Difference between the Sill and Butt Threshold in the French Door Draught Proofing Kit

French doors are a beautiful feature, but they can also be surprisingly draughty. Unlike a single door, there are gaps around the outside, beneath both doors and down the centre where the two doors meet. That gives cold air, hot air, dust and insects plenty of opportunities to get through.

The ecoMaster French Door Draught Proofing Kit is designed to treat all of these areas as one complete job. Draught Dodgers seal the top and sides of the doorway, a slim seal closes the gap between the two doors, and the correct bottom seals are supplied to suit the way your doors meet the threshold.

Once installed, the seals work with the doors rather than getting in their way. Both doors can still be opened and closed normally, while the gaps responsible for those persistent draughts are properly treated.

Which French Door Kit Do I Need?

The difference between the two kits is the shape of the threshold beneath your doors and how the bottom of each door closes against it.

Sill Threshold Kit

Choose the Sill Threshold Kit when the doors close over a raised, sloping or relatively flat sill.

This kit uses a sweep seal on the bottom of each door. The flexible seal moves across the sill as the door opens and closes, then covers the gap beneath the door when it is shut.  The Sill Kit can suit inward-opening or outward-opening French doors. The opening direction simply determines which face of the doors the RP5 seals and perimeter seals are fitted to.

The Sill Kit suits:

• • Doors up to 920mm wide each
  • Bottom gaps of up to 19mm
  • Inward-opening or outward-opening French doors

Butt Threshold Kit

Choose the Butt Threshold Kit when the doors close against the upright edge or step of the threshold rather than sweeping across the top of it.

This kit uses a short length of Draught Dodger with a brush seal across the bottom of each door. When the doors close, the brush presses against the inside face of the threshold to block the gap.

The Butt Kit suits:

• • Doors up to 1100mm wide each
  • Bottom gaps of up to 10mm
  • Outward-opening French doors with a butt-style threshold

Not sure which one you have? Look at your doorway from the side and compare it with the threshold diagrams in the product photos.

Keep the French doors. Lose the draughts.