Archive through July 11, 2017

Log Out | Topics | Search Moderators | Register | Edit Profile

Author Message David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1572 Registered: 03-2002 Posted on Monday, July 10, 2017 - 12:05 pm:    I found out on Friday (a week after the CDs were issued) the new school project is being built near an old landfill. The school district is concerned about methane gas leaching into the building through the slabs on grade. The architect wants to issue a CCD for a thicker under slab membrane. I told him I don't think a thicker membrane will do anything. The school should hire an ground gas mitigation expert. Have you had any similar experiences with radon or other ground gasses? David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC Liz O'Sullivan Senior Member Username: liz_osullivan Post Number: 230 Registered: 10-2011 Posted on Monday, July 10, 2017 - 12:27 pm:    I agree that the school should hire a methane gas mitigation consultant - they are out there. Several below-slab waterproofing systems also work for keeping gas out of buildings, but these are entire systems, with seams sealed, gravel course and pipes for gas to escape through, designed transitions from below-slab to other parts of the foundation, etc. It is design work for an expert. Lisa Goodwin Robbins, RA, CCS, LEED ap Senior Member Username: lgoodrob Post Number: 320 Registered: 08-2004 Posted on Monday, July 10, 2017 - 12:57 pm:    Yes, Liz is right, there are experts for this. The Architect's current consultants may have someone who could do this as an additional service. They should prepare their own specifications. And yes, this should have been done long ago, when geotechnical reports were being done. - Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Monday, July 10, 2017 - 12:54 pm:    I once saw a "methane zone" marked on the plans for a very large scale project in California; natural gas was somewhere subsurface. I can't say much more than that. Greta Eckhardt Senior Member Username: gretaeckhardt Post Number: 61 Registered: 08-2013 Posted on Monday, July 10, 2017 - 02:50 pm:    I would echo all of the above statements and add that because methane is combustible, the mitigation approach may be quite different from radon or other chemical gases in the soil. An expert is definitely needed. David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1573 Registered: 03-2002 Posted on Tuesday, July 11, 2017 - 11:47 am:    The architect informed me that the school district has hired a mitigation consultant. Whew! I will be curious what the consultant recommends for mitigation. I will be sure and post their findings and information. David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC