How do I fix cold floor in corners of kitchen extension

[Sean M]

Hello,

I am spending my first winter in my "new" house, it is about 10 years old. The floor in the kitchen area is done with ceramic tiles. The kitchen has a bit of an extension from the main house. The foundation runs fully underneath this extension. I have noticed that on cold days the corners of this extension are much colder than the rest of the floor. I am looking for solutions to better insulate this area.

My basement is un-finished. I have started to finish it and noticed that the insulation and vapour barrier are not well installed in some places. The vapour barrier is just packed up against the insulation between the joists, there is no taping of the vapour barrier between the joists. I am thinking that if I tape up the vapour barrier in this area and possibly add some foam board or spray foam between the joists it may warm up the kitchen floor above. Any comments from the experts out there? How do I warm up these corners?

Many thanks,

-Sean

[No]

Sean - The vapor barrier should be toward the heated side in colder climates. If you are finishing your basement, and its to be heated and or cooled you do not need insulation between floors. Any area that is cantilevered or over an unheated space should have insulation with, like I said, a vapor barrier toward the heated space. Its hard to really picture exactly what you have. I would make sure your insulation is not compressed, fully fills all areas and that any cracks are caulked. Maybe remove the insulation, caulk everything that may let air through (From underside) and then re-insulate. If this area is exposed to the outside then you can seal up further with some plywood and/or vinyl soffit material.

I hope this helps, if you can post a picture that would even be better.

-B

[Sev]

I would start by pulling back the top part of the insulation- (is it fiberglass?)- then make sure there is no air intrusion, ie that there is a good seal between foundation and cap plate. Not sure what kind of caulk/sealer is used for this if it needs doing- ask at the store. Then I think you could continue as you suggested. Are you planning on heating this finished basement? If you plan to use only occasionally, and keep at a lower temp than upstairs when not in use, you could insulate under kitchen floor, ie basement ceiling- with vapor barrier facing warmer space above, or without vapor barrier I think would be fine if basement tends to be dry/ low humidity.

[barry]

Probably due more to cooling via kitchen walls. Given what you mention below, I'd suspect some shoddy work inside the wall cavities there too.

OTOH, I'd first try some fleece-lined slippers, if the perceived cold is _the_ issue.

J

[Doug Kanter]

In addition to the other advice given so far, put your hand in front of electrical outlets on a windy day. You might be surprised at how much cold air comes out. Home stores sell a product containing foam pads for sealing the outlets. They're under two bucks.

[jerryrigged]

Cold corners are a common problem when the corner was not insulated properly during the rough framing.

When a framer builds the corner it's usually with a combination of studs that are stacked together. On the inside of the stack, a framer may cheap out and use blocking instead of one full-length stud. This is an acceptable practice as long as the voids between the blocking are filled with insulation before the exterior sheathing is installed. It is impossible to insulate those voids after the exterior sheathing is installed because the voids are not accessible from the interior after the wall goes up. In my area, if a framer builds a corner like this, the building inspector should (but most times doesn't) check to make sure any voids in the corner have been insulated. The reason he doesn't check is because the exterior sheathing (plywood or OSB) is usually put on the wall before it is lifted up so when the inspector shows up he can't see if the corner has been insulated. He basically has to trust the framer or builder that it has been done.

There is one solution that might work. You can drill several holes directly into the corner so you penetrate these voids. Spraying expanding insulating foam into these voids will fill them and hopefully cut off some cold spots. Just be careful not to drill all the way as to penetrate the exterior of the house and be careful not to drill into any electrical wiring that may be routed thru the corner frame.

[Sean M]

Thankyou for the advice. The insulation is fiberglass. I will peel it back in that area and check for any air leaks. Sounds like a good idea to seal it up. After that I will put insulation in place and redo the vapour barrier. There are no plugs on the wall in the extension area. I will see if this improves the situation before attempting to drill and inject spray foam.

The basement is heated but is slightly cooler than the rest of the house.

Is there anything better than fibreglass to insulate this area. Would solid Styrofoam type insulation cut to fit the space between the joists be a better solution?

-Sean

[Chris Lewis]

According to Sean M :

While styrofoam gives you better R value per inch, it's _extremely_ difficult to get styrofoam to do a good job laid between studs because of leakage around the edges. Even with taping etc. to meet the effectiveness of a full batt, you'd have to install at least two layers of foam too.

Foam should usually be installed only on flat surfaces.

Batts are better for between joists & studs.

I suspect you'll get the biggest bang per buck out of your project by making sure that the vapor barrier is installed properly, and the batts are installed neatly without voids. And spray foam in the corner if necessary.

I also wonder if there's an air leak from the corner to under the subfloor in the corners.

[gary]