HEWNWOOD OAK FRAME UK
OAK FRAME BUILDINGS & TIMBER FRAME COURSES
GETTING STARTED
Send us your plans or sketches for an initial estimate.
Once a Deposit is paid we will do a set of working drawings based on your outline plans. When you are happy with the design I will then submit the drawings to a structual engineer for aproval, if necessary.
We have a lot of experience in co working with all the other building trades and have recommendations for Local
Builders, Architects & Planning consultants. We can advise your builders on the setting out & finish as necessary.
Doing Business the Hewnwood Way
Terms & Conditions
As the majority of the work involved in creating a frame, is done in the workshop, often only requiring a few days to assemble on site we suggest the following payment schedule. A 10% deposit is required to reserve a place in our building schedule and commission the design and working drawings to be done. Once design and structural calculations are complete a firm quotation can be given. The next stage payment of 40% is to cover timber costs and get construction underway. After this there will be a second stage payment of 40% to cover work completed, with the final payment of 10% due at the end of the raising.
PLANNING THE BUILD
Term & Conditions
PROGRAM OF WORKS
Please try to be realistic in setting your program. While we will do everything we can to avoid any delays, construction does not take place in a factory and we can be affected by weather and other factors. Please note that any design changes after drawings have been agreed can be expensive and time consuming, especially if the frame is already under construction and should be avoided if at all possible. If you have a very tight time scale please discuss this with us at the outset. We will not accept claims made against our final account for late delivery.
GROUND WORKS & MASONRY
It is the client or his/her representative who is responsible for ensuring the accurate setting out of any ground works required according to the dimensions stated on our working drawings of which you will have a copy. These should be checked and re-checked to avoid any last minute calamity, should the foundations and the frame fail to marry up.
We also request that any cavity work be closed, or otherwise robustly constructed to allow adequate support for the oak frame sills or plates.
TANNIC ACID
Tannin is a natural product contained in Oak and contributes to its durability. It is normal for this to leach out of the frame when it gets wet. Although this usually weathers off external faces after some months it may leave a residual stain. Therefore, if you are using a pale coloured stone or other similar material (internally or externally) that is prone to staining, it is essential that you provide adequate protection for it before the frame is brought to site.
GENERAL FRAME INFORMATION
Terms & Conditions
TIMBER SPECIFICATIONS
Green timber: We use green timber for the majority of the frame construction for reasons of cost and workability. It will therefore be subject to shrinkage over time (see below).
Air-dried: A fair proportion of our frames incorporate air-dried material because we prefer to use stable timbers in some critical areas. The most usual components that require drier timber are the wind braces, wall braces and other curved members. Quality air-dried curved stock is nigh on impossible to buy commercially, so we source our curves when green and keep them in stock until needed.
GROUTING BENEATH SILLS AFTER ASSEMBLY
Your builder will need to grout beneath the sills of our frames once we have finished assembly as the frame will sit on oak slips. This is traditional practice and allows us to make any minor adjustments to the sills necessary.
THE RAISING
Our Quotation assumes adequate access and a suitable hard standing for safe delivery of the frame to site, as well as sufficient space for the stacking laying out and sorting of timbers. A suitable hard standing will also be needed for the crane (where one is required), which is not impeded by telephone wires or other encumbrances above or below the ground.
It is also the responsibility of the client, unless otherwise agreed, to provide access scaffolding for the raising. We will be able to advise on what is required. We assume the provision of normal site welfare, power and water.
DIFFERENT FINISHES
Externally an oak frame will weather to a soft silver grey and does not require any further treatment.
Internally however you may wish to make some allowance for cleaning and/or finishing the frame. While a lot of our clients like to see the carpenter’s marks there are various methods for cleaning the frame. The most common method is sand blasting which will remove all the band saw marks, ink lines and temporary carpenters’ marks. The best time to sand blast is after covering in but before completion of the other finishes.
Oxalic acid is another possibility and is easy to apply yourself. It will remove most of the temporary marks. However, in my experience it will only soften the appearance of band saw marks and ink lines. As oxalic acid needs to be rinsed
off
(a pressure washer is best for this) you
will want to allow time to do this soon after raising. If required we often undertake this in the yard before raising, but obviously the raising process can be quite muddy in this climate so you may want to allow for further cleaning time yourself.
Scudding is a method of hand planing the frame to give a slightly scalloped finish that imitates the finish you would find on a traditionally hewn frame. This is obviously quite an arduous and time consuming process, which needs to be done in the yard before assembly, but does give a lovely finish.
We do not generally recommend any other finishes as the woods we use are naturally durable.
GENERAL FRAME INFORMATION
Term & Conditions
DRYING OF OAK FRAMES
As timber dries, it changes its looks and characteristics. The more it dries, the lighter and stronger it gets. Our joints are designed so that, as the timber dries, the joints lock together to increase that strength. This drying process does produce some issues though that need to be considered both in the design of your structure and for the aesthetics of the finished frame.
The gentler the drying process the better for your frame. Sometimes frames are assembled and left for some years to weather before being covered in. This does them no harm at all, on the contrary, it allows the frame to dry gently and naturally. However, the drying process does cause ‘movement’ in the timber, over time. The three main effects of this drying process are:
Shrinkage: The cells of the timber, as they lose their moisture, shrink in diameter, but not in their length. This means that, by the time a piece of oak has settled down, it will have lost up to 10% of its width, but its original cut length remains the same. Therefore shrinkage is likely to cause gaps between the frame and other materials, such as glazing and wall sections. A skilled carpenter will understand this and take it into account during the build.
Shakes: A shake is a crack, either very small, or in some cases quite substantial, that appear in the timber as the grain separates, and is very common in a drying frame. Sometimes they can look quite alarming, but surprisingly do not alter the structural integrity of the frame These shakes add enormously to the character of the frame, but are an important consideration in the aesthetics and well worth taking into account if, for example, you were expecting a smooth finish.
Twisting: This is largely dependent on the straightness of the grain of the timber. We do our best to minimise the likelihood of this happening in our frames by careful timber selection and placement within the frame.
STORAGE OF FRAMES
Ideally a frame should be assembled as soon as it is ready; however we understand that sometimes delays happen. Where very long delays happen due to circumstances beyond our control the client should be aware that extra costs may be incurred to refit joints negatively affected.
Questions? Contact us today, our team is always ready to help.