Attic Trusses for Attic Conversion

Attic Trusses

Bespoke designs for projects of all sizes and complexity.

Attic Conversions

High Quality Roof Truss Manufacturers

Attic trusses are essential in creating a room in a roof to maximise the living space within your home – making use of what would have previously been dead loft or attic space and creating an additional room within the roof is becoming more and more popular.

If your roof design has the headroom, Minera Attic Trusses (Room In The Roof) are an ideal way to increase the habitable area of a house or improve storage area, whether it is for a bedroom, study space or extra living space. There has been a growth in property extensions, rather than moving, in order to maximise and invest in property which saves moving costs, adds value and creates additional space that is currently unused, a truly cost-effective option. With home improvement programmes, such as Grand Designs, highlighting the benefits of improving and extending a home rather than moving, this has inspired many creative extensions and loft conversions.

Our Services Include

Full Roof Designs
Collateral Warranties
Feasibility Studies
Friendly Advice
Bespoke Attic Truss by Minera Roof Trusses

Shapes & Profiles

Our attic trusses are all bespoke and whilst their shape is relatively standard, they can be built in a range of shape variations and profiles to suit any requirement. No matter how complicated your design please contact us we will be happy to discuss your requirements with you and tailor a specific solution. Even if you are unsure whether your truss requirement will be too large you may be surprised. Whilst the usual maximum size for creating and transporting a single truss is 15 meters we can manufacturer trusses much larger than this which simply come in two pieces and are assembled on site.

Truss Attic

Stubbed Attic

Space Joist Attic

A Stubbed Attic Truss is very similar in properties to the Attic Truss but the ends at the supports are heightened so the height of the soffit is usually above the bottom of the bottom chord. This can achieve more height inside of the room where span is limited and pitch isn’t very steep.

The Space Attic (or Posi-Attic) is the same as a Stubbed design, but the solid timber member used for the floor section (the bottom chord) is replaced with the ITW Metal Web Joist system. The overall depth of the “bottom chord” will be more than the traditional 222mm.  It could be as deep as 354mm. This allows space in a zone to run your cables through for electricity, plumbing, MVHR and home cinemas. With a traditional Attic and Stubbed Attic, they have to be run in the areas outside of the room. You must not drill holes or notches to run these cables/pipes, so the Space Attic may be a better solution depending on your design preferences for the room.


They are manufactured in a similar way to standard options but we design them to allow for domestic floor loadings and also create the habitable section for the room. They also tend to have larger timber sections starting at 150mm deep which takes into account regulations regarding insulation and ventilation air gap.

Our expert team can design these products to any specification – every job we do is bespoke so you can be assured that your truss will be created precisely to the parameters that you supply.

The above photographs show three different projects each featuring attic roof trusses. Whether it be for a bedroom or a study, why not make use of that extra space above your heads and create some extra accommodation. We are available to supply the high quality and affordable attic trusses for your project.

From the point of enquiry, our dedicated and experienced design team is on hand to ensure that your truss is designed and created exactly the way you need them. Each solution is designed for a specific application using leading edge software. Our team will liaise with you directly to ensure that they have all the information they require to design your bespoke roof trusses effectively and accurately, including how much actual room width you require (please note the room width required can dramatically alter the price).

In addition to the sizing requirements they will require details relating to extra features that you may be considering within your attic space which will have an impact upon the truss design for example roof lights or a dormer window to add light to your space. Dormer windows also have the advantage of adding height in low rooms and can be particularly useful positioned over a bath or toilet. The size and positioning of the entry staircase also needs to be given consideration. Preferably it is better for the staircase to run parallel with the attic trusses and not across them, but if that cannot be achieved, then we will try our best to adapt the design to fit to this requirement. However it is worth bearing in mind that it is easier to construct an opening of 1000mm for a staircase, than it is to construct one for say 3000mm. But please do not worry our design team are extremely experienced and will make you aware of everything you need to know as part of the process.

