Which grade of oak sawn timber for stairs? AB, B or rustic
How oak AB differs from B and mix, which grade to choose for stairs and which for furniture. Explained by the Drewno Pilarscy sawmill in Sulęcin.
We have been grading oak at our sawmill in Sulęcin for over 30 years, and this question comes back every week: which grade should I take for stairs? In short: usually AB. But not always and not for everyone, so let's go through it.
What are timber grades in the first place?
A grade is an assessment of a board's quality. It looks mainly at the number and size of knots, at checks and at other defects. In commercial practice you will most often come across:
- AB, the cleanest material, with occasional small knots. For visible elements.
- B or B/C, sound knots and natural discolouration at a sensible price.
- Rustic, pronounced, sound knots. Character rather than sterility.
- Mix, different grades in one batch, the cheapest option.
So which one for stairs?
For treads, steps and balustrades that you look at every day, oak AB is the usual choice. A clean grain pattern, an even colour, stairs that look "straight out of the catalogue".
More and more customers, however, deliberately choose rustic. In homes furnished in a rustic or loft style, the knots are an advantage and the price is markedly lower. Mix, in turn, works well for painted stairs. The strength of oak is the same regardless of grade; the difference is in appearance.
Quality starts long before the shop
For us, looking after oak starts in the log yard. We wax the ends so that the wood does not crack, and we debark the long timber before sawing. The sawn timber then sits on stickers in a covered seasoning shed for 6 to 24 months. We do not cut that process short, because oak does not forgive it. The board that ends up on your stairs is, quite simply, stable.
Glued laminated oak or solid?
It is also worth considering glued laminated timber for stairs. Laminating the layers removes internal stresses, so the treads do not move the way solid wood does. We make glued laminated stairs from oak and ash in grades AB, AC and rustic. If you are not sure which will suit your project better, give us a call and we will advise.
Frequently asked questions
Which grade of oak sawn timber is right for stairs?+
For treads and visible elements, grade AB is the usual choice, as it has the fewest knots and defects. Rustic grade, with visible knots, works well wherever the natural character of the wood is an asset.
What does the mix grade mean?+
Mix combines boards of different grades in a single batch. Technically it is fully sound material at an attractive price, simply with greater variation in appearance.
Does oak sawn timber have to be dried before stairs are fitted?+
Yes, wood for stairs should have a controlled moisture content. At the Drewno Pilarscy sawmill, sawn timber is air dried naturally for 6 to 24 months, and we also carry out drying for joinery.