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HomeMy WebLinkAboutRe: foundation wall review , ' �1 engineers ��.w��«»►�� 5201 E.River'Road,Suite 308 Minneapolis,MN 55421-1027 Phone:763.571.2500 Fax:763.571.1168 July 10, 2008 Robert Beissel Homes LLC i718�agle Lane _ _ Mound,MN 55364 Attn: Robert Beissel Subject: ew 3768 N Shore Drive,Wa zata M lteig_Project No. 208.0987 To Whom It May Concern: The purpose of this letter is to report the findings of a structural engineering review of a distressed foundation at the above residence. ASSIGNMENT Ulteig Engineers has been retained to provide a structural engineering review of the distressed cast- in-place concrete foundaHon located at 3768 N Shore Drive in Wayzata, MN, as directed by Robert Beissel, the builder. BACKGROUND The above residence is currently under construction. Rough framing is nearing completion. DPM Masonry placed the cast-in-place concrete foundation at the end of 2007. Since placement, several cracks have formed at the exterior foundation walls. The City Building Inspections Department is requesting a structural engineering review of the foundation wall distress. Minneapofis, MN•Detroit Lakes, MN•Fargo, ND • Bismarck, ND• Sioux Falls, SD www.ulteig.com Robert Beissel Homes LLC Ulteig Project No.208.0987 July 10,2008 Page 2 DESCRIPTION The building is a one-story wood-framed structure with a cast-in-place concrete foundation, full basement, both lookout and walkout at the rear, and an attached slab-on-grade garage. OBSERVATIONS AND COMMENTS 1. The following information was obtained through a site inspection on July 1, 2008 by Trevor Axner,PE of Ulteig Engineers: a. The foundation walls are 8" thick cast-in-place concrete. The full height foundaHon walls are nine feet tall and the lookout foundation extends three feet above the basement slab-on-grade. b. The overall basement size is approximately 70 Eeet wide by 32 feet deep. c. The foundation wall distress noted consists of five crack locations spread around the perimeter of the structure. Unless specifically noted in item ii below, all cracks observed vary between '/�6' and hairline in width. i. Beginning at the intersection of the rear lookout wall and the full height foundation between the attached garage and house basement, a crack extends down at an angle at the base of the lookout wall over less than a 2'-0" vertical and horizontal distance. ii. The second crack is located along the same lookout wall at an angled comer closer to the walkout section of the basement. This crack is the largest of the five at approximately 1/a' near the top of the wall. This crack is oriented primarily vertically and decreases in width over the height of the wall. iii. The third crack is at a corner of the lookout wall on the other side of the structure. This crack is oriented vertically. iv. The fourth crack is at the front full height foundation near the right side at an outside corner. This crack is primarily vertical but extends diagonally away from the corner near the top of the wall over approximately a 16" horizontal distance. v. The final crack is on the other end of the front foundation. This crack is oriented diagonally, but the crack is hairline in width and located at an intersecting full height stoop wall. d. The foundation walls are relatively plumb. e. Waterproofing below grade could not be observed. f. The soil on-site is reported to be a primarily sandy material with some fines. g. The builder reported that the foundation was subject to freezing conditions over the previous winter before being capped and heated. Robert Beissel Homes LLC Ulteig Project No.208.0987 July 10,2008 Page 3 2. The following information is noted in regard to the observed foundation distress: a. Based on the orientation and location of the distress, the cracks are likely the result of minor differential settlement and / or frost heave, as well as potential intemal shrinkage stresses inherent in concrete construction. The size of the larger crack may also be due to the possible lack of a continuous horizontal reinforcing bar near the top of the wall at this location. b. Regardless, foundarion walls are intended to span vertically between supporting floor systems. The primarily vertical nature of the observed crack, as well as the corner and intersection locations, do not reduce the ability for the walls to support exterior grade and vertical house loads as intended, and ensures the continued adequacy of the existing foundation walls to support all required design loads. c. Waterproofing is typically flexible enough to span over small foundation wall cracks if installed in accordance with the manufacturer's requirements. If the builder is concerned with water infiltration, Ulteig recommends injecting the larger vertical crack in the rear lookout wall with a urethane injection material to help reduce the potential for future water infiltration. Other sealing methods may also be suitable for the condition noted. Ulteig is not responsible for current or future water infiltration problems PROFESSIONAL OPINION 3. It is our professional engineering opinion that the existing distress does not affect the structural integrity of the foundation. No structural corrective measures are required. Refer to the above recommendations for additional information. GENERAL 4. The informallon, observations, and opinions stated in this report are based on an inspection made by Trevor Axner, PE. The inspection consisted of a visual walk-through observing exposed elements and those accessible without the removal of finished materials. 5. The observations and opinions expressed in this report are based on our professional engineering judgment and professional practice, as well as the visual inspection. 6. No other engineering was performed or requested for this project. This document pertains to a structural review of the cast-in-place concrete foundation only. The builder may monitor the foundation for additional movement. If additional movement occurs, please contact a geotechnical engineer for a soil related review. 7. All construction is to be in accordance with the Code and standard industry practice. Robert Beissel Homes LLC Ulteig Project No.208.0987 July 10,2008 Page 4 If you have any questions, please contact us. Sincerely, ULTEIG ENGINEERS � V � Trevor Ax er, PE I hereby certify that this plan, specificaHon or report was prepared by me or under my direct supervision and that I am a duly licensed professional engineer under the laws of the State of Minnesota. � � Trevor Axner, PE Minnesota Registration o.45470 Date: 7-10-OS