Standard Fascia and Soffit Board Sizes (UK)
Quick Answer
Fascia boards come in 150, 175, 200, 225 or 250mm depths, 16-18mm thick, in 5m lengths
Those five depths are the standard uPVC fascia sizes stocked by UK roofline manufacturers. Full-replacement board is 16-18mm thick and fixes straight to the rafter feet; a thinner 9mm capping (reveal liner) board is available for covering sound existing timber rather than replacing it. Soffit board is sold in widths from 100mm up to 605mm, typically 9-10mm thick, and is cut to the actual eaves width on site. Figures verified against the Freefoam and Eurocell roofline ranges, see sources below.
uPVC Fascia and Soffit Sizes at a Glance
| Component | Size | Thickness | Length | Note |
|---|---|---|---|---|
| Fascia board (full replacement) | 150, 175, 200, 225 or 250mm deep | 16-18mm | 5m | Direct-fixed to the rafter feet; no timber backing needed at this thickness |
| Fascia capping / reveal liner | 150, 175, 200, 225 or 250mm deep | 9mm (9-10mm on some ranges) | 5m | Fits over sound existing timber fascia; not a stand-alone replacement board |
| Soffit board | 100mm up to 605mm wide | 9-10mm | 5m | Sold as fixed-width sheet and cut to the actual eaves width on site |
Depths and thicknesses cross-checked against the Freefoam and Eurocell uPVC roofline ranges (see sources below). Wider fascia depths up to 300-450mm and narrower soffit trims are also stocked for larger or bespoke eaves.
Worked Example: Matching Old Imperial Sizes to Metric Stock
Fascia depths are still commonly described in inches on site, a habit left over from when boards were timber. Converting the old imperial names to millimetres and rounding to the nearest stock size lines up with the five standard depths:
- 6 inch: 6 × 25.4mm = 152.4mm, rounds to the standard 150mm board
- 7 inch: 7 × 25.4mm = 177.8mm, rounds to the standard 175mm board
- 8 inch: 8 × 25.4mm = 203.2mm, rounds to the standard 200mm board
- 9 inch: 9 × 25.4mm = 228.6mm, rounds to the standard 225mm board
- 10 inch: 10 × 25.4mm = 254mm, rounds to the standard 250mm board
That is why merchants and installers still refer to a “6 inch fascia” when they mean the 150mm board, an “8 inch fascia” for 200mm, and so on. Always order by the metric size when buying: it is the figure printed on the board and on the merchant’s price list.
Full Replacement or Capping Board?
The 16-18mm full-replacement board is thick enough to be fixed directly to the rafter feet and to carry gutter brackets on its own, with no timber behind it. The 9mm capping (also called a reveal liner or cover board) is a different product: it is designed to be fitted over an existing timber fascia that is still sound, rather than to replace it. If the timber underneath is rotten, split or the rafter feet themselves need attention, a capping board will not fix that, and a full-replacement board (or a new timber fascia) is the correct choice.
Worked Example: Sizing the Soffit to the Overhang
Soffit board is sold as a fixed-width sheet and cut down on site, so the width you buy only needs to be at least as wide as the horizontal gap it has to bridge. As an illustration: if the fascia is 200mm deep and the wall face sits roughly 100mm back from the rafter feet, the soffit has to span at least 200mm + 100mm = 300mmbetween the back of the fascia and the wall, so you would buy the next size up, a 300mm or 350mm sheet, and rip it down to the exact measured width. Always measure the actual gap on site rather than assuming a figure: eaves overhangs vary from house to house.
Soffit Board Types
Soffit boards come in three broad types. Solid (general-purpose) board has a plain flat face and is used where no extra ventilation is needed. Hollow board has a tongue-and-groove-effect ribbed face and is lighter; it can be fitted with circular vents where airflow into the roof space is wanted. Pre-vented board has continuous factory-formed slots along its length for airflow, without the need to drill individual vents. All three are cut to width with a fine-tooth or circular saw once the actual eaves gap has been measured.
Lengths and Joints
5m is the standard stock length for both fascia and soffit board from the major uPVC roofline ranges, and inline joint trims are used to cover the joint where two 5m lengths meet on a longer run. One detail worth knowing before ordering dark woodgrain or foiled finishes: Eurocell’s own installation guidance for its 18mm foiled and laminated fascia limits individual lengths to 2.5m, to allow for the extra thermal expansion those darker, foil-laminated finishes see on south-facing elevations. Plain white and light coloured board does not carry that restriction.
Sizes and thicknesses cross-checked directly against the Freefoam (freefoam.com) and Eurocell (eurocell.co.uk) uPVC roofline product ranges, including Eurocell’s 16mm flat fascia, 18mm standard Euroboard fascia, 9mm capping board and soffit board listings, and Freefoam’s 18mm Magnum Ogee full-replacement fascia, reveal liner cover boards and 10mm general-purpose soffit board. For quantities rather than sizes, see our how much fascia and soffit do I need answer. Last updated: July 2026.