Partial Refinish Question

[JamesP]

I am in the planning process for my basement remodel. I am only planning on finishing about 2/3 of the basement. The current plan is to putting 2" EPS insulation along the walls around the entire basement and the putting a stud wall in front of that. I want to create an air barrier around the basement.
On the floor, build a subfloor by putting 1x4 spacers and 3/4" EPS insulation with 5/8" OSB on top. I will most likely put a floating laminate floor on top of that.
Here is the actual question. Will it make a difference if I do not do the floor in the unfinished area? The area is taken up by the furnace, oil tank and future workshop space. It seems like a waste to do the floor in this area and I cannot imagine there is much heat loss back through the unfinished floor.
Also, I have been reading a lot against putting a "vapor-barrier" on the walls as it will simply trap water against the wall, but I cannot find as much info on whether there are a good idea in the floor.
Opinions?

[homebild]

First, you need to check with your local Building Code Office to determine just how much wall/floor insulation is required by law for your locale.

For most moderately cold US climates, the average is about an R20 required for basement wall insulation.

Since 2 inches of rigid foam insulation will provide only about 50% of that required insulation, you may need more than twice the thickness of rigid foam insulation to meet minimal code requirements.

Since rigid foam costs at least 2-3X that of fiberglass batts, the use of rigid foam is not often an economical way to insulate under most any circumstance.

Second, it is true that polyethylene plastic sheeting should not be used to cover basement foundation walls, but that is only if the sheeting cannot be continued over the footer and under the concrete floor slab. The reason is that condensation WILL occur on the foundation side of the plastic and will pool downward causing puddling and its resultant mold and mildew growth and flooring and framing damage.

As long as the plastic sheeting can be installed to cover the footer before the concrete floor is installed OR if the sheeting drains into an already existing top entering peripheral drain (like a B-Dry system) only then can plastic be used directly over the block walls.

You can see a very thorough, clear and detailed treatment of this subject here:

http://www.extension.umn.edu/distribution/housingandclothing/DK7051.html

Third, Most 'modern' basment floor require no plastic sheeting as vapor barriers because codes within the last 30 years or so have required plastic sheeting to be placed UNDER the concrete slab before pouring.

This means that the vapor is trapped in the earth under the floor and never makes it to the surface of the concrete.

This should not mean that you can pre-suppose your house to have this plastic already under the floor and should do a simple test to see if you have floor vapor infiltration by taping a square of plastic over a section of floor and then observing for any trapped moisture under this test piece.

Lastly, the more common approach to vapor treatment for basement walls and floors is to treat the foundation walls and floors with a vapor proofing coating such as DryLok for walls and Epoxy based resins for the basement floor.

Walls can then be framed and insulated with standard faced fiberglass insulation.

The floors can be left unframed and uninsulated providing you meet your overall insulation code needs with wall insulation and other energy saving techniques.

I am NOT a big fan of framed flooring because it hides potential water infiltration problems down the road and makes repairs using below floor concrete drains nearly impossible.

MY suggestion is to treat all walls and floors with DryLok and Floor epoxy, forgo the raised/framed basement floor instead installing finished floor directly on the concrete, and then use fiberglass insulation in framed walls only.

[rlvarcoe]

I agree with the last post regarding the floor, most laminates can be put over concrete with no problem unless it is old and uneven. If you are going to put in a sub floor I would us 3/4 instead of 5/8

good luck

[JamesP]

Thanks for the advice so far. I am now thinking of doing Pergo flooring right on the slab (with the Pergo approved underlayment under it). Should I paint the floor with DryLok or a similar product first?

I have another question though. As far insulating the walls. Upon taking some final measurements, I discover that my oil tank is only 2 inches from the foundation wall. Obviously, I cannot get behind it to put EPS up on that wall. What will the effect of not insulated one corner of the basement wall be?

[homebild]

As previously mentioned, DryLok is NOT made for floor use.

There are floor epoxies that can be applied and will act as vapor barriers for the floor. There is no harm in applying them and sealing the floor with a vapor barrier coating can only help.

The best way to deal with the oil tanks is to frame your walls as a room around the tanks with a door by which the tanks can be accessed, then insulate the walls that are common to the room and living space .

[JamesP]

As previously mentioned, DryLok is NOT made for floor use.

There are floor epoxies that can be applied and will act as vapor barriers for the floor. There is no harm in applying them and sealing the floor with a vapor barrier coating can only help.

The best way to deal with the oil tanks is to frame your walls as a room around the tanks with a door by which the tanks can be accessed, then insulate the walls that are common to the room and living space .

Maybe I should have been clearer. I was not referring to the DryLok waterproofer, but the DryLok Floor Paint (http://www.ugl.com/dryconcflr.html).

I guess that will be the only way to go with the oil tank. It is unfortunate because there are only three windows in the basement and one is directly above the tank. Also the tank's proximity to the bulkhead stairs will make it rather awkard to try to frame in. The tank is literally next to you when do come down the bulkhead stairs.