Truss roof design and build

[mickthetree]

Afternoon all

Work is underway for our rear extension but we keep changing our mind about the roof. The design is set, but ideally we would like to vault the ceiling.

We had originally thought of having two steels, one at the top of each side, but it seems to be adding more complications than its worth.

We could purchase some fink trusses at 600mm centres and have a standard ceiling with "tunnels" through to the velux windows. This

Does anyone have any experience, or can point me in the right direction for getting some feature trusses designed? It might be that I build them to someone else's drawings, or we just pay someone to design and build. Either way I think this could be the way to achieve a nicer finished space.

I'm not looking for an oak framed solution.

We are already up to DPC so making changes to the ground works is not an option.

Thanks in advance for any pointers you can give!

 

[Woody2Shoes]

Hi - it might be worth talking to a truss manufacturer or two in your area - they often offer "free" design services. Another option might be to have a steel structure designed by a structural engineers e.g. using steel tie-beams etc. Cheers, W2S

Edit - sorry re-reading your post, you seem to have discounted one of the possible steel options - on cost grounds?

 

[RobinBHM]

I did a vaulted ceiling on an orangery, the type with a tiled skirt around 3 sides, overall size 6m x 6m.

I got our steel guys to make 2 cranked steels, the cost was about £2k from memory. On plan the steels were set parallel to each other, they were then joined by timber beams to form a square on plan and then the common rafters pitched from the square and hips from the corners.

I designed the roof so the cranked section was in line with the common rafters and then I did the insulation in between and over the rafters too. The roof was a warm tiled roof, ie counter-battened just below the tile battens for ventilation and then no ventilation gap needed between the rafters.

 

[mickthetree]

Thank you both for taking a look at this.

I have now spoken with a local guy who specialises in making trusses but to a structural engineers designs and calcs. He has given me the structural engineers number so I will give him a call.

Robin do you have any images or drawings from the orangery so I can see if this is similar to my situation?

I have marked on here in red where the two steels were originally going to go. We were going to have a gable wall at the end instead of hipped. I was then going to build the roof off of these.

Were your steels cranked like this? or were they also pitched in towards the centre? If the steels are welded in permanently in this way, then does that prevent them from creating any sideways load and therefore not require any joists?

Again many thanks for your feedback

 

[RobinBHM]

Yes, the steels were cranked like you show. Although being an orangery, the angled lengths of steel were quite short.

Yes the steels were welded. The jointed ends of each beam had plates welded on and tgese were then welded together (from memory, which too good these days!).

The welded cranks meant there is no sideways force so allowing a vaulted ceiling
Ill see if I can find some images when Im back in the office on Monday

 

[HOJ]

I have just finished this one, not the same as yours I know, but the Truss manufacturer did help to resolve a lot of the issues, however this still proved very complex with the hips and valleys as we had different pitches on all sides which also made lining up the fascias and soffits more complex, this has a vaulted ceiling without any visible trusses.

 

[mickthetree]

Many thanks Robin, much appreciated.

Hoj, that is great, helps to see what a supplier may provide and good to know that they can do some of the structural work too!

 

[Freddyjersey2016]

No personal experience of them, but Crendon Timber Engineering near Aylesbury which is not far from Tring may be worth talking to http://crendon.co.uk/

 

[mickthetree]

Many thanks Freddy, I will give them a call too.