One of my tasks since a retired 5 weeks ago is to track down the cold drafts in this house.
We doubled the size of the house 8 years ago but since then its always been cold at floor level.
Now we have gorgeous wood floors and nowhere for there to be air leaks so I was confused So I began to look closer and found these things in order of importance.. I.e when they were fixed made the biggest difference.
We have a forced air system. I would not have gone this way as an HVAC engineer but it was what was expected in the local market at the time..
Anyway.. the list of leaks were as detected by the back of the wet fingernail (most sensitive way to detect moving cold air without a thermal imaging camera)
1) Around the floor boxes where they attach to the subfloor. These were tiny leaks, some of them not visible! but when using the wet fingernail were quite pronounced! Sealing them made a big difference. But it was still cold!
2) Back of the hall closet: I had made the drywall panels removable so to access the plumbing to the back of the shower if necessary so the panels were not taped and mudded.. Nor were they sealed. There was also about a 2*3" hole at the bottom that I had forgotten about right at the back where a vent pipe went though... Spray foam and caulked around the edges of the panels.. Huge improvement!
3) crawlspace access.. also in hall closet.. Amazing the little gap around the edge of the access was leaking a lot of cold air... I caulked this up with decorating caulk.. easy to just cut it with a box cutter to gain access and the caulk is $1:19 a tube.. I have several in stock!
4) Pipe penetrations under sink and in laundry room.. Surprisingly large drafts again.. out with the spray foam.
Thats what I have done so far.. the thermostat last night was 4 degrees lower and my Wife was still warm and cozy!
But of course we are mustacians and if this perfectly built house had these air leaks right under my nose... what other leaks are there?
Well we have the gorgeous wood floor with stained molding at the base of the walls.. wet finger test along the bottom of this molding has detected unmistakable air leaks..WHAT?.. Well the old part of the house has 2*10 planks as a subfloor then tap paper and the oak strip floor laid on top. At the edges of the floor there is a small gap to allow for expansion, and this gap is covered by the molding. Now because the molding is stained it does not have any caulk thus is not sealed to the floor, plus the subfloor also has 1/4" gaps in the planks.
Bottom line, air is getting up between these planks, up through the gap between the floor and the walls behind the molding and into the room, even though the underside of the house is fully insulated between the joists.
To test this in our bedroom we have a section of wall that we didn't finish wallpapering and so I left the molding off so the gap is exposed.. wet fingernail in the gap.. sure enough there is a tiny draft.
I am considering what to do next.. Easiest is to use some brown caulking under the molding to seal it to the floor (but not the wall). Not perfectly effctive.
Alternatively (but more work) is to remove the molding.. seal between the edge of the wood floor and the wall with spray foam and replace the molding.. With a brad nailer this could all be done in about a day.
So there you are, tiny leaks that I never thought would ever be a problem when we built the house but added up made a significant difference.
Frank
