Replies

1. GBA Editor
   Martin Holladay | Dec 01, 2011 04:24am | #1

   Steve,
   The two main choices are ordinary caulk or gaskets. The best source of gaskets is a company called Conservation Technology.

   For more information on the topic, see Airtight Drywall.

2. 
   dickrussell | Dec 01, 2011 12:13pm | #2

   Martin, item 5.2.3 in the Rater Checklist says: "Sheetrock sealed to top plate at all attic/wall interfaces using caulk, foam, or equivalent material." Does that last phrase "or equivalent material" give the rater flexibility to accept air sealing at such locations if done using MemBrain on ceiling and walls, with the overlaps taped properly? Or are they looking for only a sealant of some sort?

3. GBA Editor
   Martin Holladay | Dec 01, 2011 12:38pm | #3

   Dick,
   I'm not sure what the Energy Star Home program expects, but I'll give you my answer: MemBrain will not seal the crack between drywall and the top plate, or the crack between drywall and the bottom plate. To seal air leaks through those cracks, you need caulk or a gasket.

4. 
   dickrussell | Dec 01, 2011 06:32pm | #4

   By overlaps, I meant those where ceiling and wall sheets of MemBrain meet. On my house, what I did was to hang strips of poly at the tops of interior partitions on the upper level. The MemBrain on the ceilings in the rooms was taped to these poly strips. At the exterior walls, strips of poly were placed under the bottom plates and over a bead of sealant; the MemBrain on the walls were taped to these strips at the bottom and to the ceiling overlap at the top. Thus I have a continuous sheet material at the outer shell, with no gaps or cracks at tops or bottoms of wall sheetrock.

   I suspect that the Energy Star wording is aimed at an ADA approach to air sealing, but I haven't seen much in the way of alternate methods for achieving tightness in ES. Did I miss something? It does seem that the ES folks are open to suggestion for revisions that make sense, given that there have been four revisions to Version 3 so far.

5. 
   user-2003068 | Jan 17, 2012 01:33pm | #5

   The energyStar requirement mentions attic/wall interfaces...my assumption is that you should seal at top and bottom plates of all exterior walls, even on first floor where you'd just have the second floor above. Do you agree?

6. GBA Editor
   Martin Holladay | Jan 17, 2012 02:01pm | #6

   Noah,
   It's meaningless to recommend "sealing at top and bottom plates of all exterior walls" unless we know:
   1. What these plates are being sealed to.
   2. The intended location of the air barrier.
   3. Whether the air barrier is continuous or interrupted.

   There isn't just one way to create an air barrier. If you are sealing the bottom plate of your wall framing to your subfloor, and your top plate of your wall framing to your drywall, that might make sense -- as long as you continue the air barrier to make a complete circle (sphere) around your conditioned space.

7. 
   wjrobinson | Jan 17, 2012 06:32pm | #7

   Dick, you did overkill and my inspector would approve and love it.

   As to drywall seals, quart tubes of adhesive run on all framing as drywall is applied would do the job very nicely.

   Modular homes have glued drywall for years so as to add shipping strength. Not a big deal or cost.