type with (MS)
Restrictions
MS
Restrictions :
No
RS1
0.50
2500
I I
Designation
Restrictions
RS2
0.45
3000
Vc
Type with (HS)
HS
Not
Designation
Type with (HS)
HS +
Permitted
V + Pozzolan
Designation
Pozzolan or
Not
RS3
0.45
3000
or Slag
plus Pozzolan
Slag
Permitted
Cement °
or Slag
Cement E
Cement E
A) Concrete compressive strength specified shall be based on 28-day tests per ASTM C391C39M
B) Alternate combinations of cementitious materials of those listed in ACI 332-20 Table 5.4.2 shall be permitted
when tested for sulfate resistance meeting the criteria in section 5.5.
ANDY FRANTZ Page 10 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
C) Other available types of cement such as Type II I or Type I are permitted in Exposure Classes RS1 or RS2 if
the C3A contents are less than 8 or 5 percent, respectively.
D) The amount of the specific source of pozzolan or slag to be used shall not be less than the amount that has
been determined by service record to improve sulfate resistance when used in concrete containing Type V
cement. Alternatively, the amount of the specific source of the pozzolan or slab to be used shall not be less
than the amount tested in accordance with ASTM C1012/C1012M and meeting the criteria in section 5.5.1 of
AC 1332-20.
E) Water-soluble chloride ion content that is contributed from the ingredients including water aggregates, ce-
mentitious materials, and admixtures shall be determined on the concrete mixture ASTM C1218/C1218M
between 29 and 42 days.
Superficial damage may occur to the exposed surfaces of highly permeable concrete,
even when sulfate levels are relatively low. To control this risk and to resist freeze -thaw deterio-
ration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact
with soils that are likely to stay moist due to surface drainage or high-water tables. Concrete
should have a total air content of 6 percent t 1.5 percent. We advocate damp -proofing of all
foundation walls and grade beams in contact with the subsoils (including the inside and outside
faces of garage and crawl space grade beams).
CONSTRUCTION OBSERVATIONS
We recommend that CTLIT be retained to provide construction observation and materi-
als testing services for the project. This would allow us the opportunity to verify whether soil
conditions are consistent with those found during this investigation. If others perform these ob-
servations, they must accept responsibility to judge whether the recommendations in this report
remain appropriate. It is also beneficial to projects, from economic and practical standpoints,
when there is continuity between engineering consultation and the construction observation and
materials testing phases.
GEOTECHNICAL RISK
The concept of risk is an important aspect of any geotechnical evaluation. The primary
reason for this is that the analytical methods used to develop geotechnical recommendations do
not comprise an exact science. We never have complete knowledge of subsurface conditions.
Our analysis must be tempered with engineering judgment and experience. Therefore, the rec-
ommendations presented in any geotechnical evaluation should not be considered risk -free. We
cannot provide a guarantee that the interaction between the soils and the proposed building will
lead to performance as desired or intended. Our recommendations represent our judgment of
ANDY FRANTZ Page 11 of 12
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
those measures that are necessary to increase the chances that the building will perform satis-
factorily. It is critical that all recommendations in this report are followed.
LIMITATIONS
This report was prepared for the exclusive use of the Client. The information, conclu-
sions, and recommendations provided herein are based upon consideration of many factors in-
cluding, but not limited to, the type of structure proposed, the geologic setting, and the subsur-
face conditions encountered. The conclusions and recommendations contained in the report are
not valid for use by others. Standards of practice continuously change in geotechnical engineer-
ing. The recommendations provided in this report are appropriate for about three years. If the
proposed building are not constructed within three years, we should be contacted to determine if
we should update this report.
Our exploratory borings provide a reasonable characterization of subsurface conditions
at the site. Variations in subsurface conditions not indicated by the borings will occur.
This investigation was conducted in a manner consistent with that level of care and skill
ordinarily exercised by geotechnical engineers currently practicing under similar conditions in
the locality of this project. No warranty, express or implied, is made. If we can be of further ser-
vice in discussing the contents of this report, please call.
CTLITHOMPSON, ING:
James A. arker, P E:; P.G. JJPJ.�s
Principal Engineer - _�-
ia Parker ctlthom sarLG0t 0f,JAL
ANDY FRANTZ
1711 COUNTY ROAD 331
CTLIT PROJECT NO. GS07096.000-120
Reviewed bv-
_ s R,
?� Ryan R. Barbone, P.E.
Associate Engineer
rbarbone@ctlthompson.com 4/30/2026
Page 12 of 12
NOTE: BASE IMAGE FROM MAXAR (COPYRIGHT 2026)
0 1000 2000
SCALE. 1' - 2000'
171 1 County
Road 331
'A.
ANDREW FRANTZ Vicinity
FRAN'TZ RESIDENCE
OTILIT PROJECT NO. GS07096.000-120-R1 Map
.4
FIg. 1
0 50 100
SCALE; 1" = 100'
LEGEND:
TH-1 APPROXIMATE LOCATION OF EXPLORATORY BORING.
NOTES: 1. BASE IMAGE FROM GOOGLE EARTH
(DATED JULY 6, 2023)
2. BORING LOCATIONS WERE ESTIMATED USING GOOGLE
EARTH AND SHOULD BE CONFIRMED BY THE CLIENT'S
SURVEYOR.
