Making a cut roof / trusses without gang nail plates

[garyo]

Having fished around for prices for pre-made trusses for my front extension, the prices are pretty eye watering given the amount of wood involved, so I want to make them myself.

I'm fairly happy with what I need to make, but I want to avoid using those pressed gang nail plates, because when I've used them in the past they've been almost impossible to hammer in without most of the nails collapsing.

Is there an alternative - e.g. plates where I hammer real nails through? Or have I been using cheap plates? I've had a search in the archives and it seems I'm not the only person with a dislike for the things!

Cheers

Gary

 

[noseall]

Build a cut roof using nails/screws for fixings.

Why the predisposition for gang nails?

 

[garyo]

No predisposition as such, but I thought it'd be the best method if there was a way of doing it.

Nails and screws sound good to me. I'll be asking for further guidance when the time comes and when when I have detailed truss plans/measurements.

Cheers

Gary

 

[mikric]

Is your extension covered by building regs
If so you may need to provide BC certain information ie
Will you be able to provide the structural calculations for the design/loadings?
Can you source TR grade timber easily?
Why not just put a traditional cut roof on using standard C16 grade timber ?

 

[garyo]

Is your extension covered by building regs

Yes

Will you be able to provide the structural calculations for the design/loadings?

Absolutely not! My current plan is that the very detailed drawings I've submitted as full-plans will mean that they're happy, and have approved the constructiont themselves.

Can you source TR grade timber easily?

I don't know what TR grade timber is! I expected to buy some treated timber from a merchant and... er... saw away!

Why not just put a traditional cut roof on using standard C16 grade timber ?

I'm not 100% sure I follow what you mean- I thought that was what I was doing? Google tells me that c16 timber is typically used for rafters so that seems like a good idea. I'd not got as far as understandind timber grading, so any advice is most welcome, especially as I'll be resubmitting my building control plans over the next few days.

Thanks

Gary

 

[noseall]

What we are both saying Gary is either build a cut roof yourself and forget about gang nails or buy a truss roof from a manufacturer.

Your drawings may be ok with building control but if you don't comply with them.......

 

[mikric]

Ok, Do your approved drawings/ spec, state manufactured trussed roof etc.
There are mainly 3 types of timber grade, C16, C24 and the best is TR 26 or even 30 these are used to make trussed rafters hence TR which as far as I know is not readily available.
If BC approve pre manufactured roof trusses it is because they are specifically designed and calculated to work on a particular job.

 

[garyo]

Thanks Mik/Nose.

I'll propose a cut roof then, based on C16 timber, and nails/screws. My current drawings to include things that look a lot like gang plates, and I don't want to give the impression that I'm having them manufactured and supplied with calcs, so I'll remove those and make it clear.

Gary

 

[noseall]

The one thing about a manufactured truss roof is their ability to span large distances unsupported. This is something that a cut roof will struggle with because of the unfeasibly large sections of timber required, particularly on clear spans of joists, rafters and purlins.

 

[garyo]

Well, I've just re-submitted my calculations and made it clear that it's a traditional cut roof using C16 grade timber, and removed the gang plates from my drawings that might have misled BC into thinking I was fitting a manufactured truss roof that came with calcs.

Fingers crossed!

Incidentally, one of the manufacturers that provided a quote also provided CAD drawings including a table of live loads, dead loads, and statements about loads conforming to BS6399, CP3 Chapter 5 etc. Are these the kinds of calculations BC expect to see?

Thanks

Gary

 

[noseall]

Incidentally, one of the manufacturers that provided a quote also provided CAD drawings including a table of live loads, dead loads, and statements about loads conforming to BS6399, CP3 Chapter 5 etc. Are these the kinds of calculations BC expect to see?

It will depend upon the design of the roof. Occasionally a typical, simple roof may be accepted without calc's. Ask your b.c.o.