Replies

1. GBA Editor
   Kiley Jacques | Jun 01, 2021 03:34pm | #1

   I am borrowing an answer from Brian Pontolilo to a similar question:

   This is a pretty critical detail to get right, both for the construction process and for energy efficiency. When it comes to getting the plate level, I've seen builders do everything from shim with wood or steel, to knocking down the high spots on the foundation wall with some sort of chisel to planing the installed wood sill (which seems pretty crazy).

   Here are some articles and a video that may be helpful:

   https://www.finehomebuilding.com/2003/09/01/mudsills-where-the-framing-meets-the-foundation

   https://www.greenbuildingadvisor.com/article/air-sealed-mudsill-assembly

   https://www.greenbuildingadvisor.com/article/part-2-of-gbas-video-series-on-a-passive-house-project

2. 
   jacobtig | Jun 01, 2021 08:16pm | #2

   One option (if adding an extra 1-1/2” of height is ok) would be fasten the mud sill and gasket down tight to concrete, and then add a second sill on top that is shimmed level. Air seal with caulk between the two plates where they are tight, shim to level where needed (shims directly underneath joist layouts), spray foam the spots where there is a gap and shims.

3. 
   Chopsbuilds | Jun 01, 2021 09:07pm | #3

   Thanks! These replies are exactly what I need. It is a step down stem wall to save money on concrete so I will be building these all as pony walls. I can use a double bottom plate in this section only and I have the thread height on the 5/8" anchor bolts too. I think i will rip a lengthwise shim from another 2x6 to carry the load across the whole mud sill. From there it will be easy because I'm toenailing the studs. I'm using Poly-Wall liquid applied WRB and their liquid flashing will work perfect towards a tight house.

4. 
   qofmiwok | Jun 01, 2021 11:42pm | #4

   https://protectowrap.com/product/premium-energy-sill-sealer/ I read about this, maybe it would be part of the solution.