Insulating over concrete block foundation...need opinions???

[ND_Fisherman]

Just finished putting a second coat of Dry-Lok over my concrete block foundation in my garage. The foundation forms a 'L' shape since the garage is attached to the house. I installed R-13 over the 2x4 stud walls which sit on top of the foundation. I believe there is a 2x6 between the foundation and the wall which forms a step on top of the blocks. I'm debating if I should insulate over the foundation somehow (maybe some sort of rigid polystyrene over the blocks and then sheet over that). My main concern with this is loosing floor space which is at a premium in my small one stall garage. From my research concrete blocks have an R value around 1. Most the rigid polystyrene I've looked at is around 5. Since I live in North Dakota, it gets plenty cold outside so I'm looking to insulated as much as possible but also don't want to loose space either. What to do....

 

[K'ledgeBldr]

The correct way to have done this is in the attached file.
By putting the EXP board on the outside, there's no damage and it also provides a vapor barrier for the block wall.
As you can see from the detail once the sheathing and siding are installed they will overlap the EXP board. Generally, if the board is exposed on the exterior a parge or stucco is applied over it to protect it.

At this point it's pretty mute- I'm sure you'll have more leakage are the garage door than the thermal transference from that small portion of wall.

 

[ND_Fisherman]

Thanks for the information. I took a look at that diagram and it looks like that's geared towards new construction. You do make a good point about how this area is relatively small for the amount of heat that will transfer. I'm thinking for now I will paint the blocks the same color as my walls. I could always come up with some sort of insulated wall covering later.