Lintel choice

[booky1]

I\\\'m building an extension that will be externally rendered and would like the decorative stone lintels above the windows to be flush/slightly proud of the render. Do I buy the standard 100mm thick lintel and set it 20mm forward of the outer block leaf or do I need a 120mm thick lintel? I\\\'d appreciate any advice.

 

[mikric]

just use normal lintol (catnic etc) and sit decorative head forward 20 mm is how i usually do it .

 

[noseall]

agree with the above.

any decoration, be it corner stones, keystones, lintels, quoins, ashlar etc, can be achieved either with the render itself or with 'stuck on' decoration.

 

[^woody^]

I would say that it is the decorative lintels which should be thicker so that they are flush with the back of the external leaf and project past the render.

Don't forget to prop the lintel in the centre!

 

[booky1]

Thanks for your comments. I should have said that I didn't intend using a steel lintel as I did'nt want to see the 30 or 40mm of steel protruding beyond the face of the window frame (the windows don't have the traditional extended head detail with drip groove etc so the steel won't be completely covered).

I intend the decorative cast stone lintel to be load bearing - does this change your advice?

 

[mikric]

You would be better to ask the manufacturer of your stone lintols about your query. Most decorative stone heads,cills etc do use steel in their construction but you will need to find out if they are suitable for bearing loads.

 

[^woody^]

Yes, most decorative lintels only have steel in them to stop them breaking in transit or when installing - they may not be load bearing - even for their own weight

If you are not using steel lintels because you dont want to see them, then what are you doing about closing the cavity, and avoiding any ugly joint of infill material and the feature lintel?

 

[booky1]

Again, thanks for your comments. I had intended to specify load bearing lintels when I placed the order.

I'm trying to achieve a couple of things with this arrangement. Firstly, I want to use independant lintels on the inner and outer leaves of the cavity wall to minimise cold bridging. The intention is to fit cavity closers at all positions (top, bottom & both sides) within the window opening and sit the window frame in the outer leaf overlapping the closers by about 20mm (the frames are 70mm deep). Internally, the closers should provide a good base for plastering the reveals. I intend to fit a rigid cavity tray over the lintel with stop ends and weeps etc.

Secondly, I want to avoid seeing any exposed steelwork. If I used a standard independant steel lintel in the outer leaf to support the decorative lintel it should stop about 5mm from the outer face. This would mean that about 45mm of the steel lintel will project beyond the window frame.

If anyone can suggest a better way of avoiding cold bridging, avoiding exposed steel lintels and having the decorative lintel 20mm proud of the wall to allow for rendering ---- I'd appreciate your views.