The above three photographs show the correct way of planning your attic room space using attic trusses (room in the roof). The available attic room space is shown shaded. The top picture indicates the central area that is your available loft space. Ideally dormer windows should be lined up in the front and back of the building.

Attic Trusses by Minera Roof Trusses

Our experienced and qualified engineers will design even the trickiest of various shaped roofs, taking into account staircases, dormers and roof lights.

Those little extras

Minera Roof Trusses can supply your complete package which will include bespoke attic trusses, standard trusses, dormer trusses (on request) and all loose timber infills to dormer, keylite roof windows and staircase sections. Add to that all the required stability bracing and metalwork hangers and clips.

For an extra charge you can have all your timber pressure treated in our specialised treatment plant and purchase cut end preservative tins for touching up the ends of any timber cut on site.


At Minera Roof Trusses, we manufacture our roof trusses, attic roof trusses and engineered floor joists using the strongest grade of timber that is available to the UK market. There are many different types of timber available in the UK, some of which you may have seen at your local builders merchant or hardware store. These timbers will of been given a stress grade of timber.

Stress Grading can be done visually but more commonly via machine. Each grade of timber has its own limits as to how much load the timber can take. The timber is also inspected to access the amount of knots in the timber and the wane.

TR26 grade timber has been a cornerstone product of roof truss manufacturing for a number of years. All our products are manufactured using this strength grade of timber. The TR26 grade timber that we source is in accordance with BS EN 519 and is kiln dried and planed all round. The TR26 grade timber is the equivalent of the old SC5 grade.

Listed below is the TR26 Timber sizes that are available. These are finished sizes but could be -/+ 3mm.

  • 35mm x 72mm
  • 35mm x 84mm
  • 35mm x 97mm
  • 35mm x 122mm
  • 35mm x 147mm


  • 46mm x 72mm
  • 46mm x 97mm
  • 46mm x 122mm
  • 46mm x 147mm
  • 46mm x 172mm
  • 46mm x 197mm
  • 46mm x 222mm

The 46mm thick timber option in the TR26 Timber Sizes is more commonly found in these designs and raised tie trusses. With sections of those truss shapes used to form part of a room, they will have insulation and an air gap so the timber section will usually start at 46x147mm for the rafters and/or joist.

The 35mm thick timber in the TR26 Timber Sizes are used on standard roof trusses. The domestic W shaped Fink truss for a house, Queenpost shaped for garages and various other truss shapes.

As always, you can have your timber products pre-treated within our on site treatment facility and you can also purchase cans of cut end preservative for treating the ends of the loose timber that you have cut in on site.

We are also committed to ensuring all the timber we purchase is sourced from legal and sustainably managed forests so we only use suppliers that are certified to the PEFC scheme for responsible management of the world’s forests. Finally, we are certified under the ISO 9001 : 2008 Quality Assurance Scheme which guarantees traceability of products and documentation within our organisation. You can read our sustainability statement here.

CLS grade timber is taken from Spruce (Whitewood), and is graded in accordance with British Standards to either C16 or C24 grade, which is the equivalent of the old SC3 grade. This is a joinery grade of timber or possibly rough sawn. It is also Kiln Dried, Planed and finished with Eased Edges. We do not manufacture our products with this grade of timber. We only use rough sawn timber for the stability bracing which is 100 x 22mm in section, as stated in the British Standards.

How to Build an Attic Truss

Attic Trusses come to site in one solid component, so there is no need to construct the roof and rafter levels separately. Once you confirm your order, we can get them to you in 5 working days.

Please note that we do not currently offer an on-site installation service, it is the clients responsibility to organise this.

Building an attic truss involves a very similar process to building a roof truss just to a slightly diferent specification – details of which can be viewed here

For a free quotation, please contact us or you can fill in an online quotation form and we will send back a quotation as soon as possible.

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