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CIV{T,/6HOTRCHMCAL
SOIL AND FOUNDATION INVESTIGATION
FOR
PROPOSED DITLOW RESIDENCE
SECTION 6, T5S RSOW TRACT IN SWSE LYING NWLY
OF CR 24I & SELY OF EAST ELK CREEK
3683 24I COUNTY ROAD, GARFIELD COUNTY
NEW CASTLE, CO 81647
PROJECT NO. 23.3713
AUGUST 25,2023
PREPARED FOR TIIE BUYER:
DAVID YOUNG
3285 COUNTY ROAD 24I
NEW CASTLE, CO 81647
davidg@r.andhnrechanical. conr
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P,O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 r.rr.nv.LKPEngineering.c,om
TABLE OT CONTENTS
EXECUTIVE SUMMARY
SCOPE OF STUDY
SITE DESCRIPTION
PROPOSED CONSTRUCTION
,,.,2
....2
,,..2
....J
FIELD INVESTIGATION .J
SUBSURFACE SOIL AND GROI.INDWATER CONDITION ,,4
FOUNDATION RECOMMENDATIONS,..... ,..,...,4
SLAB CONSTRUCTION
RETAINING WALLS......
UNDERDRAIN SYSTEM
5
SITE GRADING AND DRAINAGE
6
6
7
LAWN IRRIGATION ..8
LIMITATION...................8
FIGURES
LOCATION SKETCH
SUBSURFACE EXPLORATION LOGS.
SWELL/CONSOLIDATION TEST RESULTS ..
PERIMETER DRAIN
DRAWINGNO. I
....FIGURENO's1-2
.... FIGURE NO'S 3 -6
....FIGURE NO. 7
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-A307 wwr.v,LKPEnginsering.com
EXECUTIVE SUMMARY
The proposed Ditlow Residence can be supported with
conventional type spread footings, designed for an allowable soil
bearing pressure of 1000 psf. They should construct the footings of
the entire foundation on the undisturbed silty, sandy gravel with
cobbles. See Foundation Recommendations.
SCOPE OF STUDY
This report presents the results of a subsurface Soil and Foundation Investigation for the
proposed Ditlow Residence on Section 6, T5S R90W, Tract in SWSE lying NWLY of County Road
241 & SELY of East Elk Creek, 3683 241County Road, Garfield County, New Castle, CO 81647.
The purpose of the subsurface soil and forurdation investigation was to determine the engineering
characteristics of the foundation soil and to provide reconlmendations for the foundation design,
grading, and drainage. Geologic hazard studies are outside of our scope of services.
SITE DESCRTPTION
The property is l0-acre parcel of land, on the west side of the road at 3683 24I County
Road, Garfield County, New Castle,CO 81647, north of the town of New Castle, Garfield County,
Colorado. Existing residence is within the proposed building site for the new residence, which
P,O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 wr,vw.LKPEnsineerinq.cotn
J
will be demolished. The vegetation surounding the existing building consisted of grass. The
topography of the site is steep down frorn the road and moderate to the west of the existing
residence. Drainage is to the west, towards East Elk Creek.
PROPOSED CONSTRUCTION
We understand that the proposed residence will consist of two stories, wood frame
construction, with a walkout basement on a conuete foundation. We anticipate loads to be light,
typical of residential construction.
If the finalized plans differ significantly from the above rurderstanding, they should notify
us to reevaluate the recommendations of this report.
FIELD INYESTIGATION
The field investigation, conducted on August L9,2023, consisted of drilling, logging, and
sampling two bores. The test bore locations are shown on Drawing No. 1. Drilling of the test
borings was done with CME-45, 4-inch diameter, continuous flight power auger on a track
mounted, drill rig. Soil saurples for laboratory soil analysis and observation were taken at
selected intervals with a California and Standard Split Spoon Samplers, advanced with an
automated 140-pound hammer, falling 30 inches.
We show the soil profiles of the test borings on the Subsurface Exploration Logs, Figure
No's 1 ffidz. Soil samples for laboratory soil analysis and observation were taken at selected
intervals.
