Insulation, Radiant and Vapor Barriers - Insulation above sill plate?

I want to insulate the space above the sill plate in my basement. I have read that you should use faced (vapor barrier) and also read to use unfaced insulation.

Which is correct? If I should use faced should the facing be towards the inside or outside?

Also....what R rating would be sufficient? Was thinking R19.

Just had another thought....should I caulk any of the joints before putting the insulation in?

You should caulk or foam where the sill plate sits on the wall. It would be an even better idea to get a 200bf package of 2 part foam and foam the rim board and the sill to foundation area. Then put in R-19 or R-30 faced fiberglass with the face toward the basement. The fiberglass won't help quite as much if there are air leaks around it in the framing.

Ken

You should caulk or foam where the sill plate sits on the wall. It would be an even better idea to get a 200bf package of 2 part foam and foam the rim board and the sill to foundation area. Then put in R-19 or R-30 faced fiberglass with the face toward the basement. The fiberglass won't help quite as much if there are air leaks around it in the framing.

Ken

Ken

Thanks for the input...but I need some explanation :o

I need to know what you mean by the rim board and the sill to foundation area. I just learned the term sill plate today :D

I also have no clue what kind of foam you are referring to when you say 200bf package of two part foam!

Sorry I'm new to this stuff!

The sill plate lays flat on top of the foundation wall. There is usually some sort of sill seal between the two but it is generally a joke. The rim board stands on top of the sill plate flush with the outside edge of it and is usually the only thing besides a 1/2" plywood layer between the outside air and the basement. That's why the big liability for heat loss and air leakage. I will provide a link to the foam kit. It may take some experimentation but if you want to do the job right, consider it. http://www.tigerfoam.com/products.php

There are a few more manufacturers but this one is representative of what is out there.

Ken

The sill plate lays flat on top of the foundation wall. There is usually some sort of sill seal between the two but it is generally a joke. The rim board stands on top of the sill plate flush with the outside edge of it and is usually the only thing besides a 1/2" plywood layer between the outside air and the basement. That's why the big liability for heat loss and air leakage. I will provide a link to the foam kit. It may take some experimentation but if you want to do the job right, consider it. http://www.tigerfoam.com/products.php

There are a few more manufacturers but this one is representative of what is out there.

Ken
Ok...so foam where the sill and rim board meet?

Yes, it is a good idea to foam 1" thick on the entire rim board. From where it touches the underside of the floor to where it sits on the sill plate. Then also where the plate meets the foundation wall. If you have enough foam, an inch on top of the sill plate is not wasteful either. Then add the fiberglass and you have a tight, well insulated rim.

Ken

Yes, it is a good idea to foam 1" thick on the entire rim board. From where it touches the underside of the floor to where it sits on the sill plate. Then also where the plate meets the foundation wall. If you have enough foam, an inch on top of the sill plate is not wasteful either. Then add the fiberglass and you have a tight, well insulated rim.

Ken

ok...thanks for all the info!

My sill gasket is actually in really good shape and seals tight.

There is a local company that makes and sells 2 part foam...Fomo-Products. I will give that a shot.

Ken, I have a thread about using the foam product (handi foam = TigerFoam) for a basement. If you have any first hand experience, I'd love to hear it.

Thanks

I need to know what you mean by the rim board and the sill to foundation area. I just learned the term sill plate today


Sill plate and rim (AKA header) joist locatons:


http://www.sweethaven02.com/BldgConst/Bldg02/fig0801.jpg

Very nice graphic aid. I can barely figure out how to get a smiley face in my post and you do that. It is really worth a thosuand words.

davidfarmer, I use the 2 part foam a couple of times a week and can probably answer most of your questions. A few things that are more important than they seem at first glance. Temperature needs to be between 70 and 80 degrees F for it to work. The surface being applied to should also not be ice cold or extremely hot. I have tried every combination and ended up with a mess. I now have both containers in an insulated box with silicone heaters on each bottle and a line voltage room thermostat inside the box. It is plugged in all the time at the shop and when we transport it, it gets plugged back in as soon as we get to the job site. Otherwise there are application problems.

Ken

thanks Ken, my basement should be around 70-75 year around anyway, so i'll make sure the product is a bit warmer before making an attempt.