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Home My WebLink AboutEngineer's Foundation LetterColleen Wirth Øgrhæe C/¿dÇ¿n¡4bt an From: Sent: To: Subject: Follow Up Flag: Flag Status: Greg Hermann <bearbvd@mindspring.com > Tuesday, August 2,2022 1 1:59 AM Colleen Wifth; Maureen Re: FW: [External] BLMF-06-22-76A7 - Mauree 24 CR '111, Carbondale Follow up Flagged Etn/a/r>o ? -*ti óeartzV n A O'Brìen Manufactured Dwelliffi - Hello-- Sorry I missed this email the first time by My soils report letter for the subject lot means exactly what it says. There are NO helical piers, nor ANY other deep foundation devices used or íntended to be used in Maureen's foundation. I have stated soil bearing pressures in units of 'KiP's/ sq. ft.' in soils reports for decades, and likely in nearly a thousand soils reports, because, in my carefully considered opinion, these units reflect the number of sígnificant figures of precisíon possible in determining acceptable soils bearing pressures FAR better than statíng the allowable pressure in 'lbs.lsq. ft.'does. Regards, Greg Hermann On81212022 8:1-5 AM, Colleen Wirth wrote: Hello Maureen, Thanks for checking in with me on your permit review. Last week, I had emailed your structural engineer of record concerning the foundation design and am waiting to hear clarification and confirmatíon from the engineer. Perhaps they are out of town or tied up with other projects? I did receive response on driveway, thank you and now have that filed. The building permit application review is otherwise fínished, I have no other questions other than understanding the foundation design. l'm workíng remotely today and have your blueprínts I application form setting next to my desk at the maín office in Glenwood. Colleen Wirth Plans Examiner Garfield County Building Divisíon L08 8'h Street, Suite 401 Glenwood Springs, CO 8L601 cwirth@ -countv.com 1 office (970) 945-L377 ext. 1610 From: Colleen Wirth Sent: Tuesday, July 26,2022 2:37 PM To: bearbvd @mindspring.com Subject: BLMF-06-22 -7607 - Maureen A O'Bríen Manufactured Dwelling - 24 CR 1-11, Carbondale BLMF-06-22-7607 - Maureen A O'Brien Manufactured Dwelling - 24 CR tl,t, Carbondale Hello Greg, The O'Brien resídence in Carbondale area is now under review. Reading through your structural notes and soils investigation report, I see desígn soÍl conditions are 4.5 KiP/ sq ft. While project designs vary, it is more common in Garfield County for us to see desígn professionals list a KíP in reference to special foundatíon systems as helical píers, caissons or something pre-cast, while site poured conventional footings list a (# pounds / sq ft). May I re-confirm the intended site poured foundatíon contains no helical piers? I want to stamp the FIELD COPY appropriately and not create confusion for our building inspectors. Thanks for your feedback, Colleen Wirth Plans Examiner Garfield County Building Divisíon L08 8th Street, Suite 401- Glenwood Spríngs, CO 8160L cwi rth @ garf ield-countv. com office (970) 945-1377 ext. 161t 2 Ecar Uallq Orsign, Lfd. Engin?dr - Conrulfanf¡ P. O. Box #7lo+ls STEAMBOAT SPRI NGS, COLORADO, 8o477 -o47 5 MOBILE: (gZo) 8ZS-S+S+ E-MAIL: <bearbvd@mindspring.com> lune 3,2022 Ms. Maureen O'Brien PO Box 663 New Castle, Colorado, 8'1.647 Subjecfi Soil investigation for a proposed residence to be located at 24 Garfield County Road #ILL, in Garfield County, Colorado. Dear Mr. Reed, Per your request we performed a soil investigation and evaluation on the subject site in April of 2022. The investigation was performed for the purpose of providing soil design parameters for the construction of the foundation for a single family residence. The proposed structure is anticipated to be of two story factory built, wood framed construction with a full basement and an attached carport. The foundation ís proposed to be constructed with reinforced concrete walls bearing upon reinforced concrete spread footers. The lot is nearly flat and is covered with grass vegetation with some brush and varied uncontrolled fill. The site slopes gently downward toward the north from the County road and is separately from Colorado highway #133 to the west by a path and a drainage ditdr. A test pit was advanced on the parcef in the immediate vicinity of the proposed residence. The pit