Door threshold details connect the door system to the building’s floors and weather protection. A low-profile sill may look simple in a photograph, but it still needs a coordinated section. Access, drainage, structural support and the indoor-to-outdoor level relationship should be resolved together before a custom door is ordered.

Start with finished floor levels

Show the interior floor finish, exterior paving and structural support beneath the sill. Include planned tile, flooring and waterproofing thicknesses instead of drawing only the structural slab. A detail that ignores finishes can leave the threshold unexpectedly high or bury a drainage outlet.

Ask the designer and installer to agree a reference level. Mark it on the shop drawings and verify the prepared opening against that reference. Do not ask the supplier to infer the final sill position from a photograph of an unfinished slab.

Define the access requirement

Explain who uses the entrance and whether a particular accessibility requirement applies. The responsible project professional should check the complete passage, threshold shape, operating force, hardware and approach space under the applicable rules. A product name containing accessible or low threshold is not a complete assessment.

Review the route on both sides of the door. A convenient sill can still lead to an awkward step, narrow landing or poorly positioned drain outside. Coordinate these details on the building plan rather than treating the door as an isolated item.

Trace the water path

Ask how water is collected and discharged by the proposed sill and surrounding construction. Show exterior falls, any channel drain and the connection to waterproofing. Identify which party supplies each component and who checks the interface before it is concealed.

Compare the exact sill option with the system’s performance documentation. A reduced-height alternative may have different limits or installation conditions. Do not modify a designed drainage channel on site simply to make the floor appear flush.

Confirm support, maintenance and scope

The sill needs the support required by the selected system, especially beneath sliding tracks carrying heavy panels. Ask how the installer checks level and alignment and how later adjustment remains accessible. Keep drains and tracks reachable for cleaning after the finishes are complete.

• Approve a dimensioned threshold section.
• Record interior and exterior finished levels.
• Confirm access and weather-performance requirements.
• Assign waterproofing and drainage responsibilities.
• Check the completed detail before handover.

Explore Shanghai Slang doors, including sliding, bifold and ADA door options. Use these as configuration references and request the actual sill detail for your project before deciding how the interior and patio should meet.