I have a 1948 Cape Cod and last year I decided to put rolls of insulation in the attic behind the knee walls. I rolled it out on between the joists so its above the ceiling in the living room(where my stove is at)....could this be preventing my heat from rising?? There isnt any insulation under the floor of the bedrooms upstairs just behind the knee walls throughout the 2nd story where the flooring would be if it wasnt attic space. I also put the rolled insulation between each truss to prevent heat from going through the roof.
Too much insulation??
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So you have some insulation between the kneewall studs, and it runs down between the exposed floor joists behind the KW's, out to the edge of the roof? is it tight out to the roof sheathing? or is the roof itself also insulated and properly vented? if there's no insulation between the upstairs bedroom floor and the living room ceiling below it, then that heat should rise. it's just going to take forever to conduct thru the floor - you would do better (possibly) to cut thru and add in a vent grate.
You nailed it!! The heat just isnt going through the floor or maybe it is and I just dont realize the difference. My heat has to go through a short hallway and then through a doorway and a sharp right to get up the stairway so needless to say its tough heating the upstairs. However my living room is always 80-90 degreesEdthedawg said:
you can just tell the heat is wanting to go somewhere but the cool air coming down the stairway is blocking it. The box fan at the bottom of the stairs facing out of the hallway into the stove room(living room) wasnt doing a very good job so I tried a different box fan that blows alot harder and it made a 4-5 degree difference upstairs. It was 35 degrees last night and my first floor was 75-80 all night long. The thermometer in the hallway upstairs leading to the kids rooms was at 70 degrees this morning. It felt substantially cooler up ther but 70 is nothing to shake a stick at IMO...As far as the roof goes...I added rolled insulation between each of the trusses inside the knee wall part of the attic. I wonder if I shouldnt have done that? There is no insulation between the trusses above the ceiling. There is a vent in the attic and I also have one of those big attic fans in the hallway upstairs.For the really cold nights, you might want to put a box fan in the stairway to help direct that heat up the stairs and into rooms without being absorbed into the walls and floor.
it really feels like you have a severely limited convection loop situation. you gotta move the cold out to get the hot in. it has to cycle.
As for the 70 deg upstairs feeling not so hot, you just went thru a minimum -10 deg delta-T to get there - of course it "feels colder"
As for the 70 deg upstairs feeling not so hot, you just went thru a minimum -10 deg delta-T to get there - of course it "feels colder"
Yep thats what I did and it does help alot. I actually just replaced the box fan I had been using which doesnt blow very hard with an older one that blows very hard and the upstairs was warmer in just a couple minutes....spoon059 said:
About the insulation: if you haven't blocked the attic's ability to circulate cold air (ie, you didn't run your batts all the way to the underside of the roof over the soffits, thus blocking the air from the soffits getting to the attic) what you did can only help lower your heating costs.
As others have pointed out, it's all about the cool air having a way to get back downstairs. Our main floor (1900 sq ft, cement slab) is an 'L' shape, with the bedrooms off a central hallway on the long leg. The stove is located at the bend, more or less, in a large open area occupying the foot of the 'L'. The second floor is a straight run along the long part of the 'L'. At the very end of the hallway, furthest from the stove, there is a one-foot-square vent in the ceiling between the first and second floor. The stairs are on the foot of the 'L', at the opposite end of the house from the vent, with a door at the top of the stairs. There is about a 1" gap at the bottom of the door, and we keep it closed. The ceiling between the two floors is insulated everywhere (we surmise the upstairs was the previous owner's teen-aged children's hangout).
On our last visit (woodstove is at the cottage) when we had 20C in the far corner of the stove room, we had 17C just under that vent. I didn't measure the temp upstairs, but it was warmer enough not to cause the electric heat to come on, so had to be at least 10C. Outdoor temps were just below 0C.
As others have pointed out, it's all about the cool air having a way to get back downstairs. Our main floor (1900 sq ft, cement slab) is an 'L' shape, with the bedrooms off a central hallway on the long leg. The stove is located at the bend, more or less, in a large open area occupying the foot of the 'L'. The second floor is a straight run along the long part of the 'L'. At the very end of the hallway, furthest from the stove, there is a one-foot-square vent in the ceiling between the first and second floor. The stairs are on the foot of the 'L', at the opposite end of the house from the vent, with a door at the top of the stairs. There is about a 1" gap at the bottom of the door, and we keep it closed. The ceiling between the two floors is insulated everywhere (we surmise the upstairs was the previous owner's teen-aged children's hangout).
