Repairing, Protecting, Refinishing the Exterior of the Main Floor Joist Assembly
Part 1: Assessment and Preparation
As we are limited in what we can do in the interior until the asbestos is removed, we have begun tackling the exterior at the main floor rim joist. We were not 100% sure what we would find, but we had several goals:
Assess the condition of the wall, as well as the assembly components
Protect the rim joist assembly and foundation below with a WRB
Create Air Barrier
Create an exterior air barrier to be sealed to the foundation wall and (at minimum) the subfloor (ideally the bottom plate of the stud wall). We will continue the air barrier on the interior wall and seal it to the bottom plate and subfloor
Repair & Replace Cladding and Watertable
Repair and replace the siding where required, and recreate the water table detail at the base of the siding, (this was removed during the flood but can be seen in older photographs)
Finish Foundation Wall
Finish the exterior foundation wall with parging
Assessing the Conditions – Exterior
Before doing anything else we needed to assess the current conditions of the assembly.
We started on the outside. The siding is historically protected, meaning that although we can replace siding that is damaged beyond repair, the goal is to preserve as much of it as possible. This was difficult! The paint had worn off in many areas and rain damage, in combination with its age and the fact that it is so thin at the upper edge, made removing the siding without cracking it at nail penetrations extremely tough.
We used a combination of techniques as required – a variety of crowbars, and the jig (shown) to help us with difficult nails while holding back and protecting the siding. Some was unusable after removal, unfortunately, but much of it was saved. Additionally the boards were often 14 or 16 feet long, often allowing us to salvage at least part of it.
We were excited to find original building paper still relatively intact. Getting under the building paper would require removing 2-3 courses of siding, depending on its condition.
The sheathing was rough cut lumber, approximately 7” in height, and in very good condition. We decided to adhere the air barrier to the bottom course of sheathing, and that the sheathing and bottom plate would be sealed on the inside. The air barrier could be continued on the interior from there (more on this in a future post).
Assessing the Conditions – Interior
We wanted to make sure that the sheathing was in good enough condition to complete this plan, and that the current paper was performing since we intended to lap underneath it. To do this, we cut several interior holes in the wall.
We were pleased that the wood was in excellent condition and showed minimal or no moisture staining. There were some problems at the rear door but this will be addressed after the asbestos abatement.
At the window boxes we found and retrieved what we thought was the time capsule, but turned out to be an old moonshine bottle (at least this is what we are choosing to believe, it was marked XXX Mountain Dew). Gord drank what was left and had a nap for the remainder of the day.
The subfloor was comprised of 3/4” thick rough cut lumber in varying widths at a 45 degree angle. There were quite a few gaps. Although these aren’t structurally problematic, we were concerned that if mice were using these gaps regularly, they might chew through our brand new air barrier before we had a chance to get it covered. We measured each hole and filled it with plywood, cut at 45 degrees.
To Be Continued in Part 2: Rim Joist Air Barrier and WRB