Feedback on proposed roof design

[Obi_wan]

Undertaking a renovation of a bungalow and quickly approaching the most complicated part of the renovation, the roof. 
 

The renovation involves a 1 1/2 story extension being built in the middle of the house. This made the joining together of roofs complicated and large chucks were being removed anyways. It was proposed by the engineer and architect that replacing the whole roof would be more sensible. Which I think is correct. Truss manufacturer has provided a proposal but advised they are supplying 2/3 of the roof as loose timber and believe a traditional build might be cheaper. Engineer is advising I should stay with trusses. 
 

I want a warm house that is wind, water tight and as air tight as practical. This part will be mostly up to me. 
 

link shows the 3d design.

 

any thoughts and advice appreciated. 
 

https://sketchfab.com/3d-models/x55138a-80d3ee68d50d471387bbe02d507b80be

Edited March 18 by Obi_wan

[bassanclan]

That looks ok in its self, but can we see what you are starting with?

[Obi_wan]

12 hours ago, bassanclan said:

That looks ok in its self, but can we see what you are starting with?

this is the takedown 

[bassanclan]

It looks like the existing house is a bit of a hodge-podge of add ons and bits added here and there.

 

Considering the cost, time and trouble you are going to, I am not sure the design of the overall building will look harmonious.

[Iceverge]

Would you care to add some plans too please?

[Obi_wan]

19 hours ago, bassanclan said:

It looks like the existing house is a bit of a hodge-podge of add ons and bits added here and there.

 

Considering the cost, time and trouble you are going to, I am not sure the design of the overall building will look harmonious.

you’re not the first to say that 😂. I am afraid that it is too late and I’m a reasonable way through, although plenty still left. I am content that the design works, if the roof goes well. 

Edited March 20 by Obi_wan

[Alan Ambrose]

I think your new roof design looks great . Will you not just get Pasquill to deliver that as designed?

[Obi_wan]

16 hours ago, Iceverge said:

Would you care to add some plans too please?

 

[Obi_wan]

4 minutes ago, Alan Ambrose said:

I think your new roof design looks great . Will you not just get Pasquill to deliver that as designed?

I would but they keep advising that they are supplying 2/3s of it loose timber and I’ll be paying a premium for trusses. I think I might have got a workable outcome with the engineer yesterday where I can buy c24 for everything up to the dormers and then switch to trusses. Once that is fully confirmed I’ll be able to price the cost difference and see if there is enough to bother splittt it.
 

I like the idea of loose as it can be worked on site, especially if the walls are not straight or square etc given that the original part is 100 years old. 
 

the feedback from the engineer is that the trusses can do things that he couldn’t due to the consistency of truss joins compared to on-site fabrication and I will need to incorporate 5 additional steel beams and use multiple flinch plates were the truss manufacturer doesn’t. 

[Iceverge]

Ah I didn't realise you were underway.

 

The plan looks fine in that case. I was thinking you were still at the design stage. 

[Alan Ambrose]

Check with other suppliers who might provide more than 1/3rd factory constructed? They should be able to tell you just on sight of the design.

 

A 3-way call between you, the SE and Pasquill to see if the SE can explain their concerns, allow Pasquill to respond and see if a compromise can be worked out or a more optimum / less risky solution that suits everyone?

 

Seems to me the SE is saying Pasquill's designs don't work in practice and need extra support / therefore Pasquill to defend / explain. See if they can convince the SE? In the end which expert do you trust most, whose PI would you claim off if it all ended in tears?