#21 SBF search and seal

Part 1- Resolving the melting spots
In the last post I described how I was able to see the melted spots on the roof and identify escaped heat.  How exactly the heat was escaping and why was somewhat unknown.
I assumed air was allowing the heat to get through the envelope above the top of a wall on the second floor.  We found that the wall plate penetrated the envelope creating a thermal break and the air sealing was  not great.  This was confirmed with a blower door test.  We were able to see and feel warm air coming from underneath the ceiling sheetrock.  It was warm air we were able to see because it was not very warm in the house and it was a sunny day, so the heat from the metal roof was coming in through the cracks.  This was later in the day and all the morning frost was melted from the roof.
I also felt into the cavity around the cellulose where the melted spots were seen.  So the insulation contractor offered to come back to densify the area I was concerned with.  I retaped the seems around where the new cellulose was injected, caulked the ceiling sheetrock/plastic air seal and called it good.  apparently the sheetrock did not make a good seal with the gasket that seal it to the plastic air barrier that was taped to the top plate of the existing wall.
The tape was not ideally used here either as the top plate was rough cut wood which it not really appropriate for taping to.  Unfortunately, caulk is the best method for sealing to this.

On the next frosty morning we had a light snow.  It was accumulating everywhere lightly and the house was warm.  The spots of concern were not melting!  This was a good sign.  It was also noticed that the last areas that were not air sealed around the entry doors, because they were just installed, were melting, showing the warm air's path of least resistance.

Part 2 - The first blower door test.
This test was conducted before all air sealing was done and the plumbing lines were all open so we were not able to get any numbers.  But we did find our leaks after most visual air sealing was complete. What we found:
1. a gasket on the upstair door to the cold attic has a gasket on backwards and was letting air in under the door.

2. The seal to the top plate of the 2nd story bearing walls had leaks.  Some from the Siga tape to the rough sawn top plate and some from the ceiling sheetrock to the plastic air barrier connector.  This work was not done under supervision and the siga tape was being asked to do a little too much to stick to the rough sawn wood.
3. The vaporblock seal taped connection of the 10 mill plastic air seal connector to the handhewn wood sill that sits on the granite foundation.  Poor tape for the job.  Probably needed to be adheared with some kind of caulk.
4. The site built bulkhead door was not gasketed.  Easy fix, add gasket.
5. The second floor joists penetrated the sheetrock air barrier and were taped with Siga tape.  Taping to rough sawn wood is not working.

6.  The rebated, double gasketed Linnwood doors were tight except at the bottom corners were the adjustable sill sweep met the side gaskets.  They did not overlap or join together and air was allowed to leak.
7.  There was also some expected leaking at the taped joints of the plastic air barrier in the basement.  The 3M red tape was inferior to the Siga tapes.  I tried the economical approach with just using the red tape, but will have to reseal spots with better tape.  I will be trying a more local importer of quality tapes - Pro-Clima tapes from FourSevenFive in NJ.