Timber can be treated to further protect wood from the elements, such as fungal decay and insects (risk in South East England). The specific risk to your timber will be dictated by your geographic location and where the timber is being used in the construction. It is an additional cost to have your timber treated (around 10% of the cost of your structure) and the process includes covering your timber with a special preservative that is specifically designed to protect wooden structures from the elements.
Current HSL guidelines give the following advice:
- two-person teams – loads up to 48 kg;
- three-person teams – loads up to 70 kg;
- four-person teams – loads up to 95 kg.
- Trusses that weigh over 95 kg should not be handled by manual means alone. Some form of mechanisation or mechanical assistance should also be used
Further recommendations specify that the area where the trusses are to be carried should be kept clear and noise levels should be reduced in order to ensure effective communication between the manual handling team. For the full guidance visit HSE
While the cheapest way of building a roof is with a standard roof truss, they do not allow for future expansion. An attic (or room-in-the-roof) truss is specially designed to maximise space and allow for further room development. Attic trusses do cost more to buy, you can typically expect to pay between 1.5x-2x more than for a standard roof truss, but the main advantage to selecting an attic truss are that they will add value to a house due to the additional square footage, regardless of whether the space is finished or not.
As with standard roof trusses, attic truss systems must also be braced to ensure structural integrity, both in the short and the long term. The Trusted Rafter Association has created a specific guide for the bracing of attic trussed roofing systems.http://www.tra.org.uk/media/file/PDS/pds5%202013.pdf
You must brace your roof trusses in order to create a stable structure. Incorrectly or non-existent bracing can compromise the trusses, resulting in distortion or structural failure. The Trusted Rafter Association has created this excellent guide to the correct methodology for bracing your roof system. http://www.tra.org.uk/media/file/PDS/pds4.pdf
The levels of thermal insulation required for building are set by the Building Regulations and are expressed as a U-value. The required U-value will depend on a number of factors such as country (England/Wales/Scotland), whether the building is domestic or commercial, whether it is a new build or existing building and the actual application itself e.g. (floor, wall, roof). The recommended U-Value for new build, domestic pitched roofs, insulated at ceiling level, is 0.11 and the same build at insulated rafter level is 0.16. To guarantee sufficient insulation, it goes without saying that sourcing high quality insulation and a professional is important. Suppliers such as Kingspan, in fact, give excellent advice about their products and applications such as this Kingspan Guide to Insulation. In our opinion, it is best to utilise the services of a trained expert, competent in calculating U-Values, such as your architect. Skimping on professional advice at this stage could lead to not meeting Building Regulations and having to start over.
We will need confirmation of the measurements for each truss span, floor joist and/or timber frame, with the alterations clearly marked on our original quotation and/or CAD drawings. Depending on how many alterations there are, we may need to submit a full set of new drawings. If the changes are insignificant, we will revise the existing drawings with new site dimensions. We do not charge for the first set of revisions but you may incur some costs for any subsequent amends.
We often hear this question, and it is usually because there are wires or piping to be fitted retrospectively following installation. are frequently asked this question, usually because an electrician or plumber wants to drill holes to fit wires or piping. We would never recommend carrying out any alterations without consulting us first and often we find that we are asked too late and serious damage has already been done. Roof trusses and joists are their to support your building structure and any alteration to them; cutting or drilling, will compromise their integrity and the forces that act within them to keep them structurally sound. The only way to avoid expensive repairs or replacements due to retrospective work is to ensure carefully planning, that consider all of your building planning stages, including electric and plumbing.
We do offer a 5-day delivery service within mainland UK from approval of your design.
There is no legislation that requires you to treat your timber in these applications, however some areas, such as the South East of England, do have problems with beetle infestations that can damage the integrity of your timber structure.