What is a four-season door front (vierseizoenenpui)?
A four-season door front is a glazed front made up entirely of doors, so that in every season you can open exactly as much as you want. In Dutch it is called a vierseizoenenpui. In winter everything stays closed and you still have plenty of daylight. On a warm summer’s day you can open up the whole facade, so that the patio, balcony or garden becomes part of the living room.
Two versions
1. Bi-fold door (concertina front)
The front consists of glass panels hinged to each other that fold away along a track to the left, right or both sides. When open, the opening is almost completely clear; only the stack of folded panels stands at the side.
2. Doors on fixed posts
All doors are hung on fixed posts and can each be opened individually. Nothing has to slide or fold, which in the long term is less prone to stiff-running tracks. Disadvantage: open doors swing out onto the patio and take up space there. So you need a larger patio.
What to look out for
- Structure above: a wide front without intermediate posts requires a strong lintel or steel beam. When enlarging an existing opening in a load-bearing wall, a structural calculation is required.
- Deflection: a bi-fold door usually runs on a top track. If the beam above deflects, the panels will jam. Have the permissible deflection agreed with the supplier.
- Threshold and weatherproofing: a flat, level threshold looks good, but driving rain can then get in more easily. Provide good drainage outside (a fall, a channel drain or grating in front of the doors).
- Insulation: choose HR++ (high-performance double) or triple glazing and ask for the U-value of the complete front, including frame and joints. Many joints mean a greater risk of draughts.
- Burglar resistance: in the Netherlands, ask for hardware and locks that meet the Politiekeurmerk Veilig Wonen (the Dutch police secure housing quality mark).
- Permit: in the Netherlands, a new door front in the rear facade is often exempt from a permit, but not for a monument or in a protected townscape. Check the Omgevingsloket (the Dutch online planning portal).
Related terms
- Glazed front
- Front beam
- Sliding door
- Conservatory
- Veranda
- Patio
- Lintel
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.