ANDREW FRANTZ Aerial
FRANTZ RESIDENCE
CTLIT PROJECT NO. GS07096.000-120-Ri Photograph
Fig. 2
TH-1
TH-2
LEGEND:
0
—7
0
Ile
CLAY, SANDY, GRAVEL, COBBLES, SLIGHTLY MOIST,
STIFF TO HARD, BROWN, TAN. (CL)
00
SAND, CLAYEY, GRAVEL, COBBLES, MEDIUM DENSE,
9/12
19/12
MOIST, BROWN (SC)
5
00,
THE SYMBOL 9/12 INDICATES 9 BLOWS OF A
140-POUND HAMMER FALLING 30 INCHES WERE
00,
REQUIRED TO DRIVE A 2.5-INCH O.D. MODIFIED
4, 20112
14/12
CALIFORNIA-BARREL SAMPLER 12 INCHES.
00,
10
10 —
NOTES:
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LU
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p
LLJ
"
EXPLORATORY BORINGS WERE DRILLED WITH A
TRUCK -MOUNTED DRILL RIG AND 4-INCH
00,
SOLID -STEM AUGER ON APRIL 9, 2026. THE
0
25/12
50/8
o
BORINGS WERE BACKFILLED IMMEDIATLEY AFTER
15
Of 15
EXPLORATORY DRILLING OPERATIONS WERE
00,
COMPLETE.
op 40
2•
GROUNDWATER WAS NOT ENCOUNTERED IN OUR
EXPLORATORY BOORINGS AT THE TIME OF
DRILLING.
50/12
26/12
20
141
20
3•
LOCATIONS OF EXPLORATORY BORINGS ARE
APPROXIMATE.
4.
THESE LOGS ARE SUBJECT TO THE
00,
EXPLANATIONS, CONCLUSIONS, AND LIMITATIONS
40
IN THIS REPORT.
50/12
25
25
ANDREW FRANTZ
FRANTZ RESIDENCE
CTLIT PROJECT NO. GS07096.000-120-R1
Summary Logs of
Exploratory
Borings
FIG. 3
0
0
-2
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a
x
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-4
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0
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W
a
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�
!
mac-- ADDITIONAL CONSOLIDATION DUE TO
WETTING UNDER COSNTANT PRESSURE
i
i
I
0.1 1.0
APPLIED PRESSURE - KSF
Sample of CLAY, SANDY WITH GRAVEL (CL)
From TH-1 AT 4 FEET
0
-2
-3
-4
z
O
z -5
Q
IL x -s
W
z
0
-8
W
IX -9
2
0
U _10
10
100
DRY UNIT WEIGHT= 113 PCF
MOISTURE CONTENT= _ 5.8 %
ADDITIONAL CONSOLIDATION DUE To
WETTING UNDER CONSTANT PRESSURE.
ONE
111111
NMI
I
0.1 1.0
APPLIED PRESSURE - KSF
Sample of CLAY, SANDY WITH GRAVEL (CL)
From TH-2 AT 9 FEET
ANDREW FRANTZ
FRANTZ RESIDENCE
PROJECT NO. GS07096.000-120-R1
10 100
DRY UNIT WEIGHT= 104 PCF
MOISTURE CONTENT= 7.6 %
Swell -Consolidation
Test Results
FIG.4
SLOPE
PER
OSHA
COVER ENTIRE WIDTH OF -
GRAVEL WITH NON -WOVEN
GEOTE MLE FABRIC MIRAFI
14ON OR EQUNALE
BACKFILL
PREFABRICATED
DRAINAGE
COMPOSITE
(MIRADRAIN 6000 OR EQUIVALENT)
ATTACH PLASTIC SHEETING
TO FOUNDATION WALL --�
2" MINIMUM
�I 8" MINIMUM
OR BEYOND
1:1 SLOPE FROM
BOTTOM OF FOOTING
(WHICHEVER IS GREATER)
STRUCTURAL FLOOR
4-INCH DIAMETER PERFORATED RIGID DRAIN PIPE.
THE PIPE SHOULD BE PLACED IN A TRENCH WITH
A SLOPE OF AT LEAST 1/8-INCH DROP PER
FOOT OF DRAIN.
ENCASE PIPE IN 1/2" TO 1-1/2" SCREENED
ROCK. EXTEND GRAVEL LATERALLY TO FOOTING
AND AT LEAST 1/2 HEIGHT OF FOOTING. FILL
ENTIRE TRENCH WITH GRAVEL
CRAWL SPACE -1
VAPOR BARRIER
RECOMMENDED
NOTE:
THE BOTTOM OF THE DRAIN SHOULD BE AT LEAST 2 INCHES BELOW BOTTOM OF
FOOTING AT THE HIGHEST POINT AND SLOPE DOWNWARD TO A POSITIVE GRAVITY
OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING.
Wall
F�oundation
ANDREW FRANTZ r r a l I Drain
FRANTZ RESIDENCE
CTLIT PROJECT NO. GS07098.000-120-R1 Concept
Fig. 5
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