Roof Truss Metal Plates - Mending Plates - Need Help!

[Lionheart]

Hi guys

I'm building a large four port garage in timber, essentially copying the pre-made one we bought from Chart Stables at our old property.

My question is about the roof trusses. The previous ones had metal plates that look kind of like nail plates, but they are pressed out so that the 'nails' are all part of the plate. They were fitted on to the sides of the truss where the wooden sections meet.

See images:

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• Lionheart
• 15 Aug 2014
• 1

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• Lionheart
• 15 Aug 2014
• 1

Looking at images of trusses it seems that these plates are quite common in truss construction.

I had a look at my local building suppliers and they do lots of roofing stuff, and nail plates, but none of these types of truss plates.

I've Googled and found these:

http://www.raygrahams.com/products/...g-plate.aspx?gclid=CP355_SYlcACFfOhtAodYioAzA

http://www.wickes.co.uk/Wickes-Mend...43364522812|&gclid=CODpqfKYlcACFcsJwwodIzQAbA

But it specifically says in the images NOT FOR TRUSSES!!!

Need some help here guys. Why are these not suitable (too soft a steel??) and where can I find some suitable ones online? It seems these are used on most trusses, so can't believe they're so hard to find!!

Many thanks!

 

[AronSearle]

Trusses are designed using computer software and pressed together in factories, the latter means quality control allows the built product to match the computer design.

They say they are not suitable due to liability issues (if you make something structural and it's not pressed in right or designed right, they want in NO WAY for it to bite them for selling the product).

They are the same products.

 

[Lionheart]

Ah... So they are the same products, but they put that text on them to cover any liability??

 

[AronSearle]

Does building control come into this, is an engineer involved?

Engineers may refuse to design it, and building control will want calcs.

Essentially the design values for these plates typically assume factory production control.

Its not impossible to do, but as rafters are so cheap there is often little desire for people to tread down the path of DIY rafters.

 

[theoldun]

A mending plate is in the name. Mending plate and is not intended for structural use which includes trusses.
If you think that you can design and make your own trusses, then you are in a fantasy world.
Either buy your trusses or pitch a cut roof.
Regards oldun

 

[Lionheart]

Hi guys

Yes, the name mending plate did confuse me. But they seem to be used on most wooded trusses as standard?? Or at least something that looks a lot like them.

Why is it such a mission to build your own trusses? I have the design and measurements already so an unsure why it's such a big thing??

Images of what we'll be recreating from our last (Chart Stables) garage:

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• Lionheart
• 15 Aug 2014
• 1

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• Lionheart
• 15 Aug 2014
• 1

 

[tony1851]

The metal plates on trusses are pressed in by machine under factory conditions; they are not intended for knocking in with a hammer.

 

[Lionheart]

Ok, so it would probably be wiser to use a wood plate or nail plate instead of these truss mending plates?

 

[noseall]

Did you not read Olduns' post?

Either build a cut roof, buy some factory made trusses or get a shop joiner to make some.

You have got it into your head that you can somehow replicate and use the components that make up a factory assembled trusses. Forget this idea - quickly.

 

[Lionheart]

Hi there

Ok, I understand this. But nobody has explained why...

Surely they are lengths of wood cut at specific angles? It does not seem like rocket science to recreate this - but it seems that I'm missing something here??

Surely it can't be impossible to make trusses?????

Why are people saying don't make them buy them?

 

[noseall]

Surely it can't be impossible to make trusses?????

Firstly, it is not impossible to make a truss. It is just not very easy to make a truss like they do when they make factory manufactured trusses. These are made with minimal timber and gain a lot of their strength from the design and the gang plate hydro-nails.

To do the same yourself would require heftier timber and a lot of joinery.

This is why we use the 'cut roof' method when building roofs.

Why are people saying don't make them buy them?

Because they are not particularly expensive and that you will not be able to replicate the joins or use the same section timber.

In other words it is simpler and cheaper to build a cut roof than it is to try and create your own version of a truss.

Geddit?

 

[theprinceofdarkness]

The main thing about these factory made trusses is the quality of the timber, that why there are so skinny as compared to 6" X 2" of home made roof structures. The main purpose of the metal which is circled in red is to keep every thing in the correct position until the roof is fully loaded when they could be removed as the weight will lock the struts as they are. But without them, craning the trusses or loading the roof asymetrically would cause the whole truss to fall apart.
Frank

 

[theoldun]

Last post really made us chuckle.

If you really want to make up three trusses to support purlins then make up three TDAs, but they will cost you more then 3 fink trusses
Regards oldun

 

[Lionheart]

Thanks guys - really helpful.

I'll get a quote for pre-made ones.

BUT I can't see it being cheaper than the £50-100 or so it would cost in timber to make ourslves?

I would imagine that delivery alone would be more than that??

Can someone give me an educated guess at the price of a 24' fink truss develiered??

 

[noseall]

BUT I can't see it being cheaper than the £50-100 or so it would cost in timber to make ourslves?

What are you building a dolls' house?