I am trying to find out who I should contact to ensure the internal modifications I wish to carry out in my attic are safe. Can you advise?
If you wish to make internal or external modifications to an existing roof structure, then you need professional advice from an Architect or Structural Engineer before making any changes. If not then there is a risk you will devalue your house by creating weathering issues or causing roof loads to be transferred to parts of your house that were not designed for that purpose.
The institute of structural engineers has some good information and provides a search facility to allow you to find a local structural engineer. https://www.istructe.org/building-confidence
What fall arrest systems can be used with trussed rafters?
TRA would always recommend perimeter scaffolding and a temporary working platform within the structure directly below the Trussed Rafters as the most effective means to address fall risks and increase efficiency of installation.
Proprietary systems are available to aid working at height within the trusses and one example would be http://www.donaldsontimberengineering.co.uk/pdf/safestep.pdf.
Alternatively discuss your specific needs with your TRA truss supplier who can often design additional members within the trusses to support working platforms or other access needs.
Where can I find method statements for truss installation?
Here is a link to the current TRA guide on safe installation https://www.tra.org.uk/download/2579/ .
This document is intended to provide an example of Truss installation over masonry to assist contractors to develop their own site specific method statements. For information in relation to installation over Timber Frame you can view the latest TRA video via this link https://youtu.be/evgMHodz9Lg
We also have a further document, the TRA Roadmap which provides some useful pointers towards safety topics for consideration and can be found here https://www.tra.org.uk/download/2576/
How long can trusses be stored on site ?
We advise that trussed rafters are installed and protected from the weather as soon as possible. Where trusses are stored on site they should be raised off the ground on suitable level bearers and appropriately braced to minimise distortion and to prevent accidents. Trussed rafters can sustain reasonable exposure to weather during construction but the TRA would not recommend leaving trusses unprotected from rain and sun for more than four weeks, as longer term exposure to repeated wet / dry cycles could potentially weaken the trusses.
Why should I use trussed rafters?
When you build with trussed rafters the sky is the limit. Trussed rafters can be used on a wide range of building types including timber frame, masonry and steel frame. From circular roofs to curved roofscapes, TRA members have the design expertise and the right equipment to produce the design solutions your project needs.
Trussed rafters are designed to your exact specifications, fabricated in a factory-controlled environment, and then delivered to you, saving you time, effort and money. No matter how complex your roof design, TRA members can develop a truss to support it.
What timber is used in the manufacture of trussed rafters?
The timber used varies from supplier to supplier. However, all TRA members commit to only using timber that has been responsibly sourced from sustainable sources certified by either the Forest Stewardship Council (FSC) or Programme for the Endorsement of Forest Certification (PEFC).
How much do trussed rafters cost?
There is no set price for trussed rafters as this will vary from manufacturer to manufacturer and there are many variables, such as rafter size, that can affect the cost.
We recommend you contact your local TRA member who will be happy to give you a custom quote for your precise requirements.
I need to compare trussed rafter quotes. How can I be sure I am comparing ‘like with like’?
No one likes hidden extras. When you ask a TRA member for a quote, they will prepare a detailed, itemised quotation listing all the items that you require for your project. Typically , this will include all roof trusses, the required stability bracing, timber to timber metalwork and all structural loose timber above the wallplate.
What are metal web joists?
Metal web joists are engineered structural beams that combine structural timber with high strength steel webs to form a lightweight, structural beam for use in a range of floor or wall applications. Metal web joists (also known as Open Web Joists, and often sold under brand names such as Posi Joist, easi-Joist and Eco Joist), provide huge benefits – read more here.