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5.1. SR 09-19-1994 I ~\.( ( II IIi{ River ITEM 5.1 MEMORANDUM TO: MAYOR & CITY COUNCIL FROM: PAT KLAERS, CITY ADMINISTRATOR DATE: SEPTEMBER 15, 1994 SUBJECT: PROPOSAL FROM INSPEC, INC. Attached to this memo is a report from Building Official Cliff Skogstad regarding the proposed services from Inspec, Inc., to help the City with its ",Fire Department J;oofproject. We have asked Eos Architecture to review this Inspec proposal and they have indicated that the scope of services and the fees are in line with this type of project. By percentage, the fees are high based on our estimates for the total cost of the project, but professional services on a small scale project are always high when looked at on a percentage basis. We certainly hope that by using Inspec on this project we will get some very good bids and some cost savings in the project. . Staff recommends that the City Council authorize the hiring of Inspec, Inc., to work with the City on the Fire Station roofrepair project. . P.O. Box 490 . 13065 Orono Parkway · Elk River, MN 55330 · (612) 441-7420 · Fax: (612) 441-7425 r I ~\.( ( II !Ii{ River TO: MEMORANDUM FROM: PAT KLAERS, MAYOR, AND CITY COUNCIL CLIFF SKOGSTAD, BUILDING 'I. IJ OFFICIAL C:b DATE: SEPTEMBER 8, 1994 SUBJECT: BIDDING PROCESS FOR RE-ROOFING THE FIRE STATION . On September 8, 1994, I met with Mr. Fred King from Inspec, Inc. I requested this meeting to acquire a price for services of site verification, construction documents, and special inspection and test on the Fire Station. Attached to this memo is Inspec's fee for the services requested. The last three items in the proposed fee are for construction observation, testing, and reimbursable items; the price on these items will depend on the construction contract. If the bids come in at approximately $30,000 dollars, the total of the three aforementioned items would be $840.00 dollars; with a total estimate of $5,400 dollars for services. With the use of these services, I feel it will pay for itself in the long run, considering a longer lasting life of the new roof, minimal call back and repairs, and a complete bid package with no unseen over-runs. In addition, the special inspectors will assure proper application of the construction package. If you have any questions, feel free to contact me at the City Offices, or, if you wish, I could attend Monday nights meeting. . CS.bidJBZ P.O. Box 490. 13065 Orono Parkway · Elk River, MN 55330 · (612) 441-7420 · Fax: (612) 441-7425 SEP - g 1994 / ""NSPEC, INC. . 580 I Duluth Street Minneapolis, MN 55422 Ph.612.546.3434 Fax 612.546-8669 555 West LaytooAve. Suite 420 Milwaukee, WI 53207 Ph. 414.744.6962 Fox 414.744-6981 . Engineering & Architectural services fOr . roofS,pavements, exterior walls, and outdoorsports mcilities. September 8, 1994 Mr. Clifford Skogstad City of Elk River P.O. Box 490 13065 Orono Parkway Elk River, Minnesota 55330 Re: Proposal for Engineering Services for Reroofing of Elk River Fire Station, Meeting Room and Apparatus Area Roofs Dear Mr. Skogstad: As requested, we are pleased to provide this proposal to furnish engineering services for the development of construction documents and to provide construction observation and quality control testing for District reroofing projects. SCOPE OF SERVICES Site Verification Roof-related details will be verified in the field using test openings to allow for dimensioning and sketching of the actual existing conditions. Along with dimensioning the building, this information will be used to provide a basis for the development of the reroofing design. Construction Documents Drawings and a project manual will be prepared for this project. If, during the design phase, it is determined there is a reasonable potential that one or more new roof systems could offer performance and/or cost advantages, but would add significant load to the existing structure, we would recommend a structural evaluation be conducted. This structural evaluation would determine the total load capacity of the existing structure based on the original building drawings. The fee for the structural evaluation would be determined upon review of the original building drawing s. The potential exists for asbestos-containing roofing materials to exist on this project. Should this be discovered during the field verification work an asbestos consultant would be required to properly address this concern and we suggest these costs be paid directly by the City of Elk River. . . . City of Elk River September 8, 1994 Page Two Based on the background information, viable roof system alternatives will be determined and presented to you for a final decision regarding the reroofing design to be fully deveioped into construction documents for this project. Once the construction documents have been developed, we will assist you in issuing the project for bid. We will send a set of the documents to the State for their review. We will consult with you regarding the more qualified contractors to notify regarding the availability of this project to bid, and will then contact those contractors. A pre-bid conference would be held one to two weeks prior to the bid opening to discuss the scope of work with the contractors at the project site. We will attend the bid opening and provide bid tabulation forms. Once bids are received, we will assist you in the evaluation of the bids and provide a letter of recommendation if requested. Construction Observation This service would include the review of contractor submittals, a pre-construction conference with all parties, periodic construction observation during reroofing, verification of pay requests and a final walkover of the roof. Our on-site observer not only would act as your representative regarding the technical aspects of the project, but would also act as a liaison between you and the contractor with regard to coordination issues that affect the building owner, such as access