Expert: Dan Griffin - 6/16/2010

Question
QUESTION: We are having a 28x12 studio/flat built with a 6x12 bathroom inside one end. When done it will be set on our property on 10 piers. Q) Can we place since on piers our leach field area of property? ALSO we are planning on tieing into exsisting septic tank and well water... do you see any problems or challenges? Thank you. An 80 year old in NM

ANSWER: Terry, if this is truly a leach field, it should have a waterproof membrane that prevents any and all effluent from entering the ground water system and forcing everything up for evaporation.  If you build a pier system over the location, provisions will need to be made to ensure the continued integrity of the system.  I'm sure this will be addressed by a mechanical/plumbing inspection.

I don't have any other particular concerns.  There is the potential for odors, ehich may not be noticable now in the open air, but might become an issue when trapped under structure.  You may end up haveing to "move" the leach field by removing it from under the  proposed structure and adding the capacity back elsewhere.  A good septic contractor will be able to answer your questions better than I.  I would suspect that your system has enough capacity to handle an additonal bathroom, but, again, best asnwered by plumber/septic man as the fixture count will be larger.

I hope this answered your question or sent you in the right direction.

---------- FOLLOW-UP ----------

QUESTION: If there was a country of great answers you would be the President. Q) On our new 28x12 new flat/studio they are planning to use R38 in ceiling and R19 in walls (2x6) and R19 in floor BUT for .50cents extra per sf ($168 bucks extra) they will put R38 in floor (this flat/room will be on 10 piers above ground skirted). IS IT WORTH IT or is R19 fine for floor? We are in Abq NM 87048 and I hate heat.

Answer
Terry, there will be so many "well for a few bucks more, we could do this>>>>"  type issues in any remodel.  $168 on the total cost is chump change.  Look at your bids, envision how many more "little upgrades" may be involved.  If the insulation bucks fit in your budget - do it.  Insulation/Rvalue in the floor is not as important as walls and ceiling.  I know this is not answering your question directly, it is just one of those many little decisions on the way.