was advanced using a rubber tire mounted backhoe. The test pit revealed twelve to fifteen inches of brown, slightþ moist, silty clay topsoil overlying a stratum of very rlrghtly moist, dark brown, hard, Î,at clay subsoil approximately 6 feet *úck, whidr in turn overlay a very dense ,vet¡y slightly moist, medium brown sandy gravel which extended to the maximum depth explored, ten feet. No free ground water was observed in the pit. Our experience witJr similar soils, taken together with our observations in the test pit have led us to form tlre opinion that the lower, very dense, sandy gravel will provide stable bearing for the Page #1 of3 foundation of a stmcture of the proposed type. Spread footers for the proposed structure should be designed to bear on the lower, very dense, sandy gravel, with a maximum net bearing pressure of 4.5 KSF. No minimum dead load will be necessary. Any retaining structures should be designed to retain pressure equivalent to that which would be exerted by a fluid weighing 70 PCF. Because of the highly pervious nafure of the lower gravel, the footers for the foundation need not be surrounded with a footer drain. Flowever, in order to provide for the possibility that the water table might rise at some future time, a sump extending thirfy inches below the slab on grade floor of the proposed basement must be provided, along with an appropriate sump pump and a disdrarge line (protected from heezing by a vacuum breaker) leading to a point on the lot at least fifty feet away from the structure. Eighteen inches of ground cover above the discharge line is sufficient provided that it is protected by a vacuum breaker and has a uniform dor,rrnward slope with no low spots going toward its ouffall. Frost protection for the foundation must be provided by maintaining a minimum oÍ ß" of earth cover over the footers, measured ir *y direction, The finish grade should provide Íor a minimum aÍ 2% slope away from the structure in all directions for a minimum of L0 feet, as well as for positive and continuous drainage away from the buitding without any ponding. Native subsoil materials will provide appropriate bacKill. This backfill may be capped with a maximum six inch thick layer of the native fopsoil. The native backfill material must be placed in lifts a maximum of 10 inches thick, with each lift moistened and compacted to 93o/o of its Standard Proctor density. The nature of the native clay subsoil baclfill material will minimize the possibility of surface water andlor roof runoff from penetratíng to the underlying gravel. If at aII possible, we recommend the installation of rain gutters so as to minimize the chance of roof runoff penetrating the backfill. In order to control moisture as well as to minimize heating costs for the proposed residence the surface of the subsoil beneath the floor slab in the basement must be covered with a six mil thick sheet of visquene. Provision must be provided for positive venting of radon gas from beneath the basement slab on grade floor should future testing, completed after construction of the residence, prove such venting to be necessary. Because of the fact that radon gas is extremeþ more dense Page #2of.3 than air, our recommendation is to provide a forced draft fan to accomplish venting through the roof. This fan should be installed at as low an elevation as possible above the basement floor. The high densify of radon gas makes it very difficult, if not impossible, for an induced draft fan installed at a higher elevation in the building to exhaust radon effectively The basement slab on grade floor must be appropriately reinforced and placed over a ó mil thick sheet of visquene, whidL in tum must be placed above approximately one foot of compacted granular fill (we recoÍunend the use of crusher fines), which, in turn should be placed above the native sandy gravel. ALL of the native day subsoil must be stripped from above the gravel beneath the fulI extent of the slab floor. Because the underlying sandy gravel is completely non- expansive, there will be no need to provide expansion joints in partitions situated immediately above thebasement floor slab. Thank you for the opportunity to have been of professional service to you in this matter. Sincerely, ^f It \,1¿\ 1'--\* H. Page #3 of3