On our last visit (woodstove is at the cottage) when we had 20C in the far corner of the stove room, we had 17C just under that vent. I didn't measure the temp upstairs, but it was warmer enough not to cause the electric heat to come on, so had to be at least 10C. Outdoor temps were just below 0C.
[quote author="ourmoneypit" date="1225387019"]About the insulation: if you haven't blocked the attic's ability to circulate cold air (ie, you didn't run your batts all the way to the underside of the roof over the soffits, thus blocking the air from the soffits getting to the attic) what you did can only help lower your heating costs.
Ok I may have screwed up then ...I ran insulation as high up in the knee wall part of the attic as I could and it ran it all the way down to where the soffit is. Maybe I am blocking some circulation?
Ok I may have screwed up then ...I ran insulation as high up in the knee wall part of the attic as I could and it ran it all the way down to where the soffit is. Maybe I am blocking some circulation?
drtnshtr said:
If you look at the unheated attic space outside the knee wall as a triangle, with the sloped part being the roof, what you want is for the air to be able to circulate freely from the soffit vents to that unheated space, and to be able to continue up the slope to the area under the peak of the roof. You can insulate the horizontal and vertical sections (finished attic wall and first-floor ceiling) as much as you want so long as that air circulation isn't hindered. This page has a diagram showing what I mean, scroll down to 'figure 3': http://www.cmhc-schl.gc.ca/en/co/maho/gemare/gemare_001.cfm In new home construction, they now use what they call attic vents (made of styrofoam or cardboard) stapled to the underside of the roof sheathing between each of the trusses to ensure circulation from the soffits can't be completely blocked.
That said, blocking that air circulation isn't going to have a significant impact on your heating costs/efficiency. What it is going to affect is the life of your roof. Lack of sufficient outside air circulation is one of the primary causes of premature failure of asphalt shingles. It can also cause snow on the roof to melt, and refreeze, forming ice dams that get up under the shingles and then leak into the attic. (assuming you are in an area where you get snow)
Thanks for the link money pit. I am going to inspect this and may even get some of these styrofoam vents to put in ...my last house had those...ourmoneypit said:
Wow, I wish I had that problem...
I have a modular cape from 2001. Only the first floor was finished so ALL of the ceilings between the first and second floor have 10" of insulation. The scond floor was unfinished, so I had to build the knee walls up there and added an extra 6" on the joists behind the knee wall. You do want that there so the heat does not shoot up to the attic.
Anyway, with all of that insulation, I have to leave the bedroom doors open and WOW, does that foyer have a draft coming down from the bedrooms. No heat can get through the floors so we rely on the doors to control everything.
Vents would help, but we are used to our set up now...we stay warm downstairs, cool upstairs.
cheers!
I have a modular cape from 2001. Only the first floor was finished so ALL of the ceilings between the first and second floor have 10" of insulation. The scond floor was unfinished, so I had to build the knee walls up there and added an extra 6" on the joists behind the knee wall. You do want that there so the heat does not shoot up to the attic.
Anyway, with all of that insulation, I have to leave the bedroom doors open and WOW, does that foyer have a draft coming down from the bedrooms. No heat can get through the floors so we rely on the doors to control everything.
Vents would help, but we are used to our set up now...we stay warm downstairs, cool upstairs.
cheers!
One of the problems I have is my cape was built in 48 and they put arched doorways throughout the first floor. They are very nice to look at but they keep the warm air trapped up near the ceiling and do not allow it to flow to the next room very easily if at all. Fans are a necessity for us. The good part is the guy that built this house was a very well know and great builder in the area. He built this home for himself so he done a very thorough job it seems. when he vinyl sided it 10-12 years ago he put 1 inch foam on top of the celotex that was already on the house and had new insulation blown in. The blown in is very dense as I found out when installing my vent pipe for my pellet stove. The only other issue I have is they installed new windows upstairs but not down stairs so thats something I need to do very soon.
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