Small window, Do I need a lintel?

[johnAB]

Hello folks,

1940's little cottage. Not 100 % sure of lower wall make up but from eve height on gable to apex is 300mm mass concrete.
I want to put a little window in here but could I get away with no lintel? Nothing resting on gable as far as I can see and no purlins.
I don't have a lot of "meat" at each window corner so getting a lintel in would be even more problematic. Any thoughts? I have choice of 2 windows, pvc one on diagram, other is 64 cm but very strong teak. I have attached a rough diagram.Thanks very much in advance.

 

[^woody^]

From your drawing there is a ridge board bearing on it!

All openings should be supported, and whilst mass concrete may have more tolerance to self-support, those slim bearings will be a weak point.

Perhaps some heli- bars slotted in to deal with any cracking risk?

 

[johnAB]

From your drawing there is a ridge board bearing on it!

All openings should be supported, and whilst mass concrete may have more tolerance to self-support, those slim bearings will be a weak point.

Perhaps some heli- bars slotted in to deal with any cracking risk?

View attachment 325519

Thanks Woody, appreciate the reply. The ridge board is there however just barely touching the gable. Had not known much about these helibars, now Ill have another look. Maybe also some 100mm angle iron slotted in and bedded, one from each side, would work?

 

[^woody^]

Masonry with a window in that location with a lintel, tends to crack horizontally along the bearing joint. Concrete mass however, would tend to crack diagonally - if it does that is, hence the idea of reinforcement bars like that.

If you are minded to fit angle iron as lintels or any lintel, then I suspect you'll be better off taking the apex down and rebuilding it.

 

[johnAB]

I understand. So you are saying the danger is not necessarily that an unsupported area above the opening would drop down, rather that it may crack at the corners?

 

[George_engineer]

Do you have a photo of the wall? Mass concrete wall construction is very unusual.

 

[johnAB]

wall in question attached