Acceptable deflection - glazed conservatory?

[norrbottenstorpet]

I have received quite good help with load calculations and sizing beams for a planned sunroom construction from Moelvens' calculation software for glulam beams. BUT what is an acceptable deflection for a glazed sunroom really? 0 mm is out of the question. Is this stated in the installation description of the glass section, or where should I look for the information?

According to my calculation result with snow zone 3.0, I can choose to accept anything between 1 and 18 mm deflection. 18 mm sounds outrageous, but 1 mm would, on the other hand, require a 115x630 mm beam, and both the wallet and the design manager aren't too pleased

Where to look?

 

[Gabbe1]

When sizing floor structures and other building parts, the rule of thumb is that the maximum approved deflection is the span/400.

 

[norrbottenstorpet]

Thank you for your response!

It would be 10 mm in my case, but there might be a difference between a floor joist and the beam above a patio section?

I have managed to read in some other suspicious documents on the internet that 10 mm is the maximum when glazing balconies. The question is how much flexibility there is in the profiles of the glazing systems? If they become rigid, it will either be impossible to open/close or directly result in broken windows.

 

[Mats]

Do you not have space to put a beam for the roof and then have a weaker stud that holds the actual glass section? That way, you can possibly let the whole thing move a bit without problems.

 

[norrbottenstorpet]

Good evening!

Of course, it's a thought, but there's a bit of a lack of space. On the other hand, it might balance out, to accept a bit more deflection and thereby choose a smaller glulam beam. I'll do some calculations on that...

 

[Ripper500]

Many conservatory suppliers allow for a deflection of a maximum of 2-5mm.

 

[norrbottenstorpet]

Found in Santex's description for vikdörrspartierna "The glulam beam shall have a camber of 3 mm in tolerance at the top edge." A bit amusing language, but should it be interpreted as a maximum of 3 mm sagging (what is cambering?).
http://www.santex.se/kampanjer/nyheter/SantexProduktinfo_vikdorrar.pdf

But it may vary between different brands and models

Possibly the sliding door parties can handle 7 mm? http://www.santex.se/media/58702/star skjutbara partier.pdf

 

[Drosen]

Maybe they mean that the glulam beam should have a negative deflection (curved 3 mm upwards instead) before it is loaded, so that it becomes essentially straight after loading.

 

[anaitis]

Maybe they mean that the glulam beam should have a negative deflection (arched 3 mm upwards instead) before it is loaded, so that it becomes basically straight after loading.

That's probably it. It's usually called camber.

 

[norrbottenstorpet]

Now I received a response from Skånska byggvarors customer service and they had an 8 mm limit.

 

[norrbottenstorpet]

That's for sure. It's usually called camber.

How does a hobby builder practically achieve this?

 

[cem77]

How does a hobby builder achieve this in practice?

The hobby builder does like other builders and orders the beam with desired camber from the glulam manufacturer.
http://www.svensktlimtra.se/page.asp?id=23

 

[norrbottenstorpet]

Sounds expensive

 

[llehs]

Or as a forum member here on build a house. Makes their own glulam beam!

Just can't remember the name...

[edit] Saturnus was the name!
http://www.byggahus.se/forum/byggmaterial-byggteknik/94599-mer-limtra.html

 

[norrbottenstorpet]

Have not yet ordered any beams and have not received the building permit either. Could lightweight beams (like masonite beams) be an option in a sunroom environment (unheated in winter)? Such beams have a significantly lower self-weight, which should be positive for the overall load case.