Small Project Design

 View Only

  • 1.  Re-Roof of Museum

    Posted 08-21-2012 07:07 PM
    This message has been cross posted to the following Discussion Forums: Small Project Practitioners and Practice Management Member Conversations .
    -------------------------------------------
    I am inquiriing about a Museum Re-Roof. The owner  needs a zero-water inflitration clause in the documents. I need to know if there is a definition of "zero - water infiltration" ? What is the best way to adddress it in the documents and enforce it during construction? Does any one have a good guideline for pre-qualifing reroofing contractors.?  I have the "x" number of years experience of reroofing similar size and complex roofing. I will demand that Certified superentendent and installers are required to work on project.  I am concerned because it is a public project that if a contractor can bond it they will bid it.

    The project is a very nasty tear off and reroof with single membrane product.

    I would welcome any suggestions, definitions or comments from anyone who has experience on a similar project. Thanks in advance for any comments or help.

    -------------------------------------------
    Richard Shanahan AIA
    Richard M. Shanahan Architects
    Bozeman MT
    richard@shanahanarchitects.com


  • 2.  RE:Re-Roof of Museum

    Posted 08-23-2012 02:06 PM
    My advise: run!  A museum is putting on a single-ply roof?  Run faster!  There is no industry standard for 'zero-water infiltration'.  Require a hefty liability insurance limit.  You may want job insurance for yourself.  NWS can predict 0% chance of percipitation and still a shower sneeks up.  You may want to require an interior protection sub, but of course, they could knock over something priceless.  Up your experience requirements.  Ask bidders to submit a written plan of action in case of unexpected rain and his method for night tie-offs which will be used to evaluate bids.  This will require judgement in evaluating and can be used to weed out idiots.

    -------------------------------------------
    John Bigham AIA
    Owner
    Bigham Roof Consulting
    Lakeland TN
    -------------------------------------------








  • 3.  RE:Re-Roof of Museum

    Posted 08-24-2012 11:23 AM
    There are some good responses in this posting.
    Question for Mr. Bigham- What kind of roof would you recommend and why?

    -------------------------------------------
    Mary Price AIA
    Principal
    Price Group Architects & Planners
    Norman OK
    -------------------------------------------






    Original Message


  • 4.  RE:Re-Roof of Museum

    Posted 08-27-2012 02:45 PM
    First, let me say that initially it was not clear whether this 'zero water infiltration' was during construction or afterwards.  I assumed the former, and other respondents have assumed the latter.  If I were going to spec a roof for a museum or other facility where the value of the contents made the cost of the roof of little consequesce, I would call for a 4-ply BUR capped with a fleece back thermal plastic membrane.  This roof would have the puncture resistance of a multi-ply roof plus the reliability of welded seams.  I have never used them, but for this project, I suggest you look into electronic leak detectors.  They will have a grid of wires built into the roof system and will transmit an alarm if they detect moisture.  If the museum cannot swing the 5-ply roof composit roof, then I will endorse all that Mr. Colburn said, except I would not go so far as to call warranties worthless.  They do have their limitations, but a 20-year NDL will help weed out the worst roofers, get the manufacturer's rep on the roof and protect againts a catastropic material failure.  Shy away from writting your own warranty.  You can unwittingly raise the cost unnecessarily and scare off the best roofers, leaving only the most wreckless.  Keep in mind that a good roofer can give you a good roof with mediocre materials, but there is no hope for the best materials in the world installed by a bad roofer.

    -------------------------------------------
    John Bigham AIA
    Owner
    Bigham Roof Consulting
    Lakeland TN
    -------------------------------------------






    Original Message


  • 5.  RE:Re-Roof of Museum

    Posted 08-24-2012 03:43 PM
    Single ply roofs have no redunancy.   Would recommend a 3-5 ply built up SBS or APP sytem.   Much more bullet proof and longer lasting.   We do many roof replacements for the state of Idaho and most are 10-15 year old single ply systems that have failed or are failing.  With any roof - workmanship is key.   Require resumes and experience of the job foreman and key personnel.   Minimum 5 years experience and minimum 10 projects with same roof system as an example.   Get references and go look at previous roofs they have completed - the older the better.   Pre-qualify them for bidding.   Require a full time job super and the manufacturers rep to attend the pre-construction conference and sign off on the job at the end with a letter saying they accept the project and will honor the warranty.   The manufacturers warranties aren't worth the paper they are written on - to many exclusions, pro rating, etc.   (read one all the way through when your bored sometime), Develop your own warranty.   The state of Idaho has -

    http://dpw.idaho.gov/architect_engineer/

    Look under forms at the bottom.  Idaho pre-qualifies the roofing manufacturers and requires them to submit a letter saying they will honor the States warranty.   They also require a 3 year labor and material warranty from the contractor.

    Even with all this - roofs leak so I would get a rider on your insurance policy if they insist upon the zero water infiltration clause.

    -------------------------------------------
    Richard Colburn AIA
    H2A Architects, PA
    Coeur D Alene ID
    -------------------------------------------






    Original Message


  • 6.  RE:Re-Roof of Museum

    Posted 08-23-2012 03:36 PM
    First of all, I would ensure that all the detailing of the roofing at perimeter and penetrations is well detailed.  Second, I would ensure the design of the roof gets as much water as possible off the roof as fast as possible, with no possibilities for ponding or "bird baths". (Maybe a steeper slope than usual, with a greater number of roof drains.)  Third, the best guarantee that the roofing installation is correct and to the best levels of installation is to require full time inspection by a qualified roofing inspector. Inspector should be a third party professional with no ties to either the Contractor, or Installer.  Fourthly, keep maintenance traffic off the membrane.  Detail walk pads around all equipment and lay out walk pad paths to reduce the number of chances that maintenance workers will take a short cut across the membrane. 

    What is the duration of the "zero-water" requirement?  5 years?  25 years?  50 years? Forever? This appears to be a much tighter requirement than many roofing manufacturers will warrant.  I suggest that you consult with several manufacturers of the memebrane type you are considering regarding this "zero-water" requirement.  I suspect that you will need to get the Owner to agree to a continuing maintenance agreement that requires at least semi-annual inspections and corrective work as needed to maintain the roof in a "zero-leak" condition. 

    -------------------------------------------
    Terry Alexander AIA
    Architect
    Leo A. Daly
    Minneapolis MN
    -------------------------------------------








  • 7.  RE:Re-Roof of Museum

    Posted 08-24-2012 11:39 AM
    Selection of installer is absolutely key. A roofing manufacturer we consult with has partnered with the Arizona State University Performance Based Studies Research Group www.pbsrg.com to develop a thorough installer performance/prequalification process for critical roofing/reroofing projects ("best-value contracting"). We developed bid and contract documents to facilitate this project process.

    In addition to thorough investigation of proposed installer and personnel past performance, the process requires installers to submit a project-specific quality assurance program. It is this quality assurance program that will detail the tear-off/protection provisions to ensure ongoing protection of the building contents during the work. Project requirements include experienced roof inspectors on the roof during work.  

    These projects include manufacturer/installer partnering to provide extended maintenance and 24/day response to storm events, etc. Not your cheapest low bid solution, but not necessarily carrying a high surcharge, either. It is used for mission critical roofing programs around the country.

    The message to your client is that you get what you plan, enforce, and pay for. If the client wants to retain the lowest bid installer and expects to get superior on-the-job and post-construction performance from them, they are badly misinformed. The best roofing installers are not chasing low-bid projects; they don't need to.

    -------------------------------------------
    Philip Kabza AIA
    Partner and Dir Technical Services
    SpecGuy
    Charlotte NC
    -------------------------------------------