accessible door sill detail

one lesson-learned from a new house we built for jessica in 2004 was the impact of exterior door sills.  finding the proper balance of “flushness” (minimizing the “bump” at the door) and weather control (keeping the elements outside where they belong) is the ongoing battle, especially when accommodating a wheelchair.  we thought we had adequately addressed the issue in 2004, but we were wrong. those doors have a very robust weather-resistant sill assembly.  unfortunately, that equated into a robust wheelchair barrier, as well.  we were able to mitigate to some extent by installing small aluminum “ramps” at each door, but the solution remains a basic “fail”.  so, in this house we’ve been determined not to repeat that mistake (we’ll just create some new ones!).  the following documents our low-impact door sill detail.

section detail showing basic components and dimensions.  note: dimensions are specific to the drewexim profile and dimensions.

section detail showing basic components and dimensions. resulting “bump” at interior door sill is about 3/8″ – an easy roll-over for jessica.  one reason we liked the drewexim doors was the availability of this low-profile sill.  the biggest challenge in this detail is providing a suitable thermal break between the edge of the floor slab and the granite.

photo showing recess in foundation wall for lowered sill assembly.

photo showing recess in foundation wall for lowered sill assembly.

here it is at rough install stage.  when backfilled/paved, the granite sill will mostly disappear.  granite seems like a somewhat "precious" material to bury, but these sill pieces only cost about $60 each.  a small price to pay for the durability of granite in this harsh environment.

here it is at rough install stage. when backfilled/paved, the granite sill will mostly disappear. granite seems like a somewhat “precious” material to bury, but these sill pieces only cost about $60 each. a small price to pay for the durability of granite in this harsh environment.

here's what it looks like from exterior.

here’s what it looks like from exterior.

we look forward to exterior paving and jessica’s first “test drive”!

 

 

2 thoughts on “accessible door sill detail

  1. maybe no bump but a potential water penetration issue, with resultant frost-heaving. sub-stone flashing trays would normally have end-dams and be sloped for positive drainage. be sure the landing is sloped away from the house, ever-so-slightly. consider a trench drain between the landing and foundation wall, filled with gravel and a perforated drain pipe to a drywell or storm drain system. waterproofing is a big challenge here in the northeast!

    • hi deb, all good points. thanks! given the frost wall/slab-on-grade foundation (i.e.: no wood), we are comfortable with the durability of the materials and detailing. positive surface drainage away from door is a must, but must be shallow enough so jessica can remain stationary when needed (opening/closing door, etc.). our sub-surface drainage includes very pervious material and a complete underdrain system connected to the municipal storm drainage system. in addition, due to unsuitable soils, we over-excavated the site and backfilled with gravel – this site drains well! perhaps the most important detail not mentioned is to provide a roof over the door. this will help keep direct bulk water from finding the door (and its sill) as well as provide protection when coming and going. the doorway highlighted in this post is the one door (of 4) that does not have a roof (but it will have a brise soleil above that will help, a bit). we determined that no roof at this door was acceptable given its less frequent use. indeed, the challenges (joys?!) of building in our climate!!!!

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