and staging areas, shutting down air intakes and resolving other unforeseen problems that may develop. Testin2 Testing of the roof materials and the completed roof system will be conducted. The types of tests will depend on the type of roof system specified. Our on-site observers have the capability to conduct many of the roofing tests on site, providing prompt test results to the contractor, avoiding "after-the-fact" conflicts. Those tests that cannot be conducted on site will be conducted in our in-house laboratory. PROPOSED FEES Site Verification Construction Documents Bid Process Construction Observation Testing Reimbursables NTE $1,000 NTE $3,000 NTE $200 NTE 2 % of the construction contract NTE 1 % of the construction contract Actual - 0.8 . . . City of Elk River September 8, 1994 Page Three Reimbursables would include such items as the advertisement for bids and the State Plan Review fee. REMARKS We request that you review this proposal and, if satisfactory, sign and return, or prepare a purchase order as our authorization to proceed. We appreciate your continued interest in our services. Very truly yours, INSPEC, INC. J~:ifr, FK/jmk Accepted By: City of Elk River Ene. By: Title: Date: 37 ...MINIMIZING PONDING USING ....LAT INSULATION DWIGHT F. JENNINGS and DWIGHT D. BENOY INSPEC. Inc. Minneapolis, Minn. In the 1950s, designing totally flat roofs was common practice. When roofs were designed to be totally flat, the end result usually was not. Unless camber was built into the structural system to allow for anticipated dead and live loads, deflection between bearing points resulted in low points on the roof. Typically, roof drains were located along beams or bear. ing walls, which turn out to be the high points in the roof system. There also was very little room for error in construc- tion. Everything, from the footings on up, had to be con. structed to very close tolerances in order to end up with equal elevations across the building. The industry gradually learned that ponding water acted to reduce the serviceable life of a built-up roof. Getting the roof dry enough to patch a leak was also a problem. And, much more water entered the building if leaks did develop. Most major manufacturers in the United States eventually . came to recommend V.-inch-per-foot slope for new roof design using built.up roof membranes or manufactured single-ply membranes. However, there are many, many buildings out there already that have no slope and have excessive water ponding. The most opponune time to cor- rect this condition is when reroofing becomes necessary. Ideally, eliminating all ponded water would be the best for the long-term performance of the roof system. However, there are times when eliminating ponded water is not prac- tical because of the complexity of the solution or limitations posed by the existing conditions. It is imponant to keep the design as simple as possible. A complex design may be the most effective, but costs will rise proponionately, and the contractor may have difficulty in actually executing the work. In these cases, the cost to eliminate the ponds exceeds the advantage of doing so. Many expens believe a roof pond that dries within 48 hours of a rainfall will have little effect on the long-term performance of a roof membrane. . REROOFING DESIGN APPROACHES Once the existing conditions and the cause of the ponding problem are determined, approaches to the reroofing design can be developed. Many times the addition of roof drains or scuppers is not feasible. Adding insulation of varying thick- ness, not necessarily tapered insulation, can be a viable solu- lion in many cases. flat and Tapered Insulation System In response to the industry movement toward slope in roof systems for complete drainage, manufacturers are market. inltapered insulation to give slope to relatively large sec. tions of roof area. Tapered insulation board is available in several different types, including polystyrene, perlite-aggre- pie, isocyanurate, cellular glass and fiber glass. The slope available in each type varies. The slope should be sufficient to achieve positive drainage, yet not so great that insulation thicknesses become difficult and costly to deal with al the details. Maybe it's not necessary to use tapered insulation to slope the entire roof area. There may be existing deck slope, no matter how slight, to take advantage of, even in an essen. tially flat roof. Let's look at a simple example of a 50.year-<Jld building with an essentially flat concrete deck. The deck has gradually deformed and sagged between suppons through the very slow process referred to as "creep". To compound the prob- Jem. new HVAC equipment has been suspended from the deck. The net result is a slight slope in the roof section from the suppons to the center. The roof is drained at one roof edge through scuppers over one of the bearing walls. The result is substantial ponding in the central ponion of the roof area (Figure 1). The reroofing design could include tapered insulation from the scuppers to the opposite roof edge to eliminate ponding. But half the existing roof is .a1ready sloping in the direction for drainage to the scuppers, so why not take advantage of it. Flat insulation placed over this half of the roof will have a net positive slope toward the scuppers. Tapered insulation with enough slope to counteract the negative slope of the deck in the other half of the roof will provide a net result of positive slope across the entire roof area at the membrane level. This approach minimizes the insulation thickness so one can better deal with height limitations at existing flashings, such as through-wall flashings, and at large mechanical units. Likewise, blocking requirements at the details may be less. The final product provides the desired drainage at less cost than a fully tapered system. Tiered flat Insulation System Another, typically less costly, method of reducing ponded water is to increase the thickness of insulation in steps, or tiers, from the drainage points to the perimeter of the area. These tiers are typically made in Ih-inch or 'II-inch incre- ments with tapered edge strip installed to provide a smooth transition from one tier to the next. The same basic concept as in the first example is appli- cable here. Take advantage of the existing deck slope on half the area. In this case, the insulation is stepped down in four increments rather than a continuous taper (Figure 2). The steps are located more closely in the area of greatest ponding, or negative slope, to minimize the existing highs and low'. The disadvantage of this approach is that it does not com. pletely eliminate the ponding in all cases. However, it can reduce the depth or ponding to a tolerable level by displac. . 