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 wwrv,LKPEngineering.com
4
SUBSURFACE SOIL AND GROUNDWATER CONDITION
The soil profiles encountered in the test borings were somewhat similar. Boring No. I
had few inches of topsoil over grayish silt over blocky, silty to gravelly clay over very soft
slightly sandy, silt and clay with pockets of topsoil ( (possibly man-made filIor very loose,
alluvium deposit) over interbedded layers of firmer silty, sandy gravel and softer, fine sand to
sandy silt, and layers of sandy gravel with some cobbles of siltstone and sandstone rock, to the
maximum depth explored of 20 feet. Test Boring No. 2 was drilled within the existing concrete
driveway, and it had about 6 inches of concrete over interbedded layers of sandy silt" silty, sandy
gravel, and slightly sandy calcareous silt with traces of gravel, over layers of firmer, calcareous,
silty, gravelly sand, sandy gravel with some cobbles. and sandy silt with sparse gravel to the
maximum depth explored of l9.5feet. Ground water was not encountered in either boring.
We sampled the soil in the test pit at random intervals. The soil sarnples were observed,
logged, and tested for natural moisture content, natural dry density, and swell-consolidation. The
test results are shown on figures 3 through 6.
FOUNDATION RECOMMENDATIONS
The upper soils (about 6 to I feet) in test boring one, exhibited high potential for hydro-
consolidation (additional settlement upon addition of water under constant pressure of l000psf).
We recommend that the entire foundation excavation is extended to the finn, silty-sandy
gravelly soils. The firm, gravelly soils, were encountered at about 8 feet below the existing grade
in test boring one, and at about 4.5 feet below the existing grade in test boring two, The depth of
the suitable soil can vary. Foundation supported on the firm, silty-sandy to sandy, gravelly soil
can be designed with conventional fype spread footings, designed for a maximum ailowable soil
bearing pressure of 1 000 psf.
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 r.rr,r,r.v.LKPEngineering.com
5
We recommend a minimum width of 16 inches for the continuous footings and? feet for
the isolated footing pads. Continuous foundation walls shortld be reinforced top and bottom to
span an unsupported length ofat least l0 feet.
We recommend a minimum of 48 inches (or the minimum required per the local building
code) of backfill cover for frost protection of the footing subsoils. The fottndation excavation
should be observed by the undersigned engineer to verify that the soil condttions encountered
during canstruction are as anticipated in lhis report. The fotrrdation excavation should be tree
from excavation spoils, fiost, organics and standing water. We recommend proof-rolling of the
foundation excavation. Soft spots detected during the proof-rolling, should be removed by
overexcavation. Any overexcavation within the proposed foundation should be backfilled, in 8
inches loose level lifts and compacted to 100Yo ofthe maximum dry density and within 2percent
of the optimum moisture content as determined in a laboratory from a Standard Proctor test
(ASTM D-69S). A structural fill, placed under footings should be tested a qualified professional.
SLAB CONSTRUCTION
The natural on-site soils, exclusive of topsoil, loose silqv-gypsiferous soils, and organics,
are suitable to support lightly loaded slab-on-grade construction. The subgrade for the slab-on-
grade construction should be proof cornpacted to detect and remove soft spots. They should
backfill overexcavated soft spots and other underslab fill with the on-site soil, free from topsoil
and organics, or other suitable material, compacted to a minimum of 95 percent of the maximum
standard Proctor density (ASTM D-698). Suitable material should be free from man-made fill,
topsoil, organics, and rock fragments greater than 3 inches.
The concrete slab should be constructed over a 4-inch layer of clean gravel consisting of -
3l4inch gravel with at least 50Yo retained on the No. 4 sieve and less than 3 percent passing the
No. 200 sieve.
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 i.r.'u.rry,LKPEngineering.com
6
They should reinforce the concrete slab-on-grade and score control joints according to the
American Concrete Institute requirenrents and per the recommendations of the designer to reduce
darnage due to shrinkage. The concrete slab should be separated from the foundation walls and
columns with expansion joints to allow for independent movement without causing damage.
