Floor joist, sill plate, crawl space insulation.

[Unregistered]

I live on a 3 block crawl space in Michigan. I began putting 2 inch foam board around the block walls (liquid nails and dirt to hold in place). I also was cutting pieces of fiberglass insulation to tuck between the floor joist and sill plate. Is it proper not to cover the opening of the top of the block so moisture can escape? Or shouldn't I worry? I do see a bit of light coming between the sill plate and block in some areas.

Home is a small ranch, built in the 1950's with asbestos cement siding, on 3 block, however for the most part 1 3/4 to 2 block deep on the crawlspace side. What a job it has been so far! I'm glad I'm still slim enough to do the work... :)

[Mr T]

Your sill plate usualy covers the block openings anyways.. The blocks are semi porus.. They can breathe.
Find the openinngs from the outside and seal from there. If cold air moves through that area, moisture can condense on everything when it contacts warm air.. Helllllo rotting. If you have no air moving through there (carefull use of a candle/lighter will help find moving air). You can loosely tuck some insulation in that cavity.

With the exception of closeable vents (you should have plenty). you should see no light from inside your crawl.

[scipolla]

I've been reading a lot of info on venting and insulating crawl spaces. Especially how venting crawl spaces during humidity can do more harm than good. From what I have read, if you go with an unvented crawl space one should cover the floor with plasic barrier, close and seal foundation vents, insulate walls except for a small strip left open for insect inspection and leave the underside of the overhead floor uninsulated.

[Mr Fixit eh]

There is an excellent article in the current issue of Fine Homebuilding magazine about replacing a rotted mudsill.