News & Insights

Thermal Insulating the New Basement Floor and Perimeter Walls

Carl Christianson

Framers arrive and hit the ground running today.
As the garage is erected in a day, and trusses are set things are starting to go together quickly.

Now is also the time to pour the new floor for the basement area. Look at the 7” tapered foam blocks used as a thermal break against the existing perimeter walls in the basement when pouring the new floor. The taper allows us to pour the new concrete floor back over the newly installed 3” rigid insulation and gain a thermal break from the ground as well. In the past this 3” foam insulation barrier was visible around the perimeter of the house and showed as a blue or pink line that in turn would need to be covered with framing. In our case this would have been covered as we are framing within the walls to gain additional wall insulation. This taper cut allows us a bit more of a ledge to attach our new framing to other than a ½” overlap for our 2×4 walls. If no over framing was done you would need to come up with a floor surface that would easily cover the perimeter insulation. Hard surface like engineered floors or tile would work best but I have seen the line of insulated foam in houses in the past with this added thermal break where tack strips and glue were used to try and hide this. Taper cutting the blocks even allows for the thermal break and simply polishing the concrete if this is the chosen floor finish.

While many at this point would have considered the installation of hydronic heat, the owners decided to instead go a different route for heating and cooling that will be discussed in detail later.

Here are a few photos of the ICF blocks mentioned earlier and a few of the curved walls showing the three cuts per block and foam glue used to gain the radius for the walls that are so time consuming with ICF blocks.

Now is also a good time to mention the two 3,000 gallon tanks mounted in the ground that are roof fed and lead to an overflow discharge for rainwater irrigation in the summer months. These can also be fed by the two wells on the property but are for irrigation purposes only.