RETAINING WALLS
Foundation walls retaining earth and retaining structures that are laterally supported
should be designed to resist an equivalent fluid density of 60 pcf for an "at-rest" condition.
Laterally unrestrained structures, retaining the on-site earth, should be designed to resist an
equivalent fluid density of 40 pcf for the "active" case.
Passive earth pressure of360 psfcan be used for the lateral pressure against the sides of
the footings. Resistance to sliding at the bottom of the footings can be calculated based on a
coefficient of friction of 0.5. Undisturbed soil or a stntctural fill cornpacted to 100 percent of the
maximum dry density and within 2 percent of the optimum moisture content shall be used to
resist lateral loads at the sides of the footings.
The above design recofirmendations assume drained backfill conditions and a horizontal
backfill surf'ace. Surcharge loading due to adjacent structures, weight of temporary stored
construction materials and equipment, inclined backfill and hydrostatic pressure due to undrained
backfill should be incorporated in the design. They should try to prevent the buildup of
hydrostatic pressure behind the retaining wall.
UNDERDRAIN SYSTEM
To reduce the risk of surface water infiltrating the foundation subsoil, we recommend
P.O. Box 724,EagIe, CO 81631 Tel. (970) 390-0307 wwr.v"LKPEnqineerinq.com
7
installation of a foundation perimeter drain (see Figure No. 7). The foundation perimeter drain
should consist of a 4-inch diameter, perforated pipe, sloped to a suitable gravity orttlet, or to a
sump pump location, at a I 14 inch per foot for flexible or at a 118 of an inch for rigid pipe. The
bottom of the trench adjacent to the footing should be lined with a polyethylene moisture barrier
glued to the foundation wall. The drain pipe should be covered with a minimum of 6 inches of -
3l4-inchfree-draining granular material. Geotextile (Mirafi 140N or equivalent) should be used
to cover the free-draining gravel to prevent siltation and clogging of the drain. The backfill above
the drain should be granular material to within 2 feet of the ground surface to prevent a buildup
of hydrostatic pressure.
SITE GRADTNG AND DRATNAGE
The following recommendations are general. Exterior backfill should be compacted at or
near the optimum moisture content to at least 95Yo of the maximum standard Proctor density
under pavement, sidewalk, and patio areas and to at least 90% of the maximum standard Proctor
density under landscaped areas. They should use mechanical methods of compaction. Do not
puddle the foundation excavation.
The site surrounding the building structure should slope away from the building in all
directions. A minimum of l2 inches in the first 1 0 feet is recomfiiended in unpaved areas, and
three inches in the first l0 feet in paved areas. The top of the granular foundation backfill should
be covered with a minimum of I foot of relatively impervious filIto reduce the potential of
surface water infiltrating the foundation subsoils.
Surface water naturally draining toward the proposed building site should be diverted
around and away from it by means of drainage swales or other approved methods. The roof
drains and downspouts should extend and discharge beyond the limits of the backfill.
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 s,rvrv.LKPEngineering.com
8
LAW}[ IRRIGATION
It is not recornmended to introduce excess water to the foundation soils by installing
sprinkler systems next to the building. The installation of the sprinkler heads should ensure that
the spray from tle heads will not fall within l0 feet of foundation walls, porcheso or patio slabs.
Lawn irrigation must be controlled.
LIMITATION
This report has been prepared according to locally accepted Professional Geotechnicai
Engineering standards for similar methods of testing and soil conditions at this time. There is no
other warranty either expressed or implied.
The findings and recommendations of this report are based on field exploration,
laboratory testing of samples obtained at the specific locations shown on the Location Sketch,
Drawing No.1 and on assumptions stated in the report. Soil conditions at other locations may
vary, which may not become evident until the foundation excavation is completed. If soil or
water conditions seem different from those described in this report we should be contacted
immediately to reevaluate the recofirmendations of this report. We are not responsible for
technical interpretation by cthers of the data presented in this report.
