Angled/Sloping Window Lintel?

Westford

More queries....
I'm at the early stages of my build, and I', trying to address some points that will appear later. My house contains a few windows, that follow the slope of the roof. I'll try to explain better....They are on a gable end, and the bottom of the window is horizontal, and the sides are vertical, but the top of the window will be sloped to match the line/fall of the roof. They will not run the whole way up to the sofit, instead there will be some block work (nap plaster) over them.... probably about 500 to 700 mm.
Has anyone had experience with solving the lintel problem on such windows...Some are telling me to cast in place, with plenty of steel, brought down to the wall plate, and bent back to run along the wall plate. Other are suggesting the use of ply & expanded metal...
Any suggestions, or advice is welcome.

muffler

Can you post up a snapshot of the plans or that particular elevation

Westford

OK muffler..The section of the elevation is up (I hope).

sydthebeat

personally i would use a prefabricated steel lintel from the like of steelite catnic etc.

check out the apex lintels here:
http://www.steelite.ie/

Mellor

It took me a secone to figure out what you were talking about, but it think it is something like this;


How wide is the window? It is was narrow enough, a angled steel window would be suitable.



edit: by the time I found a pic it appears you got a sample up

Westford

Mellor...Window opening will be about 700mm (800mm max).
sytthebeat....the steelite option looks good....I'd just be a little worried that the weight pushing down, would be directed downward, and outward. And since this is a gable, I don't have a long section of wall (running in the same line as the gable) to counter-act this force. Is there a danger that it could push out the end walls? I think this was the argument behind casting on site, with steel, and running the steel down to the top of the end walls, and bending it to run for a couple of meters along the wall plate (thus distributing the force over a section of the wall).
Of course this is not so straight forward....Hence my query for alternative approaches.

sydthebeat

the only force acting on the lintel is the minimal blockwork over, The vast majority of the roof forces are transfered onto the wall plate... so i wouldnt worry about the forces. Theoretically the ridge board doesnt transfer any down force.

Mellor

All you want to do it direct the forces down, to do this you just have to have horizontal bearing pieces. In my opinion, a steel angle welded to suit be be fine. To ensure blocks/bricks stay on it and don't create a horizontal force simple weld on an end piece. This will cause the unit to act as one.

Insitu concrete is another option. But running the steel right down to end walls wont really help, the load will be acting over a small triangle below the ope, regardless of how long the wall is. Even though the ope is angled, the load on the lintel is vertical as long as bearing pieces are horizontal. Self weight will keep it there

odonoso

I am just address the same problem myself.
I am using a 4X8 RSJ
I got a local person who good at stee to bend and weld this for me
I have two foot leg on each side so the block can go on these to support it

Westford

Odonoso... What will go on top of your RJS... Concrete block/stock bricks ?
Have you added anything to create a horizontal platform for the blockwork/brickwork over the lintel (steps or "horizontal bearing pieces" as per Mellor's suggestion)?
If not how will the blockwork be built.....Surely the blocks will not be laid on the same angle as the head/lintel?
BTW, has your steel fabricator added anything to the underside of the lintel to take plaster (e.g mesh)?
It will probably be a few weeks/months before I need to solve this issue. Let me know if you learn any lessons along the way.
Did your engineer come up with any 'interesting' recommnedations?

Mellor makes a good point....if I can take steps to ensure the force/weight is always in a vertical downward direction, then the lintel shouldn't be any different from a normal horixontal lintel. Of course it the achieving this that's the key.

galwaytt

Steelite do lintels like this, as do, iirc BAT in Limerick. Both offer plaster keys for the reveals.

AckwelFoley

Intresting read

bakerbhoy

If the room inside the windows has a vaulted ceiling ,consider stretching the windows up to rafter level. I have a window similar to this in my build and the steel is in effect the wall plate with no masonary over it and the soffit returns to the window frame.

odonoso

Hi All

We put the steel up for the window yesterday and I tool a few photo with my phone

Putting a few block around it next Tuesay

Westford

Odonoso - This looks like a solid option....
I'd be interested to see the blocks on it.... & to see if you block layer has much difficulty builing on it. I guess you'll need to tack on some mesh for your plasterer.
I see you have a steel joist tying the 2 storey & a half walls together. Will this be visible (boxed in) inside in the room? I'm facing a simial challenge....but was hoping to get away with plenty of collars, and perhaps a steel I-beam acting as a purlin.

odonoso

The block layer had no problem with the blocks

ircoha

Just wonder could u post a pic so as we can see the finished gable as it seems to me that the final solution is a bit different from the original sketch, which shows a chimney in the middle.
Thanks