Lintel for 3m bifold doors - 150mm timberjoist OK?

Discussion in 'Builders' Talk' started by Ed209, May 23, 2020.

  1. Ed209

    Ed209 Member

    I am doing an orangery with 3m bifold doors. Can I get away with a 150mm timber joist over the doors? The thing will have a flat roof so the "lintel" won't actually be holding anything up, I'm just worried there'll be too much flex for the joist?
     
  2. Are you building a timber frame?

    How are the doors supported... at the base or head?
     
  3. Ed209

    Ed209 Member

    Sorry, I should have explained; the sides are 2-brick piers, and the base is brick. These will be PVC.

    Am I right in thinking you can get BF doors that have a runner in the base which takes the weight, while the top is just a guide?
     
  4. Yes you do have the choice. If you’re having base supported doors then a timber beam as a lintel should be ok but would need to be confirmed by a structural engineer.
     
  5. John.h.

    John.h. New Member

    Why would it need to be confirmed by a structural engineer? If the rest of the flat roof is all 150mm joists what difference Is the door way.
     
    geraint690 likes this.
  6. Severntrent

    Severntrent Screwfix Select

    150 x 50 timber spanning 3m will have a deflection due to its self weight of 0.3mm
     
  7. Because I’m not one and wouldn’t just assume something will do, which @Severntrent has actually pointed out.
     
  8. John.h.

    John.h. New Member

    If 6x2 is fine for the roof structure it would be the same for the door way. The span would even be less at the doorway as there is pillars at the sides.
     
  9. Severntrent

    Severntrent Screwfix Select

    But the roof joists are allowed a certain amount of deflection which, may or may not be, acceptable to the door sliding mechanism so you can't just say if its suitable for one situation its suitable for another. Then again I guess you can and just take a chance.
     

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