This report has been prepared for the exclusive use of Dave Young, for the specific
application of the proposed Ditlow Residence. at 3683 241 County Road, Garfield County, New
Castle, CO 81647.
Sincerely,
LKP ENGINEERING,INC.
4x h\
LuizaPetrovska, PE
J:\ WP X4-LKP\ 2023\23-37 I3SL'I'-SND-CL-GRV-IIORL.DOCX
P.O. Box 724,Eagle, CO 81631 Tel. (970) 390-0307 www.LKPEngineerinq.com
B-1
BI2
NOTE: THE LOCATION OF THE TEST EORINGS lS
APPROXIMATE, IT IS NOT BASED ON A SURVEY,
LKP
CML,/GEOTECTTNICAL
Engineering, Inc.
P.0. Box 724, Eaqla, CO 81651
T6l (970) Jso-0J07 www.LKPEngineoring.com
LOCATION SKETCH
3683 241 COUNTY ROAD
NEW CASTLE
GARFIELD COUNTY. COLORADO
PRoJEcrNo:
23-g713
scALE: _ 1,,= 30,
DRAWNG NO.:
1
DATE OBSER\ED: AUGUST 19, 2025
ELEVATION:
BORINC NO. 1
DEPTH
FEET
BLOWS
PER Ff,
s
Y
M
B
o
L
s
A
M
P
L
E
DESCRPNON OF MA|ERIAL
AND SAMPIE LOCAN$,I
UBffiAIORY
TEST RESULIS
REMARKS
-6
-10
-16
2fi
Et/|2
5/2
26n2
tJl2
7/6
t6//6
t]
tr
tr
I
I
Few inchas of Topsoil ovar
graylsh silt over blocky, silty to
grovelly clay over very soft
slightly sondy, silt and cloy with
pockets of topsoil
lnterbadded layers of firmer silty,
sandy grovel and soften flne
sand to sandy sllt, and lalnrs
of sandy gravel wlth some
cobbles, siltstone and sondstone
rock fragments
DD- 90.2 pcf
MC= ll,7 t
DD= 78.1 pcf
MC- 15.8 f
(possibly
man-made fill
or very loose,
alluvium
deposit)
grinding
grinding
Bottom of boring @ 2O feet No Ground Vfoter
Encountered
I,EGEND:
Cl - Z-lnch O,D, Callfomla Llncr SomplcI - Spllt Spaon
21n2 - Drlw cample blov count lndlcatcc that 21 blows
of a llo-pound hammer folllng 3O lnchae vcre
requlred to drlvc the Callfomla or thc Sllt Spoon
Sampler 12 lnches,
DD - Naturut Dry Dcnsity (pcf)MC - Naturol Molsturc Contcnt
-2AO - Pcrccnt Posslng No, 200U - Llquld LlmltPl * Plastlclty lndcxCW - Ground watcr
Q
Slanr
NOTE: fhc soll tronsltlons arc approximota raprascntatlon of tha soll condltlone ln the tcet borlngc. Soll
samples ara obtalncd at sdact lntervols and tha lalnrs ore fntarpolotad, Varlatlona may exlst,
I,TP ENGINEERING, INC.SUBST]RFACE SIPTORATION tOC
FxI,':Si',f,lt 23-371J
IFEEIA,'
DATE OBSERIED: AUGUST 19, 2025
ELEVATION:
BORING NO. 2
DEPTH
ffET
ELOWS
PER N.
s
Y
H
B
o
L
s
A
M
P
L
E
DESCRFNON OF HA|ERIAL
AND SAMPLE LCICANON
UBORATORY
IEST RESULIS
REUARKS
-t
_t0
_15
_m
ton2
t5n2
Jen2
t3/6
l6r/6
tr
About 6 lnches of concrete over
interbedded lalters of sandy silt,
sllty, sandy grovel, ond sllghtly
sondy calcoreous silt with traces
of grovel
Loyers of firmer, calcoreous,
sllty, gravelly sand, sandy gravel
with some cobbles, ond sandy
silt with spdrse gravel
DD- 97.7 pcf
MC= 5.5 Z
DD= 94,5 pcf
MC= 2.9 t
DD= 114.7 pcf
MC- 3.9 X
grinding
grinding
Bottom of boring @ 19.5 feet No Cround Water
Encountered
I,EGEND:
tr - Z-lnch O.D. Callfomlq Llncr SamplcI - Spllt Spoon
24n2 - Drlw aampla blott count. lndlcatas that 24 blowe
of a llo*pound hommcr falllng 30 lnchcs ncrc
raqulrcd to drlw tha Collfornla or thc Spllt Spoon
Sampl* 12 lnchcs.
