Timber can be treated to further protect wood from the elements, such as fungal decay and insects (a 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’s 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 preservative specifically designed to protect wooden structures from the elements.
Current HSL guidelines have 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 more than 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 reduced to ensure effective communication between the manual handling team members. For full guidance visit HSE.
While the cheapest way of building a roof is with a standard roof truss, they don’t 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 one-and-a-half times and twice as much as for a standard roof truss. However, an attic truss will add value due to the additional square footage, regardless of whether the space is finished.
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.
You must brace your roof trusses to create a stable structure. Incorrectly installed or non-existent bracing can compromise the trusses, resulting in distortion or structural failure. The Trusted Rafter Association has created an excellent guide to the correct method of bracing your roof system.
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’s a new build or existing building, and the actual application itself eg 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 to install it is important. Suppliers such as Kingspan give excellent advice about their products and their application, such as this Kingspan Guide to Insulation. It’s best to employ 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’ll 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’ll revise the existing drawings with new site dimensions. We don’t charge for the first set of revisions, but you may incur some costs for any subsequent amends.
We often hear this question, and it’s usually because an electrician or plumber wants to drill holes to fit wires or piping retrospectively. We’d never recommend carrying out this type of alteration without consulting us first; often we find we’re asked too late and serious damage has already been done. Roof trusses and joists support your building structure and any alteration to them by cutting or drilling compromises their structural integrity. The only way to avoid expensive repairs or replacements is to eliminate the need for retrospective work through careful planning that considers all of your build stages, including electric and plumbing.
We offer a five day delivery service within the UK mainland following the approval of your design.
There is no legislation that requires you to treat your timber, but some areas, such as the South East of England, have problems with beetle infestations that can damage the integrity of timber structures.