31 . ing the water in gradual increments. As with the tapered in- sulation example, height restrictions at the details are more easily dealt with. The primary advantage of this approach compared to the tapered insulation approach is cost. De. pending on the type of roof system and the complexity of the insulation layout design, the installed insulation cost for the tiered system can be 10 percent to 40 percent less than the tapered system. This cost saving can go a long way to offset any loss in service life of the roof system caused by minor ponding with the tiered system. Scuppers Ind Downspouts Once the surface water gets to the drain, it must be able to flow off the roof. Often the extra materials used to flash in the drain, or scupper, result in a build.up around the drain and some damming of water. This effect can be minimized by placing the drain, or scupper, in the center of a depressed area made by tapering the insulation. The tapered area' should be slightly larger than the largest flashing sheet. In climates where freezing temperatures often occur, ice damming at scupper outlets and ice damage to the down- spout arc often problems. The open.faced down-spout was developed to minimize the potential for plugging while con- tinuing to provide the waIl protection and control of water flow afforded by a totally closed downspout. Using a dark color for the downspout allows solar heating to help keep the downspout as ice-free as possible. Cenain types of buildings, such as school buildings, may have other special considerations. It is amazing how a new downspout can provide children with access to the roof. A W-shaped open-faced downspout securely anchored to the wall is a design that doesn't leave much for children to grab (Figure J). Also, there should be no projections or sharp sheet metal edges that could cause injury. This design has an advantage over the more conventional open-faced down- spout when using factory color-coated sheet metal. The en. tire exposed face will have the colored face showing. The in- side of the more conventional open-faced downspout shows the reverse side of the metal, producing a "racing stripe" on the building unless the inside is painted. This "child-proof" downspout provides a reasonable solution to a couple of typical downspout problems. Contractors that have used it have found it to be fairly easily fabricated and installed, while providing essentially the same function as the more . ~ conventional open-faced downspout. Likewise, building owners are satisfied with the reduced potential for injury and traffic on the roofs. Inside-Outside Drains A beller approach to edge drainage in nonhern climates is to install an inside-outside drain. This is usually more expen- sive than an exterior scupper and downspout. But its ability to remove snow.melt water is much beller, and the risk of damage from ice falling off the wall is eliminated. It is also relatively vandal-proof. This type of roof drain system is simply a roof drain in. stalled at the low point of the roof surface. The drain leader runs down the inside of the exterior wall and discharges out through the waIl a foot or two, above grade (Figure 4). The interior location keeps the drain and leader open during cold weather. Ice build-up at the discharge is minimized because the draining water has warmed slightly. Damage from any ice development is minimal because it forms at grade level, not at roof level. REMARKS There are still many buildings out there with ponded ,,'ater on the roof. With some thought at the time of reroofing, most of these conditions can be reduced or eliminated using some relatively simple methods. The resulting roof system is more likely to reach its maximum serviceable life, at the lowest Iife-cycle cost. 1" insul. 3" insul. -t Area of substantial ponding 1/e"/ft. tapered insul. Scupper-'7 B ROOF PLAN No Scale 1"insul. 1/8"1It. tapered Insul. 3" insul. Root surface slope ~ . Deck slope B TAPERED INSULATION SECTION No Scale FiguTt J .' ',". .0, . 'cI'o". "'.? '0"-;' It Deck Slope Exist. concrete deck showing exaggerated deflection between bearing walls . ~ 1" insul. I 1" insul. 1 'h " insul. 2" insul. Scupper ./' 01 (11 4' 4' ROOF PLAN No Scale Tapered edge strip to provide a smooth transition 1'h " in sui. 2" insul. 2'/." insul. 3" insul. . Deck slope 8 TIERED INSULATION SECTION No Scale' Figurt ] . 211z" insul. 3" insul. Areas of substantial ponding A Roof surface slope ~ 39 L Deck slope Exist. concrete deck showing exaggerated deflection between bearing walls . . . 40 Figure J Fasten new sheet metal downspout with 3116' dia. masonry anchors lhru neoprene washers at maximum 3'-0' on.center thru slotted holes , , r \ I ,,______________.;J Cover open face of /f - downspout with 8' L-- deflector plate at top and bottom of downspout. fasten with screws or rivets DOWNSPOUT DETAIL No Scale . . . , , I, , , , I , I I I Min. 1/S"/ft. slope s' 1 I Secure leader to deck ~ --- and wall with straps Provide insul. pipe wrap Carefully bore neat hole thru wall. fill void w/grout Splash block .1 Cast iron roof drain with bottom outlet and deck clamp Tapered insul. lS" INTERIOR/EXTERIOR No Scale Figur. 4 ROOF