Helpful? 0

Exterior door thresholds on slab-on-grade

I'm currently sort of scratching my head over this.

When using under slab rigid insulation and the slab is floating over the footing wall.

Typical details calls for 1" rigid between the slab and the concrete foundation wall as a bond break.

Fig 1 from

Now what happens at entry door thresholds (or floor to ceiling windows)?

Extending a lip from the slab towards the outside (effectively eliminating the 1" joint) would cause thermal bridging, so that's out of the question.

Keeping the 1" bond break, would call to carefully select the door threshold, since most door sills are nailed to the floor right where the bond break is located.

One can specify certain manufacturer and model for the entry door sill, but what to do on a fairly large opening? For instance, a Lift-and-Slide patio door.

Those even have the lower tracks recessed in the concrete slab.

Or maybe I'm just over thinking this and just resting the sliding door track or the entry door sill above the bond break isn't such a big deal.

Fig1.jpg42.09 KB
Posted Wed, 02/20/2013 - 15:24


1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Helpful? 0

"....just over thinking this and just resting the sliding door track or the entry door sill above the bond break isn't such a big deal."

That's my take on it! No, you can't just nail or screw into foam and there may be some necessary adjustments when installing it, but it's hard to imagine the configuration that would make it a really a big deal.

Answered by Dana Dorsett
Posted Wed, 02/20/2013 - 17:45

Other Questions in Green building techniques

The differences between mass and insulation

In Green products and materials | Asked by Nathaniel G | Sep 15, 14

Most cost-effective method for achieving 3 ACH 50?

In Green building techniques | Asked by Nick Sisler | Sep 17, 14

Tudor half-timber battens and exterior stucco — rainscreen assembly

In General questions | Asked by Ani Brown | Sep 17, 14

Has the Oak Ridge study on convective heat loss in blown fiberglass been updated to cover newer materials?

In Energy efficiency and durability | Asked by Neil Weinstock | Jul 21, 14

Liability insurance - what would that cover?

In General questions | Asked by George G | Sep 12, 14
Register for a free account and join the conversation

Get a free account and join the conversation!
Become a GBA PRO!