Steel beam size

[sami69]

Ok guys,

I have agreed a soulution with 2 SE'

We are going to put in 305 x 305 x137UC and raise the beam height by 20mm. Even if we had max deflection of 20mm it won't imapact sliding doors. On top of the door fame there is also a seperate 20mm trickle vent piece which can be taken out (building control want trickle vents for new extensions)

So even in the worst case I have 40mm to play with. I have been told the max deflection with this beam with all dead & live load will be 20mm.
The glass company are ok with this - "We can supply a 30mm trim which will sit above the doors, and we can pack out the door frame so if the steel does deflect by 20mm, then this will be allowed for"

I'm so glad I came onto this site as I'm sure you guys have saved me from making another potential disasater with beam spec. Our original SE came up with a new beam of 254x254x132UC. When challenged this morning on "the total deflection of this would not more than 7mm" he started to tell me that he was taking into account a felt roof not asphalt (he has known for months that the roof was asphalt) and that he would have pre cambered the beam to - nothing that he had mentioned with his new spec that he gave in writing.

I'm scared to look at this thread now - just incase you guys come up with some other problems!!

On another note someone asked me today why asphalt roof - we should be doing fibre glass.. What do you think?

Also I keep getting comments that my glass walls are not practical but no reason why except that I have lost useable wall space of 5m. I am keen to hear some serious reasons why...

Anyway -big thanks to all (even if you hate what I am building), from knowing nothing about beams I think I know more than my SE !!

 

[noseall]

It's not so much a case of losing wall space more that if you put stuff in front of the glazed side bits, it begs the question.....why bother with full height glazing in the first place.

Make sure you rake out any small pebbles when mowing that lawn too.

How are you going to fix the head of the frame with all that potential movement on the beam?

 

[sami69]

It's not so much a case of losing wall space more that if you put stuff in front of the glazed side bits, it begs the question.....why bother with full height glazing in the first place.

Make sure you rake out any small pebbles when mowing that lawn too.

How are you going to fix the head of the frame with all that potential movement on the beam?

No plans on blocking the glass so we can't see out of it. If you saw the other picture I posted, it will similar use of space - dining + relaxing corner. This new extension is open on the other side (with a large brick pier in between) leading to the living room.

I'm not sure 100% how the head of the frame is fixed but as I quoted from the glass guys's earlier they will allow for 20mm deflection.

 

[indus]

Hi Sami

Though I completely understand what you are doing and have seen such designs turn out to look great there are some impracticalities. The wall space is one but also things like privacy and you can have too much light/sunshine. I'm sure you've got top quality glass but the room might get really h ot in summer and difficult to keep warm in winter

Your panels are all straight but a friend of mine has a huge high end orangery with many different panels of glass. He had some quotes over £10k to make bespoke blinds for each section of glass.

I have an extension that has quite a bit of glass (nowhere near as much as yours) and I have my TV in that room. On a sunny day I struggle to see the screen and end up having to draw the blinds in the middle of the day to be able to watch it.


So there are 'impracticalities' to these glass designs but one hopes they are outweighed by the positives

 

[freddiemercurystwin]

I'm not sure 100% how the head of the frame is fixed but as I quoted from the glass guys's earlier they will allow for 20mm deflection.

There are several methods but all use the same principal, google 'glazing deflection head detail'.

 

[Roofer]

Sami, I love what you are trying to do. I really hope you find a way to resolve the issues.

But please please please post pics once it is all sorted, I'd love to see the finished item!

+1 on that. I think it will look fabulous!