Detailing an Irregular Basement
I’ve done a ton of reading on this site and honestly, my head’s spinning. Could use some advice on this…specific and somewhat unique situation.
Situation: 1920s era home built on a hillside in Zone 5 (southeastern MA). Very humid subclimate due to proximity to the ocean, the hill and the lake it’s built alongside. Sandy loam soil.
Indoor humidity is ranging from 45-50% in the winter to 70%+ in the summer. No water pooling. Heating costs are astronomical due to lack of insulation. Upgrading the home slowly & carefully.
Being a hillside property we have effectively 2 basements. See the attached diagram. Basically, divide the house in two. The back side is below grade on basement level 1 but above grade on the front side, and basement level 2 sits below the above grade portion of basement level 1. Basement level 2 is connected to basement level 1 in the back right corner where the mechanicals (water, heat) go up to then run inside the crawlspace to the living areas above it.
Heating is supplied via an oil furnace & 1 pipe steam radiators, hot water via a propane on-demand heater recently installed.
Given how unconventional my basement situation is, before I proceed with the standard suggestions (vapor barriers on floors and walls, insulation on rim joists, insulation on walls when possible), is there anything else I should be thinking of?
My oil furnace appears to vent directly to the chimney via a metal duct. The duct does have a damper on which opens when the furnace is running, presumably drawing in interior air. Is this a problem if I seal up the crawlspace?
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Replies
MA has an energy saving program. You should check out what they offer.
Yes, they want to vapor seal and insulate the underside (the floor above) and do nothing with the crawlspace itself.
MA's programs are great if it fits your plan. They're very one size fits all so I don't trust that they're going to recommend what is necessarily the right move for our project. If it fits I will take advantage of it. This is what they offer:
In the crawlspaces we will lay a vapor barrier over the dirt floor. We want to create a barrier from the moisture within the dirt. Then the crawlspace we have access to from the basement we can add 6” fiberglass batting to the ceiling.