DD - Notural Dry Dcnslty (pcf)
MC - Notural Moleturc Contqt
-200 - Parcant Paaslng No. 200U - Llquld LlmltPl - Plaetlclty lndcxeW - Ground watar
(x)
Slerc
NOTE: The soll traneltlons ara approxlmotc repreacntotlon of tha soll condltlons ln thc test borlnga Soll
samplcs arc obtolned of sclcct lntcrwls ond thc lolars orc lntcrpototad, Vorlotlons moy cxlct.
I,XP ENGINAAnING, INC.suBsunFAca gxPtoRAnoN toc
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APPLIED PRESSURE - ksf
1.00.1
From: Borlng I at 4 feet
pcf
percent
Sample of : Ton, sllty cloy ond topsoil
Naturol Dry Unit hteight : 78,1
Ndtural Maisture Content : l1,E
IKP Englnadng lnc,Swell - Consolidation Test Results 2J-3713
4
No,:
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CONSTANT PRESSURE OF IAOO PSFitllilllrl
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0.1 1.0 to 100
APPLIED PRESSURE - kef
Sample of : Tan, sllghtly clayey, sandy sllt
Natural Dry Unlt htelght : 97.7 pcf
Naturol Moisture Content = S.S percent
From: Eoring 2 at 3 feet
lJ# Englncslng, lna Swell - Consolidation lesf Resu/fs 23-3713
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IKP Englnatlng,23-37t3Swell - Consolidation Test Results
6
.COMPRESSION W|EN WETTED UNDER
CONSTANT PRESSURE OF |AOO PSFl r til|t l l
0.1 t.o to 100
APPLIED PRESSURE - ksf
Sample of: Tan, calcareous, sondy silt
Natural Dry Unit Vleight 94.5
Natural Moisture Content = 2,9
From: Borlng No, 2 at I fect
pcf
percent
t t|llt t l
..oOMPRESSION W4EN WET|ED UNDER
CONSTANT PRESSURE OF |OOO PSF
I
1.0 to
APPLIED PRESSURE - ksf
o.t to0
Sample of: Ton, gravelly sllty sond
Ndtural Dry Unit Vlelght :
Natural Moisture Content :n4.7
3.9
pcf
percent
From: Boring No. 2 of 13 feet
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AWAY FROM BUILDING
R BACKFILL WITH A MINIMUM
OF ONE FOOT OF REISTIVELY
IMPERVIOUg SOIL
FABRTC (MrRAF|
14ON OR EQUIVALENT)
US 3/4.INCH DIAMETER,
COARSE, CLEAN CRUSH ROCK
30 MIL MINIMUM THICKNESS,NCH DIAMETER PERFORATED PIPE SLOPED TO
PLASTIC LINER, GLUED TO A DAYLIGHT LOCATION AWAY FROM THE
FOUNDATION AT 1/4.INCH PER FOOT FOR
FLEXIBLE AND 1/8.INCH MINIMUM FOR RIGID PIPE
FOUNDATION WALL
cffrL/cEoTEcHMCAr
Engineering, Inc.
P,O, Box 724, Eogle, CO 81651
LKP
Ter (e70)390-0J07 www.LKPEngineering.com
PENIMETER DNAIN
368?241 COUNW ROAD
NEW CASTLE
GARFIELD COUNTY, COLORADO
FRQECT No':
zg-a71g
scALE N.T.s.
7
|IGU'<L NU.: