What header above a window or door in a timber-frame house?
Above every opening in a timber-frame wall — a window or a door — there must be a header. Its job: take over the load that the cut-out studs would normally carry, and pass it sideways onto the framing studs (king stud and trimmer), and from there down to the bottom plate. The wider the opening, the bigger the header section — because a longer beam deflects more.
Indicative section table
The values below are an indicative starting point adopted in Oczep.pl — typical workshop practice for single-family walls, to be confirmed by a structural engineer for the specific load. These are not design values.
| Opening width | Min. section depth | Example |
|---|---|---|
| up to 1200 mm | 145 mm | 45 × 145 |
| up to 1800 mm | 195 mm | 45 × 195 |
| up to 2400 mm | 240 mm | 45 × 240 |
Headers are usually made of 2 plies of lumber nailed together, so that the combined thickness matches the stud width and fills the wall.
What the section really depends on
The opening width alone is just one variable. In reality several factors decide the required section at once:
- the span of the opening — the longer the beam, the greater the deflection,
- the load above the opening — whether there is only wall above the header, or also a floor, a roof or another storey,
- the snow zone — the snow load on the roof differs by region,
- the timber grade — structural C24 has a higher strength than ungraded timber.
When a structural engineer does the sizing
The table is enough for the initial layout of the wall, but for openings wider than about 2.4 m, when a floor bears above the opening, or when the opening is in a load-bearing wall, the section has to be calculated — timber beam design is done according to Eurocode 5 (EN 1995-1-1). That is a job for a structural engineer, not for a table.
How Oczep.pl applies this
Oczep.pl selects the header for the opening width based on the practice above and warns when the section looks too shallow for the span — a signal that this opening deserves proper calculations. This is a warning rule, not a load-capacity guarantee: the final section under a floor or in a wide opening is confirmed by a structural engineer.
Create a free accountSources and disclaimers
The section depths given are indicative (working) values adopted in Oczep.pl as a starting point for typical single-family walls — they do not come from calculations for a specific building. Actual sizing of a timber header is done according to Eurocode 5 (EN 1995-1-1) and requires knowledge of the loads and the snow zone. For openings wider than ~2.4 m, headers under a floor and load-bearing walls, the section is determined by a structural engineer.