Surface Finishes for your Oak Frame
There are a variety of options for finishing the surface of the timbers in your oak frame. These methods each leave the wood with a particular and distinct character. Ask to see our samples if you want to get an idea how this will appear in the finished frame.
External Finish
From the outside the frame may be fully in view, with glazing, lime render, brick, or even wattle and daub in the panels between the timbers. Curved bracing can be jointed into the frame to present a traditional external appearance.
Alternatively,many people choose to present the frame internally and clad the exterior elevations. For the cladding, there is a wide range of options. Boards can be arranged horizontally or vertically; presenting a flat, overlapping or staggered surface; using oak,elm or larch. With vapour membranes and rigid insulation material,the frame is superlatively weather-tight and warm.
Sand blasted sawn finish
The oak arrives from our sawmill with a sawn finish. The frame is jointed and erected on site. The frame can then be sand blasted. The impact of the sand erodes the softer summer growth in the grain and the winter growth rings stand out in relief. It is always best to do this after the roof is on and the frame is no longer subject to rainwater staining.
Planed Finishes
The oak is all planed to remove any saw marks and leave a perfectly smooth surface prior to jointing. During the workshop and site phases of production the frame inevitably sustains some marking and also may get wet on site, causing water staining. We therefore recommend one of the following two options to re-clean the enclosed frame.
- Option 1 - Sand blasting
- The frame is lightly sand blasted to remove any marks and staining. When the frame has been planed beforehand, sand blasting will give a better finish than a frame that is sand blasted from rough sawn timber.
- Option 2 - Manual cleaning
- After the frame has been erected and enclosed we clean the planed timbers with oxalic acid, scrapers and sanders. This then gives a clean, smooth finish, very different from sand blasting.
Oiled Finishes
Oiling the timbers has a dramatic effect on their appearance, and has another beneficial effect. By slowing down the rate at which the exterior of the timber loses its moisture, the surface cracking, so characteristic of oak, is reduced.
- Option 1 - Workshop oiling
- The frame is cleaned after jointing and is then oiled at our workshop prior to delivery. When erected with an oiled finish it is less susceptible to water staining. The frame is still vulnerable to marking during cladding and from plastering and painting etc.
- Option 2 - In-situ cleaning and oiling
- The frame is planed and jointed and erected on site. At an agreed construction stage (usually after the plastering around the frame is completed) the frame is hand cleaned and oiled.
Lime Wash
The effect of washing green oak with lime is to initially produce a brown colour as the lime reacts with the acidic sap. This fades a little with time and chalky residue can be seen in the fissures of the surface. When regularly applied this eventually fills the surface cracks of the timbers and the joints. The darker colour is often thought desirable where new timber is next to old timbers, in a restoration context for example. The lime wash can be applied after sandblasting or planing, and can be followed with oil treatments as above.