Oz07

I've found timber span tables you can get 63x220mm c24 to do the job on 400 centres. Expensive though. I'd be interested what works out cheaper c24 or engineered timber joists

Thats a good idea are they readily available? Is there span tables anywhere?

Do you have holcim round there? We have a local quite advanced batching plant. Local businessman set it up and they bought him out. They do it too. Even some of the volumetric boys are doing it round here now but I'd be a bit wary of them.

Did they take it back at their cost?

I'd be surprised if glulam is cheaper so I'd lean towards steel. I have a garage 5x5m with 45x 225 timber joists. Was looking at extending the width to 6m and I don't think you can make it work running the joists this way. I can either put a steel over garage door and run timbers 5m way, put rsj in where current 5m wall is, or you can get I beam/jji joists/posi joists to span the 6m. Would that be a solution for you?

I mean with all the modern ways of sealing up builds how much does the design affect it? What's that loop they spray under pressure gets in all the nooks and crannies

Some caulks say its the paint that cracks with the movement not the caulk. Don't know how true that is. Ive been using the crown own brand with a green label not sure if good for you though.

Did you have to pay them or did they just accept being blown out? Maybe I'm a control freak but I always find they need heavy handed steering! That said i never used any of the more expensive firms perhaps these are better?

How thick are your boards. 3mm feels more like a scratch than a groove. Id be looking for more like 6mm you will have to do a test piece see what you prefer. I don't think sockets will look bad with the grooves going into them.

@craig I was talking about small joinery manufacturers. They aren't getting testing done on their system if the bulk of their work is bespoke. Decent upvc beats timber then? Even without any special glues for the units or filling in the chambers. I honestly haven't seen alu spacers on newbuilds in over a decade. I reglazed some of a 30+ yr old timber conservatory the other week and that was 4:6:4 aluminium spacer

I think most units for new windows are specced with warm edge spacers nowadays aren't they? Interesting that timber normally beats upvc. How do the smaller manufacturers (particularly timber with big profile manufacturer back up) calculate their u value? From my experience they just quote the unit u value. I know the accoya performs well thermally. Are other timbers the same?

And what is a reasonable target to aim for? Excluding passive house craziness

Well the law changed last week and our new application has been submitted. Ready for the long wait now...

Interesting. I'm sure when I looked into it the cost difference of triple glazed windows was never going to pay back the energy savings over double in the life of the windows. Unlike single glazed to double where they do save you money. The improvement wasn't as drastic with 3g vs 2g. That rules them out for me although @JohnMo said it was more a comfort thing.

But the custom ones come with welded joints. How do you keep the strength? What brand did you use?