Using a steel UB in a valley

[garyo]

My SE has said he thinks I'll be better off using a UC instead of a deep valley rafter (5 metre span)

It seems to be that this is going to cause me a lot of extra b*ggering around trying to fix 20 odd rafters in to it, so I'm wondering about steering him back to timber.

Having never used a steel in a valley before (not being a full time builder/roofer!), I don't have full awareness of the pro's and con's... are there further considerations that I should take in to account?

I presume it also means some more custom fabrication cost in getting the top end of the UC bolted in to the steel ridge, but it's more the on-site construction time that concerns me I think.

 

[tomfe]

No idea on your loads etc but what about a flitch beam?

 

[tony1851]

Perfectly feasible using timber; this valley beam was two 300 x 50 c24s screwed together. Can't remember the span but it was not less than 5m. Much easier than using steel.
Having said that, the roof was relatively steep. If your roof is lower in slope, deflection might be an issue. Nevertheless, get the SE to work hard at trying to get

a result with timber.

 

[Ian H]

Why do roofs need a steel ridge when 70 years ago a bit of skirting board was fine?

 

[tony1851]

Are you perhaps confusing a ridge board with a ridge beam?

 

[stuart45]

Are you perhaps confusing a ridge board with a ridge beam?

Common mistake.

 

[Ian H]

I'm not sure. I mean the highest part of the roof, horizontal bit where the front and back rafters meet.

 

[stuart45]

A Ridge board is a thinner bit of timber used to nail the rafters to, whereas a ridge beam is a thicker piece of timber which is a structural member used for things like a vaulted ceiling that has no ceiling joists.

 

[garyo]

Yes, mine is a structural ridge beam... And needs to be due to not being able to tie the rafter feet together with a joist as you normally would.

 

[garyo]

, the roof was relatively steep. If your roof is lower in slope, deflection might be an issue

It's 45 degrees. I'll ask him to calculate it out.

 

[John D v2.0]

With the cdm regulations now the SE has an obligation to consider how the beams will be installed safely. That means that they should specify bolted timber as much as possible which would be safer and easier to lift.

 

[noseall]

I'm not sure. I mean the highest part of the roof, horizontal bit where the front and back rafters meet.

Here's one we did last week.....

20170322_085233

• noseall
• 30 Mar 2017

20170322_085235

• noseall
• 30 Mar 2017

 

[Ian H]

So that stops the top of the roof from dropping and pushing the wall plates off?

 

[stuart45]

Yes, it stops the roof spreading.

 

[garyo]

It's 45 degrees. I'll ask him to calculate it out.

Or more accurately... my roof pitch is 45 degrees.. the valley is oblique to the roof plane, of course, meaning it's more like 35