Preventing Racking and Improving Envelope
Hi all – I’m Neil and I’m a long time listener, first time caller… I am as of recently the owner of split-level house ‘installed’ in Gibsons, BC (Climate Zone 4) in 1955 (brought over on a barge, but constructed at some unknown date in the lower mainland – the pinstripe detailing of the hardwood flooring hints to me at 1940s or earlier).
The walls are constructed of (in to out)
-16” horizontal drywall strip with plaster scratch and smooth coat
-fibreglass batt insulation
-2×4 stud wall
-horizontal (not diagonal) 1×6 sheathing
In the lowest level of the house, there is just normal drywall, and poly vapour barrier (just stapled on) on the inside of the insulation.
There are 2 chimneys, one of which is connected to a ‘high efficiency’ (i.e. sealed) methane/butane fireplace. The other is an artefact. Windows are okay – about 15 year old 2x pane.
I have been working on sealing gaps and and have added poly in the places I’ve replaced the drywall (for bathroom renovations – fortunately no asbestos to be found). There used to be rats in the house, but in closing holes we seem to have excluded them, though they had nests and tunnels in places where insulation was exposed (basement, attic), but no evidence seen where it was covered by wood or drywall.
The stucco is in pretty bad shape. Likely from ’55. Lots of fissures throughout. Also I hate stucco. But it is not visibly delaminating from the structure that I can see at least.
The house has shifted a lot since summer, with some interior doors becoming uncloseable. No doubt some of this is due to humidity increase (it rains most days from mid-sept to March), but I think that this is combining with racking due to the weakened stucco and poor racking resistance of horizontal board sheathing.
In the summer I would like to put a new envelope on, and getting rid of the functionless chimney. I am thinking a peel and stick vapour permeable membrane, and 80 mm dense mineral wool over top, and a rainscreen with a aluminum sheet and siding mix as cladding.
My questions are these:
1. Does the above seem like a good idea, or will I run into condensation issues due to the lack of interior poly? I can’t really rip up all the interior walls, as we are living in it.
2. If I do the plan above, should I do something to beef up the racking resistance a bit over the existing board sheathing (e.g. 1/4 or 3/8 plywood over the whole, or maybe just corner reinforcements)?
Thanks for your input!
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